Document xj8dkX27a9EZO8RZRNo57RzzQ

* USG RED TOPICS A National Plastering loumal iii 3 .la. 5 ?joiisned y United Stales Gypsum Ca. Chicago. Monday, Jecemoer 1, `341 Circulation 53.CC0 ALL-OUT for PLASTERING And How You Can Help To Achieve It FS S MD TOPICS. DICCMBIR 1. 1941 la tUi firaplaca (1m irckitKt, Ralph Htiugk, kit Hiinrtd walk fmid* aa tflietivi hackgrovad fat wraaght i tckimJ aacabla rmlti with pattaraad dataila ia raliaf. balaacar* aad ctair rail ia this mart, madara apartmaat. Practical, taugmati** architatta ara fisdiag naw wapt ta obtain ndti| datiih ia tbair datigii with planar. Paj* 4 RID TOPICS, DKCIMBfR 1, 1941 FACTS (Continued) speed in building, together with its other superior qualities, sc* count for the fact that it has be come the most popular of all other forms of plaster in the United States and in many for eign countries. Scratch Coat Plaster is applied in not more than three coats, which are des ignated as "scratch", "brown", and "finish." The "scratch" coat is applied first. Its primary function is to act as a bonding coat to attach the body of the plaster securely to the lath or masonry. Gypsum mortar for "scratch".' coat most have sufficient plasticity and co hesion so that it can b<* worked welt over the base. The "scratch" coat should be applied thick enough to cover entirely the plas ter-base. After it has been ap plied and before it has set, it should be thoroughly cross-raked to receive the second or "brown" Brawn Coat The "brown" or second coat forms the main body of plaster on the plastering base. It is the' function of this coat on a given type of lath to fill within 1/16' to H' of the grounds. The "brown" coat governs the resis tance of plaster to the transmis sion of heat, fire and sound. The "brown" coat must necessarily be sufficiently hard to form the wearing base of the wall and the proper base for the "finish" coat. The "brown" coat should be red ded and darbied to a straight, even and uniform surface, ready to receive the "finish" coat. Finish Cost The "finish" or third coat used depends upon the finish desired. There are three principal types of "finish" coats: 1. White coat finish, consist ing of the admixture of lime putty and gauging plaster troweled to a smooth, glossy finish. 2. Prepared white gypsum fin ish, requiring the addition ot water only and troweled to a smooth, white finish. 3. Sand float finish, obtained by either using prepared or job mixed gypsum and sand to give a rougher texture, ii desired. It is imperative on the "finish" coat that it be free from cracks; it must be hard enough to with stand abuse, and above all, it must present a pleasing appear ance. Plasticity Since the "finish" coat is ap plied in a thickness of from 1/16' to H' over a dnr, "brown" coat, the plasticity of the material is exceedingly important. If the material is not sufficiently plas tic, it is physically impossible t use it at all for "finish" coat work. The choice between the vari ous finishing plasters depends on the job and its requirements. Where low cost and quick dec oration are the primary consider ations, Red Top White Trowel finish and Red Top Grey Trow el finish should be considered. These are ready-mixed gypsum finished plasters which may be decorated as soon as they are dry. They need only the addi- AVeriest! Milos of Lepen. lac. Ages i| plum vu seregoissd u sanitary atonal. Om af tks fin* : record*! laws that evidence this feet is foaad ia the Old 'r--------------- Ac ' that tiae it vu required chat beams occupied by lepen meet be plastered ; before they could be lived ia by ether*. Modsm srieaco baa ebrowa a light ea tbit plague which, through celeuies such aa the eve shewn above, u gradually baiag brought uader caatral througheat the world. tion of waiter to be made ready for use and should be applied over a fairly dry basecoat Where fine, hard, white finishes are re- ' qtured, a good finishing lime is sometimes preferred. EFFECT OF SAND ON STRENGTH OF PLASTER S9r- -XV- the scratch test, plaster was applied M-iach thick ea gypsuas lath aad permitted te dry ia tba ream, Whan dry, e steel point was ross tba surface of the paael at e uniform rate ef speed, the point being leaded with a 22-pouod weight. The poiat was made af )/l"x H"* 5", ground ta a V poiat. The materiel "plowed op" by the paint was collected aad weighed, aad tha results s as weight ef material lost por inch of length ef the scratch. The chart at the right shew* these remits. Tba affect ef this iaee ef various proportions is shewn by this series af photographs. Tbs illustration at tha outruns left above was sanded one to m, two te east upper right, three te see; at left halaw, faur-ta one; at Itwsr canter, flvoio me; aad lower fight, tin te one. 1:1 t:i 3:1 4:1 3:1 6:1 Parts aaodparpartp/aafar-by waiqit SCRATCH TEST Te detenaiae the quality ef e plaster wall, scratch it with a sharp point. A lab* oratory test to compere qualities ef plaster chewed the depth sad width of the scratch, er material "plowed up** was much great er with high saad coo teat. This chart shews comparison ef different proportions. Photographs at left show teat tpscimsas. P23 4 lea than ?:i 130 Abo* tSO? last c Ahoutre>*Jessrhar IK Cl 3:1 4:1 5:1 6:1 Pur/a aanaparpartpJaatar-by maiyht COMPRESSIVE STRENGTH The higher the compressive strength, the better the plaster. This chart shews that sacreasiag tba saad eaataet fnu tvs te three parts, by weight, decreases csuiprss ave itreegth approximately >4%. lacreaalag saad ceeteet ta four parts decreases cempreetive strength approuiamtely !%, niustneoM Ceurwst Grpsua Asmastton forts aandparpartptaahr-by waryht TENSILE STRENGTH High tensile strength is soother require ment ef good platter. Ovenandiag cuts tensile strength, at the above chart shews. Teesile strength of plaster decreases 2J% by iacreasieg sand centeet from two te three parts; 14% by racreessag mad to four porta, aad 74% lacresang te five. .VAV/ // Kl 2:1 3il 41 3:i 41 . Parti aandparpartp/aaHr - by waiybt HARDNESS TEST ^ .... At the quanity ot sand is -- increased,40 is the qua* ity of baler Id brinqlhe p*aster to normal consu tancy - workability-- creesinq the water | re tiofeeutti'iadecreased strength and hardeeaaj | Kl 1 3:i 4:i 311 6:i forta aandparpartptaatar-by ma/yht MASTER CONSISTENCY-WATER RATIO If plaster ia te continue aa first choice for Aa tha mad content of plaster is increased, walls, it mast be hard te withstand abuse. ' int ef water per 140 pounds ef The Moeocroa hardness test shows that nut* aim be increased te get plaster with two parts of sand is I times This chert, prepared from as bard as plaster with three parts af mad; twice aa hard as with four parti; a re00 m gypsum b increased, the strength aad } H rimet aa hard aa with five parts. a ead hardness ef the plaster are decreased. O \A UD TOPICS. OICEMim 1. 1941 Fiji S A USG PLASTER for Every Purpose II biMeMU M aa *bif tdTtsuii, tba fact tbi tks? apaad caaatructiaa ( ml' wodtra duadi hr quick cwpItaM af job* would wpUia why thay ara tkc hvarit* plutar tad*7> USG btaadi doacribad abaca ban baoa racogaizad Indtn ia tba pngtm "fliitw bu mi ia M*tii| tk* damaada of dam mairartioa. A Urp ataif f mtarck wgiawn ara wauwly aaarcbiag far ttill |rwtw bapmamal ia plitur. Aa ia tkc pact, aaw diacavariaa will ba Lacorporatod ia Rod Top wkoaoaor tbay ara thoroughly provad. %- -I I I Ia thia ago of Rocklath aad Rad Top plaitan, boM coal trovbloa bava baae graatly rodacad. Notable prograaa baa aba baaa mad* ia improving fiaicb caac material*. The demand for aaw decorative traumata baa raaalcod ia aa iacreaaad aombor of fiaiab pUatara. Each baa cortaia feacorm aad advaatagaa, aad plattarara who woald keep chair malarial ia tha j laad aa the favorite wall fiaish, will tudy aacb fiaiab to ba abla to rocammaad eba aaa mott edvaatageoaa for aacb job. I i 1 4JP9 RED TOPICS, DECEMBER 1, 1941 3 steps TO FINER FINISH COATS! In d Uaitniila Cnuity Conn Hauaa it Mwidiu, Miiwniyyi, SebinUa as walU mad Mating o4 tW Cosrt Room hu coutributad * tU ncmnd comfort that hu raolttf from mailsraristiau of ckia hniMisg Tho viav of iN( Cosrt Hosao shcwa kata, illsotrsMa bow Sabsaita miita lha fsqniramonta at nodaia Sacoration. With ochar accosidcat matarials, tbo plaatar may bo onaittod on tho araaa trstad, With Sabimta, tba flamtaror gata mar* work, and profit, than would ba had in any ochar way. ` ` .. * r Promote Sobinite for Profits, Plasterer Urges... " That old timers in the plastering business are alert to changing conditions is demonstrated by the case of Jim McManus, prominent plastering contractor of Meridian, Mississippi. - When modernization of the Lauderdale County Court House was proposed, Mr. McManus immediately realized that acoustical treat* meat would he required. Mr. McManus went to the architect and explained the advantages of Sabinite. He made the sale. The results obtained with this treatment have been most satis factory and the appearance of the rooms has produced much favor able comment. Is it any wonder, then, that Mr. McManus urges all plasterers to take advantage of the opportunity this material pro vides them to increase the volume of their business. Jin McKisu says, "If ptaasaron milsod the advaaeagos hbtuu ha* vor ochar acoustical troatmaau. chay would lot tviryso* know nboat it." For a bard, smooth finish coat on your next job, try Rod Top Trowel Finish. It's used as a plaster finish coat instead of lime and gauging plaster. . Red Top Trowel Finish forms a 'lifetime** bond with any gypsum base coat plaster -- results in a superior quality wall It is ready for use after water has been added and tha batch has been thoroughly mixed. Decorating may begin once the finish ie dryl Thaw illustration* thaw tbo chaago that was produced by modernizing tho outorior of tbo Laodordalo Countv Hoorn at Maridian, Mississippi. In addition to 5abinito,whora acoustical treatment wot ruquirod. Rad Top Gypsons Piaster, Rod Top Star Gauging, No. 1 Moulding and Grand Prise Finishing Lima warn used. Kraus* fc brassSold, Maridian, worn architects; Newton and Schmell, Hattiesburg, general contractor; Jim McManus, Meridian, plastering contractor. Craftsmen of Tomorrow at McKinley Vocational High School See your local building materials dealer for detailed in formation about Red Top Trowel Finish and the complete tine of Red Top Plasters. Or, write the United States Gypsum Company, 300 West Adams Street, Chicago, Illinois. . . where research builds better, safer building materials. Good workmanship is essential if plastering is to continue as the favorite interior finish. Voca tional schools are playing an im portant part in assuring good craftsmen in the future. At Mc Kinley Vocational High in Buf falo, New York, plastering is one of the courses taught. The course was started in 1923 with the co operation of Local No. 9 Opera ting Plasterers and Cement Fin ishers Association. Above, thr finishing of a mould and the final shellacking are shown. Suggestions on Mixing Plnster While the proper method of mixing piaster is well known to the trade, there are a few fundamental rules that should be observed for best results. This is particularly true with regard to machine mix ing, which Is being adopted in some localities to help meet the competition of dry wall construction. Good results naturally can be obtained by either hand or machine mixing. The only requirement of the fin ished material is that it be thoroughly mixed, and the procedure suggested is recommended because it produces the most thorough mix in the shortest possible time-. On smaller jobs, with machine mixers there is a tendency -to mix too much material ahead, resulting in quick set before the entire batch is used. Over-mixing of plaster or slow and irregular mixer charging must also be avoided. KID Tones. DECIMXK 1. 1*41 Pj -7 Hand Mixing The Bertir box for head mixing should be raised et m end. la the upper ead of the box a layer of tend should be placed, tbea ooe of piaster.' This ` should be hoed dry from one ead of the box to the other) tbea bock agala, working dry aaad aad platter thoroughly together to e uniform color. Add water as mos as wad and plaster hare bean dry mixed, bee the plaster iota -the -#ater, i-ring thoroughly to briog to the proper consistency for ap* Wood fiber is asod without sand as a rule.The plaster should be hood into the water aad al lowed to seek at least 10 min utes, after which it is mixed to the correct working coasisceacy. If it is to be sanded, use aa equal weight of piaster aad clean, sharp sand. The same mixsag procedure should be follow ed as wbau mixing cameat pins- Machine IVIl'vin Cf ****? plasterer! say machine mixing makes their jefa easier. Contractors alao knew it halpe them to moot the competit!on el substitute iTilAlJIg materials. This is particularly important in defense bousing construction whsm autay new methods aad typos of materials are being used. Wi -p^7 Add eaougb water to obtain required consisteacy. Batch should be mixed until uniform in color aad no dry sand or plaster can bo seen. Dump batch when in this condition. While batch is mining, plaster may be pulled hack in bon with bon or shovel. Do not mix mote material chan can bo used within ossa boar to avoid quick setting. With continuant uao of minor, sat plaster may eccumaleta on bli.lrt, shaft aad sides, grad ually acceleration . nog time. Ia such cases, the mixer shout-2 .-i cleaned at intervals. Flask mixer thoroughly with water to remove et plaster. This always t^oald be done st boos aad night. - If water dee* not remove all plaster, break it lon* with shovel. N|i EO TOPICS. DECEMBER 1, 1H1 STRANGE AS IT SEEMS............................................................................by John Hix vh-.j - SI- Question: Do you recommend the use of moulding plaster for patch* ing finishing coats? George W. Kreger ' 404 North Elm Street 5=-\ ' Pittsburg, Kansas. Answer: We recommend Red Top Patching Plaster for small cracks, etc. However, Moulding Plaster may be substituted sat-'- isfactorily. For repairs, including large areas, USG Lime may be gauged with Moulding Plaster, provided the set is not too ouick for completion of the patch. Otherwise, we recommend Slow Set Gauging Plaster mixed with USG Lime. ---- gp^Ti-E IN THEA,r/ ^"VhE WALDORF-ASTORIA. N.Y C- TALLEST Jr ft SUPPORTED BY CUSHIONED*5nLTS" TO ELIMINATE VIBRATIONS FROM TRAFFIC... NO PART gP THE BUILDING TOUCHES Question: I expect to remodel an attached garage into a dining room. It now has cement plaster on metal lath. Should I use white lime finish, Keene's cement or Oriental stucco to get a nice finish over the old cement? _ - Olin A. Warren "' 255-24 Walden Place v Great Neck, N. Y. 'r- Answer: The material depends on the finish desired. Assuming by cement plaster you mean gypsum cement plaster, care should be taken to be sure it is free from all dirt, dust, grease, paint and any other foreign matter that will prevent the finish from proper ty bonding. It a smooth finish is desired, lime putty finish or Keene's Cement Finish may be used. A colored texture or sand float finish may be had by using Oriental Interior Stucco. ; Question: Will you please explain why Keene's cement check- cracks? ' ' : Charles Buck " 641 D'Uts Avenue ~S. ' Ambridge, Penna. '' Anawer: Keene's Cement may checkcrack for one or a combina tion of the following reasons: First, insufficient troweling; sec ond, too little Keene's Cement in the finish. Keene's Cement finish requires more troweling than ordinary finish because of its slower setting nature. Until the set takes place shrinkage cracks are likely^la occur unless,jthe.finish is. properly troweled. Keene's Finish should contain not less than 100 lb. Red Top Keene's Cement and 60 lb. lime putty. * ~ Question: I have been using hard plaster on concrete walls for several years and had no trouble In recent specifications on jobs I have figured, it says not to use hard plaster on concrete walls. What is the right way to do such work? V. E. Figg, Ekalaka, Montana. Answer: You are fortunate if you have been using hard plaster on concretee walls with no trouble. For best results we recom mend concrete walls to be furred and lathed wherever possible, otherwise Red Top Boadcrete could be used. Bondcrete is a product formulated to correspond in volume changes the same as Portland Cement. The concrete should always be dry, free from dirt, grease or efflorescence and thoroughly roughened before application of Bondcrete. Interiors of dignii'tv and beauty--these are monuments to the skilled hands of the workmen who executed them. These cornices, coves and soffits and plaster ornaments must be perfect in de tail. This perfection, in turn, requires a quick-setting, finely-ground plaster. Red Top Moulding Plasters are manu factured with extreme care. They are characterized by uniformity of grind, depend ability as to setting time and mixing qualities, and freedom from excessive beating and expansion during setting. Red Top Moulding Plaster is made by a special ariaite process from selected white gypsum rock. It produces hard, dense cast ings, free from bubbles and pin holes. Let your local building macerial dealer tell you about it or write the Question: I frequently have requests for a skim finish on plaster to paper or paint over, instead of white or lime putty finish. What do you recommend for such a job? - W. B. Nicholson. Chapman, Kansas. Answer: We recommend Red Top White Trowel Finish or Red Top Gray Trowel Finish. These are ready-mixed gypsum finish plasters, which may he decorated as soon as they are dry. They need only the addition of water to be made ready for ue. We do know, however, from the general section of the country from which this question comes that Red Top Skim Coat is also suit able for such jobs, and is trade practice. Not more than 2S% lime should be added with this material, and complete directions are printed on the bag. Question: What causes white coat to "tear" sometimes when troweling with water? '. A. F. C. 101 Park Avenue Summit, New Jersey Answer: Tearing of the white coat indicates that suction of the base coat is too great. Question: When a job is to be tinted, we find it always more suc cessful to dry mix lime and color. Now, by what method would you suggest to add color to new lime when the box already con tains water? John M. E. Shultz, . 1052 Berg St.. Johnstown, Penna. Answer: We recommend that if lime putty is to be colored the color first be completely and thoroughly dispersed in water to eliminate any tendency for lumps, which eventually could cause streaking. There is always the possibility when dry mixing lime and color that complete dispersion is not made. United States Gypsum Company, 300 W. Adams St., Chicago, III. . . . where research develops better, safer building materials. Correction--In the chart on plaster bases published in the October issue of Red Topics, the amount of sand required with Weather- wood Lath ahould have been shown as 1 cubic yard per 100 square yards of wall surface, instead of 1.6. Those who have kept this 09 chart will want to make this correction. ' CD o o lVhat art jour questions on lathing and plastering? You will receiet a dollar for each one published. Send them to the editor. Red Topics. 300 B5'. Adams Street. Chicago, III. o r> o vO an hour after fire wa* discovered in the basement, smoke wa* pouring from the building. Spreading was helped by wood parti* ~ dons between basement storage spaces. - . . . i. (Billing* Gwctte Phot- The result of the worst fire in the history of Billings, Montana. Notice that in spite of the tetrtfic^j heat and smoke, the plaster showed little discoloration - - , --- ,' - - - $750,000 Fire Proves Value of Metal , ..... .. . (BOSaca Guam Phow) ^Flames roared through the dndcr*tike structore and soon produced I right soch as this. Flames and falling walls threatened fire fighter*. ~' t elevator shaft is visible through the smoke and fire. Lath and Plaster Construction T-is ----------------------------- v - The $750,000 fire which roared its way through the old Northern Hotel of ^ Billings, Montana, last September proved one fact conclusively to residents o of this western city. Metal lath and plaster construction resists fire.j J ...................... ' ' sjrr------------- - For when the smoke from the worst fire in Billings' his-, tory had cleared away, only the elevator shaft, protected by metal lath and plaster, was left intact. The rest of the 200rbom hotel was a pile of debris. The Billings, Montana,' Gasette said; "Fire-fighting forces worked throughout the night, wetting down timbers and furnishings which still were smoldering Thursday af ternoon. Sections of walls and the hotel elevator shaft stood 'J r v . ` l-V- . .ZS-r, as grim reminders ofthe city's^ . most expensive blaze.'V ^.v .^Residents commented on_thet unusual fact that in spite of*\ the tremendous beat and theW volume of smoke generated byj the fire, .the plaster showed V very little discoloration. -I islsas- f<f 1 RED TOPICS, APRIL IS, 141 Foundations LOOK TO RESEARCH FOR CONTINUED IMPROVEMENTS IN PLASTER^ Ever since the latter'part of the 19th century wheh'plaster researcn pn olfCrack Complaints duced a retarder which made gypsum plaster suitable ior commcrcial'use thi part research Has played in the improvement of plaster,. ha$ ^beei^one. of in^ Poorly designed or poorly built foundations fre- creasing importance. ** " 'r~ ' UjyjUy are to blame for marred ceilings and ruined lecorations. They cause buildings to settle' un evenly-with the result that unusual strain is placed oirthe plaster, an inert material which will not of itself. .. . . It should be remembered that soil is a yielding material which is compressed by a building load; ~ ~therefore, every building will settle to some degree. s.TO assure"an even and equal settlement throughout ^the building structure, the areas of the foundations ^should be in proportion to the load carried by them. Oversize Wall Footings May How to Tell a Good Footing f Cause Unequal Settling and a Bad One i fotfiBiSsi Frequently the foundation . The trench for a wall foot r-..placed, under concrete or brick ing should be perfectly flat and T exterior walls is over-designed. level. The trench for footing ' instance,'. the 2x2-foot shown at right in the diagram, ^ foundation in figure 1 was improperly dug; it is deep t an interior column may er in the center than at the jCaload produced by 100 sides. It forms a wedge which ' 'jffeet of. floor surface, will settle faster than a per ___ a funning foot of wall fectly flat footing. ajSonly cany, the load pro The . footing at left is. too ved. by .5; square feet. of shallow, even though that por * sSiSggfel:-:. ^ tion of it which comes in con tact with the ground is suffi ciently large and properly pro portioned^- A heavy load on it may punch through the foot ing. If for any reason it is necessary to make a shallow footing for a column or a wall, it should be projxtrly designed and tested.- __ r:-;T*be footing in the center is a goodone. Its base isAyide^ _and deep enough to hofdlaload; -?,`t, Plaster cracks! What5causes them?; In the following.issues ofrRed-rTopics- we"Uptake up; some of the other reasons-.why cracks-^appear. on;' plastered walU:- ^T-4-;---------------------- Invention of Retarder Opens Up New Use for Gypsum Plaster _Vi _. Before . 'suitable. reorders were produced, gypsum plaster was seldom used as a wail plas ter because on an average, it "set" in 25 minutes---much too fast for a workman to mix and apply it. But a gypsum- wall plaster was needed. It would set much faster than lime plas ter which became "hard" only after six or seven years. Lime plaster sets by absorb ing carbon dioxide from the air and, as air contains only -1 % carbon dioxide, the lime plaster hardens slowly.. The surface always hardens first and asthe carbon dioxide is Jun&ble . to reach the core or inner surface. that oart of the wall remains- soft rfof a longer' time than fi? lwthaecjduonri would if the plaster sets from setting' gypsum^' the inside to the outside.,, ._v. needed, so research, develoj oneT USG researchTmen~ Plastering In Europe Was not satisfied, however.. They-^- A Slow and Laborious Job discovered that if plastcring^j^ As a result, many European plasterers applied lime plaster in ^-inch layers at six-month intervals; a layer hardened suf ficiently by that time. Fine plastering jobs were such a slow process that they fre quently lasted six years. . Lime plaster is highly alka conditions were unusual, the normal setting time was often retarded oraccelerated. Weath-j-SSrcr conditions, mixing, amount; and grade of sand, water im-: purities, age of plaster--all 2^: these affected the set of ~re-fjjp5 tarded plaster. ` y- - 1935 Sees Development of%^- line. Unless decorating.is post USG Set Stabilized Pluter^ poned until the lime has car Then, in .1935, after years of.5^ ' < bonated, the free lime in it may tiesting and retesting, the ySGSS^tt I burn the paint or discolor the Research Department an*' wallpaper. . Lime plaster also [oounced Set. Stabilized ' requires a large amount of sand <hc biggest improvement so that shrinkage cracks may: plaster since the invention be prevented as mortar driest retarder. Set Stabilized PI , haat fngredientsXadded . serve to counteract fluctuate *iiTsetting time brought about'-' by. abnormal conditions, such as described abovei/sA pi 'using it has almost positive___ suyancc; that;plaster^whicfajsgg .'supposed to set in. the required^! time will do just that, regard^ less of the circumstances which he does not control. " ' ' Improved Plaster Provides Insurance for Plasterers, re Set Stabilized -Plaster^-Tnii "mixes' plasterdryouts** ofi acqimtered^whttithe^weati i^L<^and;dry7 orfwKc5?ti muefiairia"allcrwedtocirculati fxRedTop 1 PlastCTera;_ ______ .... n i,' ---3:r g-j-.v - - ------ .sands acf.tteiaLn acoelerafor*i New Soper Highway Cats Travel Time ^pWsteCmixy-^Ucdqvii _. conations w^teratcdiwcat c Betweenv Pittsburgh and Harrisburg taining two parts ol^sand by^ weight; iwfl^aetftaM^s' ' ^ rStretcmng out across 160imiles:_of ; Pennsyl- vania^s America's; new sup_erhighway -i the Pennsylvania' Turnpike.' This newest example of therbad-buildingskyrof American"engineers cuts vania ^Turnpike^_wili ; permit^ three to fdur puts of sand by^jgj. smootiu uninterrupted travel at' ^ghfe\Vfen5e^Sfilwfized|^Sh speeds once considered* unsafe . Plaster is usM^towevefr botfi? foe public..highwaysrv.lt will;, coats, willJiavtL.appraxixnatelvi'^a not be crossed by a railroad oiv highway throughout; its entire, less of the;above. amounts; of ; sand^usecLan~eacK.B. .t,.tat length. ; Dangerous grades' and ^ImproyVmenti43^rthes<s <mrvescomnxnTorf other high-' have proved to'olasterers" the^.f hours' ofiftravel time be1' 'wa'ysTrivebeeheIirranated.TTfer lmportahc^^fvtfe^fi^^meh^igS tween Pittsburgh and Harrisburg, by going through the Allegheny maximum ascending grade is 3% ; curves are no greater than 6 degrees.- Ramps are con structed-so as to permit en search who itork quietly, and^*^ unassumingly, day after day, ;-v^ making plaster a better, and^sr safer building materiaL^Nexti^^ Mountainsr. instead ' of trances and departures with a - issue there'll be another around or over them. maximum of safety. on developments end improve-^^y ments in the plastering field. THAT TELLS YOU How to Get Best Results from ./: ;" Plaster Products u this handbook is based os m chan SO years of experience by USG with fdsorar usage and trooblc-comctiou in every action of the country. Gives causes of most plaster troubles, with rtmadut, in handy chart * focBuVrita for your copy todar.-y.'-p- UNITED STATES GYPSUM COMPANY JOO Wot Adorns Ofiemg*, UL Map. shows route of 160. mile super-1 ' PittstmrgH~and I TIME FAILS TO MAR IEAUTT OF TEAR-OLD.CUBAN STUCCO J0IJjS3 ' Time had done' little to the stuccoed beauty of. Jos de^ Ajuria's^ Havamff hdiiifeg^^g^ After 14'yirars, the, t^autiful^^ 1 i^S, o^ntaL.HSS.,5!iy#5 looked like new. - But where time had fafled,^ -? (Acom Photo' iwmy which. connects electricity triumphed. In order .1 .% to get at the wires for needed.'. electrical repairs., the^ stucco^hadtoiie'ienioved'urseveia?*^ - Should Prove Vita] Military ; The Pennsyl^uaVTuri*ipike' In response to-/ . Artery ____ is a concrete highway with four Ajurio's urgent _ request^ thei^i : By.providing a speedier and. 12-foot lanes exceptin thetun^ ySG^Expon.Depart * - safe^weantTof^trari^iertshg nefei-where sjxk*:peiinit^.Ofdy^ ^ptuhed'hoW^ftt^ttlS . men, equipmentand munitions, two 11^-foot lanes. East and matching color of USG Oria^^^ 1 the! Pennsylvania Turnpike , west traffic is. separated by a tal Stucco whidi^ would iestdti ^promises 'to he a vital link xn lO^foot'center parkwayf^^ hiaThome to iT - our scheme of. national defense,; (CefldaMd oa peg* some appearan FHAllNDICATES CONTINUED INCREASE Fireproof Insalating LathTills Heeds INJMALLHOMECONSTRUCTION of TodayYrfiomfr Builders ^Buildenjof-lowrtii^Die^ * ____ homes'find^ Over 50% of New Single Family Homes Valued Below $5000 ........ . . that fireproof Insulatingl^ocklath fills themoaSnjf ^.Xhe mqrtgage'insurance operation of the Federal Housing Administration show ah unbroken trend year after year towards lower priced homes, Admin- need for a superior plaster base with high insulation, efficiency--all at low tost XstratorAbner H._Ferguson~^nn6unced' fecentlyT" ~ " : ~ _u.Take the case of JEhrhartZweUdkxuSiC. Chicago Builder. He used Insulating Rocklath~iri~ SlJ .'M6r% than half of the new single family homes constructed under the FHA every one of 40 medium-priced homes erected in'a J-y Plan in 1940 were valued at less than $5000. If the trend continues, and all Chicago suburb. ---vindications are, that it will, an even greater'part jjf 1941 construction will be "I wish to-maintain..good the Insulating qiialiti^aVif flltiml ' i'hSrnes~in"thinbwer'price~bracket.^^^^gtVT.j^ESt ......... lathing !'and "plauering^hi^ffky^ sTfOemuinn^5ftbnili^MbacAk -ggypyaimnit^tfgt^hr^aitf^r' V. gfSnull Homes Are Big Busl- ^ . .- kind of insulation ? Just these r jVfl ItualWlI -smiweis - V-.. f -t. . .. If a more expensive 'type of in thc boilding in- insulation;-is used, /sacrifices J^-^Jdukry^hoilild "recognize -the must be made somewhere in importance - of the growing order to keep the price of the * preference foriow-cost homes house within reasonable limits. ' among medium income fami- Maybe it will be reflected in the \ ;^ lies. And there are sound rea- quality of the bathroom fix J-" v^sons for this preference. Fami- tures, "the woodwork, or the ` T -'v lies know that ''present-day heating system. Maybe a sub v'/;- $4000 to $5000 homes are corn stitute will be found for lath er 77- parable in quality to those cost- and plaster! ~ ing considerably more a num- . -.And if no insulation is used, ^B^tshgr of-years ago.^No longer. - ti^bomeowner suffers. Chilly tbey expect a low-cost home .'.rooms,'unusually high fuel bills rPSKa * *n appearance or: construction/In addition, fami- --maybe unlooked for and un-' necessary doctor bills. Any of "aBg^lies are wary of /'over build- Mj^in^^&atris7^*7s-p. sepnenddiningg 'mi ore Jig/for a home than one's income ^^ ` jusdfies. JTr-Soundly *' built, homes are possible today main- Jybecaiise of streamlined meth ods of building and because of ^the many better, safer building "^tenals^available^which -]are onlyjefficicnt^but economy , too.7-Thistcbihbination re-' these, may. result from a lack of insulation. ........ U a Vapor Barrier Needed? In a modern insulated house a vapor barrier is advisable. Moisture in the house is under pressure--vapor pressure, not air pressure. This pressure will cause vapor to pass through ordinary interior wall construction. When this vapor reaches the colder air inside the wall, the vapor condenses in the_ form of dew/ just as it does on the .surface of -a cold water ., glass'or Iwindow/ Vapor bar-; ... ..-(CoMiiuMd on Pag* 4) . homes," said builder Ehrhart One^bc--cu---pan*t of a two-story/ .when asked why he.usedin/ ^Sfirreej^cpoom house. teUa'^pj^usmg:; sulating Rocklath. "AndTCl^- ^'oonnllyy^^ssiix-tons 'of 'j&&oaT/CoiSu^-ag_ have had very good reports oxr $52.00 during the beating i__ _ fuel bills--so there's -another Json.^Another used'oi^^eva^: reason why I'm sold on In-] tons of coal the' first year in aLl sulating Rocklath: it assures five- room, one- story - housed low heating costs. ' ' The latter case is all the more M1 am going to build quite remarkable when one considers a few new homes this spring that fuel bills in new buildings-: and summer," T Mr. Ehrhart are usually higher because*of went on to say, "and will use the'moisture which is. ]in the; Insulating Rocklath in all of building. -- ^-'-7/-- them." , -' _ _ i' -- Insulating' Rocklath Ap. Low.FuelBllls .Reported by 'proved by Residents T^The insulation wbich is prch^ s hying videdby. Insulating^ _ Ehrhart's homes na1ve proof of for"only *a moderate idditioral^ ^cost per square foot mon " ^standard Rocklath; rTTRA* minimum fequin bln addition, the aluminum^...... badc~acta as a^Srapo^barTrcr^ which helps to prevent condra^ > jsotionAlt offers build^sVffa^ ^solubpn to theproMraJofl^w/ to insulate the low-cost home.* . MLflbows plastering contractors^ ybov^terffake'^tnoreiaoneyTOn: Its fa homes which are mod-. i~ corrvenient, and fire" and ither"" ` ` ' gJh. David .Daridson^/t^ ^plastering contractororfhomes^ ffi`ttii^bdiviiioirfeaa Do Lath and Plaster __ Into This Picture? " ( Builders and buyers of every' price home know of the advan tages of lath and plaster con- < struction. Plaster provides the smooth, unbroken, easy-to-re- decorate surface which home- owners^find so d<airable.jDyer^ plastcfT you cahpaiht/put oh' texture,-wallpaper. or* fabrics. A row of trim, well-built, well-insulated houses erected by Builder Ehrhart In his new subdivision, " It's the universal'wrall sur face! It will .not harbor vermin and, if properly applied Aluminum Foil Proves Value as .. . over a Rocklath or Metal Lath plaster base, will resist fire up Insulating Material in Many Fields to one hour.'. Ahiminum foil insulates gainst heat and cold.' 'That fact has Home owners ^choose'tlath been prCved over and over again by its continued^use on both4, ;*nd -plaster, construction . for large and small products of industry. these reasons! .Yet, now for Everyone knows that the glass container of a' thermos bottle is almost no extra cost they can silver shiny to keep the contents either hot or cold for long have insulation and a vapor periods of time. Aluminum protects chocolate from heat, light ^barrier, too! and moisture--keeps it fresh and crisp. Aluminum foil is used/, : Insulating Rocklath Pro vides Efficient Insulation and too, in modern streamlined trains, and ocean vessels such as the Burlington Zephyr train and many battleships in our Navy. Barrier Against Vapor Used by Admiral Byrd and Try This Simple Test ' owners -- and many _.. -'rr* builders--are surprised to dis* cover that when plasterers use i`- '/-Insulating Rocklath, they can \ ' "1iave insulation and an effective vapor barrier for a very mod - erate additional cost over that Professor Piccard . In the fields of exploration and science, aluminum foil has proven its value as insulating material. Professor Piccard, the famous Belgian scientist, of standard Rocklath. Think lined his balloon with it so as ^what this means to the builder, to be able to resist the extreme *`the contractor/and the home cold of the stratosphere. Ad l owner, all of yrhom want miral Byrd, the noted explorer, Ihirisbed bouse to possess * . used rfat the'South Pole. ' " tnahyTof the modern conveni- Take the aluminum paper-from a package of cigar ettes or from a candy bar. Cup your hand and lay the foil over it. Notice how warm your hand gets. That's because your body heat is retained by the foil and returns to your hand. This is exactly what happens in a home. Furnace heat is re tained in winter--the sun's beat is reflected fa the^summeriSmre ? races as it carv. Authorities agree. -that insulation and apor barrier are highly desir- ;;able. And now a plaster base, . : ^Insulating Rocklath, provides L /them Jor a very small extra Thanksto Mr. B. D. StowelJ We ore Indebted to Mr. Stowe of Billings, Mon tana, for the tip on the front page "fire" story 1 ; fottjc^AfhfceMeimGuje overotherInsulations with * llNSUUinHGJROCKUSni ftr M* m / VvM 1i i fllM" m v* nw - Cww' Om**r BM Mid- ' tm m VMf* Sm d ' 4t Ml tw " i Mai fowl __ h Oi Amtm Om =e:' mmt iw * * Mit Tm MQf ` Why Use an Insulating Plas- 7ter Base? .. .. rWhat are the advantages of felling Jwboilderi ^and . home ^^owners -oh this %^cxpensive ^Thermos bottle and streemlmed train msulated with 1*7,7,-- :_~r; ahtminnm foiL ' 'JFTT TTr^'^Z'. UNITED STATES GYPSUM COMPANY krr* riiMrri jferriopr better, refer ta/Mni| sirttridli RED TOPICS* APIUl. 20, 1MI Book Beview and Trade Accessories "ABCs of "Plastering,"-"h hew book recentlyhublishedby/ the Gypsum **Association~of Chicago, Illinois, gives plaster ing information to architects, building commissioners, etc. It has *been received -with consid erable enthusiasm by them, by faculty and student of archi tectural schools and by others in the building business. ~y*In 'hop-technical languageTit explains plaster and the proper mixing and application of jt.. With this mformatioh^it -Sis" hoped that the layman will be able to recognize good plaster when seen in any of its stages^ Discussed are main requis ites of a satisfactory plastering job. They are (1) thickness, (2) quality of sand, (3) quan apparently are only where the lath was cut. In other build ' ' togs in this village no rust spots tity of sand, (4)-workmanship, have been reported, in whkb we Research Proves that Temperatures and (5) ventilation. -1.... 4 - , * * r* definitely know that metal lath was used to reinforce ceiling cor BHectjSet of Sagged Lime Patty .. ., The . Gypsum Association, ners and inside wall corners. We would greatly appreciate it if you __ ______ 211~W^Wackej^Drive> jCW-I b^i^^tje~roorr^^^t"gaugingr cage,: lianavhas also released . could -give ^assurance-;,whether,^ pamterTlafe wouldjasuaBy'daoscT JSGjtesearch Departments osed^tbequicker theact.When ' at^'drop m-tempera?- -slow-iiet-gauging -is increased* ` ........ ........................... the set also lengthens. : i ^It-must be7remembered that. -i booklet containing a suggest-: ed plastering ordinance which it hopes all cities wifi soon write -into their building codet' Coghi -t'*.spots>at-pbints-vwfaere pami\fifl ^mightbe damaged jor if gah ,. iced lath-will-ever catse such `jVspots. . Some information relative s&.to naDs -nsed -witfa RodrisriMnlU ? ^T^utty-tetnperature and walls are at 40 in one instance and ; at JOVor 55^in 'a ^second in stance when smother lime is parativdy few'aties how men-' . don. plaster or plastering a in --''also be appreoatecLcWe are par-~ ' bcularly anxious for this toformai.;tion since the FHA.specifies ~=ner 'reinforcement, - bid ee TV If you wish either or both - competitor* have skipped it and | .used.: the results will Jbe very "different and knight he'wrongly attributed, to the limtTor gaug ing plaster.iJXhis is true of any .oKth^^bpolo^mrite-to -Jhe, .GypsumtA*xiatjon720 North' Wadcer Drive,- Chicago, HI. away_ with.the omission on liFHA.-fioahe---------------------- ---*?-tog rust disl _ - -------- E.7. T. lime^and is a^condidon that FHAilNDICXTESIN- ANSWER^-It hrtrite tbit thereIf :should always beconsidered. -4-CREASE IN SMALL" ~a certain amount of corrosive'ac-,: ' tioa-'caused by -the ~wet plaster ^SnperHighway^CntsTravel^ etw^iPitbbarghtandjHanislnirg^ t -- ` -fraaP*.)l drthiieeerrfer.asfomhroeinurgold.na(I*lnwesa.uyrlosaobtimenpgMlRaoeoeadoc.f-^j. _f^to^onqi.utiitctkdiopl`.yendmtfo'aafe.fy'wlepioipiisafsomtroct'le.yiud"acggoamurbseauetcnaak-l.: lath is placed that way with the to--n-p--o--r-a-r-y--_--c-o--r-r-o--s-i-v-e----sLt~a1b to be toT>w heavyTraf fic in every season of the year. In order to provide travelers ; moisture barrier foil facing the framework and at least a J4 in7 air space.) Since the frame work space is not a vacuum, ^- floated -to-the-surface.--In h. --experience, however, we find that to only die most unusual cases will rust stains come out on finish coot surfaces where uniform fi" with convenient stopping-off places, ten modern service stadons. have becnjerected along d^way^Tbeyare.ofT^nsyU, vama^Coloniai^rirlutricture/ circulation of air will absorb the small amount of moisture which may seep through--thus reducing/condensation^rfa^j usuaHy ahows jtself.jn damp thickness of plaster is applied. This also applies to rust marks occurring over Kocklath nail -heads. Always remember that a- ^withstboe masonrywalls, slate walls, musty rdoms and ruined roofsand wood trim. The prin decorations. cipal,^ or midway station, is situated near Bedford, Petin- Insulating Rocklath Ideal for Use In Small Home Field _ Insulating ..Rockbth.^is lay efficient beouse of an alum inum foil back--it actually in creases the resistance'of. the' wall to Are. Aluminum foil is known to builders as a reflec tive type of insulation. It re flects heat. Thus, room heat is retained in cold weather, and summer heat is prevented from jcakAerttl view of Pennsylvania ^Turnpike showing . world** ^deepest highway cut (150 ft.) j?Ttmgrtc*rGreatest HIghway '^Project - (Acme Photo) Pennsylvania National Guard testa value of "Turnpike" as / -V vital military artery. . sylvania; intermediate stations entering during hot weather. No extra labor is required to install Insulating Kocklath. It "rides'* along on-the job giving extra benefits for the home owner and plasterer."' T^s l^e greatest single j^Poghway project ever attempted 7^r}n tbe_ United States. Seven ^tmneU,'x of which were par-, "dally -bored in 1883 by the ^builders of the long-abandoned. GEf&ttk^Pri&IKanway^are re-1 f^xmsible for the elimination of Lgwany ^perilous grades and ^curvea^. To further reduce acipBdcntv.'the super-highway is 'preated, wherever possible, on `v' e~sooth and western slopes hills ra order to receive the iximum .benefit of sunshine ^ring icy"and snowy weather. are placed at approximately 15mile intervals..___ ... . Service Station Plastered with USG Productsl^/p. ' USG products were used by Mr^ J. Confer*,Johnstown,, (Continued from Column 2) Pa., plastering contractor on the "Turnpike's" 10 modem service stations. -- "I used a large car of Red Top Neat Plaster, another of Rocklath, Corner Beads^ldetal Lath hnd a'minimum caF'of USG Lime," said Mr. Confer when asked about the jobr~g7 `'All the mate rials were of high grade quality and the men stated it was a pleas 11Ten Modem Service Stations ure to work Erected on Tnmpttce Midnf 5otm on the Pom* with Red Top ^ .._ _ ^fcJThe Pcmsvlvana Turnpike --------jyiymni. Ttmtpike. materials.J. Confer v-. - ... What are your questions _ on lathing, and plastering? v You will receive a dollar for v" each . one published. Send : TOPICS LATHING AND PLASTERING Putttked by United Stiles SffiMi C*. Braihtm 46,000 AGARIST [Stains in Lime Plaster Finish Explained... So natural in appear* ance, they tempt one to fee! the fabric, these modern ornamental plaster draperies repre s e n c a superb achievement in the art of ornamental plaster ing. Tlw wodorn firi fiad* tint nadm Meting in tko ftp Michigan Km of Chicago1* fwtw U|twim bock Hocoi. Nocico kow tko gracofwllp ntldtd pluttr drtptriM ktlp to bring owe kor cool boowtp! It tkit tplondid bit of crofttniowthip it iodicctiow of i now trend, oow appreciation 1 of tko fioo ort of ornoMontol plottor work? A Fredericksburg, Virginia dining room of 1750--one of Mrs. James Ward Thorne's famous collection of American Rooms ia miniature -- onetwelfth actual size. Notice the unusually rich ornamental plas ter ceiling, the pains taking craftsmanship exhibited in the deli cate . .designs in die overmantels. This new series - of American rooms,_ the first time ever exfcilpted, can be seen' at the 'Art Insti tute, Chicago, through December 1941.- P*4 t RID TOPICS. JUMI 14. 1M1 Plostei GrachsCaused WHAT CAUSES STAINS IN by Poor Framing LIME PLASTER FINISHES? Cracks around window and door openings are very often due to faulty construction. Usually, no provision is made for the load formerly carried by the studs cut away for the opening. The burden frequently is shouldered by only a As long as lime putty wall finishes have been used, there have been cases of undesirable staining and discoloration. Discoloration may vary both as to color and the way it comes out on the surface of the wall. Color may vary from a light yellow or ivery to a buff or brown, and in single "header" and single studs at the sides of the opening. some instances, it may be brownish red. I Double Header and Extr.' arch opening should be ~ Studs Help Support Weight framed as inj^igure 3. Generally and technically coloration. Use a fuel with surface of the materials in To help carry this extra Headers have been dou the intensity of discoloration little or no sulphur in it. the wall or in the plaster load the single "header" or bled and set on edge, as have is dependent on the moisture 5. Open Fireplaces. Cer backing. Stains are only a lintel should be doubled and the plates and door studs. conditions of the wall and tain woods, oak and pine film but when scraped, they braced, and the studs at the 2"x4" truss members and the atmospheric conditions particularly, give off fumes return like weeds. with respect to humidity. which wifi sometimes dis It is important that the Slow drying walls, walls that are continuously damp, and walls that are subjected to alternate dampness and dry color white coats. Usually the ceiling will discolor first and the stain will gradually come down the side waits. causes of stains be generally recognized. Let's all make an effort to prevent them. The benefits and advan THIS* Mi *SN|ft" CMCSS IpftCATW* SITTUiMM CAtlSIS IV WIAK SCAM Ot TOSS IMMINi OVtl TPS OPfAIN* ing conditions are most like ly to stain when the causes are present. Stains usually appear first in the brush marks left in the white coat Recommend fireplace fuel other than pine or oak. 6. Pine Mixing Boxes and Mortar Boards. Fresh pine tages of good lathing and plastering will sell them selves to the public. People have never complained about when the wall is water- brushed after finish trowel ing. Patched areas will usu ally show stains soonest. As far as is known now, this may occur over any type of lathing base and is not con i of the^openin^s should i blocking gives additional ` " ' *` ` ` ' l^treagth and rigidity to .the ___ thvw^ji^k.|rhtTnuf con-! Ban^pdractioa^vealy /distributes fined to any one type of lime or plaster. The exact chemical com position of stains has never ................kS9gw-*pot been - satisfactorily deteriiqc<L-->:But much more is [wjwaboot-the causes of ~ `"that -is .what RWff 'flamr faiA ittia wfcicfc nigfct bi mcid u *ay irftk* cWM Jncribad ia tUa utkb. _ . he^OTa*detf "bad-3 -errand .studs may .jag uneder.Tthe :?*tram'-of /carrying |the load. The stress wiu be "transmitted to the plaster :'and plaster base. Eventual - ly this strain will result in plaster cracks. Truss Framing Needed for Wider Openings When openings are wide, such as in the archway shown in Figure 2. the fram ing problem is a more dif rto^STproperty-in creased number of studs on either side of the opening. rFor smaller openings the truss arrangement shown in Figure 4, will provide suf ficient strength. Another cause of plaster cracks allied with those al ready discussed, is the poor ly built door frame. If it holds a heavy door, frequent slamming of that door may soon produce cracks around the opening. 1 r-1 *3 UMWH [Trussing Doable Ktor-St1ud 1 =s =r 11 V CX J Sr 1 Fig 3 ficult one. The single plate and header, as explained above furnishes insufficient framing. Plaster may crack between the top of the open ing and ceilings. Because the frame will be unable to support the weight of the building adequately, this Why to Correct Structural Dofocts! Cracks caused by structu ral weakness will not disap pear when covered up by new plaster. If structural defects or weaknesses are allowed to go into a build ing to begin with, plaster rar~ paper stains __ pear on -outside .Creosote. ; When creo__ tber.U used as a stop Termites, it may contrib ute to stain formation. Bar creosote fumes at least un til the plastered wall is well cured. 3. Sands. When sand con tains soluble salts like so dium chloride (common table salt) this salt some times comes out on the sur face of the white coat as a fuzzy, white deposit efflores cence). Paint won't stay on these surfaces. 4. Unvented Gas Heaters. Any type of unvented heat er that burns a fuel contain ing sulphur may be a pos sible cause of white coat dis lumber gives off a secretion of pine oil. Use old but clean mixing boxes and mortar boards wherever possible. 7. Sugar or Molasses as retarders for gauging plas ter. Don't ever use! These materials may come to the surface and cause discolora tion. 8. Dirty Tools. Don't ever use! Even dusty tools may cause discoloration. Plaster Won't Cans* Stains In considering stains, both from the standpoint of pre vention and cure, remember there is nothing in lime, base coat plaster or gauging plaster that might cause dis coloration. Stains come as a result of a chemical reaction between lime and fumes, or by bleeding through to the good jobs. It's only the bad ones that give the plastering industry a black eye. No plasterer can afford to skimp or short-cut any job. The small saving just isn't worth it. Follow this interestingand illuminating series of arti cles which show the value of USG Research in the next issue of Red Topics. Watch for it. ' First Man: "Why did you have a winding stairway put in your house: Second Man: "To give me something to do -- I wind it up every night and un wind it in the morning." cracks are bound to show up. Plastering contractors un derstand these construction essentials. They know why plaster cracks. It is to the best interest of the plaster ing industry to promote sound instruction. Every serious plaster crack is a black-eye to plastering itself. Superior, beautiful and en during walls and ceilings are so easily obtainable with plaster over a good plaster base. That's why it's so im portant that a job be struc turally correct. When it isn't, your best work is wasted. * Follow this interesting sue of Red Topics will dis series on the real causes of cuss still more of them. plaster cracks. The next is Watch for it. THIS TRUSS IS RfCOMMCNOEO OVfft ALL OPiHIHAS OF HOftt THAN THAI! STUD SPACINftS Oft FOUR FCET Fig. 4 j] " RED TOPICS, JUNE 14, 1*41 Ptfc 3 ^lasterFinishPnjtectedAgainstStructuralMovements : A wall of gypsum lath and plaster will not crack of - itself. Cracks which do appear can usually be traced f to some hidden force behind the wall. ^~For reasonable assurance 'against cracks on walls and ceilings, USG research has developed several plastering . `systems''. Specially de signed, field-tested clips are the keys upon which these systems function. They "sus pend" walls and ceilings; minimize danger of cracks caused by faulty founda tions, green lumber, poorly braced framing, vibrations, and structural movements. How to Apply the Resilient Rocklath System (SI4wll em4 Ceiling). A .Vo. 2 Clip is nailed to each stud at the angle of svall and ceiling. Butt clips to the underside of joints where joints run at right angles to wall, and line dips on other two sides to same level. Run ceiling courses at right angles to joists. Start ceiling construction in a cor ner of the room by engaging the edge of the Kocklath in the No. 2 Clips. Place No. 1 Clips at free edge of Rock lath and nail dtps to side of joists. Work from oppo site sides of the room so that by bending the clip p..~2gs the last course can be swung , T rzissnassm ROCKLATH RESILIENT SYSTEM T" s No. 1 Clip--Resilient System No. 2 Clip--Resilient System No. 4 Clip--Resilient System 1-- irn How Resilient Walls and Ceiling look ft 2 cto usedas comer dpet wf#4c*^ngr -- _ i i Resilient M ' Ceiling , --WBOCKLATH- piaster----- - 2$'/WJW Studs---------- No. 1 do epomdet -li Resilient Rocklath Wall Construction y :! -------- 1 ! | , No. W22,^ eras afRochloth twfawpi studs Bridjoint Rocklath Wall Construction into place and the prongs bent back. Install top course of Rock lath on walls by placing top edge into the prongs of the No. 2 Clips and then secur ing Rocklath at all studs with (No. 1 or No. 4*) clips nailed to each end. A'o. 1 Clips are nailed to the side of stud. Where the stud spaces are filled with wool insulating ma terial a face nailed No. 4 Clip should be used. Apply No. 2 courses of Rocklath from ceiling down ward. Then nail a No 2 Clip to each stud buttingjrijp clip to the base grounc^-flace (No. 1 or No. 4) clips^-jr the upper edge of the -'Ha course of Rocklath ar Ml clips to each stud. -> 5 Continue with su^sive courses upward in ;JrTjhilar manner, breaking all end joints. Bend prongs of the clips outward for last wall course; swing Rocklath in to place and bend clips back. The Iridjoiat System Works This Way Apply Rocklath so ends fall between studs as near to center as possible. Work down from the ceiling to ward the floor, breaking end joints in successive courses. Nail Rocklath 4* o. c. verti cally at every stud bearing. Every intersection of a ver tical and horizontal joint will be supported by a W22 Bridjoint Clip. . No. 2 c*p use* <n Starter CIp St MM--- ft-. V / Vhbod groundfresh flooring-- -y 2 rH-- >K3/ - -- RSfe'itoodground *- -- -ytood Mm ijjX Rough flooring - *r?7?y;yy; * Installing Last Course of Rocklath in Resilient Wall 2 ttr Section Tf-r- - -No. 1 i-- l Studa /6`9fe -ROCKLATH nailed to studs Nods sooced C apart - - No. W22 -tyPOCXLATH- / r-%6`Gypsumabater---- -- - Z {--*h'POCKLATHJ | J--Wl'Ctor^noc -- 4 +4-' I 2 >f ' rB--ilimt Wall --- i \\ /4jt?'Cyft*wr* -- f* plaster ' No. W33 .. nods RocMAh at ermers Plan of Nail-on Wall xr-Av.iw. .a ir Plan of Bridjoint Wall J l Sts'ROCKLATH--I -j --------- If!===i' is No 4 (yrotadn face -adrg an stud nhen neuioLno >*ooi <s usee W.J2 Ciif Eridfrfrt System Run ceiling courses at right angles to joists. Start ceiling construction in cor ner. Rockljth in clips at the ceiling wall angles. No. 1 Clip is nailed to joist at free edge. Work from opposite sides of room so that by bending clip prongs the last course can be swung into place. New Rocklath Stagger System Score a panel of Rocklath vertically and break in two. I BRIDJOINT AND NM.-ON 'CONSTRUCTION Door Detail S"--u --j i m-- J. No. W33 No. W22 . '^H'Ojpsum plaster - USG PLASTERING SYSTEM ROCKLATH ON WOOD FRAMING 9 "St*l|r" system ee tffliid by Mr. S l*rii Milter, Kami City Iwldrr. o Then you have two panels 8 in. wide and 48 in. long. (Ceettwead ee faga *, CW. 4) Pf 4 RID TOPICS, JUNE 14. 1941 Life House Builder Enjoys "Astounding" Results with USG Plustering Systems! Mr. Thomas J. Crowe, well-known Chicago builder, has every reason to be enthusiastic over US^jj^silient Rocklath & Bridjoint Plastering Systems. Jt have been "astounding" for him. He finds resi dences in which he has installed thes^^Vms in the past 30 months are "99.9% crack free.' Last fall, Mr. Crowe built one of the popular LIFE houses in Lincolnwood, Illi nois. and used Resilient and Bridjoint Systems through- \ve s aggressive has since drawn ilies to this beau^ tome. espite the fact that I knew it would be visited by thousands of people," he said, "no structural provi sion was made to care for this traffic. The house was built according to the orig inal plans and specifications, but I used your Resilient Rocklath and Bridjoint Sys tems throughout. Over 65. 000 people tramped through the house last winter and in the next several months we will probably show i t t o twice that many. So far not a crack has shown and I'll wager none appear." B0NDCRETE Bondcrete is a plaster especially tailored .. tough requirements of plastering over concrete. 1 mits free evaporation! It is not affected by the > out of concrete 1 ' Add only water! Bondcrete is ready to apply easy to work and provides the hard, dense, firep base coat that will take any trowel and sandfloat Find out more about this pre-conditioned plaster Drop in at your USG building material dealer ' us direct. -. j Bondcrete is made by- United Stans Gypsu pany . . . where research develops better, safer I materials. An "army" of 65,000 people has tramped through the living room of the Life House. Yet notice the smooth, unmarred _ walls and ceilings. _ Resilient and Bridjoint Systems rate highly with ar chitects, Mr. Crowe has dis covered. Although his bid in large residence, several month ago. was higher than some others, he got the job by offering to install a Re silient Rocklath System in stead of the lathing speci fied. "The architect was de lighted." said Mr. Crowe. "M o s t important, in my opinion, the owner is getting the best job that money can buy." Enthusiastic approval of builders and home owners, too, is almost a certainty when plastering is done over USG's Resilient Rocklath and Bridjoint Systems. It's the smart way of minimizing the effect of cracks caused by structural movements. First Farmer r sanitary to have ' built over the hogj way." Second Farmer: don't know. We i hog in 15 yearsl" Builder (proudly), there is a house " flaw." Woman: "My { do vou walk.on!" h The smartly furnished modem bedroom of the Life House has . already seen more traffic than the average house ever does. ^ I Its plastered surfaces are still fresh and unmarred, chough. AKE a ride in any new car. Its makers brag about the T"ride"--smooth, gentle, easy! Walls and ceilings can "ride" easily, too. When they do, it meansforJeutrplotter crocks, reduction #/seamd tronsminiomfrom room to room mnd the eliminotkm of Utb strtmkif ISN'T ALL THAT WORTH SELLING? You can offer that kind of job to your customers! Just recom mend the USG Reulient RockUtb PUstering S/sfem. First, you get the safety of Rocklath, the fireproof lath. Then, the cost of the entire system is low. It's an outstanding USG development. You can make your full profit on ic There's no need to cut comers because this system gives you ertros to sell--extras every orchitect, builderand tunercan appreciate and is willing to pay for! United State* G^nm Co., >00 W. Adame Sc., Chicafe, HI. Let mi giro jom complete detoih Atk yoetr motorist deoltr or write todoj C HERE'S HOW irS USED! * lets am w ~ Htmrm* Ifmm M m*. Tm , RID TOPICS. JUNE 14, 1941 P9 S The Importance of Sand to Good Plastering e Don't underestimate the importance of sand to a good strong plastered wall. For basically a plastered wall is simply sand held together by gypsum. Two-thirds to three-quarters of the base coat is sand! 1 part gypsum plas- 1 part gypsum plaster to 1 pan sand. ter to 2 pans sand, 1 part gypsum plas ter to 3 pans sand. The strength an<l durabil ity of a wall are dependent upon the amount and the grade of sand used. Over sanded plaster results in a decrease in strength, a de crease in bond, and a de crease in fire resistance. Each grain of sand in the wall should be cemented by the gypsum plaster to the grains on all sides of it. (Fig. 1) Sand Must Be Clean Use sand that is clean. It should be free from clay, loam or other foreign mat -- ine whether resent, rub a mp sand beigers. If your dirty, you d is also dirty, ^of determining ^a bottle with an nt of sand and iy or loam sediy, will come to a short while. Each grain of sand should be cemented to grains on all sides of it. When the proportion of sand to plaster is too great, the sand grains are not properly cemented and a weak wall results. Um of extremely flee sand Inadvisable It is not advisable to use extremely fine sand, even though It ^^proportioned correctly' by* weight " Fine sand makes a smooth-look ing mortar which works well under the trowel, but it re sults in a soft wall. The Am erican Society for Testing Materials permits 5% of properly graded plaster sand to pass a 100-mesh screen, but no more! Well graded, coarse sand is best it makes a good, hard wall. Ight of sand varies accoto the grade and the Int of moisture each conts^Sre. Different grades have been known to vary in weight as much as 25 lbs. per cubic foot; and in mois ture content as much as 3 to 6%. This makes it prac tically impossible to propor tion sand and plaster by weight with minute accur acy. The following method is recommended as being ac curate and practical under most conditions. Shovel Is Convenient Unit of Measurement The simplest way of see ing that you get the correct proportions is to measure the amount of sand to be used with a shovel. Just re member that a new No. 2 shovel holds about 15 pound of sand; a No. 3 shovel holds about 18 pounds of sand; and a No. 4 shovel holds about 20 pounds of sand. 1 Fine sand covers too much area . Investigation of the sur face area covered by fine and coarse sands gives us a clearer picture of this. Sand l which will pass through a 48-mesh screen has a surface area of 5,460 square inches I per pound. That is approxi mately one-half the surface area covered by a fine grade of sand such as will pass ' through a 100-mesh screen. From this you can see why fine sands require an | additional amount of plaster to cement the large number of grains together; or, why k the amount of sand you use " may be decreased when it is fine. A well-graded sand . complying with A. S. T. M. specifications has a surface area of approximately 4.000 *. square inches per pound. | . If gypsum plaster is sandi ed 2 to 1 by weight, one pound of gypsum will prop- i rly cement 8.000 square inches of sand as recom- , mended for use by the A. S. i" T.M., and make a good, hard wall. If a pound of gypsum, 2. however, is required to ce ment 15.000 or 24.000 square inches of fine sand, you can see what will happen. To get correct proportions of two parts of sand to one part of plaster, you can use thirteen No. 2 shovels or ten No. 4 shovels of proper grade sand to a 100 pound bag of plaster. Occasionally, plas terers misinterpret these specifications, believing them to mean two shovels of sand to one shovel of plaster. Understand, this is a proportion of 2 to 1 by weight. Be Wary of Excess Sand For your own protection, stay away from the use of excess amounts of sand. Sometimes a wall which is slightly over-sanded will Tensile strength of plaster de creases with addition of sand. stand up reasonably well, but if the same wall were subjected to slow-drying conditions it would probab ly be a complete failure. Chart Proves Effect of Sand ' on Tensile Strength Chicago. Illinois, for their book, "The ABC's of Plas were subjected to the scratch test. A steel point The chart shows that hard wall plaster sanded 2 to 1 by weight has a tensile strength of approximately tering," shows what hap pens to the strength of a wall when plaster is mixed with sand in various proportions. Loaded with a 22 lb. weight was drawn across the sur face of each panel at a uni form rate of speed. 175 pounds per square inch. That is, one square inch of plaster will support 175 lbs., the weight of a good sized man, without breaking. The same material sanded 4 to 1 has a tensile strength of on ly 70 pounds per square inch. The weight of a small boy will tear it apart. We re commend that you choose a good quality of sand; see that it is properly graded; 1 pan gypsum plaster to 4 parts sand, 1 pan gypsum plaster to 9 parts sand, 1 pan gypsum plas ter to 6 pans sand. and use it in the recom It is common practice to The depth and width of mended proportions. scratch a plastered wall with each scratch panel were in Scratch T$t Proves Value of Correct Sanding a sharp point, such as a nail fluenced by the amount of or key, to determine the sand present in the plaster. quality of the plaster. The The greater the sand con This interesting series of Gypsum Association "used tent, the greater the depth photographs developed by somewhat the same method. and the width of the scratch the Gypsum Association of Six mixes of plaster, --and the weaker the wall! Its Easy to Choose The RIGHT Plaster.: Base When You Know Rocklath U on ideal plaster base! lust leek at its features. Only tide type of plaster base provides all el them. 1. fin protection ---mads oi gypsum reck. L Strong -- mere rigid walls. 4. Excellent plaster bond -- six pouods per square inch. 1 Mere crack resist. aot-Hie expansion or contraction at loth. 9. * Permanent--not affected by time, decay, ver min or moisture. 6. Quickly erected--can be scored and broken requires fewer ""jl* 7. Fewer piaster droppings more euctioa in Rocklath, a Leek to Perforated Bocklatb ter these extras: INCREASED PLASTER BONDI The perfora tions provide a mechanical plaster key which holds plaster in a double grip. INCREASED FIRE PROTECTION! Vt inch of piaster ever % inch Perforated Reddath gives the wall a better than 1 hour Bre rating. INCREASED OVERALL WALL STRENGTH! Large 16x32" or 46" panels provide extra rigid supports for frames. Perforations increase strength. AS the advantages of Plain Rocklath -- plus insulation! Insulating Rocklath is the only type of Braproof insulating plaster base avail able at tow cost Use it on outside walls. It provides eflective resistance to summer hoot and winter cold. Insulating Reddath, properly applied, has Insulating efficiency equal to that of ineh of beard term insulation in ass. A moisture barrier, tool Insulating Rockiatb bas been proved by tests to be a better mois ture barrier than glossy asphalt paper. Know ell three kinds of Rochletb -- where they fit -- where they'll do you end your cus tomers the most good. See your loeel USG building deeler for information or write direct to the United States Gypsum Company--where research builds better, safer building meterials. _ BB005 001 Pat* * RED TOPICS. JUNE 14. 1941 414% INCREASE IN USE OF GYPSUM LATH IN 13 YEARS Each year the swing to gypsum lath increases. In 1940 U. S. Government figures indicate tb x 1,461,439,000 sq. ft. of gypsum lath were sold. This amounts to a 414% increase jX\l928 when 284,440,741 sq. ft. were sold. Even the latter is quite a siz able fouU^^pu'll admit. fCeertnssed frmm Papa )) Plaster Finish Protected Against Structural Movements Apply one in one corner of room. Follow with full panels of Rocklath until you? reach the far etui of the ing. Then applv the other halt. ' mArta/< W/V/&M/V& /SMS Seuara fra* ef a: Orpna talk aaldR During almost the same 1,600,000,000 -- J In 1930 wood ,100,000,000 ft err j__ j_ ~i r 900,000,000 TOC, 1X0,000 J Itto IPet i 10 11 ax IP90 1ftsa ift34 1S 1M IP ST 130 19 3P IP Graph Shows swing to gypsum lath. Here is convincing proof from cracks that fire proof Rocklath makes pos* How Su||tr System coaytni wid Standard mstkod of application. The second course is ap plied with full size sheets of Rocklath as shown. The joints fall halfway between the joints of the course on either side. Follow this pro cedure. breaking end joints for each successive course. Continuous vertical joints are covered with metal lath. 1 Clean, White Color ^ It pvt* a weE-leoHnp finish coat on a watt--the kind that make* jm wsst _ tc point whh pride. ' 4 Smooth,Easy Working I set a kiek out of trowolinp fat, - r rich, UW Ron potty. It pee* --g * tmooth cod oeay -- Rke soft boWorTW 3f Excellent Coverage!' lay, dee* H spread ovtl I wre pot plenty "mile* to the feBoo" wHhj^ | U$e time. ^ Them feetvre* end more are ahray*^ foend in Rnbhinp Ume made by :4Bk ( USG Rnbhinp Lime ii made by^ U S 6 from cerafuRy selected, eoh - { formly homed reek. The entire i fectvrinp proceei b under the k need in Lime production. If* j*dj eMother nsemple ef the lheumphea**j of US research which for over * yean he* been mekinp better, i boildinp materiel*. t Mad, b, UNITED STATES aYl SUM COMPANY -- k~. M | meko* better, safer bnfidinp mete RED TOPICS, JUNK 14, 1941 P| 7 Lather Demons rates Flexibility. Quick Application oi NEW CORNER READ "Job" Picture* Prove Adaptability of Red Top No. 4-A Flexible Corner Bead Expert "bead" men like the flexibility and all-around features of the Red Top No. 4-A Flexible Corner Bead. This dual purpose bead can be formed to fit any degree of curvature or can be used on straight corner or bead work. Follow Mr. Fred Davies, one of the ace "bead" men on the crew of Lathing Con tractor Herman C. Frey, through this interesting se ries of actual job pictures. They were taken in a charm ing home built by Mr. A. W. Ehrhart on Chicago's far south side. David David son is the plastering con tractor. A jdat a made by xaeerciag a wicb the heed cut off batweea the two MCtioaa of Conor Bead. Edge* ere cboa crimped together, that "weldiag" tbo two MCtioaa into oao cocure An S peaay fiaiduag anil ia jmac right for tKi pai'guee. Tlia irch or uf dar cm be "beaded" qvkklf with Red Tp Ns. 4-A Flexible Comr Bead. Th* 1--d ia formed to cemnn dwiwd by nippia| mm aid* of fleage only ef mecel -- aad beading Co fit. Il goon up qwickly! On# ceatiaoova piece of Rod Top No. 4-A Flexible Conor Bead waa need to form the right ado of the arch. Loft half of arch it ready for aailiog aad tpliriag ta right tida of arch. ; _ .' 1st Little Boy: "YVe're putting rubber ceilings in our house. . 2nd Little Boy: "What's the idea?" 1st Little Boy: "So when mama gets mad and hits the ceiling, all shell do is bounce around." -- (Editor's Note: Someone ought to tell them about USG Resilient Plastering Systems.) Hcrc'i Rxml Flexibility! Fieribla Conor Bead* toko both the thorp cam of telepheae riche end the every day acraighc corner aad bead work ia acrida. See how cerefally Bead ia leveled before aoiliag. Flatterer* have jaac applied the ecraccb coot co the arch. The 79* eagle of Fierihie Conor Beedt provide ample pUacor grenade -- balpe pUnaftn to give keaaa ewaar* the baaacifaUy plaacerad meden archea they treat. * RedTopNo. 4A *ffexi/e Comerdead SHARP CURVES* Ht. ORDINARY CURVES STRAIGHT CORNER AND BEAD WORK BB005 0020 Want 4 flexible corner heed that fits any curve--one that can also be used for straight comer and bead work? Cheek these features against the comer beet! you ere now using! 1. Dual Purpose Bead. Can be bent to curvature desired or can be used on straight corner and bead work. 2. Only one side of flange need be cut. Faster operation because lather's snips cut only 3/8' of metal. 3. Definite designed bending points to assure a smooth even bend without "kinks." 4. Full 1ft' flanre. Larger than most other "beads" of this type for quicker more secure application. 5. H' nail holes. Right sise for nails generally used on "bead" work. No "loose" nailing or nailing through steel. 9. Made of 29 gauge, soft, annealed, gal vanised steel. 7. Available in stock lengths: 9, 7, 8, 9, 10 and 12 ft. 8. Patched 10 pieces to the bundle, in crates containing approximately 600 lineal feet. Ask to see the new Sad Top 4-A Flex ible Corner Bead! Plasterers everywhere are turning to this latest product of USG Research. It baa exclusive features not found in any other corner beau!! See your local USG Building material dealer now or write direct to United States Gypeum Company, 300 W. Adams St, Chicago, 111-, -- where research builds better, safer building materials. % Page a RCD TOPICS, JUNK 14. 1941 -C Style Note Madame Wears "Wei Plaster" This Season There is glamour in plas ter after all. Sak's Fifth Avenue with fashionable shops in New York and Chi cago think so. They've just introduced ``wet plaster" a brand new color to them which is alluringly described as "a completely new gray." Men's fashions aren't be ing neglected, however. The Baskin Stores of Chicago have also announced a "new?" color. It's called "wet sand". After this aus picious beginning, it would not surprise us at all to run across "Lime Finish White" or some other such color in our fashionable shops. You cant make a Profit QUESTION -- Why not use screened neat plaster for gauging in lime putty instead of gauging plaster? Why does the brown and white coat pop off Rockiath nail heads occasionally? C. J-H. Warren, Ohio. ANSWER--We do not recommend the use of screened neat plaster for gauging in lime putty instead of gauging plaster. In recent years our Red Top Gypsum Plaster has been greatly unproved in many ways, one of the improvements being a much finer ground ma terial. This fine grinding increases plasticity, ease of application and coverage. Naturally, ooe of the re quisites of a gauging plaster when used with lime putty is a coarse grind and quick soak. You can see, therefore, that die base coat plas ter made today would be much harder to mix with lime putty. 1 know that you can obtain the very best results by using our Red Top Gauging Plaster, which can be ob tained in either quick set or slow set and which is made especially for use with lime putty. You are not the only one who is occasionally troubled with plas ter popping off Rockiath nail heads. After investigating many such cases, we find that the prim ary cause of this is the nail heads are not driven home or properly anchored--thus they work loose. We also have found that the best results are obtained by using blued Rockiath nails, \V%m long with a head. A thin coat of plaster plus lumber movement also con tribute to plaster popping over nail heads. QUESTION - After a bouse is lathed, 1 know a contractor who runs s saw through those sections of Rockiath which are butted to aether tightly. What is this done tor? When using Rockiath should you leave joints open or drive them together? When you plaster a bathroom, what can be done to stop the plaster, after white coated, from cracking or shrinking away from the bathtub? I. W. D. Washingtonville, Ohio ANSWER--The contractor who ran a saw between the Rockiath ends, evidently believes that the mechan ical key is necessary for satisfac tory bond. There is really do need for leaving a space between the Rockiath ends, as thousands of small pores in the Rockiath sur face insure adequate bond with the plaster. However, it is optional with the user whether joints are close butted, or separated up to M about Y+ inch. If a mechanical 4bond is desired. Perforated Rock- lath will answer your purpose much better. Your last question is particular : t ly interesting is it happens in so many cases. The plaster does not shrink away from the bathtub, but the bathtub settles away from the plaster. It must also be taken into consideration chat a bathtub, being made of a material that has a co efficient of expansion and contrac tion, is greatly affected by use. #For instance, a bathtub is quite cold sod when someone pieces hot water into it, the tub expands. 1 Therefore, it either forces the plas ter up or the bathtub down. As soon ts it is cool again shrinkage occurs, leaving a crack between the tub and the wall area. The main feature in this type of com plaint is that the crack allows mois ture to get in behind the finish, and if the base coat consists of gypsum, the moisture attacks it and causes a sweat-out or rotting condition. Caulking compound forced into (he opening may solve your trouble. QUESTION - Would you advise ' putting a hard finish coat on an old hair mortar ceiling, which has been scratched? ) s. Providence, R. I. t ANSWER--If the old hair mortar ceiling to which you refer is dean, free from cracks, of good strength, a hard finish can satis factorily be applied. However, if any of these conditions are not satisfactory, we recommend that the base coat be removed and replaced. i What are your questions on lath ing and plastering? You will re ceive a dollar for eadi one pub lished. Send them to the ediror. Red Topics, 500 W. Adams St., Chicago, III. if. LASTER droppings are waste! Discourage chem! P Use USG 4-Mesh Z Rib Lath! Its smaller mesh openings provide excellent plaster keys -- greatly reduce plaster droppings! 4-Mesh Z Rib Lath is flexible! It bends around curved surfaces. Yet it has sufficient rigidity to prevent bagging under trowel pressure. Its smooth, tight laps allow easy troweling. Tie it or nail it! Sheets are 27 inches wide and 96 inches long to facilitate easy handling. mfc oi 4-mtOt 2 SJb Lwh. Now Ml fcliHg and wniap. This popular metal lath works wonders on both curved and straight surfaces. Ask your USG build ing material dealer or write direct to us. Made by -- UNITED STATES GYPSUM COM PANY -- where research develops better, safer building materials. . .. o o IS) [g] laL 3 Rc. 3 USGRED/ A NATIONAL JOURNAL OF Ctmap, FrWvjr, Jsgvst IS, 1941 | TOPICS LATHING AND PLASTERING feMshttf Sr (JmM Slabs 6rfnwi Ca. StmUmi 4SJM NOUNCING! NEW..IMPROVEOSG HYDRATED FINISH LINE -Story oi Pay* 3- How to Select Lime for New Building Needs Story i Pajt 2 - | HOW THE LATHING AND PLASTERING CRAFTSMEN OF TOMORROW LEARN THEIR TRADES TODAY! Lathing apprentices at work on a dome ceiling in the shops of the Washburne Trade School. They receive expert instructions in the basic requirements of their craft. 'the Washburne Trade School, Chicago, Illinois, plastering apprentices are thoroughly Ceiling completed l Projects are built to scale because of space lio Gnd"Ur' "thrir "ta"inOT"*' TM * f* - '*-* p--**-- * inv|vri ' - (Turn to poge 6 for complete story) remain the same regardless of the sile of the job. ree 1 RED TOPICS* AUGUST IS, 1941 How to Select the Best Lime HOW LIME IS MADE Limestone for Faster Building Needs Most of us are familiar with lime as a building product. For centuries it has served as an essential material for walls, both as a plaster and as a mortar for masonry. (High calcium, CaCOs or Dolomitic, CaCOa. MgCOsj T Heat (wood, coal or gas) As plasterers, it is interesting to know that the use of lime for finishing walls Quicklime ante-dates its use as a mortar for masonry by many centuries, however. From the (Lump, crushed, pebble, finely ground, pulverized) pages of history we learn that some 10,000 years ago the early Egyptians plas tered the walls of their mon umental pyramids with lime and gypsum. It was not un til the middle ages, centur ies later, that cathedrals and fortresses were erected with straight lime mortars, and they represent the first size able structures erected in which straight lime was used for masonry. During the long period from the first use of lime until the beginning of the 20th century there was lit tle improvement in limes, Encouraged by the suc cess of hydrated lime, re search workers continued their studies and, since then, other improvements have been made in quicklime products, as well as the de velopment of other new ma terials. As a result, plasterers now have a choice of a number of types of lime for their work and a thorough under standing, of the properties of each is desirable in order to obtain the best results at the lowest possible cost. Quicklime except in the methods of ca& While lump quicklime is which the younger genera tion of plasters readily ad mit-- if the putty is prop erly prepared. These younger students of the plastering business contend, however, that the extremely high plasticity of quicklime putty is sometimes a disad vantage under present building conditions; that on present plaster bases it is too plastic, making it neces sary to add ground stone or sand to reduce suction re sistance and, in any case, to use more gauging plaster than is commonly used with hydrated lime. Hydration Steair Pressure Hydrate | Water [Regular Hydrate] Regrinding and Classifying USG Hydrate! finishing Limn US6 Mom Hydrated limn Red Top Ivory Grand Prim Cheshire PUstimex Snow Drift Marble Rock cining, or burning the lime- too well known to old timers They also contend that it A Uiar lioM far m _ from this directory ml . is impossible to be sure of U S G pndacu. Ckmek thmm far ywr aaada taday. the quality of the product; that because it deteriorates rapidly in dealers' ware houses they cannot be sure of a uniform, dependable quality. Other objections they raise to lump lime is that it is more dangerous for work men to handle; that it may be unsound and cause swel ling in masonry walls if slaked an insufficient period or, if used in white coats, it may develop "pops" and "pits'* over a period of from long periods without losing any of their quality; and they are easier for laborers to handle. In using these improved quicklimes it is necessary to remember at alt time that in order to get satisfactory results the putty must be prepared properly. By fol lowing a few simple rules good results are far more certain than with the older quicklimes having variable activity. The following sug gestions explain the best but this is not absolutel'y-s3^. necessary and should be I * done with discretion. '-"*21 2. Add the pulverized quick- Y lime to the water as ; k rapidly as possible. If % two men are available ? one should add the lime * and the other should hoe. * Whatever system is used it is important that thor- j.' ough agitation be given 1* the lime and water dur- 4 ing the slaking and boil- ~ ing period. ( a few months up to 20 years; practice: 3. The putty should stand that it may be "burned" on 1. First place the proper for 24 hours before us brlf la stone. Lump lime was slaked and aged for several weeks in the plastering business to need description, many of slaking by using too little water, particularly if the ma terial is very active; or that it may be drowned by using too much water. Newer Quicklimes amount of water in the slaking box. This amount is usually stated in the directions that come on ing, giving it plenty of ^ time to cool thoroughly. _ 4. Protect the putty box Jf from contamination. ' - - 1 iT or months. That was before those who have started in Most of these advantages penalty clauses in building the last generation are less and disadvantages of lump contracts were thought of, familiar with it since they lime apply to the other and before speed in con have found the newer lime forms of quicklime, too, ex struction and simplification products most satisfactory cept for the finely ground of the job of building be for their needs. Those who or pulverized quicklimes. came a universal require still use it insist that it is While they apply to fine ment. most economical because of grain limes, crushed limes, Late in the last century its high putty yield. They pebble limes or granular chemists and research work point to the fact that high limes, the more recently de ers made the first major im calcium quicklime gives a veloped pulverized limes provement in this grand- putty yield from 80 to 90 have all of the advantages daddy of building materials cubic feet per ton and that of the older quicklimes with when they developed hy dolomitic quicklime yields out their disadvantages. In A large laboratory mmd a ihilUJ Niff mi tlmim cWck eba qaality mi drated lime. The obvious ad from 55 to 60 cubic feet per other words, the danger of tba it way my mi tba if. vantages of this discovery ton, while hydrated limes pops and pits is eliminated; the package. If the la Hydrated Lime made the new product an immediate favorite and, in the fifty odd years since it was first introduced, it has enjoyed wide usage. give only from 40 to 45 cu bic feet per ton. These quicklime enthusi asts also boast of the high plasticity of their putty, soaking time is reduced to a maximum of 24 hours; packed in moisture-proof paper bags, they may be stored for comparatively borer is not entirely fam iliar with the product it is desirable to withhold some water to add during the slaking operation. Hydrated finishing limes natural! v were popular as soon as they were intro duced, for they speeded the plastering process and elim I 4 iaic mt kiln* at cka Gwot, Okie plant of tka U. S. Gypcum Company, kenaa f USG, Rad Tap, Ivary and Grand Prise linn*. inated the long periods pre- - _ viously required on all jobs for slaking. Limes from _*! northwestern Ohio were pre- isK ferred from the start and Ihave been a standard white coat material since hydrated limes were first introduced. That is because the plas ticity of limes from this area is well adj'usted to the uni versally used gypsum plaster bases. They spread, lay I 4 i down well, and resist check 4ing without having the tend ency to blister that we often find in high calcium lime putties. (Continued on pafe 7. col. 1) i MD TOPICS, AUGUST 15. 1*41 Pan 3 When a mixer is used, a Patching SENSATIONAL NEW FINISH LIME DEVELOPED screen of suitable size openings Plasterers have iound USG should be placed on the box be Hydrate exceptionally good for BY JOD AND LADORATQRY TESTS fore the mixer is dumped. This patching. For work of this step is insurance against inade character, a small mixing box is quate mixing. used. In larger rooms, the mix HOW__Ho. Soikinj -- II S <5 Hydrated Finishing Lime Meets Rigid Government Speci fications -- Eliminates Expansion of -Finish Coat -- Reduces Check Cracking! Here's new and exciting information for plasterers! USG's New Hydrated Finish ing Lime is sensationally different from any other hydrated finishing lime ever devel oped. It's the first finishing lime which has been improved, basically, in 30 years. Here's what you want to know about it. USG Hydrated Finishing Umc tents of the bags by placing the and dry hydrate, mix it thor open end on the bottom of the oughly. and deliver it to the fin box in the water and withdraw ishers. In less than 10 minutes Hand Mixing On other jobs where machine mixing is not used, some plaster ers find it most satisfactory to distribute the bags of U S G Hy drated Finishing Lime at con venient mixing points. A mix ing box is then shifted from point to point. This reduces droppings of lime putty around ing may be done right in the room. In hotels, apartments, or jobs where rooms are small, the mixing box may be used in an adjacent room, or in the halls. At most, tt is only necessary to carry the putty a few feet, while with other types of finishing limes, exceptional care is neces sary to avoid having putty drop pings atl over the job. ra ... requires no soaking! It mixes Jr with water, either cold or warm, * much faster than ordinary hyirate. It can be used immedi ately upon wetting and because ing the bag immediately. When the required amount of lime has been dumped, allow the lime to "wet" for about 15 minutes. Then hoe to the desired consistency. after the laborer picks up a bag of dry USG Hydrate, he can deliver to the plasterer the sweet est-working putty he has ever cut with a trowel. the job, and saves the laborer some work since he does not have to carry water (in the form of putty) as far as on the cen tral mixed job. Proud Mother: "Yes, he is a year old now, and he has been walking since he was eight months old." Bored Visitor: "Really? He must be awfully tired." w of this, it can be applied . . . The mix will keep the consis 12 hours or a full working day tency you desire. When gauged ^ sooner than other finishing limes. it won't become "soupy" or HOW TO MIX USG HYDRATED FINISHING LIMEP As a result, fewer mixing boxes "buck up." and other equipment are re- --`-Vqutred. ' IM ... requires me special bundling! Bpr-'The lime is dumped directly into ^ - the water-filled mixing box, If, for some reason, overnight soaking is desired, that, too, can be accomplished without all the fuss and bother you are going through now. Have you ever mixed finishing lime? Try this simple, three-step method on your next job. See how it compares with old- fashioned overnight soaking. You'll be convinced of its superiority and simplicity. .shortening preparation time im\ measurably. There is also a re - duced dost problem in handling. " doesn't become "sompf -- ' doesn't "back up" ufter gouging _ piaster is added. Once ready to apply its consistency remains unchanged. I ... meets ell proposed or existixg When the required amount of lime has been emptied into the mixing box, merely level the top and leave as is I The sim plified handling procedure, made possible by using USG Hydrat ed Finishing Lime, results in fewer boxes, less dust, less muss and a shorter preparation time. `l-l ^Government specifications requiring ^.92% oxide hydration in dolonutic h finishing limes. . . . . ottoias its plasticity whether -mixed for immediate use or soaked overnight -- as preferred. . . . requires lest trowelings. It gives splendid coverage, makes thin , met coats possible. It won't slow op troweling. There is no change in gaug ing procedure or quantities with the new USG Hydrated Finish ing Lime. Add one part of dry gauging to three parts of U S G Lime putty by volume; or to each !2-quart pail of putty add two quarts of water and take up all ot the water with gauging plaster. Blend the gauging with putty to a uniform smooth mix. Apply in the customary manner. Empty ewtwti of iia i bag by placing the Open cad in the water a the bottom of the box u in photograph *t left. Withdraw bog immodiatoly u abowa at right. . can be tempered! If the mix i j is too thin, dry lime can be add'~-cd without additional overnight "-soaking and without any change -in the working qualities of the "s putty; if too stiff, water can be dded easily. Other Types of Hydreted Finishing Limes Involve Extensive Preparations, Extra Equipment and Extra Labor, as Compared with . givet a smooth, satiny sur " ` 1 emth lets imperfections. The ^surface is freer from "cat faces." r ^,, ... redacts check tracking by re"hr sisting the suction or shrinkage jof hone dry base coats. ... siimiaales completely any or * all chaucet for wall or ceiling exfrpamsitm cracks due to incomplete of the lime. This is s reason for proposed Governnt specifications requiring 92% kydratioo. * - msnrtt freedom from pits "pops." USG Finishing Hydrate . You know what a job it is to prepare other finishing limes. Lime must always be carefully sifted into the soaking box. If lumpy, screening is necessary. On windy days the lime may blow all over the job, or dust, dirt and sand may find their way into the lime white it is being sifted into the box. With the new USG Hydrated Fin ishing Lime, you place the bags on the bottom of the box in the water, and empty. No screen ing into water is necessary. To allow Kao to got < mpleteJy wot, wait 11 miaacot aftar late bag it emptiad. Then hot tha Iia* ta tba dot!rod ceatittaacy, *di ganging planar aad am. Screening of potty throagh H* to H* math tenon it rocoainwadtd for boot retalts. ver will there be loss of v'x time on jobs, as the Oear'of running out of putty and ptnof to wait for an additional : overnight is elim- ISG Rcvolirtionini the for Npiriif , lD about your ideas of iThmI labor necessary to gpepa** lime for the finish coat. VithTJ S G Hydrated Finishing a 1, 2, 3 proposition. __ ng box with about gallons of water for each bag of lime. Empty the con USG Hydrated "On the Job" Now let's see how this new finishing lime works out on the job. Suppose you have the plas tering contract for a store build ing. You are going to use a mixer for the plaster. Ordinar ily you would haul soaking boxes to the job, find a convenient place for them, and schedule the soak ing as closely as possible to the progress of the plasterers. With the new USG Hydrate, you have it delivered to the job. Then, whenever a supply of fin ishing putty is needed, you clean out the mixer, dump in water If overnight toakiag it deetred, hoeing ie anneceeeary. Merely level off t hat been dumped end leave ee it. the required am r9 4 KID TOPICS, AUGUST 19. 1*41 Here's What Plastering Contractors Say About USG Hydrated Finishing Lime Plastering contractors like the new and improved USG Hydrated Finishing Lime. It has features no other finish ing lime has ever had. Here's what they say about it: E. A. Vitzberger Plastering Coap&ny Plain A Ornamental Plastering Builders of Peraa Stone Akron, Ohio United States Gypsua Coopany, 300 Vest Adams Street, Chicago, Illinois. Gentlemen: In the past years we have used all brands of Ohio Hydrated Finishing Uses. We have had trouble of some kind or other with all brands until we started using the new USG Hydrated Finishing Line. As yet, we have not one complaint from our foremen or the men on the scaffold. Ve have been using USG Hydrated Finishing Lime exclusively for the past 16 months, and we must say that in the past we have not found its equal. As the shrink ages are not so great as other limes we get practically no check cracks, a good free spread and it works cool at all times, even with only a one-hour soak. Ve used this lime on Elizabeth Park and Edgewood Park Housing Projects. Vith the large number of men we had working and the limited amount of space we had on these projects to work in, we do not see how ve would have kept enough line soaked ahead vith the old type of lime.' Thanks to USG quick soak Hydrated Lime, these Jobs were a cinch. . Very truly yours, EAV:EHV " (signed) E. A. WITZBERGER FROM ROCKFORD ILLINOIS Charles Shugars, RR 04, Guilford Road, Rockford, Illinois. United States Gypsum Company, 300 Vest Adams Street, Chicago, Illinois. Gentlemen: For the first time in my long plastering experience, I feel that I can place ay full confidence in a finishing lime. Vben I use USG Hydrated Finishing Lime, I know that it goes on the walls to stay. There is no fear of lime hydrating on the walls and ruining the white coat at some later date. It's swell to know that I can promise high quality Jobs to prospects and know that I can fulfill these promises. I had been wondering when finishing lime would be improved. The last few years have seen improvements in lath and plastering materials. It*s about time some thing was done to improve the finish coat material -- the one part of our product that the customer sees. It's often the only way by which he can Judge our work. I have talked to painters who have painted over some of the walls ve finish coated with USG Hydrated Finishing Lime. They tell me that there is no evidence of burned decorations, pitting, or popping. You can see why I'm sold on it. Yours very truly. (Signed) CHARLES SHUGARS FROM B. H. Copeland Plastering BENTON HARBOR Contractor, MICHIGAN Benton Harbor, Michigan United States Gypsum Company, 300 Vest Adams Street, Chioago, Illinois. Gentlemen: My experiences with USG products in the past 26 years of continuous contracting have been very inter esting. I have noted many improvements in the working qualities of Red Top Plaster and Lime which have worked to the advantage of the owner and the plastering contractor. New USG Hydrated Finishing Ll< has el.en xcllant p,rfnrni..r. imHif all conditions -- In hot ar cold weather. Generally we soak this lime overnight, but many times we are caught short and must soak up a few bags to use immediately. Really, I am surprised at its good working qualities under these conditions. Ve never could do this with old types of lime. Thanks to USG! They have succeeded in saving us many hours with this improved finishing lime. (Signed) BURT H. COPELAND New Finishing Lime Saves You Time Here's real news for plasterers! The first major improvement in finishing lime in 30 yean. New USG Hydrated Finishing Lime requires no soaking! It speeds up jobs. You can suit work immediately! Mix it as you mix gypsum plaster -- then gauge and apply. If you desire, however, you may still soak it overnight! USG Hydrated Finishing Lime gives you a fat, smooth putty that's easier to apply and finish trowel. Now . . . More Positive Plaster Control This new time-saving lime gives bet ter control over finish coats. It doesn't become "stiff" or "soupy" after gauging plaster is added. Re- maim at consistency wanted--a tailor made finishing lime! 1c is mixed and applied in almost "one motion," when used immediately. There's no worry over long "soaking times" during cold weather; sudden over night frosts; water temperature; moisture and other conditions. When the surface is dry, it is ready to decorate. USG Hydrated Finish ing Lime minimizes the danger of burning or blistering the paint, cal cimine or wallpaper. And when properly gauged, it reduces the pos sibility of check cracking--eliminates the cause of lime pops. For over 40 yean, USG Research has been constantly at work devel oping better, safer building materials with more exclusive features. USG Hydrated Finishing Lime is a good example. It meets all proposed Fed eral Specifications requiring 92% oxide hydration. It has features no other finishing lime has ever had. 5m yemr V S G bntiding dealer today, tr write tie limited States Gyptmm Cempany, )00 'Veit Adams Street, Cbieaga, Illinois where research develops better, safer bntiding materials. 08005 0025 KID TOPICS, AUGUST IS, 1941 Pm A STATEMENT TO THE PLASTERING INDUSTRY N june 26th a strike was called by District 50 O of the G 1. O. at 14 plants of the United States Gypsum Company. We take this opportunity to present the following facts. The C. I. O. demanded that we agree to system, or centralized bargaining, for all our plants, or at least the plants that organization represents. We are ready, now as always, to discuss and bar gain at any time with the representatives of the employees at any individual plant on matters having to do with that plant. But we believe that system bar gaining is unfair to both employees and the company, and that it is also difficult and impractical. Here are the reasons why we have taken this position: Our company manufactures the products of eight separate industries in 42 locations over the country. The 14 plants affected by the present strike are located from Boston to California. Obviously, con ditions in a plant manufacturing roofing are quite different from those in a plant where gypsum plaster is made; and Philadelphia presents problems for workers and management different from those at Fort Dodge, Iowa or Jacksonville, Florida. System bargaining contemplates a master contract dealing with hours, wages, vacation schedules, bar gaining methods, etc., covering a number of different plants and industries in which we operate, regard less of type or location. There would not be (he opportunity to handle special local problems with the speed and individual attention which have con tributed to the high wages, excellent working condi tions and good will that have characterized our relations with our employees. Our position on the subject of system bargaining for our company is directly in line with a recent decision of the National Labor Relations Board. InJune the Board dismissed, after investigation, a petition presented by District 50, G I. O. on March 6th in which this union asked the NLRB to designate it as the system bargaining agent for at least all plants and employees of the company which it represents. The present strike was called after the Labor Board's decision and after the G I. O. demanded that we grant, without opportunity of further dis cussion or negotiation, a flat 10c per hour increase, compulsory arbitration and a revised vacation sched ule for all ofthe 14 plants which it claims to represent. As we view it, this strike was called simply to force the company into system bargaining in spite of the fact that the National Labor Relations Board had already decided against the G I. O.'s petition. We regret that this strike will cause inconvenience to the public and to the building trades, especially at a time when our plants have on hand many orders for army camps, naval bases, munitions plants and defense housing projects. However, under the cir cumstances this situation is an unavoidable one. We want to emphasize that we have the most cor dial good will toward our employees. Their skill and industry have contributed greatly to the high quality and wide public acceptance of the building materials which we manufacture. Therefore, we arc seriously concerned that the working conditions of the men at our plants should be the best possible, and for this reason we are ready at all times to negotiate with the representatives of the employees at aoy plant on its individual problems. UNITED STATES GYPSUM COMPANY 300 WEST ADAMS STREET, CHICAGO, ILLINOIS 00 CO O Q in o o rs o> Pift 110 TOPICS, AUGUST IS, 1941 Where is the Plaster Craftsman ol Tomorrow? Today, the plaster craftsman of tomorrow is an apprentice. Maybe he's working on the job right next to you -- part of the time. But a few days of every month he spends time deep in thought on the plastering problems which have confronted plas terers of every generation._______________________________________ Where is he learning all this? Many of these young craftsmen can be found in excellent trade schools lo cated throughout the coun try. In these schools ex pert instructors in lathing and plastering guide him through the steps necessary to master his chosen craft. The splendid results ob tained through these courses prove their value to the lath ing and plastering trades. and Related Subjects," by Dalton & Carlson for the teaching success he has had. Correet Use of Trowel Taught The use of the plasterer's tools is not neglected, of course. Apprentices are taught uniform, proved methods of application. At plastering trade with the steady flow of young, excel lent timber it needs. Concur ring in this belief are noted Chicago educators like Dr. William H. Johnson, Super intendent of Schools, Mr. Phillip H. McNamee, As sistant Superintendent of Schools and Industrial Co ordinator for the Board of Vocational Schools Perform Valuable Service Some people may ask, "What is the need for vo cational schools? Isn't `job experience' sufficient?" Let's see what happens to an apprentice who enters the Washburne Trade School in Chicago, Illinois -- one of the largest and most com plete vocational schools in the country. What can plast ering i n s t r u ct or Owen Hughes, or lathing instruc tor, Robert Hamilton, teach him that he may not be able to learn on the job? Apprentice Is Well Grounded in Fundamentals The plastering apprentice is taught the line points of his craft from the ground up. First, he is thoroughly schooled in measurements, scale reading and plan read ing. When well versed in the fundamentals, he learns to execute simple drawings, such as common types of arches. From there, he grad ually proceeds to the more difficult oroblems. As each step of each problem is com pleted and approved by the instructor, the student takes it to the shop and constructs it to scale. Fine examples of student work are on exhibi tion there at all times. Each plastering apprentice who comes to Washburne is indentured to the local union for a period of six months or 120 eight-hour working days. This time is spent in class. The apprentice is indentured for the remaining three and one-half years of his aprenticeship to a local contrac tor. During this time, he at tends a class one day a week or four days a month, evenly dividing his time between the shop and the drawing room. I niinnl pUsteriaf arv dwiyi am ukibitiM at i in fUand am the dnviai bwfdi and armd through to completion k the afcopt. the end of six months' train ing, therefore, each one is at once a decided asset to his contractor. Lathers Learn Trade Thoroughly Lathing is taught as the fine art it is at Washburne. Mr. Hamilton's classes plan each job at the drawing board and then assemble it in the shops--to scale. Thus, the many unusual lathing problems presented by our modern architecture can be solved by the apprentice with a minimum of material expense. "Attracted to the lathing craft are men with varied educational backgrounds," said Mr. Hamilton. "Some of them have completed only the eighth grade, while others are college graduates." Both Mr. Hughes and Mr. Hamilton are enthusiastic about their students and the future of vocational schools such as Washburne. It is their belief that the voca tional schools of this country can do much to provide the Education, and Mr. Warren E. Hill, Director of Wash burne Trade School, who are responsible for the fine work done at Washburne. 1st Man: "Your roof must be leaking. Does the roof always leak? 2nd Man: "No -- only when it rains." 1st Man: "Why do you have your front door lead ing nght into the dining room ?" 2nd Man: "So my wife's r e 1 a ti v e s won't have to waste any time." The officer of the day stopped a mess orderly as he was carrying a soup ket tle out of the kitchen. "Here, you," he snapped, "give me a taste of that!" Obediently he was handed a ladle, and he tasted it. "Great Scott! do you call that stuff soup?" he roared. "No, sir," responded the orderly meekly, "That's dish water." Red Top Wood Fiber Plaster is ideal for patch ing, remodeling, and re pairing. For these pur poses. it should, ol course, be used neat (without sand). Just add water-- and apply! Red Top Wood Fiber Plaster contains Just enough wood pulp fiber to give it cohesiveness and to improve its working control that assures the superior working qualities of other Red Top plasters. Wood Fiber Piaster may be used as a base coat for plaster over all stan dard types of lath. For such use. it may be sand ed one-to-one by weight It produces a superior kind of work and satis fies the home owner who is interested in walls above the average in quality. . RED TOP WOOD FIBERPLASTER Brings to the building the good feetvros of gypsum in evon greeter degree then cement plester. 1 . It has greeter resistance to fire. 2. Greeter hardness end well strength. q Eliminates any tend troubles because it requires only wale- to prepare it for application. A It can bo troweled to a smooth finish if desired. See your local building materials dealer or write the United States Gypsum Company, 300 W. Adams Street Chicago. -- where research develop# better, saler building materials. Emphasis Placed an Uncommon Plaster Jobs "Emphasis throughout the course," explained Mr. Hughes, "is placed upon the kind of work which the ap prentice seldom encounters on the job." Often these class assignments offer the apprentice his first oppor tunity to acquaint himself with the more difficult phases of his craft. Mr. Hughes gives much credit to the course text book "Practical Plastering W1THK- 'S -T*11 S Ol L RED TOPICS. AUGUST IS. 1941 HOW TO SELECT THE BEST LIME FOR FAS ER BUILDING NEEDS {CoHlinutd from page 2) up, resulting in a thin, soupy the United States Gypsum Preferred Brands Among the most popular of these limes are Grand Prize, Ivory, and Red Top, the three leading brands manufactured by U. S. Gyp sum Company underthe clos est supervision by the coun try's leading lime experts. These limes have won wide recognition among the best plasterers for their high qual ity & exceptional uniformity. However, these finishing limes with which we have become so familiar for some 30 or more years do have certain disadvantages. For instance, they must be soaked at least 16 hours to give satisfactory results; careless or uneven soaking results in a putty with grainy spots, knots and gen erally variable and unsatis factory working qualities; when soaked in hot weather the putty may tighten up and get grainy; and when soaked in extremely cold weather it may fail to set putty. Plasterers who use these materials constantly know, of course, that the old type hydrated limes reach their best working conditions sooner in the summer than in the winter; in other words, the condition of the putty is dependent on the weather. Since contractors cannot control the weather, it is not uncommon to find that the putty is "out of or der" when it's time, to do the work. As a result, the putty is seldom applied at its best condition. Another disadvantage of the older hydrated finishing limes is that under damp, humid conditions the bags have a tendency to swell, at the same time developing lumps in the lime that do not come out in the putty. Research Rolls Up Its Sleeves Recognizing the fact that further improvements were possible in hydrated limes, Company assigned a staff of research men to the job of finding a lime that would eliminate the delays on the job required for slaking, and that would give the best re sults at all times, regardless of weather, storing of the material and handling. This was no small assign ment, considering the fact that for over 10,000 years builders and plasterers had gone along without finding an ideal form for lime. But the research staff of U S G is used to difficult jobs, and approaches each new task with the firm conviction that a solution can be found. So find it, they have. Revolutionary Discovery The new product is hy drated under pressure -- a process that tests have shown gives to the resulting material more of the ideal characteristics for a finishing lime with none of the dis advantages of the regular method of hydration, nor the disadvantages of the various kinds of quicklimes. Among the superior qual ities that have been demon UNITED STATES GYPSUM GO. MASONS AND FINISHING LIME strated by actual job use of this new U S G Hydrated Finishing Lime are: - 1. Greater plasticity and US Hydrated finishing ? ^ Lima [Pressure Hydrated) LUSGt produced at Genoa, Ohio, r- wramnp ' ~ workability; 2. Soaking is not required (15 minutes after the product is dumped in the Shipped in 50 lb. paper valve bags. |*i mixing box it may be hoed to desired consis tency and used); 3. Neither warm nor cool I inLr 1 IHHIII 1 I u^j"ffl R*0 Tm HydratM Ftmatana bM --cMOMmMme.npiMOcinm.IIMn.p1 MniHiM*mHkWltUmeM--Harr Mr*aM n*M|Uw m Or--* Prim II)trail ruiiuiiuw Dm. OM. kM l CftMhar* ftmHvf QmtW-- Hi* Obi-- pul.ij MHrFaar--.--ilh.UTwee.1BMad USO $<mmPm Hm*M * Mm i QbhMIm HI* Cabl--rnO--*a r--m. m-- aM UFSMGQ(rMpMrMiHMMniMt ta'1* Pam-- M--.--MCMM--* 0 1 j weather affect the qual ity of putty made from it; (In one case a contractor reported that USG Hy drate frozen under ex treme winter conditions, had been thawed out and used with complete sat isfaction) ; 4. Box soaking may be done more rapidly (Best re sults are obtained when the lime is dumped into the water directly from bag without screening); --ca*iK iijfrMit tBl - fm.mUm j IM gs HFMhiMBBM| U|Wm ll MM CM-- --*--* UI0FM Or-- Mmp-iQmUm mD--a*MtMoOeeMrMaM> ** MMIMMM Mau l pBtfcHu 1 mwu MCI 5. It may be mixed with sand for float finish, or with colored pigments or aggregates dry, and used immediaMy after hand or machine mixing with water; 6. Excess amounts of lime liHamrl MeMb SmMtMMmm'* U|tnMt Um mrWirntmN*i--.inM.ae.-.n..M. r.Tp--w" baa lj--i T-- M USO FM OrM JnTi,'ri f1r'einaami,%' M--ale i do not need to be soaked to insure having enough lime for the job. If the job runs short, the proper amount of U S G Hydrate may be mixed and used at once to finish out the 1 |Sm 11 Rtd Tm Mm'1 Hr*Kit Um 0nM--t ahii*(mWtcw--aiMn*----Ci.iM*pi----'e. hulia Miawt i--p0i ittfiiBi %* C-- >n--i Mm* r--r wane job; 7. Small patching jobs are easily handled because small amounts of this putty may be mixed as Marti* M IllOWit Um M CM--. pMiil MMMlWw MMm'iQMAM* MW required; and USG lime putty may be thinned out or thickened kaa**a HW Me as desired without affect ing its working qualities. Immediately upon deter Al tn* of USO Q*Um can be mining the many advantages of this new product the Unit ed States Gypsum Company invested a substantial sum of money in a new plant and nal equipment in order to supply the heavy demand that ob viously would develop. P9 7 Every plasterer knows Diamond Mesh Lath--it's the general utility lath and represents the bulk of all metal lath produced. Red Top "Junior" Diamond Mesh Lath b the same old friend, plus a special feature that saves about 25% on plaster on the scratch coat. The important feature of "Junior** Diamond Mesh-- is its small mesh openings--about 11,000 to the square yard. These small mesh openings provide an ample plaster key, yet keep plaster from pushing through ft) cause waste and excessive droppings on the back side. "Junior" Diamond Mesh Lath sheets are sufficiently rigid for ordinary residential stud spacing, but are abo flexible enough to permit their use for all sorts of ornamental work. So/e /he keying qualities of ''junior" Diamond Mesh me/ai U/h--nn plaster waste, no excessive bumps or droppings. UNITED STATES GYPSUM COMPANY, JSO W. Adam* Straat, Chicago, ITUaoti- -whara n March davatopa battar m(*t bwldiag oiatariala. BB005 0028 pate a REO TOPICS. AUGUST IS. 1941 STRANGE AS IT SEEMS......................................................................by John Hix Good plasterers and good plasters leave little chance for job troubles that are the fault of either. The difficulty is that buildings near ly always have some after movement -- the natural movement of framing members. This is often the cause of ugly plaster cracks. The USG Bridjoint system is mighty cheap in surance against such complaints. With the Bridjoint system, Rocklath joints occur between studs instead of over scuds, thus placing the joint away from the point of greatest strain. These berweeo-stud joints are reinforced bv the Bridjoint clips, which have sufficient nexibility to allow the wall to adjust itself to the normal movement of framing members. Bowed framing members, for example, push, not against a joint, but against an unbroken wall surface char can bend slightly without fracture. The USG Bridjoint plastering system is simple and low in cost. It reduces waste be cause all odd lengths of Rocklath can be used. Equally adaptable with irregular stud spacing. Nailing is not necessary at the end of the boards--25% less nails are required. The cost and the labor of applying comerite is eliminated. You can use the Bridjoint system on jobs of every size. Get acquainted with it--see your building material dealer, or write direct for full information. United States Gypsum Company, 300 West Adams Street, Chicago, Illinois -- where research develops better, safer building materials. *1 tl*. Imdl i*1' !!*!&,""1' ............."....!.. cm*** <9 -P o o o QUESTION -- Will you QUESTION -- Some time please tell me why plaster ago we had a plaster job cracks over Rocklath? If on which the contractor we should brown coat on claimed the plaster would a job and let it stand a not take the proper month or two, and should amount of sand. What it crack, would the white could be the cause for coat fill up these cracks this? Does cream of tartar so they would not crack used for ordinary kitchen any more? use serve as a retarder in I. E. S. Marion, Ohio ANSWER-- Plaster cracks over Rocklath are primar plaster? I have seen it used and have wondered as to its qualities? LP.I ily caused by insufficient thickness of plaster, which will not withstand the normal strain and stresses of building movement. Al ways remember that plas ter should be applied onehalf inch thick or more over Rocklath to grounds. Our Resilient Rocklath System is the best assurance against cracks, if applied accord ing to specifications and assuming the framing and foundation are good. The answer to your sec ond question is that if the base coat is cracked at the time the white coat is ap plied. any continued movement in the building will undoubtedly continue, to crack through the white Arlington, Minn. ANSWER--The plaster you refer to that would not take the proper amount of sand would be called "short-working." This is usually encountered in - * ivery old stock in a plas ter that has been stored in a damp place, either in the warehouse or on the job. You are right that or dinary cream of tartar is sometimes used as a re tarder, although we rec ommend it for use in emergency cases only. iMost plasterers realize that the regular package retarder obtainable from any dealer is much more satisfactory for almost every need. coat. It is, therefore, of QUESTION--Are there any little use to let the brown different kinds of plaster coat stand a month or made for different uses, two before applying the such as for the base coat white coat. and another for the finish UESTION--What is the cause of blisters on hard finished plaster walls? Is there any shrinkage in Plaster of Paris and Hy/ drated Finish Lime? " J. S. S. Jr. Westerly. R. I. ANSWERS -- Blisters on hard finish plaster walls are often caused by the . base coat being too green, / troweling before set takes place, too much water in troweling, and insufficient gauging used in a time putty finish. I am sure that if you take care to I keep away from these con ditions, you will no long t er be troubled with blis ters. By shrinkage in Plaster |lI of Paris and finish lime plaster, we assume you ' . mean small chip cracks. : This condition can be /caused by several reasons. . namely insufficient gaug ing. too slow set gauging and insufficient troweling. ' We recommend one part coat, etc.? If not, is it okay to use one type of ? Red Top for all purposes? R. C N. Rouodley, Montana ANSWER--It is not satis $factory to use one type of Red Top for all purposes. For base coat plaster, we manufacture Red Top Ce ment Plaster, Red Top Sanded Plaster, Red Top Sanded Wood Fibre Plas iter, Red Top Wood Fibre Plaster, and Bondcrete. For prepared finish coat, we manufacture Red Top Trowel Finish, Red Top Sand Float Finish, Keene's Cement and Oriental Stucco, either In V * I terior or Exterior. .- So that you can become familiar with the specific uses of each of these types of plaster, I am sending you, under separate cover, one of our advertising booklets which illustrates and describes each type of plaster that we manufac ture. of gauging plaster to three What are ymir questions on lath- parts of lime putty by int and plastering? You will re ' volume, and if this prac tice is followed, chip cracking *hmili| not <x*rur. ceive a dolUr for each one publish ed. Send them to the editor. Red Topics. 300 W. Adams Street, Chicago. III. tel. 3 K0. 4 USG RED * NATIONAL JOURNAL Of Chicago, Wednesday, October 15, 1941 TOPICS ' LATHING AND PLASTERING Published by United Slates Gypsum Ce. Gradation 49,008 FEATURING in this issue PLASTER RASES Eggers & Higgins, Architects Daugherty & Jennings, Plastering'Contractors Photographs Courtesy National Gallery of Art The m of pUittr far vails sad eoUimgi of tha Natienal Gallery ^ An ii tribote to the txcillMct of this utarial as a <lscnti* median*. Ia this diatinfoished building, which may become the world's greatest arc center, phster tmrro% as a priscipil dstsrativi nudism. The calftrsd dams carries back to tbs Paatbsoa, arelutoctarai mas* taryisce of cho Classic Grecian pa nod, tHs domo of which was ornamented similarly. Simplicity marks the theme of plastered walls, < the Fifteenth Ceetary ItsLisa Roam, reminiscent of the Roaaisaaaco period. Those who admire the pricelem werks of art freqeeacly comment on the artistry of the bschgroond~plattsr. p<l MO TOPICS. OCTOUt IS. 1*41 What Plaster Base In choosing plaster bases, plasterers have two princi pal interests to consider: to give the building owner the best possible job; and to do it at their lowest possible cost. That sounds simple. Thoughtful plasterers, how ever, who have followed re cent developments in plaster bases and systems of appli cation to increase the useful ness of the plastering job, know that their profits will be determined by their abil ity to select and deliver the best value. To do this re quires a thorough knowledge of the advantages and dis advantages of each product. Choice of Plaster Bases Is New It is only in the present gen eration that plasterers have had much choice in plaster bases and systems. Prior to that there were wood lath, Sackett board and metal lath. These, of course, sup plemented masonry, which seems to have, been respon sible for the idea of plaster walls. Early builders real ized the necessity of cover ing rough masonry surfaces -- so developed plaster. Ecoaomy of First Import*ac On most jobs in the resi dential field and in the small er business buildings, econ omy dictated the use of wood lath. On fireproof con struction, metal lath or ma sonry were required. Sackett board was used by some who appreciated the advantages of gypsum plaster and a plaster base that saved the mechanic and eliminated job complaints so common with the quality of wood lath that was available. New Requirements Bring New Methods Then things began to happen. The United States Gypsum Company realized that in order to maintain plaster as the public favorite for interior finish, and to enable plasterers to increase profits, improvements must be made. Green lumber, air conditioning and increased construction speeds were re sulting in serious structural movement. Plaster cracks became more frequent. The public wanted better plaster jobs. But it wouldn't pay a higher price. Rocklath Leads the Way First important develop ment was the introduction of Rocklath. In quick suc cession came Perforated Rocklath, Insulating Rocklath, insulating plaster bases such as Weatherwood, Re silient Systems, Bridjoint, and various other improve ments to help plasterers along the road to greater profits. In the special chart a wide range of plaster bases and systems of application has been carefully analyzed to give a quick, clear picture of the wide possibilities now available to the plastering trade. Add your Experience To Chart Data. To get the greatest value from this chart, however, it is necessary for each plas terer to add to these facts his own personal experience in order to accurately evalu ate each type of wall. Plasterers Endorse Rocklath Most plasterers agree that, when all costs are taken into consideration, such as plas ter savings, reduction of complaints, less frequent dec oration and buyer satisfac tion, Rocklath is the better value. This fact is readily confirmed by noting the ex tensive use that is being made of Rocklath on the lowest cost jobs. Insulation Brings Opportunity The wide demand for in sulation was answered by U S G with the products, Insulating Rocklath, an ex ceptionally low cost insula tion, and special insulation boards such as Weatherwood. With these products, plasterers are given the op portunity to increase their participation in building, adding to their profit possi bilities. Metal lath, of course, is not new. However, improve ments have been made in the product and, by knowing the advantages of the va rious types, plasterers can So cbe plaater crack*! Pi-tore-- kaow tkat ao pU*c*r but will correct Krvccvral fault*, la tko ilhutratioa above, tko crack i* apparently doe to ftructural botwml la moot com* it ia po--ibU to point out to aa owner wboro tko trouble liee what actually coo--d the crack. By explaining to owaora who complain of plaecor crack* tkat ao interior wall fiaiak will eliminate this trouble, plaatorora will increase public apprecia tion of good plastering. save themselves important sums of money. The choice between board type plaster bases or metal lath, in most cases, is based on cost. Whenever possible, most plasterers recommend metal lath because it pro duces the very highest type of plaster job. Reducing Cracks To more closely approach metal lath quality with Rock lath, the Bridjoint System of application was developed. Thismethodeliminates joints at supports, thus minimizing cracking. At comers and ceiling angles the Rocklath is not nailed to the frame work, but is held together with clips, preventing trans mission of stresses from the frame to the lath and plas ter. As a result, for very lit tle more cost than a regular Rocklath application, pos sibility of cracking is sub stantially reduced. Plaster Bases for Sound Insulation Systems Either Rocklath or Metal Lath may be used with the Resilient system. The choice usually is dependent upon cost or code requirements. Masonry walls, such as gypsum or clay tile, have an old and honorable record for quality. Usually their use is dictated by building codes which are based on safety requirements. Masonry and Improved Partition Typos As a light weight, space saving substitute for mason ry, 2-inch solid Metal Lath partitions were developed. However, neither masonry nor solid Metal Lath parti tions provided an economi cal wall for duct and pipe or conduit installations, so Trussteel studs were pro duced to meet this require ment. Sound Insulation Plus The Resilient system, as the name implies, produces a flexibility in the plastered surface. Its three principal advantages arc that it min imizes cracks, eliminates streaking due to "breathing" that occurs between wood lath and joists and studs; and it reduces sound travel through walls. Because of these superior features, it has many applications and sales minded plasterers have earned themselves attractive profits by pointing out to ar chitects and building owners how inexpensively they can Since the subject of plas ter bases dc.-erves the care ful study of every plasterer, detailed information on Rocklath and Metal Lath are given on following pages. A stone mason in conver sation with a carpenter re marked that his father, nine ty years old, was still living and working at his trade as a hod-carrier. "Ninety years old. eh?" said the carpenter. "Yes." "Is his health good?" eliminate objectionable "Tain't much now. He's sound. been complaining for a few Recreation centers are "naturals" for this type of Are you Uftiag extra weight with the platter bate you uw? Few plasterer* realize that ia covering 100 *9. wall. Often corridor walls pda of wood lath with platter they are doing jutt what tbit picture thowr--lifting ea extra thou--ad pound*. and ceilings between floors Thia uanocot--ry tax on your ttrength leea platter. The difference .how* op it eliminated when Rocklath it uaad aa a platter bate becaate it require* ia the profit ledger at well, for the aevin* in material repre--nta low- of multi-story apartments red coete. Rocklath it ao platter hog. can be sob!. .^ months back." "What's the matter with him ?" "I dunno; sometimes I think hod - carrying don't agree with him." O o y i-ti-ls 1$ MONLY USED PLASTER BASES Wi AND MATERIAL REQUIREMENTS nil Bil IPN 'MlcrwH j iifo MmalPwtltlonTblcknuarlffvVjE (Inches) :,ti.'w74ri ' 'f-'ftf icomnended Plistif Ground, (Inches) (From feco of Stud) ^ IPBiffffti IfJpj&PI 111?% ?' : ; pproeimate Weight per AO. fu of Wall (Pound*) !333ITJk SmB*:*'}** If" (Both sides pleetered^tajs Smuj-' $1 ftJJi.. ... .. . (*>: ' ` re Resistance - _ , 3 .- to b. . A t 55 min. (Both sides plastered)' - > a-'l-.t :< 1' . (i) er*ge Sound Transmitetoa Lot* atrou Frequency Rang* , ) i "-7 ' ; 39 0 ;< i.. . . . Perforated \ Rochlath J% i % 13.0 1 hour 39.0 Insulating Rochlath Junior Diamond Mesh Lath 3.4 Lbe. Z-Rlb Maul Lath 3.4 Lbs. Used lor Exterior Wells only. 5% 5% V, V. V. 13.0 16.0 15.0 55 mitt. 1 hour 1 hour 39.0 38.1 38.1 Rocklsth Bridjoint System 5% '/. 13.0 No lest data No data Rochlath Resilient System % i>/. 13.0 Z-Rib Mt*l L*th 3.4 Lb*. Resilient System 5% 1V4 15.0 , Weatherwood Lath 5% 1 Gypsum Tile (3' Thickness) Clay Til* (3' Thickness) 8* Solid Mct*l Lath Partitions Trust!**! Hollow Metal Lath Partition, Z-Rib Metal Lath, 3.4 Lbs. 4: 4*4 Add 1 A* to 8' width of Trusstcel Stud used. `A . % *4' on lath side (Over (ace el (Over lac* of 14' on channel tile) tile) side V* 11.4 80 31 Vi 88 15.3 (Basis 3* site) No test data No test data 30 min. 8 hour* No published test data 1 hour 1 hour 51.9 51.9 No data 37.6 36.4 35.7 No data tateriats Recommended lacddU lion to Lath . i* . -i >. ComeHte (Hod* sontal and vert)* cel coman). fRooc,hMla4tvhkN..'aj)i.l CorneWi* Rochlath Nall (13 ga., 1 *A ' long, H' head). Cornerite Rochlath Nail 03 9a., 1 V lo"9, %' head). Cornerite 6dCommon Nall (8>,long)<wlVh' Roofing Nail. Ilga.Tie Wire. 6dCommonNail (l'long)orl14' Roofing Nail. 18 ga. Tie Wire. Bridfofnt W-SS (field) nd W>33 (Corner) Clips. Rochlath Nail 03 ga., 1A' long, head). Rochlath No. 1 (fleld)and No. t (Corner) Reslllent Clipe. Regular R. L. naiffor attaching clipe. Metal Lath Re silient Clip No. S00 V*' Pencil Rods 18 ga. tie wire. Cornerite 1V4' Blued /' Flat Head Nail. Block**! Cement (Gypsum Plas ter). Spikes or Ties for door bucks. BJbcksei Cement (Gypsum Plas ter). Channel Studs, Lath and Tie Wire Floor and Ceiling Stud Shoes or Runner Tracks Recom mended. Trussteel Studs Runner Track, Lath and Tie Wire Attach ment Shoes. Spe cial Clips also available lor at taching R. L. in lieu of Mete Lath. Lath required per 100 1450 to v< k of wall surface Piece* illii v i <4lMv.H'> 900 sq.ft 900 sq.ft 900 iq. ft 105 sq. yds. 105 sq. yds. 900 sq. ft Rock, lath. 300 Bridjoint Clips. 900 sq. ft. Rock* lath. 400 No. 1 R. L. dip*, S00 No. S R. L. Clip*. 105 sq. yds. Mete! Lath. 675 No.800 Reiillenl Metal Lath Clips. 900 sq. ft. 855 sq. ft. 900 sq. ft. 105 *q, yds. Metal Lath, Channel and Tie Wire (provides lath for both sides of partition). 105 sq. yds Metal Lath, Studs, Track ant Tie Wire. IvaatHvltaUriagMaterial* f IM Iq. 14m. < Wftll (UaMhMrriaiik) : ted TopCcmwtPUler (Pounds) ^ . >ud (Val*$JjjL; (4) Finishing biyfalliuoe (Pounds) fUjI&i Gauging PUUe^PmmA) | 1800 1000 1 i j V, i 1 300 { ISO IsJj ::j. :iso . 1000 1 300 150 1000 1 300 150 1800 1.8 300 150 - 1600 1.6 300 150 1000 1 300 150 1000 300 150 1600 1.6 300 150 1000 1.6 300 ISO 850 1 300 150 1800 1.33 300 150 4800 (S' wall thickness! 4.5 300 150 1600 1.6 300 150 Ktochlath data bind on %' lath thickness, weed Uth thickness, V4'. Wood Stud width, 3%*. ' 4 laboratory tests. Materials properly applied and plastered to recommended plaster grounds on walls with gypsum 00 tOOflflt (3) Flfvnt ar* decibel reductions as determined by awlllltd Uboritory loti on combuction built according to manufacturers' directions. Confirmation by test under ether then laboratory conditions is not guaranteed. (4) in determining these figures one yerd of send wes etsumed to weigh 8700 lbs. It it recognised that send weights ere subject to considerable variation. ID TOPICS. OCTOMft IS. 1*1 t' fiOCXLATH~> P*t* S -M'AOOCLATTf TYPICAL WALL U Naw22cuf> Tk* Aridjoint lyttom for iyflyia| lloekUtk mr wood itvdi, join or fnrriai, wai developed Co iaprovi tba quliiv at plmiriiig job* witko*t iocrnitai co*u ippnciikly. Lom naiUmf u raqoirad and tbo point of waaknoa* of tba vail (tba joint botoaan board*) i* moved from cba and. wbar* atrea* i* great***, to tba cantor of tba apace, wbora atraa* U Ianat. Rocklath ia not aailad at carman *o tbai at tbia critical point tbo aatroao Htaint tbat roaolt witb tba orifinal '`Nail-On*' application arc ^^`nad. Tba boat practica in applying Xocklatb call* for Comariio on alt intarior corner*, corner bond an all exterior corner*. Striplatb taanfarcanaant at window*. antoU, and doora) alao at and joint* of Rocklath on coiling* and langtbwiaa of tba raaw at tba cantor of coiling. Rocklath Fattens the Plasterer's Purse Rocklath is one of our youngest plaster bases. Yet, in the span of a generation, this type of lath has become the most popular. During that period this type of lath has displaced wood lath in most markets and its use continues to expand. Today, in addi* tion to its achievement of almost universally replac ing wood lath, it is also an important factor as a heat insulating material, as sound insulation and fireproofing. The reasons why plaster ers have turned to Rocklath needs little explanation to most contractors. In the first place Rocklath is easier to handle. No splinters are pres ent. Only half the amount of nailing is required. Rock lath is easier to plaster and it requires less plaster. ` Recently a plasterer said. 'Tf there was no other rea son for me to use Rocklath, the fact that I handle over 1.000 pounds more material in plastering 100 sq. yd. of woodfath is enough. I like to work, but when 1 can get a better job with Rocklath and only handle 4,000 pounds of material in a day, why should I use a plaster base that re quires me to handle 5,000 lbs. of material in order to get the same results?" Lower Cost While plasterers quite generally appreciate the labor they are saved by handling Rocklath, shrewd contractors think of this ma terial saving as money in their pocket, and these com bined reasons probably are the principal ones which ac count for rapid increase in ioiTw v'/T'ESE?! the Rocklath popularity. Quickly summarized these advantages are that: it makes the plasterer's job easier it saves money it produces a better job and it eliminated many troubles for plasterers such as lath buckles, staining from pitch, re sin or gum, shrinkage and poor bond. When Rocklath was intro duced as a low-cost improve ment over Sackett Board it soon earned the reputation of being the most foolproof plaster base ever to be mar keted. Only two directions seemed necessary: Break vertical joints, and nail to studs or joists at 4 inch in tervals. Later a third rule was added: Use a full half inch of plaster. This was TYPICAL WALL Na.4 C*p---* MO-4 CLXP Fbi- rtjnrai^aW riMk Rocklath may b* *nf witb tba Rariliant System mr wori jeaata, atvda, t*d furring, trtr maaory base, r witk ipvcul eta*] partition tanatrxc tion. Tka Baailiaat Syntn aliiiaata* latk and joist nark*, or ant* planar crack* to a anti radaca* wad paanga tkrawgk tba walk Witb tbi* , plaitamr* ara obit ta bolp baildar* aalw* aneb tranbloaaa** problems aa abjactianabla aais# batwaaa apartaaaat*, bam an nfficaa la largar bnilding*, or far rack rpacial installation* aa bawlaag allay* wbata it i* daairabla ta iaalata bar* aad cafa* fra* tba bewliag allay* cbemsotvoe. Many npnata matkod* baa* boon devised to cat *onad traaaariarion. Now, witb tba USG Resilient System, tba plaatarar caa provide a aati*- factary taiwtr ta tbaa* problem*, tberoby iacraaring bit iwinw aad profit opportunities. .,.u . AASk**- necessary because plasterers found it so easy to cover that they unconsciously seemed to cut the thickness to Yi". While the amount of cracking per job was sharp ly reduced by substituting Rocklath for wood lath, the fact that this improvement in the plaster job had be come possible made archi tects and owners far more critical of plaster cracks, so that further improvement was desirable in order to meet the demands of this quality-minded public. As a result, various systems have been developed which prac tically eliminate cracks and provide walls of the highest character. Systems to Reduce Crocks Among the most impor tant of these systems is the Bridjoint method of appli cation in which the ends of the Rocklath units come be On ba. ttla.akiipa,, wkar*, ip. aca .i* at ,a p- r.em,iam, an.d minimum w.eig.ht.i 7"'- /<? imp.TM.. tween the supports and not ppaarrtt iiaa ttbbaa dif-itiw o-f Am-erica-. In -tka ham* w-kre conservation o-f foal u vital ta oar defame program, it daei rr , . . an equa"lly mpertaat job. When plaatarar* **U Insulating Recklsch, tkay re delivering exceptional insulation on them. 1 hC end JotntS are vain*, and ncroneiag tkeir participation in tka building dollar. held by Bridjoint W22 clips. In corners and ceiling angles the Rocklath is not nailed to the framework, but is rein forced with Bridjoint W33 corner clips. Advantages of this system are that in ordinary con struction the displacement of a stud by moisture, settle ment or vibration, will stress the weakest point of the lathing, which is the meeting of the end joints over the studs. In the Bridjoint sys tem, the end joints fall be tween studs--which elimi nates vertical joints at the supports and minimizes cracking of finished plaster. Erection Simple Placing and alignment of studs need not be so accu rate when using this system, a feature which lathers par ticularly will appreciate. In other words, if the plasterer gets a job where carpenters were careless in erecting studs he is not penalized if he uses the Bridjoint method. {Continued on page 6) rt 4 rio rones, octoiir is, mi HOW TO GET MAXIMUM VALUE FROM METAL LATH Metal lath has made tine plastering economical for all types of jobs. It is also the lirst line of defense against fire, explosions, hurricanes, tornadoes, and earthquakes. And, to obtain this protection, only an infinitesimal amount of steel is required. Because of these facts, and because metal lath is easy to erect, is adaptable to any requirement, produces results of the highest quality, and its use increases the plasterers dol lar volume, it is advantageous for plasterers tb know how to use metal lath most economically. Many plasterers use USG Diamond Mesh for all their metal lath work, because it fulfills practically every re quirement. By standardizing on this type of lath, they say that jobs progress more smoothly -- mechanics are more efficient -- and they get more uniform results. Junior Diamond a Long Favorite USG Junior Diamond Mesh seems to be a long favorite over older largemesh lath, however, because it requires less plaster -- about 25% lesson the scratch coat. While it may be formed readily around curved sur faces, it is rigid enough to handle well on the job, and forms a tight level plastering surface with stud spacing of 12 to 16 inches. Plasterers known for their "sharp pencils" generally favor rib type laths such as USG 2-Rib for large, plane wall and ceiling areas. The advantages of this particular lath are: a lighter lath may be used over standard stud spacings made possible due to the increased rigidity ob tained from the ribs. There is less plaster wastage. Plas ter droppings are practically eliminated. Where Z-Rib Fits Z-Rib Lath is smooth and rigid under the trowel, takes just the right amount of plaster, insures a thorough reinforcement and is stiff tnnpl* KillThu uubb of a aodwa iouriM vividly iUoacnce* why pleatat U tW loa| favorite a* am mtarior* finish. Obviously, --col loth b wnticl m pluttr boo* for work of tkia chorsetor tad tea flexibility, together with tba niafattfBwat which it provide* to tho wall, oaaaroa tbo owoor u iatorior chot will how loos life, ! Tbo addod coat for tho decoration, which include* formed, niptabd coiling and corvod walla with roamao ' tal work, ia ottimatod at aboot $71, Par men might have bare apooc for wood paneling or ochor n-iri~l decora, tiaai that woold hava boon mock lou effective. McStay-Jackaon, architect. Coartety Mstai Lath Mfts- Ann. Tho amoli amoh of USG Jr. Diamond moah practically difliiwtw plector dropping*, catting plaotor reqairemooto accordingly. Iu flexibility ---t--- it aaay to eovm, and other intricata iehe. Z-Rib Lath require* |ma plaator waacogo (tacaaaidropping*) than any ocher pooppnnllaarr type of metal hlatuh. Ideal far piano____c_o__r_f_a_c_r_e_.PePremrmit*it*tigl!ighter' la' th ever aattand' atd' aend* (pacing" . > ~:*s. I Adaptability at flexible eon bead* ta carve* i* clearly shewn by tkia work at Wathbnre* Trada enough to reduce bagging under the trowel pressure. Plasterers also point out that, since ribs lap, perfect alignment is easily obtained, and nailing is faster because nails are driven home with out bending over, as is often necessary with Diamond mesh. Where wide stud spacings are used, or where great rig idity is needed, USG H inch Rib Lath is the favorite. The stud spacing for various types and weights of metal lath are shown in the accom panying table. A careful study of this table plus checkup by each plasterer on his experience as to the amount of plaster required will enable plasterers to se lect the most economical and practical lath for each job that comes up. Other Types In addition to the stand ard types of metal lath out lined above, various other types have been produced and marketed. These include ^ older types of punched lath,. wire woven in squares and, paper backed wire laths.The fact that none of these have won volume acceptance sug gests that they may be un economical and do not con form to the demands of ex perienced lathing and plas tering contractors. Most Important Uses While the initial higher cost of metal lath eliminates it from common use through out lowest cost houses, there are certain locations where its greater fire resistance makes its use most advanta geous and some plasterers have found that by recom mending metal lath at these locations they are able to provide better values. r.:ong these are: 1.AI1 bearing partitions and studs in exterior walls, including a bas ket to hold incombust ible material as a fire Stop. (Coat. oa p*gt 7) MINIMUM Wtl+MIS FOR MCTAl LATH WHEN NAILED TO WOOD STUD PARTITIONS rrr u : 1 UM >$:- -* *r*efrrrp~9t n; rffttveffriww/ \i*, a tviltRV Matal lath tad pla*tar ar vital ta obtata aatabla dicmtiv* affact* tack a* dut. USG Jr. Diamond eh is readily akapad ta reproduce any architacraral dengn. Aftar th* job it completed, it gravida* raiaforc--at that give* *a**rom prattetin againit cracking. PUwerer* who ancoorag* architect* ta iaclad* detail* of tkia typo ia their work are strengthening their boaii**** foundation. Tba Strong raaidanca, William Alderman architect. : r.; t* jvit rjMt rrmfj The job of inaalatiog wall* go** to th* pI actera r whoa USG Red Top Wool Blanket it uaed with Red Top , Farring Ranner* and Rod Tap Lath. Typ* Lath Mailmam Sted-Spacing bpaadad Metal t Diamond or Jr. Diamond Me*h| ........... 14-Jneh Z-Rfb Lath ......... ITJach %4ach Rib Letb . ............. iWneb MJnch JIVk-Mch Minimem Weight per Sgoem rard U lb*. 3.7* lb*. M lb*. JJ lb*. M Ibt. 3.4 lb*. MINIMUM W1IOHTS WHEN NAILEO TO WOOD CEILIN JOISTS Type at Uth Meiimam Stad.Spacing fapandad Metal (Diamond or Jr. Diamond Math) .........IR*-J#ch 14-inch *-fneh Rib Uth . IhJntb .............IT-Inch Jt-inck MInimam Wnight par Sgaara Yard ]J lb*. J.4 lb*. 1# lb*. I. lb*. 1.4 lb*. RIO TOPICS, OCTOliR IS, 1941 Ptft S HOW TO BUILD TRUSSTEEL PARTITIONS There's an easy way to build partitions, even though they're full of pipes, conduits and I air ducts. And it gives the plastering contractor the whole job -- not just the plastering. | It's the Trussteel system. I It is light in weight -- 18^2 pounds per sq. ft. of partition. It provides a 1-hour fire rating when covered with metal lath and gypsum plaster. Truss design provides maxi mum strength with minimum weight. Only four parts are required, and they are erected quickly and easily by lathing mechanics with standard tools. Either Rocklath or metal lath may be used as a plas ter base. Special attachment clips are used for Rocklath. which is easily and quickly applied. For regular parti tions. metal lath is tied to studs with tie wire. Resilient Clips for Metal Lath are also available to reduce sound transmission. Trussteel walls may be built ZYi, 41/2, 4y*, 5Yl and 7Yt inches thick by using 2, 3, 3|/4, 4 or 6 inch studs re spectively. The 6-inch walls may be built up to 20 feet in height. Naturally, cost of con struction varies widely, de pending on size of job,height and thickness of wall, num ber of pipes and ducts in the partitions, and scale of lath ers, and whether Rocklath, metal lath or the USG Resi lient System with metal lath is used. Contractors are reporting labor costs for erecting Trussteel studs and metal lath at from 64 cents to 80 cents per partition square yard (32 to 40 cents per sur face square yard). Labor costs represent from 50 to 60% of the unplastered cost of Trussteel partitions. After ppM, duct* ud ceoduica are is place. Trusteed rmaaer truck it cut te fit. Made of 24 gauge steel, it is eutilr cut eritb tu tdpt. Pm* * RIO TOPICS. OCTOill IS. 1*41 Rocklath Fattens the Plasterer's Purse (ContinueJ from p-ige ^) Since corner intersections and intersections of walls with ceilings are not nailed to studs or joists, a floating condition exists which sub stantially reduces the possi bility of cracking at these points. Resilient System While the Bridjoint sys tem is a decided improve ment over the standard method of applying Rocklath, the very best results with this plaster base are obtained by using the resil ient system which in reality provides a floating wall or ceiling. This may be applied to wood studs or joists, or furring strips, to masonrywalls or special steel con struction. The system consists essen tially of applying Rocklath and gypsum plaster by means of spring clips. It minimizes plaster cracks, eliminates lath and joist marks, and re duces sound transmission. Sailing Opportunity These factors are all of major importance to those who want the highest qual ity in their plaster work and provide the plasterer an op portunity to do a real selling job with his product. Wherever dry wall mate rials or other substitutes for plaster are specified or con sidered, the plasterer may readily point out that if sub stitutions are being made in order to stop sound travel, to eliminate cracks, or to eliminate disfiguring streaks on the wall, that all these features may be obtained at a very small additional cost, with superior results with plaster. Product Improved During the period when improvements were being developed in methods of ap plying Rocklath, the product itself was likewise being im proved. Two of the out standing improvements are Perforated Rocklath, which provides a mechanical key in addition to the regular suc tion bond that is obtained with the plain board, and Insulating Rocklath. There seems to be an even ly divided opinion among plasterers as to the merits of plain Rocklath and Perfo rated Rocklath as plaster bases. Many mechanics say the smooth surface of plain Rocklath requires a mini mum of effort to plaster. Per forated Rocklath enthusiasts contend that the holes cut the plaster from the trowel and that the mechanical key that is obtained makes it es pecially advantageous for ceilings or where fire resist ance is of special importance. Iwsulatfitf Rochletk While there is some dif ference of opinion about the comparative value of Plain and Perforated Rocklath, plasterers who have investi gated Insulating Rocklath seem agreed upon the fact that it has exceptional merit that deserves more consid eration by plasterers. These plasterers point out that insulation today is ac cepted as a necessity by many builders. They also say that for a very small ad ditional material cost and no labor cost, the plasterer is able to supply a quality in sulation job on wails and ceilings. This story appeals to builders. By using it, these plasterers find they are able to produce an attractive extra in volume of their plas tering jobs, which might oth erwise go to another trade. They also report that thorough investigation has shown them that this type of insulation has a long and effective life. Careful checks on jobs of 10 and 12 years old has demonstrated that the insulating value of the reflective foil is not reduced in that period, which offers conclusive proof that this economical insulation prob ably has as long life as any other material used f*r the same purpose. Other Improvement While the two additional types of Rocklath -- Perfo rated and Insulating -- are the most important improve ments in Rocklath, it is well to know that constant re search by USG on materials and manufacturing process have resulted in developing a better core, as well as a better paper cover. The re sult is that Plain Rocklath today is a much better plas ter base than when it was first introduced. Considering all of these facts, it is readily apparent, therefore, that today Rock lath and plaster are the key to tow-cost quality walls that will compete with any situation with which a plas terer is confronted. In addi tion, it gives plasterers an opportunity to `'sell their wares** and to become more aggressive in their effects to increase business and profit. Think whet it main* to knee e base coat plaster that ai> ways act* (be samel Rod Top Cement Plaster* are manofactured with the otmeet cere t* five you a unifemeJy excellent piaster far interior work over all the standard types of lath and mains*ry surface*. Rad Top Cament Plasters an made fibered, nofibared, end extra fbared. The meet widely uaed type is fibared, but yon get the same coaststent performance, no matter which you rkeoan. Li the Bureau of Standards report BMS7I, jwt released, fir* ratings for partition* ara (ins, wkick tho that practical coaatructiosu art available that will meet fire resitting requirement*. The report covers partition conatruction repretenting a wida rsnga of material* and design. In thoaa tests, plain -gypsum latb partition* wib taro coat* of gypsum planat wars given a H tour fir* rating and 9b' perforated gypsum latb parti tions with gypsum sad sand plaster received a ona boar firm rating. USG Rocklath moats tbo specification! of the latb* tested. HERE THEY ARE... TEN RED TOP CEMENT PLASTER ADVANTAGES THAT ELIMINATE MOST JOB TROUBLES! 1. They *et properly, whether seeded one to one or three to 2. They Mt properly with dean or dirty send. 3. They set properly with fine or coarse tend within the limits of AJ.T.M. tpeeificetions for size of tend. 4. They set properly with dean or dirty water. 5. They set from the lath out, indeed of from the surface in, giving more time to darby, trowel or float. 6. They Mt evenly, end once darted. Mt quickly. They do not Mt up spotted end uneven. 7. They Secure minimum possibility of dry-owtt. 8. They reduce differences ia sotting time coutod by hot or cold waethar. 9. 10. Thay here an unusual richness end slip that gives easy, miiiag, end fer.ipreedino qualities, resulting in meaimum coverage with minimum labor. They remain plastic end workable over long storage periods. UNITED STATES GYPSUM COMPANY, 300 W. Adarn St.. Oerme. HI. The forerunner of Rocklath was Sackett board. This earlier board was a rather expensive product to manufacture to that it was not until Rocklech was introduced at a price competitive with wood lath that plaster beard became a favorite with plasterer*- At left we am a aectioo of | Sackett board which vii recently removed from a store building to Corpus -^-Cbriati, Texaa, after >0 years ia place. This building survived three hurricane* and a flood, yet the sample removed ia bard and the applied plaster is still firmly bonded. The upper viw shews modern Perforated Rocklath, made far superior to even the tough original ea the result of continued and exhausting remarch ia the USG research laboratories. MO TOPICS, OCTORIk IS. 1941 HIGH HAT? fa 7 Fiber iunUtiog Utk i* dm / tbe Mwtr auuriiia u*4 for platter baaot. VoathorwooJ, witb it* V <dg* that make* it aaaior to apply, uf tlu "Faaaap" reinforcement, U a favorite bread. Tbo 11x41 iacb board* art light aad aary to apply. Farriag itrip* *hld bo n*od wbaa applying to ma*miiry wall*. Lack i* applied dry, witb beveled surface expoaed, aad length of board at right angle* to Rod*. Space end joint* $4 inch apart, at framing membar* apaced Uw O.C. Long edge* should be placed in moderately tight contact, proparly fitted together. Un five 1H" blnad lath nail* witb J/U" bead par stud. Th*nFa*aapn reinforcement t* ttaplad lightly a* shown. Comerit*, USO Flexible corner bead and StripUth tbonld be nailed into framing member*. NAW! HE AIN'T GONE HIGH HAT--HE'S JUST BEEN PLASTERING CEILINGS ALL DAY. HOW TO GET MAXIMUM VALUE FROM METAL LATH ( ComtinmtJ om psgt 4) 2. Ceilings under inhabited the supports. floors, especially over 2. Lath should first be ap heating plants and coal plied to the ceiling and bins. the sheets should be car 3. At chi m-n e y breasts, ried down 6 inches on to around flues and back of the walls and partition. kitchen ranges and stair 3. On walls, all lath should wells and under stairs. be started one stud away In addition, the greater from the corner and be resistance of metal lath to bent into the corner and cracking makes it advan carried on to the abutting tageous to use on: wall to avoid a joint at 1. Ceilings of prominent the juncture. rooms such as living and 4. Where rib or sheet lath dining rooms. is used on ceilings or 2. Lap 6 inch on either walls, it should be butted side of wall and parti into wall joints. Corner- tion angles and around ite should be applied over door bucks. the butting lath in such 3. Back of wainscoats and angles, and securely tile mantels. wired along each edge in 4. Across plumbing pipes all corners. and heating ducts. 5. Lathing of walls should For a typical 6-room house start at the top, working it has been estimated that down so that the lower crack reduction obtained by sheet will lap over the using metal lath in these upper. four locations costs only The most important type $42.00 which, amortized over of clips available for the a 20 year period, will cost erection of metal lath is that the owner less than 27 cents for Resilient Systems. Re per month. To get added fire silient Systems, as plasterers safety by following the sug know, are primarily to re gestions outlined, the total duce transmission of sound cost has been estimated at through walls and ceilings. $91. In addition, the resilient USHA Approves Metal Lath ceiling, plastered with metal The actual economy of lath, provides the maximum metal lath construction is insurance against cracking also evidenced by the fact and plaster breaks. The that in a very high percent pattern of wood joists and age of all jobs built by the framing on walla and ceil USHA, 2 inch solid metal ings is also reduced to a lath and plaster partitions minimum. have been used. Red Top Vs inch Z-Rib Short Cuts to Quality Results Lath is best suited for the This division of the gov Resilient system because of ernment has made extensive its rigidity. Red Top Jr. studies of the economics of Diamond Mesh is equally building materials and wall suitable, however, if care is assemblies so its selections taken to see that the lath is are based on sound analysis. stretched and tied tightly to There are a number of avoid sagging. practices that plasterers will Clips are easily erected on find lower their costs and masonry walls, frame or with improve the quality of their channels or Trussteel studs. finished metal lath job. When used on ceilings un These include the following: der flat concrete slabs and 1. The long dimension of concrete joist floors, much the sheet of metal lath less space is required than should he applied across with suspended ceilings. Protect walls and ceilings from harm ful vibrations with die Rocklath Resil ient Plastering System--allow them to "ride** as smoothly as modern automo biles with knee action wheels. Because it "spring cushions" room surfaces, the RockJath Resilient System adds these worthwhile advantages to the "taken for granted" strength and fire protection offered by Standard Rocklath applicarioo. 1 Protection from cracks caused by ordinary framing movement. 2 Reduction of sound transmission from room to room. 3 Elimination of the most common cause of lath screaks. HERE'S WHAT DOES IT! The resiliency of the spring action absorbs framing movement. In addition it dampens vibrations and reduces sound transmission. Free air circulation is also permitted because Rocklath is kept off the framing members. This eliminates the cause of lath marks. The Resilient Rocklath System is easily erected by lathers. Only addi tional materials required are clips! Home owners may enjoy its advantages for a reasonable additional cost. The Rocklath Resilient System brings ad vantages to the contractors too! It means profitable business--a full profit -- with assurances against call-backs and trouble. Ask your building materials dealer for complete details! Or write direct a to the United States Gypsum Company, co 300 West Adams Street, Chicago, 111- q inois--where research develops better, safer building materials. o o w i *s STRANGE AS IT SEEMS Mi TOPICS. OCTORKE IS. 1R41 by John Hix MEMBERS OF THE SAME FAMILY... PLAIN ROCKLATH it the oUu of Own mil. It dtm't bun btcsiu* it'i nidi tl gyptam rock. It is not affected by decay, motiture or vermin. lt uniform auction intktt it nay to ploator end low plotter ii wattod in drop- ptagi. It ntktt strong walla with a bond tbat tofts six pounda per aquaro inch. PERFORATED ROCKLATH... - basic advantages at Plain Rocklath, and tboa wait! Tha natoral bond of Rocklath and plaitar is reinforced by the mechanical grip of tke platter keys that form in the perfora tion. This double grip means stronger walls and increased fir* protection. One-half inch of plaster over s.` Perfor ated Rocklatb gives tke wall a better than l-kour fire racing. And plasterer* like the way the perforations "slice*' the platter froen the trowel. INSULATING ROCKLATH it Plain Rocklath with a smooth, bright sheet of aluminum foil mounted on the bock of each lath. It's the only type of fireproof insulating plaster bate available at low cost. Insulating Rocklath it used on outside walls, with the foil side next to the framing member. The metal must face an air space. Properly ap plied. it he* insulating value equal to fiber insulating board in use. It's a real low-cost fireproof insulating plat ter base. QUESTION! -- When applying Rocklath, should there be a space between the ends of the boards? J- S., )tn Westerly, Rhode Island. ANSWER] -- We recommend that Rocklath be nailed with the ends touch ing. However, a crack of from % inch to Vg inch is satisfactory. In eitfarr case, if Zi inch of plaster is used over Rocklath, no cracking is likely to occur unless there is considerable movement of the framework behind the lath. We have found that in those cases where poor plastering prac tices are followed, cracking is likely to occur whether the Rocklath is "butted'* or a space is left between die sheets. This not only applies to Rocklath, but to other types of plaster bases. To date, we have not been able to produce a lath which will keep plaster from cracking where poor constmetkm methods are used or where poor plastering methods are followed. QUESTION] -- When repairing plaster cracks, should one cut through the lath, or would it be sufficient to cut through the "brown" coat? T. P. P,, Washington, D. C ANSWER] --- When repairing cracks in plaster the depth and size of the crick govern how much of it should be cut away. If only hair cracks are resent, it is necessary, as a general rule, to cut through the finish to the Erowo coat only before repairing; but if there are very large, deep cracks, it is advisable to cut down to the lath so that the new material can get a good bond. QUESTION: -- What product should be used on burnt brick before putting mortar on to keep the stain from coming through the finish? E. L., Cheviot, Ohio. ANSWER] -- We assume that you refer to plastering over burnt brick. We recommend furring out and applying metal lath or Rocklath over burnt or smoky brick (masonry construction) just for such reasons as you outlined. QUESTION: -- Wby do white spots occasionally appear on die surface when plaster dries? Mrs. A. . IC, Froid, Montana. ANSWER] --- If retarder is added to the basecoat on the job and is not thoroughly dissolved and mixed, lumps show up as smalt spots. This can be avoided by a more careful dissolving and mixing of the retarder. If you have watched plaster "set," you'll note that it turns dark or "browns" in spots. These normally spread until the etuire surface "browns out." Occasionally portions around windows and doors, on which a draft is blowing, dry out before they set These white spots are usually larger those mentioned above and. because of their location are easily distin guished. Spraying plain water--or water with a small amount of alum in severe cases -- will bring about a set and uniform color to these dry-out spots. In some rare cases small spots may also show up if plaster is not thoroughly mixed with the sand. Again, thorough mixing is the solution. If your question refers to finish coats, it may be that the gauging plaster and die lime putty were not mixed thoroughly or that all the lumps in the lime were not broken down. To prevent these spots, see that the lime is screened before using and that the two are thoroughly mixed. QUESTION] -- Some time back we supplied wood.fibeted piaster for a patch or plaster repair job used on wood lath where old plaster had come off. Some time later the writer happened on the premises and discovered that in spots this wood fibred piaster had raised hard, little sliver points or blisters. Have you heard of this situation before and have you any sug gestions? K. H. W,, Mora, Minnesota. ANSWER: -- The question you asked is an unusual one, but is not hard to understand. It is evident that the wood fiber plaster was mixed and ap plied mthin so short a time that the shredded wood fiber did not have time to take up moisture and expand to its full extent Wood fiber is intended to be used as a base coat plaster only, with a finish coat of lime putty and gauging plaster applied over it. We know that some plasterers, in patch work, do use it for finish and base coat, but usually they do not entirely fill the area to be patched with the wood fiber plaster. They leave a slight space for the finish coat, and if they intend to use wood fiber piaster as a finish, they screen the fiber out before ap plying it. QUESTION: -- Sometimes contractors use needle point nails when applying metal lath. Wouldn't you think that six penny nails would he more correct1 Thomas P. Poore, Washington. D. C. ANSWER: -- On walls, a 4 penny common nail driven to a minimum pene tration of *" and bent over 2 strands of Metal Lath, or a Yt" large head roofing nail driven home, is recommended. On ceilings a 6 penny com mon nail driven at least l'/i* in the wood and bent over 3 strands of lath or a lV*" large head galvanized or blued roofing nail driven home is recommended. Whether the nail is needle or diamond point, makes very little difference if the above requirements are met. Vi'hat are your question' on lathing and pla'ttring? You will receive a dollar jor each one published. Send them to the editor. Red Topics, 300 V'. Adams Street, Chicago. III. I U3 I*. 5 PufaUslid by United Stitts Gypsun Co. Cbkip, Monday, December 1,1941 ALL-OUT Crcalatiw 63J0Q $ And How You Can Help To Achieve It kis=& ----- ----------------------------r~ .. ' 'Modern ~ Decoration Features Ornamental Plaster pit t KCD TOPICS, DECIMMft 1. 1941 minis: 0400 <>0088 la tlu fireplace the ucUlwt, Ralph Hwu|h, kaa achieved arnhb rtnlu with ptntmJ dmih ia relief. RImmiW walk provide aa tiftctivt heckgreead far ' balaecerv aad mir rail ia thia hmk, Madera apt eght iraa Practical, wt|iaacirt architacts art fiadiag aaw war* ta ebcaia aacstiag detail* ia their daaiga with pUatf. RED TOPICS. DECEMBER 1, 1941 p9 3 rRrTC Every One Should If fllf 1 M Know About Fluster IF YOU WANT PEOPLE TO BELIEVE "THERE IS NO SUBSTITUTE FOR GOOD PLASTERIN G," HERE ARE THE THINGS YOU SHOULD TELL THEM The use of plaster in buildings is so common and so generally accepted that architects and experienced builders are rarely able to tell why it is used, and hence, may fall easy victims to "sales talk" and propaganda in favor of plaster substitutes. And, because it serves every day needs so well, many lose sight of the fact that plaster is also one of our most decorative materials, as well. predetermined time under widely varying conditions of tempera ture of weather. Fast to Apply Naturally, every plasterer wants to see the use of plaster increased, rather than decreased, and the best way to assure this is to know why "there is no sub stitute for good plaster," and to take advantage of every oppor tunity to tell why. Since gypsum plaster sets quickly, one coat follows another without waiting or delay, once the job is ready for this interior finish surface. On normal houses, plasterers spend less time on the job than any other building trade. To be sure that every trades man knows the advantages of plaster, we review them here. Fireproof _ Plaster, being fireproof, is tbe material that gives most homes their fire resistance. The first record of its use for this purpose is during the reign of King George I. when a law was passed that both the interior and ex terior of bouses must be plas tered as a fire preventive meas ure. It was at this time that half-timbered construction was introduced. Sets and Dries Quickly Gypsum plaster sets fast and positively, then dries quickly and fully. It is keyed to modern de mands for speedy construction. No curing period is necessary. Gypsum plaster sets within a Maximum Bend The bond between gypsum plaster and Rocklath is stronger. That is why it requires so little attention. No Shrinkage . Gypsum plasters expand slight ly when setting to fill the spaces to which they are applied. They do not shrink away at the edges nor craze-crack. Plastic Gypsum plaster may be ap plied to flat or curved surfaces of any types, where only a plas tic material can be used. It gives free play to tbe imagination of architects and designers. The Final Finish Plaster readily covers unsight ly structural elements of a build- Tkis dramatic interior adurvaa ica baaacy through miplicity. Tha aatwral pi*racily of gyprcat makac it aa ideal malarial for aodarn decorative effect*. la thi* Living room, William Atdanaan, arclutact, bai achiovad aocabla raaoll* with oval ptletien that form raffita at cho wall far lighting. This meiterfnl frnca by MicbaUagaio oa tha walls of tho famad Siatiaa Chapel, was executed oa gyptam plaator oratorio* ago. It is eaa of tha world's moat treasured works of art. That it has stood through tha age* it avidaaca of tho durability and tha portnaaaaca of gypsum plastar. ing. It may be used to true up walls which are out of plumb or line, and changes or errors in the structure that must be concealed. It provides a continuous sweep of decorative surface that con ceals everything beneath it. No Joints Gypsum plaster is applied as one unbroken surface, regardless of the size of the area to be cov ered. There are no joints. Sanitnry For centuries, the fact that gypsum plaster is sanitary has been recognized. It is vermin and bacterta-proof. It may be painted and washed repeatedly without harm. Long Life permanent and durable wail sur face. -. $elfDcornting or Dccorablo Plaster may be painted, paper ed. or left exposed so that there is practically no limit to the dec orative possibilities with this ma terial. Function of Various Piaster Coats Now, let's look at the require ments for good plastering, for which there is no substitute. Students of plastering history agree that gypsum was man's first cementitious material. Like wise. it was the first "manufac tured" material used for pla-tering. Frescoes were the medium with which Michelangelo cre ated his most notable master pieces. These were done on gypsum plaster and, since Mich elangelo was a master builder, it is evidence of the fact that at this early time students of ma terial* recognized gypsum as a The introduction of lime, with lower first cost when used with sand, by the Romans, made it the favorite base coat material for almost 2,000 years. With the rediscovery of retarders, gypsum plaster again came into popular ity And gypsum plasters' abil ity to meet the demand for more Pf 4 JUO TOPICS. DICSMIEK 1. 1941 FACTS (Continued) speed in building, together with its other superior qualities, ac count tor the fact that it has be come the most popular of alt other forms of plaster in the United States and in many for eign countries. Scratch Coat Plaster is applied in not more than three coats, which are des ignated as "scratch'1, "brown", and "finish." The "scratch" coat is applied first. Its primary function is to act as a bonding coat to attach the body of the plaster securely to the lath or masonry. Gypsum mortar for "scratch" coat must have sufficient plasticity and co hesion so that it can be worked well over the base. The `'scratch coat should be applied thick enough to cover entirely the plas ter base. After it has been af>plied and before it has 'set, it should be thoroughly cross-raked to receive the second or "brown" coat Brown Coat The "brown" or second coat forms the main body of plaster on the plastering base. It is the function of this coat on a given type of lath to fill within 1/16" to %' of the grounds. The "brown" coat governs the resis tance of plaster to the transmis sion of heat, fire, and sound. The "brown" coat must necessarily be sufficiently hard to form the wearing base of the wall and the proper base for the "finish" coat. The "brown" coat should be rodded and darbied to a straight, even and uniform surface, ready to receive the "finish" coat. Finish Coat The "finish" or third coat used depends upon the finish desired. There are three principal types of "finish" coats: 1. White coat finish, consist ing of the admixture of lime putty and gauging plaster troweled to a smooth, glossy finish. 2. Prepared white gypsum fin ish, requiring the addition of water only and troweled to a smooth, white finish. 3. Sand float finish, obtained by either using prepared or job mixed gypsum and sand to give a rougher texture, ii desired. It is imperative on the "finish" coat that it be free irom cracks; it must be hard enough to with stand abuse, ami above all, it must present a pleasing appear ance. Plasticity Since the "finish" coat is ap plied in a thickness of from 1/16* to H* over a dry. "brown" coat, the plasticity of the material is exceedingly important. If the material is not sufficiently plas tic, it is physically impossible to use it at all for "finish" coat work. The choice between the vari ous finishing plasters depends on the job and its requirements. Where low cost and quick dec oration are the primary consider ations, Red Top White Trowel finish and Red Top Grey Trow el finish should be considered. These are ready-mixed gypsum finished plasters which may be decorated as soon as they are dry. They need only the add- 41 Ancricso Miniot of Laptn, l*c. A|u ago piaster wot recognised at a sanitary uttriaL Omo of the Arte recorded laws that ndate* this fact is foud is cha Old Testament. At that dm it waa itfsind that haaaas occupied by leper* snot bo plastered Msn they nsld ha bvad ia hy others. Modem sciooro has throws aew Ughi ea this plague which, through coloaios each as the eaa shows above, ia gradually being brought ssdor cuutrul tkruughuut the world. ,4g tion of water to be made ready for use and should be applied over a fairly dry baseeoat Where fine, hard, white finishes are re quired, a good finishing lime is ' sometimes preferred. ' EFFECT OF SAND ON STRENGTH OF PLASTER f AS To wake the .cr.uk U.I. ibc wu vrGcd W-Uch kick ~ Tr-- >* <* P~" <* ~"\T1-*JlrT' * T,,rf.c' tkc ^ .. . nmiirm rc of .pud, du ,-u. b., i<h . _-*._Tk. F~<"j** dra* .,_L J/14", U" u V put. Tk. auurUI "flurat p" bp kc p.< wu cdUctcd >d *d d. m.lu Lwd,L.V..uil k* P. kuk oTZ,* of d ur.uk. Tk. ,ck.u .. tk. ri,h. <k-.r-.ta. Tk. rffu. dO- M i du cf r.ncuo preperduu U duw. bp du. uriu of pkoto.r.pk. Tk. ill.ur.ooo < **""" kf. .koro wu uoJ^j -- ommt up cwur, ... r. 1--| -ppu titkt, .< Uft bdur, .< Uw cuur, uf >-- *. .S U S . ; 5 3" I'.l M III 4il ,:i fcl , Parts sandparpartp/astar-by miqtt , SCRATCH TEST To determine the quality of e plaster welt, scratch it with a sharp ptiat A lab- . oratory tost to compare qualities of plaster showed the depth aad width of the scratch, or eutorial "plowed up" eras stsch great er with high seed contest. This chart thews comparison of differast proportions. Photographs et Uft shew test specimens. 30% less then 2: U Abov-t50% lesst hanM AtH tit 7 %\f* ILL 1:1 Cl j: 4.I 5:i *:i Parts san*p*partpiasltr-bynaybf COMPRESSIVE STRENGTH The higher the compressive strength, the bettor the plotter. This chert thews that increasing the mad content from two to three ports, by weight, decreases eemproe> see ttrasgth approximately )!%. lacreaetag mad coateac to four pares decreases compressive ttreagth approximately )!/,. mwtrtbom Ceunsw Gypmn Asmostioa 25 % less then 2:i About 50 % less About 70%ls*ttmn2:i forts sandparpertpiastar-by wipht TENSILE STRENGTH High fondle strength is another reqir*> meat of good platter. Overmadiag cats tensile strength, as the above chart shows. Tensile strength of plaster decreases J}% by increasing mad content from ewe to three parts; 50% hy increasing sand to fesr parts, aad increasing to five. Plaster with Z Pern sand is I lb times as herd as piatfar with 3 part* sand; " 2 times as bard o* piaster with I Karts sand and 3% times as hard as | plaster with 5 Paris sane yL JV Y Ae iha quanrty ol send -- increased,so isthe quo* itv nf Wemr to bemo the piastar to normal eonsii tency--workability-- craasinqlht warorj r sfioresults indeaoaset strength and herdeeasjj 23 *i 4:i 5:i hit Parts sandparpartpkstar - by matfbt HARDNESS TEST i:i ci a:i 4: s:i 6:1 ** Parts sandparpartpbstar.by marqbt PIASTER CONSISTENCY-WATER RATIO ^ If plaster is to continue as first choice for As the sand content of plaster it increased, walla, it mum be hard to withstand abnm. . the amount of water per 10* pounds ai The Monetruon hbaarrddnue.ss tarn shows that plaster must also be increesed to got p.laster -w--i-t-h---t--w--o----p--o--r-t-s- of wed i- ^ ~------- workability. This chart, prepared from . hard as plaster with three ports of <30 laboratory tarts, shews that as the water send; twice as bard as with fenr parts; O retie to gypsum is increesed, the strength and times ss hard as with five parts. O and hardness of the plaster are Jscrismd f . . Oo 4- RED TOPICS, DICEMtiR 1, 1941 P*) S A USG PLASTER for Every Purpose If gypaam bMtcatM bd m atbor eh* fact that they ipMd cwnractfai to wilt wedora dtmaada for qakk cawplatioo of jobo woold explain why thay ara tha faaorica pUatar today. USG braada daaewbod abort ham bom mcogaixad loadam ia tha program pfa>ur ku atdc ia matting tha famuli of madam (mttnctiM. A lufi ttaif of roaoarch tngia--ra am cooataatly aaarchisg far mill graacar mpranamt ia plaacor. A ia tha put, aaw diacorariaa will ba iacarpataiad ia Rod Tap haaMti ebay am tbaroaghly prorad. la thU ago of Rocklath aad Rad Top pLwtam, baw coat traoblaa kart baaa gmatly radacad. Nocabla program haa aim boaa mada ia improriag fiaiah coat mawriala. Tha demand for now docomtava troatameta haa raaoltod ia aa iacnaiad aooibar of fiaiah plartora. Each haa tartaio faatoma mod odmotagoa, aad plaatarara who weald heap chair material ia tha load aa tha farorita wall Raid, will atody oath fiaiah to ba ablo to mcoaawiawd tbo ooa moat adraotagaoaa for asch Job. V rj * KID TOPICS, DKCKM8CR 1, 1M1 3 steps TO FINER FINISH COATS! li tU L*adrdU Cawtr Cook Hwn it Huidiu, IfiniMefl, SibiatM oe wtlb mmd rf Um Cnr Rooa has ewtribaMd t* tk tBcmiid comfort that ku rmltad from wmlmiftJM of thii lioililiof Tba view of tbo Cnr Hwn iboau boro, ilimnw bow Sibuit* miu tbo roqwiromonu of madam doundio. WUb ocbor iccmitiul oMirbli, tbo pluur m7 bo omitted on tbo arow treated. Wrti Sabtoita, tbo flaiWior goes mora work, ud profit, then weald bo had ia map other wap. . Promote Sobinite for Profits, Plasterer Urges That old timert in the plastering business are alert to changing conditions is demonstrated by the case of Jim McManus, prominent plastering contractor of Meridian, Mississippi. When modernization of the Lauderdale County Court House was proposed, Mr. McManus immediately realized that acoustical treat* mem would be required. Mr. McManus went to the architect and explained the advantages of Sabinite. He made the sale. The results obtained with this treatment have been most satis* factory and the appearance of the rooms has produced much favor* able comment Is it any wonder, then, that Mr. McManus urges all plasterers to take advantage of the opportunity this material pro* vides them to increase the volume of their business. Jim UcMum my* "If ybmnn r--lived tbs advaacagaa Sabiaita baa mr ocber eceaabcel rmimn, ebay weald 1m eerjaae kaaw ` aboat it" * For a hard, smooth finish coat on your noxt job, try Red Top Trowel Finish. It's used as a plaster finish coat instead of lime and gauging plaster. Red Top Trowel Finish forms a "lifetime" bond with any gypsum base coat plaster -- results in a superior quality wall finish. It is ready for use after water has been added and th* batch hag been thoroughly mixed. Decorating may begin once the finish is dry! Tbeae Ulaacrecioot- shew the change that vu prodneed by maderniting tbe exterior of tbe Landerdele Cooney Hoom et Meridian, Mimaaippi. la addition to Sabinito,wbore acooetical traatinant waa required, Red TepGyp* eom Planer, Red Top Star Geeging, No. 1 Moolding and Grand Prize Finishing Lime were mmd. krawee ft Inn* field. Meridian, ware architects: Newton and Scbmell, Hattietborg, ganeral contractor; Jim McMenet, Maridiaa, ptaneriag contractor. See your local building materials dealer ior detailed in* formation about Red Top Trowel Finish and the complete line of Red Top Plasters. Or, write the United States Gypsum Company, 300 West Adams Street. Chicago, Illinois. . . where research builds better, safer building materials. TRIPLE THlEAT Good workmanship is essential if plastering is to continue as the favorite interior finish. Voca- tional schools are playing an im* portant part in assuring good craftsmen in the future. At Me* Kinley Vocational High in Buf falo. New York, plastering is one of the courses taught. The course was started in 1923 with the co operation of Local No. 9 Opera ting Plasterers and Cement Fin* ishers Association. Above, the ; finishing of a mould and the final i shellacking are shown. *00 9 Suggestions on Mixing Plnster While the proper method of mixing plaster is well known to the trade, there are a few fundamental rules that should be observed for best results. This is particularly true with regard to machine mix ing, which is being adopted in some localities to help meet the competition of dry wall construction. Good results naturally can be obtained by either hand or machine mixing. The only requirement of the fin ished material is that it be thoroughly mixed, and the procedure suggested is recommended because it produces the most thorough mix in the shortest possible time. On smaller jobs, with machine mixers there is a tendency to mix too much material ahead, resulting in quick set before the entire batch is used. Over-mixing of plaster or slow and irregular mixer charging must also be avoided. BSD TOPICS. DICKMBU 1. 1941 Pag* 7 Hand Mixing The Muur box fw hand mixing ibwld b* railed c om --d. Ia eb* upper cud of the box e layer of ead abould be placed, tboa aae ef plaster. This abould be hood dry fees ee* ead ef tho bee c* tb^.ocher; thou beck tjaia, working dry rnd end piercer cbereugbly tegeeber ce suaifoev color. Add wator es ceoo ec coed sad plaator bare boaa dry mixed, aad be* cb* piaster late tho orator, auxiag cbereugbly to brieg te Wood fiber ta end without Mad aa a rula.Th* plaitar ihoutd bo hood into tho wator aad al lowed to aeah at Iraat to min ute*, after which it ia mixed to tho correct workiag consistency. If ic ia to be aaadod, uao ea equal weight ef plaster ead clean, duy aaad. The tame aiaiag procedure ahauld be follow ed aa wbeu auxiag cwet plan ter ia this ear*. Machine MiviTUV Maay plaacarera my auxiag uahea their job easier. Coatractor* also haew it help* them to moot tho compocitioa of rubcticuto ITIIAII l& materials. This is particularly impartaut la defense houaiag constructiaa where away eew metboda ead types ef materials ere baiag need. Add enough wator ta obtaia requited cooiirttacy. Batch should bo mixed natil naiform ia color aad a* dry Mad or plaator esa bo soon. Dump batch when in this condition. While botch ia mixta*, plaator lusy be pulled bach ia box with boa or shovel. Do net mix more material than can bo used within one hour to avoid quick sorting. With continuant ta ef mixer, tot plaator may accumulate on blade*, theft and ndtt, grad ually accounting teteiag time. Ia ouch cams, the mixer should bo cleaned at interval*. Flush mixer thoroughly with water to remove sot plaster. This always should bo don* at eoou and night. If wator doot not rrmov* all piaster, brook it loose with sheveL F*f I MO TOPICS. OtCtMMR 1. 1*41 STRANGE AS IT SEEMS.....................................................................by John Hix gtfSTLE m THE A)R/ "% WAWDORF-A'STORIA, HT.C..TALLEST _ HOTEL IN .THE WORLD, JSSU/LT * INCHES ABOVE THE ClHOUND/ If ft SUPPORTED sv cushioned stilts" to eliminate VIBRATIONS froTmOtUrWafEf*ic.,. Interiors of dignity and beauty--these are monuments to the skilled bunds of the workmen who executed them. These cornices, coves and soffits and plaster ornaments must be perfect in de tail. This perfection, in turn, requires a quick-setting, finely-ground plaster. Red Top Moulding Plasters are manu factured with extreme care. They are characterized by uniformity of grind, depend ability as to setting rime and mixing qualities, and freedom from excessive hearing and expansion during setting. Red Top Moulding Plaster is made by a special aridize process from selected white gypsum rock. It produces hard, dense cast ings, free from hubbies and pin holes. Let your local building material dealer tell you about it or write the United States Gypsum Company, 300 W. Adams Sl, Chicago, 111. . . . where research develops belter, safer building materials. Question: Do you recommend the use of moulding plaster for patch ing finishing coats? George W. Kreger 404 North Elm Street ' Pittsburg, Kansas. Answer: We recommend Red Top Patching Plaster for small cracks, etc. However, Moulding Plaster may be substituted sat isfactorily. For repairs, including large areas, U S G Lime may be gauged with Moulding Plaster, provided the set is not too quick for completion of the patch. Otherwise, we recommend Slow Set Gauging Plaster mixed with USG Lime. - i Qaeation: I expect to remodel an attached garage into a dining room. It now has cement plaster on metal lath. Should 1 use white lime finish, Keene's cement or Oriental stucco to get a nice finish over the old cement? Olin A. Warren 255-24 Walden Place Great Neck, N. Y. The material depends on the finish desired. Assuming by cement plaster you mean gypsum cement plaster, care should be taken to be sure it is free from all dirt, dust, grease, paint and any other foreign matter that will prevent the finish from proper ly bonding. If a smooth finish is desired, lime putty finish or Keene's Cement Finish may be used. A colored texture or sand float finish may be had by using Oriental Interior Stucco. * t)Question: Will you please explain why Keene's cement check- cracks? Charles Buck 641 Duss Avenue * Axnbridge, Penna. Answer: Keene's Cement may checkcrack for one or a combina tion of the following reasons: First, insufficient troweling; sec ond, too little Keene's Cement in the finish. Keene's Cement finish requires more troweling than ordinary finish because of its slower setting nature. Until the set takes place shrinkage cracks )are likely to occur unless the finish is properly troweled. Keene's Finish should contain not less than 100 lb. Red Top Keene's Cement and 80 lb. lime putty. Question: I have been using hard plaster on concrete walls for several years and had no trouble. In recent specifications on jobs I have figured, it says not to use hard plaster on concrete walls. What is the right way to do such work? V. E. Pigf. Ekalaka, Montana, Answer: You are fortunate if you hare been nsing hard plaster on concretee walls with no trouble. For best results we recom mend concrete walls to be furred and lathed wherever possible, otherwise Red Top Bondcrete could be used. Bondcrete is a product formulated to correspond in volume changes the same as Portland Cement The concrete should always be dry, free from 0]dirt grease or efflorescence and thoroughly roughened before application of Bondcrete. Question: I frequently have requests for a skim finish on plaster to paper or paint over, instead of white or lime putty finish. What do you recommend for such a job? W. B. Nicholson. Chapman, Kansas. Answer: We recommend Red Top White Trowel Finish or Red Top Gray Trowel Finish. These are ready-mixed gypsum finish plasters, which may be decorated as soon as they are dry. They need only the addition of water to be made ready for use. We do know^ however, from the general section of the country from which this question comes that Red Top Skim Coat is also suit able for such jobs, and is trade practice. Not more than 25% 1 lime should be added with this material, and complete directions are printed on the bag. IIIQuestion: What causes white coat to ''tear" sometimes when troweling with water? A. F. C. 101 Park Avenue k. Summit. New Jersey ftft I Answer: Tearing of the white coat indicates that suction of the " base coat is too great. Question: When a job is to be tinted, we find it always more sue- ftEl cessful to dry mix lime and color. Now, by what method would ww| you suggest to add color to new lime when the box already con tains water? John M. E. Shultz, 1052 Berg St.. Johnstown, Penna. \wm Answer: We recommend that if lime putty is to be colored the color first be completely and thoroughly dispersed in water to eliminate anv tendency for lumps, which eventually could cause | streaking There is always the possibility when dry mixing lime IB I and color that complete dispersion is not made. Correction--In the chart on plaster bases published in the October issue of Red Topics, the amount of sand required with Weather-A| wood Lath should have been shown as 1 cubic yard per 100 square yards of wall surface, instead of 1.6. Those who have kept this chart will want to make this correction. 4MXt'hai art jour questions on lathing and plastering? Yen will rtttivt1 a dollar for each one published. Send them to the editor, Red Topics, 500 IT'. Adams Street. Chicago III. li Sf) USG RED TOPICS A National Plastering Journal fol.3 IU Pnbfishd bf OnHfd State Sjpw Ca. Chiup, Wnhndi), Deoabar 31,1M1 . Grotlitm 53,000 hji fl RED TOPICS, OCCKMBIK II, 1M1 ctT CO**'9*** To R. H. Chandler, district manager and sales representatives Hi r. '* ... cr?*^. ><- r,i- *"* of USG, should go the industry's sincere thanks in appreciation for their attitude in aiding to secure lath and plaster for the Pen* dleton Airport Housing job. awarded recently by Hazen and Clark of Spokane to Harold Hiebert. Is,>la--r.. mC,--_"**for 0s*4 Flt*rt{.*--MThlfis I Faced with a certain order for materials if the job had gone as originally planned for wallboard Interior finish, these gentle t< Mk t tiaNxtjr t*hn> men "took their chances" for business, in competition with all other 13 f--ilpw--,,ni*5w*>nl--c i--n.n manufacturers of materials, in spending a great amount of time .... and money to help bring a decision for lath and plaster. In taking this action these men proved their conviction lath and ''".., -;v plaster was the suitable material for the project, but it would u.4 ** have been a great temptation to those of lesser loyalty to the proper method to have taken the easier way out and signed up .-. -.`JSS T*-w--*i*it*ta*#*hfrnV1(,tn*w*furt*-i,r*m*uttM--*f4t,t%n . la the pl--tertag atMu far r |h(Vi *< ttM ra mI] mm *f t-- latanritt(ol--andertsmlitplt*ahwtakthi*ilttat(eta4|S1*tatet*e'tVyifemnUkf**U?l*Img i* the waiting wallboard business. Reprinted (im Nortbwcet Ptawtring tiduanei 1 fear pa--at tMk yar InMnMk tf Oa pa*i i* M*| itttiiMi t* Ha -- ty, teetr?, Mlettaaa agai, "" ^-1 I MO TOPICS, OKCIMMR J1. 1941 Pl 3 PLASTERERSRALLYFOR "ALL OUT" CAMPAIGN From the Atlantic to the Pacific--from Canada to the Cult--a wild burst of enthusiasm has folluwed Red Topics' "All-Out for Plaster ing" campaign. Contractors, lathers and plasterers arc all "pitching in" tor a great offense to build an impregnable public demand for plaster. To do its part. Red Topics will supply you with an increasing volume of helpful ammunition. Starting with this issue, we will include in each issue a series of beautiful plaster jobs--jobs that you may proudly exhibit as reasons why "There Is No Substitute for Good Plastering." Why not start a scrapbook of pictures? And make sure that every one you know sees it. Let it explain why you take pride in your work --why plaster is THE finish for interior walls. If you haven't ordered stickers with the "No Substitute" emblem, write the Editor of Red Topics today for 100--free. You have made a fine start. Now is the time to "turn on the steam." L. R. Solomon, erehitact, gave piaster the leading role in planning the display roams for Eieeaborg ft Sons, exclusive designers of women's apparel (erring America's leading shops and stores. Ia the entrance, Mr. Solomon created an all-over patter* of tiny plaster casts of the Eisenberg "Crinoline Dame" trademark. Highlighting this background are surrealistic plartar lighting fixtures. (See illustration oa page 2), la the cosmetic end jewelry display mum, a froely-eryled plaster moulding spotlights the shadow box display shalvas for cite cosmetics la the curved rser wall. For this wall, plaster likewise provides the ideal hem to execute tha smooth, flowing liaos of the walk Raising Plaster Quality The plastering industry of Los Angeles has been aware of the necessity for adequate apprenticeship training since 1925 when the Los Angeles Board of Education established the Frank Wiggins Trade School. Plastering was among the first trades to be taught. As a result, a high standard of quality has been established and maintained. The teachers, under the California Plan for Trade and Industrial Training, are first selected for their ability as craftsmen and then trained in educational methods through courses of study at the University of California. Careful selection of students is made, and training is carried on to assure a complete understanding of all the problems that good tradesmen should know. Training is also offered journeymen, who can come to the school on their days off and keep up in the skills of mitering, mould running, trade problems and information on new materials. L. G. Slier is principal. The classes are conducted by Wm. Cole. After serving as a teacher f6r many years. Mr. Cole is now head of the building trades of the school, and the plastering classes are at present taught by Mr. Thomas Moran. A frame of USG Moulding Plaster provides s formal tatting for distinctive apparel. The nsutral color of the platter enhances the varied hues of women's wear. Mrki tha 40th Anniversary a/ th United States Gypsnra Campany. This busi** **' tssadsd os tbs belief that **Tb#r Is No Subititsti for Good !HaKtris|H. r**rs, (ha bsaiM has continned ia that belief. Today, it looks forward to the It firm ia its anginal belief. The experience, research facilities, terries department, sad the will of U S G te maintain plaster as a stiperier interior wall finish wilt continue to bo devoted to this goal, as ia the past. FOR YOUR SCRAP BOOK For page I of your scrapbook, a reproduction of the beautiful wall on the opposite page is available--free--to plasterers who ask for it. The three views above are from the same show room-- may be clipped and pasted on page 2 of your book. Send your requests for the picture at left, or for "There Is No Substitute" stickers to Editor, Red Topics, United States Gypsum Company, 300 W. Adams St., Chicago, Illinois. B8005 0051 Papa 4 RID TOPICS, DECKMBCR 31, 1941 THE BRIDJOINT SYSTEM AND HOW TO APPLY IT Bridjoint Is one of the most important quality developments for low cost plaster work. It is a better way to apply Rocklath than the straight nail-on method, as it reduces cracks at wall or ceiling angles and tends to eliminate cracking due to stud movement. Since Rocklath is used as the plaster base, the method naturally provides all of the advantages of a Rocklath wall: free of lath markings; all fireproof materials; normal sound insulation; and low cost. Perforated Rocklath is recommended, although satisfactory results may be obtained with either Insulating Rocklath or Plain Rocklath. Contractors like Bridjoint because it provides better walls at standard prices; because it solves lath worries, and complaints; and because it is simple and* easy to install. It helps the tradesman because it means great er satisfaction with plaster jobs, thereby increas ing the demand for plaster in place of substitute materials. Experienced contractors report the system costs about the same as a nailed on job. Savings obtained include the elimination of cost and ap plication time for metal lath corner reinforce ment; 25% less nails; and practically complete use of odd lengths of Rocklath. Aftwt etilkf it IttM, wtrk la caatfaaad aa walla. Nata W.JJ clip* at laau ri|kl aa beard baiag erected tad ia placa at joint. Wall it IttM ta flttr. Laat ennt b oat' abate %* law tbaa fanaaaiat apaca, tbaa flipped iace clip at joint* above. At corearm, beard* hm ba alippad lata WJJ caraar clip, at wall aa W.22 jaiac clip above. Extra aailiag at jotata b caved. tCO TOPICS. DfCSMHB 11. 1*41 Points to Watch rt 5 on Winter Jobs By J. H. Boyle, Service Representative United States Gypsum Company When winter comes, plaster jobs need more attention. While the fundamental rules of plastering apply to all' seasons, we shall point out some of those governed by the winter, with particular respect to metal lath. First, watch proportion ing. Scratch should be mix ed 2 to 1 by weight. It should have enough thick ness to provide suction for the brown coat, and suffi cient strength to hold the lath rigid. It has been my experience that cracking on metal lath sometimes becomes a prob lem in the winter. One of . the primary reasons for this is the lack of strength in the brown coat. When we spec ' ify 3 to 1 mix on tile and gypsum bases, the suction of these materials is taken into consideration. When you sacrifice this suction by plastering on wet scratch, it is necessary to lower your sand content to allow for this difference. That is why it is so important to stick with the 2 to 1 proportion on winter jobs. ; .v ^ond, the scratch coat should be allowed to dry, so' that the excess water has a chance to evaporate in the air. To accomplish this, it is sometimes necessary to let the scratch coat stand much longer in the winter time, because of slow drying conditions, unless artificial heat is provided. Applying the brown coat to a dry scratch coat insures a better bond and more strength; better bond be cause the suction of the scratch coat pulls the min ute gypsum crystals firmly into the pores of the scratch mortar binding the two coats more tightly together. By the same action more strength is obtained, as the water is pulled out of the brown coat, producing a denser mass. Third, it is truly essential to have proper heat and ventilation when plastering in the .winter to avoid Rales governing viator plastering art tightening. Saiaa aorthara ciciH aao tparifj tha day am which lumm uadar oaaHructioa nuat ba aaciaaad aad faraace boat turaad pm bafara frJ--"it nay bo applied. Oa that job by David Dovidaoa, Inc^ Chicago plasterer, caatmaat wiadowa oro crocbod apaa aad daor ia rlmad Faraaca ii operating to provide necessary bait Scratch aad brown coot* art Rod Tap Camtat Plaatar. Finish coat will ba Grand Prize 1 "sweat-outs". Heat is usu ally provided with salaman ders, sufficient to maintain a minimum temperature of 40 degrees F. Higher tem peratures are desirable if they can be maintained eco nomically. Where jobs are heated by salamanders, it is necessary to prevent the direct heat from these burn ers from striking the plaster surface. A shield should be placed around and over the salamander, so that the heat is evenly distributed and not concentrated in one or two spots. This precaution is es sential, as gypsum will slow ly start to recalcine at about 120* F; that is, the water necessary to hold the gypsum in its rock-like state, will be driven off, reducing the gypsum to a powder such as it was when it was taken out of the bag. Doors and windows should be covered, but some open ing should be provided to supply ventilation to carry away moisture from the rooms. If these rules are followed on all jobs, plasterers need have no difficulties with winter work. Good Mod ia vital for quality plaster. The differaate ia strength is show* by tbo tbrao fradar of sead illsstrated. Tbo boat frada rf Had it shown at tbo left, about. Balov, loft, ia shown a vail pbiMftd with Rod Toy Consent Plotter, aautf the batt grade of Mad, aad this ia ao bard a knif* voa't cat it. la tha center, a awdiaa Had it abova. Tbo plastered veil, below ccotcr, is coned and caaaos be cot away. Set it is aoc a* hard as the vsll si the Wt which racists kaife pravers. Quality plaster caa't be obtained with the fine Mad. At the right is e panel ef peer qoahty plaatar. Note bow soft it is. The kaife readily cots law it. >t Pj 4 BCD TOPICS. DICKMtfR SI. 1*41 rich white smooth-working T//A7S F/M/SM/V(rl/M! Rich and buttery In "feel," USG dean, whko color that make* walla look (heir beat. USG Finaalung timu are made from selected rack in com* pletely modem nlla. Teat* to shuts a uniform product are constantly made at every phase of manufacture. You'll like the good-looking finishing job* you can do with USG Finishing Lima*. You11 like the way h spr*ad* out, -- one result of finer grind. USG Ftntdung Lime* are the result of more than 40 year* experience in the manufacture of quality plaster* and other building material*. Grve USG Finishing Lone a try on your next job. You can get information from your local USG building material dealer or write direct to United State* Gypsum Company, 300 W. Adams Street, Chicago, fllino,*............. where research develops better, safer building materials. AN ELEVATING EXPERIENCE SWEAT-OUTS By VIRGIL ESTES, Semco Representative UNITED STATES GYPSUM COMPANY We are now at the time of year when we often hear on a plaster job, ''this plaster has been on the walls several days and is still wet." This occurrence is com monly known as the forerunner to a "sweat-out" condition. A "sweat-out" condition on a job occurs mainJy during the fall, winter and early spring months when the relative humidity is high with very poor natural dry ing conditions. During this peri od, any job that has been plas tered should be protected by us ing artificial heat during freezing weather and providing proper ventilation. - it is well known to plasterers that a good plaster job should be dried out as fast as possible after the material has set. Excess heat should not be applied and. unless weather is freezing, nat ural or forced ventilation will suffice. Since gypsum is soluble in wa ter, when excess water is left in the plaster it will gradually dis solve the gypsum. The fonger this condition is allowed to prog ress, the greater is the likelihood that the job will be lost. . On any job showing evidence of being soft and saturated with moisture the only possible solu tion should be used at once: namely, proper drying and ven tilation. Heat alone will not do the job since heat only raises the temper ature of the room or building; consequently, some forced venti lation is necessary to drive out the moisture-laden air. Proper ventilation can best be accomplished by lowering the windows a few inches, or cracking doors, depending on outside tem VwtalattM sad b**t sr* proparly provided. T!ir* Is n fog m dw windows. Tbo talunandor U throwing off enough Hose to msmtsia the aocoMsry drying conditions. It is piscod in tbo contor of tho room, so that tbo plsstor will not bo exposed to excessive boot. If it is accessary to place s tolamaader near tbo wail, Insu lating Rocklacb should bo placed between, with tbo foil side toward tbo salamander. Tbit will protect tbo plaster. perature. In cases where fans are available and on jobs Another contributing which have remained damp several days, these should be cause of a sweat-out is an turned on immediately.The best heat is between 70 & 75" F. oversanded plaster job. This extra sand necessarily dis tributes the gypsum over a greater area and the gypsum content is more likely to ab sorb more moisture. It must further be remem bered the longer a job re mains in a sweat-out condi tion the less the ultimate final strength of the wall will be. The final strength is dependent upon how much time has elapsed since the condition was found, and. for this reason, jobs should be carefully watched and, if . they do not dry out in a few 1 days, the above recommen dations should be applied. RIO TOPICS, OKCKMIKR 11, 1941 Pfi 7 -.ris-etx-- When two parti of finith lima bfdnta (dir) te M part |in|ia| by weight arc combined, a perfect putty coat it obtained, (top left); by cutting the gauging to one part in four, or 2J% ganging to 79% hydrate, check cracki are likely to occur (top right); If the min i* 19% gauging and *J% dry hydrate, expect exteative checking (lower left); it ii alao im portant to hare the correct amount of water to avoid surface bubbles Uke those at lower right. "The boss humors him! He once studied art, so now he insists on signing each wall he works on." IN DECEMBER OR IN DETROIT How to Get Best Results with Gauging Plaster Gauging plaster properly used with lime erves a three-fold purpose. First, it pro vides a surface that has an early strength, and one which will withstand the wear and tear of time. Second, it provides a smooth surface with a minimum of troweling which will receive nearly all types of decorations. And third, it permits early application of these decorations. Gauging plaster is an extremely sensitive plaster and is manufactured under most ex acting supervision. It is coarse enough to provide rapid soaking at the board, and maximum strength on the wall, yet fine enough for the average cornice work "run" on the job. As this is a specialized product, it should be treated as such. In storing on the job it should be kept dry, until ready for use. The mouth of the bag should be kept closed between gauges, to prevent contamination. To use, gauging plaster should be sifted into the water in the putty ring until most of the water is absorbed. Hastening the soak by forcing the gauging under the water knots the plaster which, when applied to ceiling or wall, causes streaks. When the gauging is properly soaked, it blends per fectly and easily with the lime putty, with a minimum of working. Gauging plaster should be used in the proportion of three (3) parts of finish lime putty to the one (I) part of gauging plaster by volume, which is equal to 2 parts dry lime by weight and one part gauging by weight. A simple rule to follow in ordering finish is to buy in units of 4 bags (50lb.) of USG Hydrated Finishing Lime to one bag (100 lb.) of Red Top Gauging Plaster. The use of the proper amount of gauging insures a perfect job and does much to eliminate the possibility of check cracking, dusting of the finish, (which leads to paint and paper failure), and bond failures. NEXT SUMMER-DRY-OUTS "Dry-out" means that the water that has been mixed with the plaster has evaporated from the wall before the plaster has set. By far the greater number of plaster troubles during the hot summer months are "dry-outs." They can be cured, but it is easier to prevent them. HOW TO PREVENT "DRY-OUTS" Since the setting of gypsum plaster is a law of nature, plaster will, in time, always set if the neces sary moisture is present. Therefore, the following three simple precautions will prevent dry-outs: First. Before plastering in warm weather, screen the openings so that the hot winds cannot strike the walls. Second. If wood lath is used, soak thoroughly the day before plastering and wet them again an hour or so before plastering. Besides helping to prevent dry-outs, wetting the lath as directed will reduce the danger of lath buckling. Third. Apply plaster to proper thickness, because such plaster is les liable to dry out than a too thin mat. J1 Detroit I 9* RED TOP PLASTER SETS THE SAME Ic Jww't matter where--it dtwa't Top Cwni Flatten, the tettiai tine ii itter wire-- yoe te Rad ritkie very marrow limit*, Standardized manafactariag practice* and ceamteat laboratory ead field invemigation, pin* USG'* 40 yean experience ia the maaefactnre of qaelity baildiag material*, have largely eliminated what we* oace a eenree mi ceaetaat trookie. Variation* la tatting time (till exact, bat the range of variation ka been *o greatly antrowed that, for all practical parpem*. ic may be taid te have canted to exist. Uniform tettiag time ia bat om of the tea Red Top Cement Platter advantage* that mlhminmts mem job troablm! Read the lin of advantage*, then give Red Top Cement Flatter a try on yoar next job! Red Top Cement Plaster Advantages | They *et property, ohether tended one e one o* throe to one. 2 TWv ** wapertv with dee* er dirty tend. a The* tot P*npnHy *e or eoerte teed *W*le the Hmfti mt 3 A. 4. T, M. tpeclffcetient ter tie* w4 tend. 4 They * property with tinea or dirty water. ^ Thm t* evenly, end. once tferted. mt edformlf. 7 They iemro ntialmem powJMUty mt dry-net. 8 They minimi** difference* la tnMnq Haw -rirty ht hot nr cold woetlwr. They hev* earned rlcbenit and tM that pivot eety mitine, f*r prnediey quditiet, rvtelHnq |* r mem I* her. (0 They remti* pietNc end -nrteMn ter Ineper period ml time. 9 CO ooU1 oo UNITED STATES GYPSUM COMPANY, )M W. Adam* Jt^ Chicago, Illmoit, where rotearck develop* better, tafer baildiag materiel*. ., STRANGE AS IT SEEMS. A FRESCO, PAINTED ONTHE PLASTER. WALL OP THE oldest throne ROOM \N THE WORLD. Pb STILL BRILLIANT AND UNDAMAGED AFTER _ MORE TUAN 4000 yEAff<=, / Enlace ofMinos- Crete... 1> TOPICS, DICIMIH 31. 1M1 .............................. by John Hix "The ANCIENT ASSVRlANS USEP PLANTER, tor. / DECORATING PURPOSES / Aheir great ClTlES STOOD IN WHAT l<=, NOW IRAQ/ PRESENT Oil CENTER OF THE NEAR EAST) ' -a. o. .'WMZ4>!4V>:V>. rvi ^an of Putter wnw BONE`S OF -STONE/ icicle^P3WtoP^RtlFhT^S AmHoOvies j 'C^> ARE MADE OF PLASTER/ "For loose snow ctvpsum is used-- FALLINGS ENOW IS OFTEN FEATHER'S OR UNTOASTED CORNFLAKES/ PLASTER BODIES... Mexico... JUST A FEW HOLES MAKE ijbard to believe that a lot of boles 14 inches apart can help us to do r job. But it's truel perforations do -- lical key to the r to Rock* ^5, ''erio* , the Perforated Rocklath---like Plain Rocklath and Insulating Rocklath -- is made of gypsum, ft is permanent--unaffected by time, decay, or vermin; it is quickly erected -- lath can be scored and broken easily. And plasterers like the way the perforations slice the plaster from the troweL Your local building material dealer can give you complete information about Perforated Rocklath or we will be glad to send you full details if you write us direct United States Gypsum Company, 300 W. Adams St, Chicago, Illinois, where research develops better, safer, building materials. Question: How can I overcome shrinking and cracking of plaster -behind wood stoves? Nick Duran 819 Maple St. Manistee, Michigan Answer: The cracks which you describe could be caused by one of the following reasons: First, dry-oats; second, calcination. If the job is of new construction and the defect shows up before completed, the trouble is due to a dry-out. This occurs because the water of crystallization dried out before the plaster had taken its set. If the defect manifests itself after a year or so of exposure to heat, the trouble is due to recalcination or driving the water out of the plaster after the set had taken place. We feel that some protection should be placed behind the stove to prevent the intensive heat being subjected direct to the plaster. Question: Is there a good bond between tar and plaster? Thomas P. Poore, Washington, D. C. Answer: We do not recommend the application of plaster over tar or asphaltic waterproofing compounds. When plastering direct to such bases, we have known of bond bilures and plaster dis coloration. We recommend always to apply furring and lath for a piaster base. Question: What product do you recommend for running an arch? What material is most satisfactory for running molds above ^kitchen and bathroom wainscots? - . - . .: George W. Kregor , . 404 North Elm Street -. Pittsburg, Kansas . Answer; Red Top Moulding Plaster mixed one part moulding to one part USGor Red Top Finishing lime (dry weight) is recom mended for all run work. Question: What causes such a terrific suction at times? A. F. C. 101 Park Avenue Summit, New Jersey Answer: Excess suction is caused by one or a combination of the following reasons: First, oversanding of the base coat; second, extremely dry base coat; third, hot weather; fourth, dry-out of the base coat Question: In a three coat job, after the brown coat has been ap plied and darby used, is it proper to use a 8oat when plaster has begun to set and thereby minimize the cracks which often occur when lath are not spaced properly? P. Crouch Lamrti ar. `M`o. Answer: In any plastering you should not work the plaster after the gypsum at the surface has started to set as this will destroy the strength of the work. The use of Rocklath would, of course, eliminate the difficulty due to spacing. Question: I have trouble occasionally with small cracks running clear through the ceiling in the same direction as the lath. One carpenter says it's caused by a sagging joist; another says it's caused by putting a narrow strip of Rocklath in the center about 4" wide. Who is right? - John Moren 102--24 St. Wellsburg. W. Va. Answer: It is possible that both explanations you offer for the appearance of a crack down the center of plastered ceilings could be correct _ The most common cause is your first suggestion, that the joists sagged. If they are not spaced over 16" on center, and are large enough to prevent sagging, no cracking should occur. However, you mentioned putting a 4* strip of Rocklath down the center. It is evident that the dimensions of the room were such that full pieces of Jath could not be used, and that you have had to fill in with a 4" strip. Where this is the case in the future, we would suggest that this strip not be put in the center, but at or near the wail intersection. In addition to this precaution, it would be well to reinforce this narrow strip of lath with a piece of metal lath wide enough to completely cover both sides of the strip. Question: I have a lot of trouble when plastering over OLD ceil ings. The old lath buckles. The only way I can get satisfaction is to use old hair mortar in three coats. First to scratch it and iet dry out and then to go back and doubte up with Red Top. Can you suggest any other way I can do it with Red Top as it is a lot of work to mix hair mortar, - J. McEntee, . 240 Geneva Ave. Dorchester, Mass. Answer: Of course, Rocklath replacing old wood lath would give a much more satisfactory job, and would be worth more than its cost to your customer. We realize that at all times you cannot secure both a lath and piaster job. so we can only suggest that you thoroughly clean the wood lath and wet them the night before, and again immediately before plastering. With Red Top Double Fibered Plaster and these precautions you should have no further trouble. IP'hat art jotr gnttriour on lathing and plastering? Yon yjill rertrnt a dollar for each one published. Send them to the editor, Red Topics, 500 XT. Adams Street. Chicago. III. ( RKD TOPICS. OKCKMBH 31. 1*41 im. m u**'CM*' co J** ..1'"',,` 1--"ill-- * ,, ,aUPm1 |IW . * 5 "rf nUuU*"1** __ *SttWf**-**' ,a*iVT ,tU * ,,4 W? "'.! *" '"T'. ' *''" ,, ,,.r. </u^" - ,,..l* '**<T c--^**rV .** w " -v'r.TT.- s*--' -csss--- ---*7 GSSSSjtt To R. H. Chandler, district manager and sales representatives of USG. should go the industry's sincere thanks in appreciation for their attitude in aiding to secure lath and plaster for the Pen dleton Airport Housing job, awarded recently by Hazen and Clark of Spokane to Harold Hiebert. Faced with a certain order for materials if the job had gone as originally planned for wallboard interior finish, these gentle men "took their chances" for business, in competition with all other manufacturers of materials, in spending a great amount of time and money to help bring a decision for lath and plaster. In taking this action these men proved their conviction lath and plaster was the suitable material for the project, but it would have been a great temptation to those of lesser loyalty to the proper method to have taken the easier way out and signed up the waiting wallboard business. Repriottd fan Noubnw Plutcrtnf InAiatrie* *042" RED TOPICS. DECEMBER 31. 1941 Page 3 PLASTERERS RALLYFOR "ALL OUT" CAMPAIGN From the Atlantic to the Pacific--from Canada to the Gulf--a wild burst of enthusiasm has followed Red Topics' "All-Out for Plaster ing'- campaign. Contractors, lathers and plasterers are all "pitching in ' for a great utTenae to build an impregnable public demand for plaster. To do its part. Red Topics will supply you with an increasing volume of helpful ammunition. Starting with this issue, we will include in each issue a series of beautiful plaster jobs--jobs that you may proudly exhibit as reasons why "There Is No Substitute for Good Plastering." Why not start a scrapbook of pictures? And make sure that every one you know sees it. Let it explain why you take pride in your work --why plaster is THE finish for interior walls. If you haven't ordered stickers with the "No Substitute" emblem, write the Editor of Red Topics today for 100--free. You have made a fine start. Now is the time to "turn on the steam." . L. R. Solomon, architect, gave plaatar tbe leading role in planning the display room* for Ei--nbcrg St Son*, exclusive doaignora of women's apporol serving America') lending shop* and atore*. In tbe entrance, Mr. Solomon created aa sU-oeor pattern of tiny plaster casts of the Eiseaberg "Crinoline Dame" trademark. Highlighting this background are surrealistic piaster lighting fixtures. (See illustration on page 2). In the cosmetic and jewelry display room, a freely-styled planer moulding spotlights the shadow box display shelves for tbe in the curved roar walL For this wall, plaster likewise provides tbs ideal base to execute the smooth, flowing Unas of the walL ' Raising Plaster Quality The plastering industry of Los Angeles has been aware of the necessity for adequate apprenticeship training since 1925 when the Los Angeles Board of Education established the Frank Wiggins Trade School. Plastering was among the first trades to be taught. As a result, a high standard of quality has been established and maintained. The teachers, under the California Plan for Trade and Industrial Training, are first selected for their abitity as craftsmen and then trained in educational methods through courses of study at the University of California. Careful selection of students is made, and training is carried on to assure a complete understanding of all the problems that good tradesmen should know. Training is also offered journeymen, who can come to the school on their days off and keep up in the skills of mitering, mould running, trade problems and information on new materials. L. G. Stier is principal. The classes are conducted by Wm. Cole. After serving as a teacher for many years. Mr. Cole is now head of the building trades of the school, and the plastering classes are at present taught by Mr. Thomas Moran. la the main show room, plaster is used to obtain a theatrical effect. The orreliant light -- reflecting surface of plaster, has boon utilised in the euro for indirect lighting. Even the rociisad tight wells in the coiling ato molded of plaster, y r- - A frame of U S G Moulding Planar provide* a formal sotting for distioctive apparel. The' neutral color of the plaster enhance* the varied hue* of woman's wear. 1*4! mark* the 40th Anniwr--ry of tko United State* Gypsum Company. This bvinow wii founded on cha belief that "There li No Swbttitute for Good Plastering". For 40 year*, th* bunnow has continued in that belief. Today, it looki forward to tho future, (till firm in ita original belief. The experience, re--arch facilities, --reice department, and the will of U S G to maintain plaiter aa a ruperior interior wall finish will continue to be devoted to thia tool, aa in the pa*t. FOR YOUR SCRAP BOOK For page I of your scrapbook, a reproduction of the beautiful wall on the opposite page is available--free--to plasterers who ask tor it. The three views above are from the same show room-- may ba clipped end pasted on page 2 of your book. Send your requests for the picture at left, or for "There Is No Substitute" stickers to Editor, Red Topics, United States Gypsum Company, 300 W. Adams St., Chicago, Illinois. 88005 C063 *M 4 RED TOPICS. DECEMBER 31. 1*41 THE BRIDJOINT SYSTEM AND HOW TO APPLY IT Bridjoint is one of the most important quality developments for low cost plaster work. It is a better way to apply Rocklath than the straight nail-on method, as it reduces cracks at wall or ceiling angles and tends to eliminate cracking due to stud movement. Since Rocklath is used as the plaster base, the method naturally provides all of the advantages of a Rocklath wall: free of lath markings; all fireproof materials; normal sound insulation; and low cost. Perforated Rocklath is recommended, although satisfactory results may be obtained with either Insulating Rocklath or Plain Rocklath. Contractors like Bridjoint because it provides better walls at standard prices; because it solves lath worries and complaints; and because it is simple and easy to install. To Ihti prida i wail* U baaadfuL ,Tht i tw mi (Ui beano iali tm ba proud for : aalactad Bridjant to ba nra of quality walla. It helps the tradesman because it means great* er satisfaction with plaster jobs, thereby increas ing the demand for plaster in place of substitute materials. . . ' * J' * ` ' - Experienced contractors report the system costs about the same as a nailed on job. Savings obtained include the elimination of cost and ap plication time for metal lath corner reinforce ment; 25% less nails; and practically complete j use of odd lengths of Rocklath. _ - - Only twa cypat of dipt ora roquirad far tba Iridjaial lyitaa. Tba earaar dip, karwi ii V-JJ, it usad at all iatartar carman. Tba wcaad clip--W-22--ia t* bind fraa aada af Irckltth togatbar bat iraaa scads. Tba waakast point wbara screw it lawart. Tba fine baard u placad ra aada faa midway batwaau studs. W.JJ coraar dip* ara appliad bafara board U placad and nailad. Tap cwtna ia appliad arsuad tba rata lint. Tba latbar awasarsa tba baard for required brokaa joist, tbaa cats to fit. With clips oa tba board, it it farcsd ia placa to fit tangly. Clips fit tightly agaiatt joists. Racklttk slips bahsad oad of otbar board. Aftar tba tap eoana is appliad round tba roan, coiling is scartad. Board is aasily slip- pad iato W. dipt alraady ia placo. Nats that a# Bails are drirea sc corners. Twa sails are drjran ia sida ef board away froai coraar. Conor clips sat nailed to frana. Eads of Rocklath most break batwaaa joists oa coiling s wall as walls. As applicatioa procaadt, a W-22 clip is plscad at sack joist. Tba sacoad coarsa of RockUtb is nsilad ia tba customary way--fire nails at aach joist, using a standard Rocklath nail. Aftar caiiiag is Iatbad, work is coetinuad ao wall*. Nats *)) dips at lawar right aa baard bain* aractad and in placa at joint. Wall is lathad to floor. Last court* is cat about 96* lots thnn ramsiuiag spare, than slippod iato clip at joints share. At cantors, boards aiast ba tlippad iato W. 33 coraar dip, ss wall aa W-22 jaiat dip abare. Extra nailing at joints it eared. RED TOPICS. DECEMBER 31, 1941 Points to Watch Pay* 5 on Winter Jobs By J. H. Boyle, Service Representative United States Gypsum Company When winter comes, plaster jobs need more attention.' While the fundamental rules of plastering apply to all seasons, we shall point out some of chose governed by the winter, with particular respect to metal lath. First, watch proportion ing. Scratch should be mix ed 2 to 1 by weight. It should have enough thick ness to provide suction for the brown coat, and suffi cient strength to hold the tath rigid. It has been my experience that cracking on metal lath sometimes becomes a prob lem in the winter. One of the primary reasons for this is the lack of strength in the brown coat. When we spec ify 3 to 1 mix on tile and gypsum bases, the suction of these materials is taken into consideration. When you sacrifice this suction by plastering on wet scratch, it is necessary to lower your sand content to allow for this difference. That is why it is so important to stick with the 2 to 1 proportion on winter jobs. Second, the scratch coat should be allowed to dry, so that the excess water has a chance to evaporate in the air. To accomplish this, it is sometimes necessary to let the scratch coat stand much tonger in the winter time, because of slow drying conditions, unless artificial heat is provided. ' Applying the brown coat to a dry scratch coat insures a better bond and more strength; better bond be cause the suction of the scratch coat pulls the min ute gypsum crystals firmly into the pores of the scratch mortar binding the two coats more tightly together. By the same action more strength is obtained, as the water is pulled out of the brown coat, producing a denser mass. Ralat govaraiag wintar planaring ara tightening. Soma northern citiai amr (pacify tba day as which boaaaa andor MUiracoaa man ba aaclotad aad faraaca haat caraad aa bafora planar may ba applied. Oa job by DtrM DtrUtta, lac^ Chicago plaatarar, caaemeat wladawt ara crackad opan aad door ia -1rrtil Faraaca ia operating to proVida aecewary boat. Scratch aad brawn coat* ara Rad Tap Cement Planar. Fiaiah coat will ba Grand Prise Lima. Third, it is truly essential to have proper heat and ventilation when plastering in the winter to avoid "sweat-outs". Heat is usu ally provided with salaman ders, sufficient to maintain a minimum temperature of 40 degrees F. Higher tem peratures are desirable if they can be maintained eco nomically. Where jobs are heated by salamanders, it is necessary to prevent the direct heat from these burn ers from striking the plaster surface. A shield should be placed around and over the salamander, so that the heat is evenly distributed and not concentrated in one or two spots. This precaution is es sential, as gypsum will slow ly start to recalcine at about 120* F; that is, the water, necessary to hold the gypsum in its rock-like state, will be driven off, reducing the gypsum to a powder such as it was when it was taken out of the bag. Doors and windows should be covered, but some open ing should be provided to supply ventilation to carry away moisture from the rooms. If these rules are followed on all jobs, plasterers need have no difficulties with winter work. Good tand ! vital lor quality planar. T1m difference in tctength U ikmra bp tba (km grade* of Mad illoatrated. Tk ban grada of Mad ii thown at tba left, above. Below, (aft, thown a wall pianarad with Rad Top Caanot Platter, wiag tba ban grada af Mad, aad tki* ia w hard a kaifa won't cat it. la tba caatar, a madiam tend it show*. Tba pianarad wall, below con tar, it tooad aad cannot bo cat away. Bat it it ao at hard at the wall at the left which reritte knife prewar*. Quality platter can't be obtained with the fine tand. At the right ia a panel of poor quality platter. Note bow toft it it. The knife reedily nu into it. Phi < MD TOPICS, DICIMIKK 31. 1941 TIm fail ramie of i iMt4at t* a aoft, inferior plutor. Tie UJutcradon 11 tbo loft aWi o well ia a nan tbac wu improperly boated and vwtiUtad. Noco bow oaaily it nu away with a bnifo. Tbo wall at tba right, with tbo earn* planar and proportion*, bat with corraet boat aad ventilation, it too hard to cot. rich white smooth-working TffAT!S i/SG F/N/SH/N<rJJM* Ridi and buttery m "feeL" U S G dean, white color that makes walls look their best. U S G Finishing Limes are made from selected rock in com pletely modern mills. Tests to assure a uniform product are constantly made at every phase of manufacture. You'll like the good-looking finishing jobs you can do with US G Finishing Limes. You'll like the way it spreads out, -- one result of finer grind U S G Finishing Limes are the result of more than 40 yean experience in the manufacture of quality plasters and ocher building materials. Give U S G Finishing Lime a try on your next job. You can get information from your local U S G building material dealer or write direct to United States Gypsum Company, 500 W. Adams Street, Chicago, Illinois.............. where remarch develops better, safer building materials SWEAT-OUTS Service Reprotontatiro UNITED STATES GYPSUM COMPANY We are now at the time of year when we often hear on a plaster job, "this plaster has been on the walls several days and is still wet." This occurrence is com monly known as the forerunner to a "sweat-out" condition. A "sweat-out" condition on a job occurs mainly during the fall, winter and early spring months when the relative humidity is high with very poor natural dry ing conditions. During this peri od, any job that has been plas tered should be protected by us ing artificial heat during freezing weather and providing proper ventilation. . It is well known to plasterers that a good plaster job should be dried out as fast as possible after the material has set. Excess heat should not be applied and, unless weather is freezing, nat ural or forced ventilation will suffice. Since gypsum is soluble in wa ter, when excess water is left in the plaster it will gradually dis solve the gypsum. The longer this condition is allowed to prog ress, the greater is the likelihood that the job will be lost. On any job. showing evidence of being soft and saturated with moisture the only possible solu tion should be used at once: namely, proper drying and ven tilation. Heat alone will not do the job since heat only raises the temper ature of the room or building; consequently, some forced venti lation is necessary to drive out the moisture-laden air. VutilitiM aad Wu in properly provided. TWrt it no fog on tW window*. Tba ulamander it throwing off aoaagb hoot to maintain tba necemary drying conditions. It it placad in tba cantor Proper ventilation can best be accomplished by lowering the windows a few inches, or cracking doors, depending on outside tem of tba room, to that tba piaatar will oat ba axpaaad to axcataivt heat. If it it aaccttary to pfaca a aalamandar naar tba wall, ["lacing Rocklath thould ba placad baewaaa, with tba foil tida toward tba aalsmaadar. Tbit will protacc tba planar. perature. In cases where fans are available and on jobs Another contributing which have remained damp several days, these should be cause of a sweat-out is an turned on immediately.The best heat is between 70 & 75* F. oversanded plaster job. This extra sand necessarily dis tributes the gypsum over a greater area and the gypsum content is more likely to ab sorb more moisture. It must further be remem bered the longer a job re mains in a sweat-out condi tion the less the ultimate final strength of the wall will be. The final strength is dependent upon how much time has elapsed since the condition was found, and, for this reason, jobs should be carefully watched and. if they do not dry out in a few days, the above recommen- fhtions should be applied. RID TOPICS, OCCIMBIR SI. 1941 Pag. 7 J -` __ ________ l -hvatj*S^jiaifr;, ' ~..................... Vka two ports of finish limo hydrate (dry) to on* port ganging by weight oro combined, perfect putty cost i* obtoined. (top left); by cutting the gauging to one port in four, or 257c gouging to 7f7r hydrote, check crocks ore likely to occur (top right); " ** *** u ,5<7f **u*ift* *ad *5<rc dry krar*"* expect extensive checking (lower left); it is oleo im pttrtaot to hove the correct omouot of water---to ovoid rorfsce bubbles like those ot lower right. ; * --T~ -- 'The boss humors him! He once studied art, so now he r*" insists on signing each wall he works on." . IN DECEMBER OR IN DETROIT How to Get Best Results with Gauging Plaster Gauging plaster properly used with lime of the water is absorbed. Hastening the serves a three-fold purpose. First, it pro soak by forcing the gauging under the water vides a surface that has an early strength, knots the plaster which, when applied to and one which will withstand the wear and ceiling or wall, causes streaks. When the tear of time. Second, it provides a smooth gauging is properly soaked, it blends per surface with a minimum of troweling which fectly and easily with the lime putty, with will receive nearly all types of decorations. a minimum of working. And third, it permits early application of these decorations. Gauging plaster is an extremely sensitive plaster and is manufactured under most ex- . acting supervision. It is coarse enough to provide rapid soaking at the board, and maximum strength on the wall, yet fine Gauging plaster should be used in the proportion of three (3) parts of finish lime putty to the one (1) part of gauging plaster by volume, which is equal to 2 parts dry lime by weight and one part gauging by weight. enough for the average cornice work "run" A simple rule to follow in ordering finish on the job. As this is a specialized product, it should is to buy in units of 4 bags (501b.) of USG Hydrated Finishing Lime to one bag (100 lb.) of Red Top Gauging Plaster. be treated as such. In storing on the job it should be kept dry, until ready for use. The use of the proper amount of gauging The mouth of the bag should be kept closed insures a perfect job and does much to between gauges, to prevent contamination. eliminate the possibility of check cracking, To use, gauging piaster should be sifted dusting of the finish, (which leads to paint into the water in the putty ring until most and paper failure), and bond failures. NEXT SUMMER-DRY-OUTS '"Dry-out" means that the water that has been mixed with the plaster lias evaporated from the wall before the piaster has set. By far the greater number of plaster troubles during the hot summer months are "dry-outs." They can be cured, but it ts easier to prevent them. HOW TO PREVENT "DRY-OUTS" Since the setting of gyptutn plaster is a law of nature, plaster will, in time, always set if the neces sary moisture is present. Therefore, the following three simple precautions will prevent dry-outs: First. Before plastering in warm weather, screen the openingi so that the hot winds cannot strike the walls. Second. If wood lath is used, soak thoroughly the day before plastering and wet them again an hour or so before plastering. Besides helping to prevent dry-outs, wetting the lath as directed will reduce the danger of lath buckling. Third. Apply piaster to proper thickness, because such piaster is less liable to dry out than a too thin coat. 1 oeraoir J BED TOP PLASTER SETS THE SAME Ic deeaa't xatUr where -it doem*t Mint whan--yon ui Rad Tap Ctont PIattar*, tk tatting tiat it, within vary ttrrtw limit*, tha tamat Standardized maanfactmring practice* and comment laboratory and field invattigatiau, plot U $ G't 40 yean axpariauca in tha Mtftettn of qaality building malarial*, hava largely aliminatad what waa anca a aonree of eonttant trouble. Variation* in aoctiag tint* will (tin, bat cfco rang* of variation hai bom to graatly nnrrowad that, for all practical pnrpoaoa, it may bo aaid to havo caatad ta axial. Uniform tatting time ia bwt on# of tho u* Rad Top Comoat Plaacor advaatagaa that etaetfnete moat job troubloa! JUad tho lift of advantage*, than give Rod Top Cement Plaitor a cry on yonr next fob! Red Top Cement Plaster Advantages | Fhay Mt property, whether loaded oaa to ar 2 They tot praparty wftti dam or Arty taad. 3 nrj 4 5 6 Thar aot avaaty. 2 They laiara mtalmem petalbltHy a* dry-oat. 9Thay fcava win*) Hchaoia aod dip that pivot oaty mMap, far ipraadlep qwaliHat, ratoltlap >a marlmam covarapa rtth mW. mvm tabor. 10 They ramala ptottte and workable far Seapar parted of time. UNITED STATES GYPSUM COMPANY, >W W. Adam* St, Chicago, Mine**, whore raaaarch develop* batter, anfar bntiding material*. PJ STRANGE AS IT SEEMS RED TOPICS. DECEMBER 31, 1*41 by John Hix w-that% FU^S KlCL&S^TOH^THlf MCVIE.E, , ^ are made op planter/ "For too^e ntw qvr^liaa 4 i*eep-- FALUNO E.NOW l*=> OFTEN p BATHERS OR UNTOAftTED CORNFLAKES / Question: How can I overcome shrinking and cracking of plaster behind wood stoves? Nick Duran 819 Maple St. Manistee, Michigan Answer: The cracks which you describe could be caused by one of the following reasons: First, dry-outs: second, calcination. If the job is of new construction and the defect shows up before completed, the trouble is due to a dry-out. This occurs because the water of crystallization dried out before the plaster had taken its set If the defect manifests itself after a year or so of exposure to heat, the trouble is due to recalcination or driving the water out of the plaster after the set had taken place. We feel that some protection should be placed behind the stove to prevent the intensive heat being subjected direct to the plaster. Question: Is there a good bond between tar and plaster? - .................. .. Thomas P. Poore, Washington, D. C. Answer: We do not recommend the application of plaster over tar or asphaltic waterproofing compounds. When plastering direct to such bases, we have known of bond failures and plaster dis coloration. We recommend always to apply furring and lath for a plaster base. . Question: What product do you recommend for running an arch? What material is most satisfactory for running molds above Tkitchen and bathroom wainscots? . . ___ ___ George W. Kregor _ 404 North Elm Street- *- - . v- Pittsburg, Kansas ` Answer: Red Top. Moulding Plaster mixed one part moulding to "..one part US G or Red Top Finishing lime (dry weight) is recom mended for all run work. . - Question:'"Whkt-causes eucht terrific suction^at'times? ~ . ; ' ' .- A. F. C * * 101 Park Avenue Summit, New Jersey Answer: Excess suction is caused by one or a combination of the following reasons: First, oversanding of the base coat; second, extremely dry base coat; third, hot weather; fourth, dry-out of . the base coat. . Question: In a three coat job, after the brown coat has'been ap plied and darby used, is it proper to use a float when plaster has ' begun to set and thereby minimize the cracks which often occur when lath are not spaced properly? LP. Crouch mar. Mo. Answer: In any plastering you should not work the plaster after ' the gypsum at the surface has started to set as this will destroy ; the strength of the work. The use of Rocklath would, of course, eliminate the difficulty due to spacing. 6l)6ata JUST A FEW It's hard to believe that a lot of holes spaced 4 inches apart can help us to do such a better job. But it's true! Here's what the perforations do -- They add a mechanical key to the strong, natural bond of plaster to Rock* lath. This double grip of plaster to Perfo* rated Rocklath gives a one-hour fire rating to partitions constructed of V: inch plaster over % inch Perforated RocklathI This double grip means increased overall wall strength! This is "plus" strength -- added to the rigidity of the large 16 x 49-inch Rocklath panels. ^iffatence HOLES MAKE Perforated Rocklath---4ike Plain Rock lath and Insulating Rocklath -- is made of gypsum. It is permanent--unaffected Question: I have trouble occasionally with small cracks running clear through the ceiling in the same direction as the lath. One carpenter says it's caused by a sagging joist: another says it's caused by putting a narrow strip of Rocklath in the center about 4' wide. Who is right? . John Moren 102--24 St. Wellsburg, W. Va. Answer: It is. possible that both explanations you offer for the appearance of a crack down the center of plastered ceilings could be correct. The most common cause is your first suggestion, that the joists sagged. If they are not spaced ove;- 16' on center, and are large enough to prevent sagging, no cracking should occur. However, you mentioned putting a < strip of Rocklath down the center. It is evident that the dimensions of the room were such that full . _ pieces of lath could not be used, and that you have had to fill in with a 4* strip. Where this is the case in the future, we would suggest that this strip not be put in the center, but at or near the wall intersection. In addition to this precaution, it would be well to reinforce this narrow strip of lath with a piece of metal lath wide enough to completely cover both sides of the strip. by time, decay, or vermin; H is quickly erected -- lath can be scored and broken easily. And plasterers like the way the perforations slice the plaster from the troweL Your local building material dealer can give you complete information about Perforated Rocklath or we will be glad to send you full details if you write us direct. United States Gypsum Company, 300 W. Adams St, Chicago, Umov, where research develops better, safer, building materials. Question: I have a lot of trouble when plastering over OLD ceil ings. The old lath buckles. The only way I can get satisfaction is to use old hair mortar in three coats. First to scratch it and let dry out and then to go back and double up with Red Top. Can vou suggest any other way I can do it * ith Red Top as it is a lot of work to mix hair mortar. J. McEntee. 240 Geneva Ave. - Dorchester, Mass. Answer: Of course, Rocklath replacing old wood lath would give a much more satisfactory job, and would be worth more than its eost to your customer. We realize that at all times you cannot secure both a lath and plaster job, so we can only suggest that you thoroughly clean the wood lath and wrt them the night before, and again immediately before plastering. With Red Top Double Fibered Plaster and these precautions you should have no further trouble. o Wbat are your qmtuiont on lathing and plastering? Yam will recent a dollar for tatb one published. Send them to the editor. Red Topiet, S 300 XT. Adams Street. Chicago, III. O n <7*