Document KG6Bj8bXa7Rap08g0odvqO4Mx

TECHNICAL INFORMATION GYPSUM PLASTER BASE COATS & FINISHES FINISHING LIME & EXTERIOR STUCCO s' r s.. r* r i ALBANY, N. Y. ATLANTA. GA. tr BALTIMORE. MD. k BIRMINGHAM, ALA. BOSTON. MAS5. BUFFALO. N. Y. U n i t e d States Gypsum For Building For Industry ' ''-V/ ' .' Gypsum Lime * Steel * Insulation * Roofing Paint GENERAL OFFICES --300 WEST ADAMS STREET, CHICAGO 6, ILLINOIS CHARLOTTE, N. C. CHICAGO. ILL. CINCINNATI, O. CLEVELAND, O. Dallas, tex. DENVER, COLO. DETROIT, MICH. GRAND RAPIDS. MICH HARRISBURG, PA. HOUSTON, TEX. INDIANAPOLIS, IND. JACKSONVILLE, FLA. KANSAS CITY, MO. LOS ANGELES, CAUF. MILWAUKEE. WIS, MINNEAPOUS, MINN. NEWARK, N. J. NEW HAVEN, CONN. NEW YORK, N. Y. OKLAHOMA CITY. OKLA. OMAHA, NEBR. PHILADELPHIA. PA. PHOENIX, ARIZ. PITTSBURGH, PA. PORTLAND, ORE. PROVIDENCE, R. 1. RICHMOND, VA. ST. LOUIS, MO. SACRAMENTO, CAUF. SALT LAKE CITY. UTAH SAN FRANCISCO, CALIF, SEATTLE, WASH. SYRACUSE, N. Y. WASHINGTON. D. C. BB01B 1448 r T4 "RED TOP," "BONDCRETE," "PYROBAR," "ROCKLATH," "ORIENTAL," "SABINITE," "IVORY," "GRAND PRIZE," "CHAMPION." "STAR" and "USG" are registered trade-marks owned by United States Gyp sum Company and are used by it to distinguish products of its manufacture. "RED TOP" identifies the particular plasters and finishes manufactured only by the United States Gypsum Com pany. "BONDCRETE-" identifies the particular plaster for con crete surfaces manufactured only by the United States Gypsum Company. "PYROBAR" identifies the particular gypsum partition tile manufactured only by the United States Gypsum Company. "ROCKLATH" identifies the particular gypsum lath or plaster base manufactured only by the United States Gypsum Company. "ORIENTAL" identifies the particular colored finishes manufactured only by the United States Gypsum Com pany. "SABINITE" identifies the particular acoustical plaster manufactured only by the United States Gypsum Company. "IVORY" and "GRAND PRIZE" identify the particular hydrated lime manufactured only by the United States Gypsum Company. "CHAMPION" and "STAR" identify the particular white gauging plasters manufactured only by the United States Gypsum Company. "TRUSSTEEL" identifies the particular truss designed stud manufactured only by the United States Gypsum Company. AP-2 Rev. 6-1949. Copyright 1948 United States Gypsum Company t f r r i r 4___________ BASECOAT PLASTERS RED TOP* CEMENT PLASTER DESCRIPTION RED TOP Cement Plaster is a neat gypsum plaster re quiring the addition of an aggregate and water on the job. It is the basecoat that receives the finish coat plaster. Complies with ASTM Designation C28-40 for "Gyp sum Neat Plaster" and Federal Specification SS-P-402, Type N. FUNCTION AND UTILITY RED TOP Cement Plaster is used for scratch (1st coat) and brown (2nd coat) wherever good plastering aggre gate is available. FIREPROOF--Made from gypsum rock, it is incom bustible and will not transmit high temperatures until completely calcined: a slow process. In this respect, gypsum plaster is unique. See fire test data page 8, for authoritative fire ratings. ECONOMICAL--RED TOP Cement Plaster is lowest in cost of the various types of gypsum basecoats because: ADAPTABLE--RED TOP Cement Plaster bonds firmly The neat plaster is low in cost and is mixed with eco V with ROCKLATH* plaster base, metal lath, fiber in nomical aggregate which increases bulk and coverage. r L, sulation lath, wood lath, PYROBAR* gypsum partition tile, clay tile, porous brick and certain other approved RED TOP Cement Plaster is highly plastic, thus is easily and quickly applied by the mechanic. plaster bases. Normal usage requires little or no maintenance. RED TOP Cement Plaster is the standard of excellence for receiving such finish coats as lime putty, Keene's Cement, gypsum trowel finish, gypsum float finish, ORIENTAL* Interior finish, gypsum acoustical plas ters, etc. It is an excellent base to receive acoustical tile. RED TOP Cement Plaster is plastic, permitting wide latitude in its use for plain or curved surfaces. UNIFORM--RED TOP Cement Plaster is manufactured on a nation-wide basis within narrow limits of tolerance. Its "stabilized set" minimizes the hazards due to impure water or aggregate and job conditions. Its set is ad justed for seasonal conditions. STRONG--When mixed with good sand according to specifications, RED TOP Cement Plaster has a compres sive strength up to 1,000 lbs. per sq. in. (see test data, page 36). It is capable of withstanding normal wear and usage for the life of the building. LIMITATIONS OF USE 1. RED TOP Cement Plaster should have aggregate added strictly according to specifications. Use of too much aggregate drastically decreases its strength. Sand content is easily calculated. A No. 2 shovel full of damp sand weighs approximately 15 lbs. The light weight ag gregates are generally shipped in 4 cu. ft. bags. 2. Under no conditions should RED TOP Cement Plas ter be applied to concrete. Use BONDCRETE* Plaster, described on page 7. 3. RED TOP Cement Plaster should not be used where contact with excessive water or moisture is expected. In such instances, use portland cement-lime plaster. 4. RED TOP Cement Plaster is an interior basecoat plaster and should not be used on the exterior where exposed to the elements. 5. Because bituminous compounds do not provide an ideal base for gypsum plaster basecoats, plaster applica tion on masonry walls and concrete that have been coated with these compounds is not recommended. *Trademark Reg. U. S. Pat. Of. Page 3 BB018 1450 & I4 BASECOAT PLASTERS PLASTERING SPECIFICATIONS (FOR RED TOP CEMENT PLASTER) GENERAL PROVISIONS In cold weather a minimum temperature of 40F.shall be maintained in the building until the plaster is dry. After plaster.has set, ventilation shall be provided to eliminate excessive moisture in the building. In hot, dry weather, all openings shall be closed with sash or cloth during the application of plaster. No plaster shall be allowed to drybefore setting. SCOPE Unless otherwise specified or shown on drawings, all walls and ceilings shall be plastered as herein described. MATERIALS Basecoat plaster shall be RED TOP Cement Plaster manu factured by the United States Gypsum Company (except that the scratch coat over metal lath shall be fibred RED TOP Cement Plaster). Aggregate (Note to Architect--Select one or more of thefollowing aggregates as desired or required to meet fire resistance rating.) Sand--Shall be clean and sharp, complying with ASTM designation C35-39. Vermiculite--Shall be standard plaster aggregate com plying with ASTM designation C35-39 for particle size and shall weigh between and 10 pounds per cubic foot. Perlite--Shall be standard plaster aggregate complying with ATSM designation C35-39 for particle size and shall weigh between IVi and 15 pounds per cubic foot. Water--Shall be clean, fresh and suitable for domestic consumption. Finish Plaster--(Note to Architect--Select the desiredfinishfrom pages 10 to Id, and insert herein the applicable materials.) GROUNDS The total plaster thickness over gypsum lath, gypsum partition tile or fiber insulation lath, shall be over brick, clay tile or other masonry, it shall be W thick and over metal lath the plaster thickness shall be H" measured from the face of the lath. (Greater thickness in grounds may be required for certain fire ratings. See table, page 8.) MIXING OF BASECOATS For Three-Coat Work, the scratch or first coat over all lath shall be mixed in the proportion of one part plaster to not more than two parts sand by weight (13 No. 2 shovels of damp sand per 100-lb. bag of plaster) or 100 lbs. of gyp sum plaster to not more than 2 cu. ft. of vermiculite or perlite. The brown or second coat over all lath shall be mixed in the proportion of one part gypsum plaster to Page 4 not more than three parts sand by weight (20 NTo. 2 shovels of damp sand per 100-lb. bag of plaster) or 100 lbs. of gypsum plaster to 3 cu. ft. of vermiculite or perlite. For Two-Coat Work over masonry surfaces (except mono lithic concrete) the base (scratch double back) shall be mixed in the proportion of one part plaster to three parts sand by weight or 100 lbs. of plaster to 3 cu. ft. of ver miculite or perlite. When perlite is used as the aggregate over masonry and it is impractical to reduce suction by wetting, the amount of perlite may be increased to not more than 4 cu. ft. {Note to Architect)--In scratch double back application ofgypsum cement plaster to gypsum lath or fibre insulation lath only the proportions shall be as follows-. Two-Coat Work, over gypsum lath or fibre insulation lath, shall be in the proportion of one part gypsum cement plaster to not more than 2 lA parts of sand by weight (17 No. 2 shovels of damp sand per 100-pound bag of plaster) or 100 pounds of gypsum plaster to not more than 2lA cubic feet of vermiculite or perlite. APPLICATION OF BASECOATS (Note to Architect). Three-coat work is the preferred piaster specification, because it is more conducive to application to full grounds. It may be used throughout the job except over masonry where 2-coat work is preferred. Three-coat work should always be required over metal lath and resilient lathing systems. Three-Coat Work--Scratch (first) coat shall be applied with sufficient material and pressure to form good full keys on wood and metal lath, wire lath and wire fabric, and good bond on gypsum or fibre insulation lath, as the case may be, and to cover well, and then be scratched to rough surface. Brown (second) coat shall be applied after the scratch (first) coat has set firm and hard, brought out to grounds and straightened to a true surface with rod and darby, and left rough, ready to receive the finish (third) coat. Two-Coat Work--Base (first) coat shall be applied with sufficient material and pressure to form good full keys on wood lath, and good bond on gypsum or fibre in sulation lath or masonry, as the case may be, and to cover well, and then be doubled back to bring the plaster out to grounds, straightened to true surface with rod and darby and left rough, ready to receive the finish (second) coat. To avoid excess suction and dry-outs, it is preferable to moderately wet masonry surfaces before plastering. MIXING AND APPLICATION OF FINISHES Use the applicable finish coat specifications selected from pages 10 to 14. 1 A BASECOAT PLASTERS RED TOP WOOD FIBER PLASTER DESCRIPTION RED TOP Wood Fiber Plaster is a factorv-preparcd gypsum basecoat plaster containing finely-shredded, se lected wood fiber. It requires the addition of water onlv on the job. Complies with ASTM Designation C28-40 "Gypsum wood-fibered plaster'' and Federal Specifications SS-P402, Type W. FUNCTION AND UTILITY STRONGER--Compared to plaster sanded 1:3, Wood Fiber Plaster has: 3 times greater compressive and tensile strength. 2Y2 times greater resistance to lateral impact. 50 per cent greater surface hardness. Consequently, has greater resistance to cracking. FIREPROOF--Generally 50 per cent more fire resistant than sanded plaster. See ratings on page 8. FACTORY PREPARED--Particularly suitable where good aggregates are unavailable. Avoids dangers of im proper proportioning of aggregates. LIGHTWEIGHT--Dead load is 25 per cent lighter than sanded plaster. COST--A wood fiber basecoat plaster job costs approxi mately 15 per cent more than RED TOP Cement Plaster sanded on the job. LIMITATIONS Same as paragraphs 2, 3, 4 and 5 under Limitations for use of RED TOP Cement Plaster, page 3. PLASTERING SPECIFICATIONS (FOR RED TOP WOOD FIBER PLASTER) GENERAL PROVISIONS In cold weather a minimum temperature of 40F. shall be maintained in the building until the plaster is dry. After plaster has set, ventilation shall be provided to eliminate excessive moisture in the building. In hot, dry weather, all openings shall be closed with sash or cloth during the application of plaster. No plaster shall be allowed to dry before setting. SCOPE Unless otherwise specified or shown on drawings, all walls and ceilings shall be plastered as herein described. MATERIALS Basecoat plaster shall be RED TOP Wood Fiber Plaster manufactured by United States Gypsum Company. Finish Plaster--(Note to Architect--Select the desiredfinishfrom pages 10 to 14, and insert herein the applicable materials). GROUNDS The total plaster thickness over gypsum lath, PYROBAR gypsum partition tile or fiber insulation lath shall be Vi"\ over brick, clay tile or other masonry, it shall be iA" thick, and over metal lath the plaster thickness shall be Vi" measured from the face of lath. MIXING AND APPLICATION On all types of lath, RED TOP Wood Fiber Plaster shall be mixed with water only on the job. The scratch and brown coats over masonry surfaces (except monolithic concrete), shall be mixed in the proportion of 1 part Wood Fiber Plaster to 1 part sand by weight (7 No. 2 shovels of damp sand per 100-lb. bag Wood Fiber plaster). The scratch coat of plaster shall be applied to a thick ness of approximately W with sufficient pressure to form a good bond. Cross rake and allow to set. When partially dry, apply the brown or second coat to full grounds, allowing approximately Mi" for the finish coat. Rod and darby to a true and level surface and roughen slightly. All porous masonry surfaces shall be moderately wet ted to provide proper suction before plastering. Brown (second coat) shall be applied after the scratch (first coat) has "taken up," but before it sets. OPTIONAL INCLUSION At the option of the contractor, all brown coats may be applied to the unset scratch coat, except when plastering over metal lath or Resilient ROCKLATH ceilings. MIXING AND APPLICATION OF FINISH COAT PLASTER Use the applicable finish coat specifications selected from pages 10 to 14. Page 5 B E O IB 145; BASECOAT PLASTERS ( RED TOP SANDED PLASTER DESCRIPTION RED TOP Sanded Plaster is a factory-sanded gypsum basecoat plaster requiring the addition of water only, on the job. Complies with ASTM Designation C2N-4U for "Gyp sum Ready-sanded Plaster" and Federal Specification SS-P-402. Type S (scratch coat) or Type B (brown coat). FUNCTION AND UTILITY RED TOP Sanded Plaster is particularly suitable where good plastering sand is not available. It provides all those features described for RED TOP Cement Plaster, plus the following: FACTORY SANDED--Properly selected aggregate cor rectly proportioned and machine-mixed. COST--Slightly higher than job-sanded RED TOP Ce ment Plaster, but more economical than other gypsum basecoat plasters. LIMITATIONS OF USE Same as paragraphs 2, 3, 4 and 5 of Limitations of Use under RED TOP Cement Plaster, page 3. r PLASTERING SPECIFICATIONS (FOR RED TOP SANDED PLASTER) GENERAL PROVISIONS In cold weather a minimum temperature of 40F. shall be maintained in the building until the plaster is dry. After plaster has set, ventilation shall be provided to eliminate excessive moisture in the building. In hot, dry weather, all openings shall be closed with sash or cloth during the application of plaster. No plaster shall be allowed to dry before setting. SCOPE Unless otherwise specified or shown on drawings, all walls and ceilings shall be plastered as herein described. MATERIALS Basecoat Plaster shall be RED TOP Sanded Plaster manu factured by United States Gypsum Company. Over masonry, RED TOP Sanded Plaster (for masonry) shall be used. Finish Plaster (Nate to Architect--Select the desiredfinish from pages 10 to 14, and insert herein the applicable materials). thick, and over metal lath the plaster thickness snail be H" measured from the face of the lath. MIXING AND APPLICATION Sanded piaster shall be mixed with water only. The scratch coat of plaster shall be applied to a thickness of approximately H" with sufficient pressure to form a good bond. Cross rake and allow to set. When partiaiiv dry, apply the brown or second coat to full grounds, allowing approximately Hi" for the finish coat. Rod and darby to a .true and level surface and roughen slighdv. All porous masonry surfaces shall be moderately wetted to provide proper suction before applying scratch coat. Brown (second coat) shall be applied after the scratch (first coat) has "taken up," but before it sets. OPTIONAL INCLUSION At the option of the contractor, all brown coats may be applied to the unset scratch coat, except when plaster ing over metal lath or Resilient ROCKLATH ceilings. GROUNDS The total plaster thickness over gypsum lath, PYROBAR gypsum partition tile or fiber insulation lath shall be H"; over brick, clay tile or other masonry it shall be W MIXING AND APPLICATION OF FINISH COAT PLASTER Use the applicable finish coat specifications selected from pages 10 to 14. Page 6 c ( < t \ ( ( ( i a td O i- CO < 4* CJl CJ < < ( f _*_______________ BASECOAT PIASTERS BONDCRETE* PLASTER r c c w r n r i c r r~ c--r f DESCRIPTION RED TOP BONDCRETE is a gypsum basccoat plasterspecially formulated to bond with rough interior mono lithic concrete surfaces. It is factory prepared, requiring addition of water only on the job. There are no ASTM or Federal Specifications cover ing this type of riastcr. FUNCTION AND UTILITY BONDCRETE is plaster especially prepared for appli cation to concrete. It provides the bonding plaster to receive a browning, or leveling, coat of_RED TOP Clement Plaster or Wood Fiber Plaster when necessary. If a leveling c : at is unnecessary, the finish plaster may be applied directly to the BONDCRETE. BONDING STRENGTH--BONDCRETE adheres well to properly prepared concrete surfaces. See Surface Prep aration under Specifications for proper conditioning of concrete surfaces. This is important. The thermal coefficient of expansion of BONDCRETE is approximately the same as for concrete. LOW COST--An economical bonding coat to provide for the application of plaster direct to concrete surfaces. LIMITATIONS OF USE 1. BONDCRETE should be used only on concrete that is properly prepared for plastering. It should never be applied to smooth concrete. 2. Maximum thickness of BONDCRETE and basecoat shall not exceed Vs" on ceilings or 5s" on walls. If addi tional thickness is reqttired, metal lath shall be secured to the concrete surfaces. 3. The same as paragraphs 3, 4, and 5 under RED TOP Cement Plaster, page 3. PLASTERING SPECIFICATIONS (FOR RED TOP BONDCRETE PLASTER) 1. Under Materials of the Plastering Specification, include the following: Basecoat for plastering over concrete surfaces shall be BONDCRETE manufactured by United States Gypsum Company. 2. Under Mixing and Application, include the following: Mix BONDCRETE with water only. Concrete surfaces to receive plaster shall be properly prepared as specified elsewhere. Surfaces of walls and columns shall have a scratch coat of bond plaster, followed by a brown coat of gypsum plaster in the proportions of 1 part of gypsum neat plaster to not more than 3 parts of sand, by weight) trowelled into the scratch coat before it has set. The brown coat shall be brought out to grounds, straightened to a true surface with rod and darby, and left rough, ready to receive the finish coat. Total thickness of plaster not to exceed Vb '. Concrete ceilings shall have a coat of bond plaster scratched in thoroughly, doubled back, and filled out to a true, even surface and left rough, ready to receive the finish coat. Total thickness of plaster not to exceed If additional thickness of plaster is required, metal lath shall be secured to the concrete surface. 3. A separate paragraph must be included asfollows: *Trademark Reg. LIS. Pat. Off- Surface Preparation. Monolithic concrete surfaces shall be cleaned of all dust, loose particles, and other foreign matter. Laitance and efflorescence shall be removed by washing first with a 10 per cent solution of commercial muriatic acid and water and then with clean water to remove all traces of acid. Grease and oil shall be com pletely removed. Note to Architect:',A smooth concrete surface resulting from pouring on smooth forms, or vibrating of concrete, is an improper base for BONDCRETE application. (See Red Top Cover Coal, page 13.) Concrete surfaces shall have sufficient roughness to provide proper bond. If surfaces are not rough, they shall be hacked or bush-hammered, or a dash-coat of portland cement grout, composed of 1 part of cement and 1J4 parts of fine sand mixed to a mushy consistency, shall be applied. Using a stiff fiber brush, the portland cement grout shall be forcibly dashed on the concrete surface with a whipping motion. This coat shall be kept damp for at least 2 days immediately following its application and then allowed to dry. Before application of the plaster, the surface shall be evenly dampened if necessary to pro vide proper suction. Page 7 BB018 1454 & i BASECOAT PLASTERS TECHNICAL DATA AVERAGE TEST RESULTS MIX: COMPRESSIVE STRENGTH--psi (dry) TENSILE STRENGTH-psi Idryl COST FACTOR, LABOR & MATERIAL WOOD FIBER Neat 2600 440 100 1:1 2100 245 95 SAND 1:2 1200 170 93 CEMENT PLASTER VERMICULITE 1:3 100:2 100:3 750 500 300 120 130 90 90 95 95 PERLITE 100:2 100:3 1000 650 165 105 95 95 CONSTRUCTION FIRE TEST DATA PANEL TYPE TYPE BASE PLASTER & AGGREGATE THICKNESS RATING AND REFERENCE Weed frame Wood frame Wood frame Wood frame Wood frame Wood Frome Wood frome Wood frame 3' Hollow PYROBAR 4' Hollow PYROBAR Solid Solid Solid Solid Solid TRUSSTEElf Stud TRUSSTEEL Stud TRUSSTEEl Stud TRUSSTEEL Stud Wood frame Wood frome Wood frame Wood frame Wood frome Steel Joist*** Steel Joist*** Steel Joist*** Stee t Joist*** Cellular Stee 1 floor Cellular Steel floor Cellular Steel floor Steel Section Steel Section Steel Section Steel Section Steel Section 'i j' ROCK LATH P o n "s' ROCKLATH P' = :n ?*" Perf. ROCKIATH "j," Pert. ROCKIATH Meta 1 loth Meta 1 loth Metal Loth Metal loth Metal Lath Metal Lath Metal loth Metal lath ROCKtATH Melol lath Metal Lath Metal lath Metal lath V% Perf. ROCKLATH Vs Perf. ROCKLATH* Metal lath Metal lath** Metal loth Meta 1 lath Metal lath Meta 1 Lath Meto 1 lath Metal loth**** Metal lath**** Metal Loth**** Metal lath Metal Lath***** Metal lath***** Metal Lath***** Pyrobar-2" Solid, or 3* Hollow PARTITIONS Gypsum-Sand 1:2, 1:2 Gypsum Wood fiber Gypsum-Sand 1:2, 1:2 Gypsum.Perlite 100:2'4, 100:2)4 141 Gypsum-Sand 1:2, 1:3 Gypsum-Sand 1:2, 1:2 Gypsum Wood Fiber Gypsum-Vermiculite \00-.2]/-y, 100:33-2 Gypsum-Sand 1:3 Gypsum-Sand 1:3 Gypsum-Sand 1:2, 1:3 Gypsum-Sand 1:2, 1:2 Gypsum Wood Fiber Gypsum Wood Fiber Gypsum-Sand 1:1, 1:2 Gypsum-Sand 1:2, 1:3 Gypsum-Sand 1:2, 1:3 Gypsum-Sand 1:2, 1:2 Gypsum Wood Fiber CEILINGS Gypsum-Sand 1:2 Gypsum-Sand 1:2 Gypsum-Sand 1:2, 1:3 Gypsum-Sand 1:2, 1:3 Gypsum Wood fiber Gypsum-Sand 1:2, 1:3 Gypsum-Vermiculite 100:2, 100:3 Gypsum Wood fiber Gypsum-Vermiculite 100:2, 100:3 Gypsum Wood Fiber Gypsum-Vermiculite 100:2, 100:3 Gypsum-Perlite 100:3, 100:3 (4) COLUMNS Gypsum-Sand 1:2, 1:3 Gypsum-Vermiculite 100:2, 100:3 Gypsum-Vermiculite 100:2, 100:3 Gypsum-Perlite 100:3, 100:3 (41 Gypsum-Sand 1:3 1 A" Vi w H" H" H' H" Y\A"' 2' 2' 2' 2K' 2" H' Vs' H' Vs' W Yff Va" w H" H' l" r i' r t' w V i Y' r Yff 45 Minutes 111 1 Hour (1) 1 Hour (1) 45 Minutes 111 1 Hour 11) 1 * > Hours (1) 1 Hour (2) 2 Hours 111 121 131 3 Hours 111 13) 45 Minutes (1) 1 Hour 13) l2<4 Hours (1) 2 Hours (1) 1 Hour (3) 45 Minutes (1) 1 Hour (11 1 Hour (11 2 Hours (1) 45 Minutes (1) 121 i 1 Hour (1) 45 Minutes (I) 1 Hour (11 t Hour 121 2 Hours (1) 3 Hours (1) 3 Hours 11) 4 Hours (1) 4 Hours (1) 4 Hours (I) 4 Hours (21 1 Hour (1) 3 Hours (2) 4 Hours (2) 3 Hours 121 4 Hours (1) (!) National Bureau of Standards. I2J Underwriters' laboratories. (3) Nationally recognized fire testing laboratory--name on request. 14) Great lakes Carbon Corporation's "Permalite" Perlite. *lalh applied with I 13 gauge nails, head ond joints covered with Striplath. 1 nails. **lafh applied with \\^ , l J gauge, l (q* head barbed roofing nails, 6* O.C. reinforced concrete slab on Riblath or 2' precast gypsum tile above. `Ceiling 9" or more below floor slab. *****Metal lath spaced minimum of ]}/* from column. Page S f Trademark Reg. U. S. Pat. Off. c i ( ( i ( ( ( ( C < ( ( < < ( to to o I-* CO Ol <J1 ( 1 ( r r c c r r c c r f' r r v FINISHING PLASTERS DESCRIPTION The finish coat plaster provides the base for final wall or ceiling decoration. It is applied to a thickness of Ifi" to Is", usually over a gypsum plaster basecoat. Several types of finish coats are available, each with characteristics to serve specific requirements, and gen erally classified according to the principal cementitious ingredient as follows: 1. Lime and Gauging, commonly known as "white coat" for a smooth white trowel finish. It consists of lime, soaked to a smooth putty, and mixed with gypsum gauging plaster. With addition of sand, is adaptable for sand float finishes. The three essentials to a good white coat job are: ' r- a. Lime must be highly plastic and completely hydrated. b. Correct proportioning of gauging plaster to lime putty (see specifications) and thorough blending of ingredients. c. Careful application and sufficient trowelling to pro duce a smooth glossy surface. 2. Lime and Keene's--for extra hard smooth white trowel finish. With addition of sand, is adaptable for sand float finishes. Also available mill mixed and colored under "ORIENTAL"* Interior Finish brand. 3. Gypsum -- Trowel (smooth), or sand float prepared finishes. 4. Acoustical Plaster--(SABLVITE*), for sound absorp tion. (See page 13 or AIA File 39-B.) ESSENTIALITY OF COMPLETE HYDRATION IN DOLOMITIC FINISHING LIMES Some years ago an exhaustive investigation was under taken by the National Bureau ofStandards in co-operation with several architects and lime manufacturers to deter mine reasons for "lime bulges" (delamination of finish from basecoat) occurring on many government and private buildings. The failures investigated occurred on surfaces which had been "white coated" with dolomitic hydrated finishing limes from the Ohio fields, which have been widely used. Failures often occur 5 or 10 years after erection of the buildings. After much analysis, it was the consensus of opinion that the delayed hydration and attendant expansion of unhvdrated oxides in the "normal" dolomitic finishing limes resulted in bulging and delamination. To correct this difficulty, United States Gypsum Com pany took the lead in developing "IVORY"* Pressure Hydrated finishing lime, a "fully" or "pressure" (less than 8 per cent unhydrated) hydrated Ohio dolomitic finishing lime. ASTM specifications C206-46T for special finishing lime and proposed amendments to Federal specifications, have been written to cover 92 per cent hydrated limes; a specification has been published by the National Lime Association. This type of finishing lime is required by ASA Specifications for Gypsum Plastering, A42.1-1946. Note that all high calcium hydrated limes (properly soaked) comply with these requirements as do high calcium quicklimes (properly slaked). B B O IS 1 4 5 6 TECHNICAL DATA --FINISH PLASTERS GAUGING PLASTER QUICK TROWELLING KEENE'S TO LIME TO LIME GYPSUM TROWEL FINISH GYPSUM FLOAT FINISH ORI ENTAL FINISH Mix by woighl of dry materials: s. Color 1:2 White 2:1 Medium Hard White 4:1 Hord White NEAT NEAT NEAT White White or Gray 12 Colors Finish Texture J Hardness in Kilograms If) Smooth 34 Smooth 50 Smooth 70 Smooth Float 55 (i) Float (t) Workability 1 4 5 23 6 Cost Factor Labor & Mat'l. 100 170 180 125 125 (|1 Kilograms required to force a 10MM ball .01* into plaster face. (J) These are hard finishes but the aggregate in the surface does not permit an indication with this test. 160 J Trademark Hcj. U.S. Pat. Off. Page 9 FINISHING PLASTERS LIME PUTTY -- GAUGING (WHITE COAT) FINISH DESCRIPTION Hydrated Finishing Lime (or Finishing Quicklime) is soaked (or slaked) to putty consistency, blended in proper proportion with ttypsum gauging plaster, and is trowelled to a smooth, hard finish usually over a properly prepared gypsum basecoat. This is by far the most widely used plaster finish coat due to ease of application, flexibility, whiteness and economy. FUNCTION & UTILITY OF INGREDIENTS LIMES: The function of lime in a finish plaster is to pro vide the "spread" and plasticity to permit fast, easy application with full flexibility and economy. Lime does not "set," but hardens slowly: it likewise shrinks on dry ing. Therefore, gypsum gauging must be blended into the lime putty in proper proportion to provide initial set and strength, and to avoid shrinkage cracks. IVORY--A double-hydrated (over 92%) special finish ing lime that will not expand measurably in the wall. Requires no soaking to produce a smooth, uniform, white, highly plastic putty. May be mixed by adding dry lime and gauging to water in mechanical mixer because it develops its normal plasticity almost immediately. This is the preferred lime. Meets ASTM Designation C206-49 Type S and Federal Specification SS-L-351, Type F, including the added requirement of not more than 8% unhydrated oxides. RED TOP and GRAND PRIl^E*--Shipped from Genoa, Ohio, are normal doiomitic hydrated finishing limes, and are only partially hydrated. They comply with Federal Specification SS-L-351, Type F, and ASTM Designation C6-49, Type N, but do not comply with specifications limiting the unhydrated oxides to 8 per cent. RED TOP Hydrated Limes shipped from Farnams, Massachusetts and New Braunfels, Texas, are high calcium limes and are completely hydrated. They comply with ASTM C206-49 Type S and Federal Specification SS-L-351, and meet specifications limiting the unhy drated oxides to not more than 8 per cent. All types of USG* hydrated lime except "IVORY" Finish Hydrate require overnight soaking. They yield a smooth, highly plastic putty of exceptional purity. Until the advent of autoclaved hydrates, such as "IVORY," they were the standards of excellence. RED TOP and CHESHIRE Brands--Are high calcium finishing quicklimes. When properly slaked and aged for Page 10 at least 48 hours, hydration is complete, (over 92%) thereby insuring against further hydration and attend ant possibilities of expansion on the wall. Comply with ASTM Designation C5-26, and Federal Specification SS-Q-351. They have unusually high plasticity and purity. GAUGING PLASTERS 1. CHAMPION* and STAR* are White Gauging Plas ters, for blending with lime putty to provide initial set and strength. They are ground to the proper fineness to blend readily and completely, thus minimizin'^ the danger of check-cracking, crazing, etc. when properly used. They give strength and hardness to the surface finish. CHAMPION has a quicker "set" than STAR Gauging Plaster. They are the preferred gauging plasters because of the extreme whiteness of the finish when used with limes of high purity. Complies with ASTM Designation C28-40 "Calcined gypsum for finishing coat (white)" and Federal Speci fication SS-P-402. Type G. 2. RED TOP Gauging is a "local" gauging plaster, so called because it is made from a rock grade that is used in basecoat plasters. It is available with slow or fast "set." It is distinguished from White Gauging Plasters by its darker color. Except for color, RED TOP Gauging Plas ters are the equal of CHAMPION and STAR Gauging Plasters. Complies with ASTM Designation C28-40 "Calcined gypsum for finishing coat (gray)" and Federal Speci fication SS-P-402, Type G. PROPORTIONING--See Specifications LIMITATIONS OF USE 1. For interior application only. 2. Recommended proportioning must be observed. Fail ure to use sufficient gauging plaster, to blend thoroughly, or to trowel adequately often results in check-cracking, crazing, lack of hardness and bond failur" 3. Designed for normal humidity conditions. Where ex cessive humidity or frequent exposure to moisture is expected, use Keene's Cement as later described. .4 Designed for normal usage. If hardness, and resistance to abrasion is required, use Keene's Cement as later described. 5. Must be applied to gypsum or lime plaster basecoat. Lime-gauging bond to portland cement plasters is in adequate. Do not apply direct to masonry. Trademark Reg. U. S. Pat. Off. 4 FINISHING PLASTERS LIME PUTTY --GAUGING (WHITECOAT) FIN IS H -- Continued r SPECIFICATIONS MIXING AND APPLICATION OF FINISH PLASTER Include the I'oilowing in plaster specifications given on c pages 4 to 7. c MATERIALS Lime for finish plaster shall be (select one): r (IVORY Finish Hydrate Lime) (RED TOR nr CHESHIRE Finish Ojiicklime) Lime shall be thoroughly soaked (or slaked and aged) according to manufacturer's directions printed on con tainers. (NOTE: IVORY Finish Hydrate requires no soaking or slaking.) Mix in the proportions of 3 parts lime putty to 1 part of eauging plaster, by volume. The equivalent by weigh: shall be 2 parts dry lime to 1 part dry gauging plaster. Mixing shall be done on plasterer's c (RED TOP or GRAND PRIZE Finish Hydrate Lime) manufactured by United States Gypsum Company. board, thoroughly blending the gauging into the lime putty. When thoroughly mixed, it shall be applied to a surface-dry basecoat. Scratch in thoroughly and imme c Gauging Plaster shall be (select one): (CHAMPION or STAR ''White" Gauging Plaster) diately double back ;o fill out to a true even surface. Thickness to be bo" to Us". Trowel once before final set, (RED TOP "Local" Gauging Plaster) and water trowel after set to provide dense surface for c manufactured by United States Gypsum Company. decoration. Brush with clean water only. r KEENE'S-LI ME FINISH A c DESCRIPTION Keene's Cement is a high strength, white gypsum plaster. LIMITATIONS OF USE 1. Keene's Cement is for interior finishes only. Keene's-Lime finish is composed of lime putty blended 2. Keene's Cement finish is not recommended where ex r with Keene's Cement in proportions required to obtain posure to water is extreme or continuous. Use portland desired hardness. cement-lime plaster. Complies with ASTM Designation C61-40 and Fed r l; eral Specification SS-C-161, Type I (Regular) and Type II (Quick Troweling). 3. For application over gypsum basecoats of high com pressive strength only. FUNCTION AND UTILITY In addition to those listed for lime putty-gauging, it pro vides: RESISTANCE TO ABRASION. Keene's Cement has ex SPECIFICATIONS The following should be included in plaster specifica tions given on pages 4 to 7. ceptionally high strength and surface hardness. See Tech nical Data. MATERIALS LOW WATER ABSORPTION. Keene's Cement, having a high density, has low water absorption. Keene's Cement shall be (Regular Keene's Cement) (Quick Troweling Keene's Cement) manufactured by United CHOICE OF HARDNESS. Keene's Cement is mixed States Gypsum Company. with lime putty in varying proportions for "hard" and Lime--(Refer to Lime Gauging Specifications, above, and *3^ "medium hard" finishes. See Technical Data and speci select one). fications. TWO TYPES. Regular and Quick Troweling. Regular Keene's sets slowly, requires more troweling and may be used with any proportion of lime. Quick Troweling Keene's sets faster, requires less troweling and must be used with a minimum of 25 lbs. of dry hydrated lime per 100 lbs. of Keene's Cement. MIXING AND APPLICATION This specification should be exactly as given for LimeGauging, except that Keene's Cement should be substi tuted for Gauging Plaster and the proportioning should be changed to one of the following: i Page 11 BB01B 1458 8/ FINISHING PLASTERS KEENE'S--LIME FINISH--MIXING AND APPLICATION CONTINUED 1. "Medium Hard" Finish shall be mixed in the proportion of 50 lbs. of dry hydrated lime to 100 lbs. of Keene's Cement. This proportion is approximately 100 lbs. of lime putty to 100 lbs. of Keene's Cement, or 35 qts. of lime putty to 100 lbs. of Keene's Cement. 2. "Hard" Finish shall be mixed in the proportion of 25 lbs. of dry hydrated lime to 100 lbs. of Keene's Cement. This proportion is approximately 50 lbs. of lime putty to 100 lbs. of Keene's Cement, or 17 qts. of lime putty to 100 lbs. of Keene's Cement. 3. Keene's Lime-Sand Float Finish shall be mixed in the proportion of 50 lbs. of dry hydrated lime. 100 lbs. of Keene's Cement and 400 lbs. of sand. This proportion is approximately 100 lbs. of lime putty, 100 lbs. of Keene's Cement and 400 lbs. of sand, or 35 qts. of lime puttv, 100 lbs. of Keene's Cement and 4 to 5 cu. ft. of sand (26 No. 2 shovels of sand). PREPARED GYPSUM FINISHES RED TOP GYPSUM TROWEL FINISH and RED TOP GYPSUM SAND FLOAT FINISH DESCRIPTION RED TOP Trowel and Sand Float finishes are mill-pre pared gypsum finish coat plasters requiring the addition of water only. There are no ASTM or Federal Specifications cover ing this type of plaster. FUNCTION AND UTILITY RED TOP GYPSUM TROWEL FINISH--is used where hard, smooth surfaces are desired. RED TOP GYPSUM SAND FLO A T FINISH--is used where a quality float finish is desired. STRENGTH--approximately twice the strength of or dinary lime-gauging finishes. EARLY DECORATION--may be painted as soon as set and dry. FACTORY PREPARED--mill selection of ingredients and formulation insure uniform results and avoid varia tions possible with job mixing. NON-ALKALINE--contain nothing injurious to paint or decorations. BOND--provides durable and natural bond to gypsum basecoat. COST--slightly higher than job-prepared finishes. LIMITATIONS 7. Designed for application over gypsum basecoats only. 2. Should not be used on exterior surfaces where exposed to the elements or on interiors exposed to excessive moisture. Page 12 PLASTERING SPECIFICATIONS The following should be included in Plastering Specifi cations: Finish Coat shall be (RED TOP Gypsum Trowel Finish) or (RED TOP Gypsum Sand Float Finish) manufactured by United States Gypsum Company. MIXING AND APPLICATION Finish Coat--Prepared gypsum finish shall be mixed with water only in strict accordance with the manufac turer's directions. Include whichever of the following paragraphs is applicable: RED TOP Gypsum Trowel Finish shall be applied in 2 coats to a total thickness of not more than H`r over a set, half-green gypsum basecoat. Scratch in a thin coat and double back with a second coat, filling out to a true and even surface. Trowel to a smooth finish free of cat faces and other blemishes. Use water sparingly during trowel ing. RED TOP Gypsum Sand Float Finish shall be applied in 2 coats to a total thickness of not more than A" over a set, half-green gypsum basecoat. If the basecoat has dried out, it shall be sprayed with water, but not soaked, before the finish coat is applied. Scratch in a thin coat and double back with a second coat, filling out to a true and even surface. Float with a suitable tool to give a surface free from slick spots, cat faces and other blemishes. Use water sparingly while floating. A FINISHING PLASTERS RED TOP COVER COAT FINISHING PLASTER DESCRIPTION RED TOP Cover Coat is a mill prepared white gypsum bonding-finishing plaster requiring the addition of water only. FUNCTION AND UTILITY RED TOP Cover Coat is a specially prepared finishing plaster designed to furnish an adhesive bond in refinish ing existing surfaces of old plaster, gypsum wallboard, textured finishes, whether painted or unpainted, or for application direct to smooth concrete (to which applica tion of Bonccrete is not suited) and provide a finish sur face ready for decoration. LIMITATIONS 1. For interior application only. 2. Not recommended for application on exterior ma sonry walls which are not furred. __ 3. Not designed for use on surfaces which are exposed to excessive humidity or where frequent exposure to water is expected. 4. Do not apply over waxed or wax glazed surfaces. SPECIFICATIONS 1. Under "Materials" of the plastering specification in clude the fallowing: Finish plaster over (existing surfaces as indicated) (smooth concrete ceiling, columns or beams) (specify) shall be RD TOP Cover Coat as manufactured by United States Gypsum Company. 2. Under "Mixing and Application" include the fol lowing: Mix RED TOP Cover Coat with water only (except for final coat w'here sand float finish is desired the addition of 1 H parts silica sand to one part Cover Coat by weight is permissible). All surfaces to receive Cover Coat shall be properly prepared as specified elsewhere. Cover Coat shall be applied in two coats over a properly prepared surface. First coat shall be applied to a dry surface in sufficient thickness to cover and embed existing surface texture and imperfections and troweled level to receive second coat. Over set dry first coat apply second coat as thin as possible and after it takes up water trowel to a smooth finish. 3. A separate paragraph must be included as follows: Surface Preparation: Old surfaces must be clean and sound. Scrape off high portions of heavy stipples. Wash all surfaces with commercial paint cleaner (not soap) removing dirt, oil and grease and rinse with clean wacer. Brush or wipe surface with 5% solution of zinc sulphate or alum and allow to dry. Patch holes and surface defects with paste of Cover Coat. Reinforce existing cracks bv embedding 2" sized open mesh gauge reinforcing tape in a paste of Cover Coat tightly against the wall surface over the crack. Over unpainted concrete remove all laitance or efflores cence by dry brushing and scrub surface with naphtha or mineral spirits to remove grease and form oil. Then brush or spray surface with 5% solution of zinc sulphate or alum-in water to "kill" surface alkalinity and allow to dry. ORIENTAL* INTERIOR (COLORED) FINISHES DESCRIPTION ORIENTAL Interior Finish is a mill-prepared and colored finish plaster requiring the addition of water only. There are no ASTM or Federal Specifications cover ing this type of plaster. FUNCTION AND UTILITY INTEGRALLY COLORED at factory, requiring no deco ration. Permits early occupancy. Avoids variations of color intensity that are possible when colors are mixed at site. COLORS (with LIGHT REFLECTION for float finish). White--81%; Sahara Cream--74.6%; Ivory--77.5%; Tusk Ivory--72.7%; Harvest Buff--66.6%; Parchment --74.2%; Golden Buff--70.1%; Mist Gray--63.9%; Caenstone--51.4%; Shell Pink--64.8%; Desert Rose-- 56.2%; and Cool Green--67.4%. TEXTURE--A finely floated surface or a textured finish --in 13 colors. STRENGTH--highly resistant to abrasion due to very great hardness. See Technical Data, Page 8. LIMITATIONS OF USE 1. ORIENTAL Interior is for producing finely floated surfaces or textures. Do not use for a smooth finish. 2. To be used on interiors only. `Trademark Rsg. U. S. Pat. Off. SPECIFICATIONS The following should be included in plaster specifications given on pages 4 to 7. MATERIALS Finish Coat shall be ORIENTAL Interior Finish, manu factured by United States Gypsum Company. Color shall be as selected by the architect from schedule of colors furnished by manufacturer. MIXING AND APPLICATION Finish Coat--ORIENTAL Interior Finish shall be mixed with water only in accordance with the manufacturer's directions. ORIENTAL Interior Colored Finish shall be applied over a set and half-green gypsum basecoat. (Select one of following): Float Finish--Scratch in a thin coat and double-back with a second coat, filling out to a true and even surface. Sur face shall be floated with a cork float to give a surface free of slick spots, cat faces and other blemishes. Do not use water while floating. Texture Finishes--Textures shall be applied in such a manner that they will match the sample approved by the architect or his representative. Page 13 E B O IB 1460 FINISHING PLASTERS' SABINITE* ACOUSTICAL PLASTER FINISHES SABINITE TROWEL FINISH "M" DESCRIPTION SABINITE Trowel Finish is a highly efficient acoustical plaster, scientifically prepared to produce a continuous trowel finish of exceptional sound absorbent qualities. It is manufactured in four standard colors and white and re quires the addition of water only. Basically mineral, it is incombustible. SABINITE FLOAT FINISH "F" DESCRIPTION SABINITE Float Finish is a highly efficient acoustical plaster which provides afloat finish effect. Having a harder surface than SABINITE trowel finish, it is more suitable for side walls which require sound conditioning. It is manufactured in four standard colors and white and requires the addition of water only. SABINITE 38 DESCRIPTION SABINITE 38 is an hydraulic acoustical plaster pre pared for use in locations subjected to high moisture conditions. It is manufactured in white only, and pro vides a float finish. SABINITE 38 is effective for sound conditioning in shower rooms, for ceilings in swimming pools, etc. LIMITATIONS (All Types) 1. Designed for use on ceilings and areas not exposed to rough usage. 2. To insure best results, SABINITE must be applied in strict accordance with manufacturer's directions. (See A/A File 39-B for complete Technical Information and Specifications.) EXTERIOR STUCCO FINISH ORIENTAL* EXTERIOR (COLORED) FINISHES DESCRIPTION ORIENTAL Exterior Finish is a factory-prepared stucco for exterior application over a portland cement-lime basecoat. It requires the addition of water only on the job. Colors: Pewter Gray, Eggshell Ivory, Sun Tan, Stone Gray, Copper Rose, Alamo Buff, Mission Green, Cascade Green, Pueblo Tan, Indian Coral, Rancho Brown and White. PLASTERING SPECIFICATIONS GENERAL PROVISIONS When exterior stucco is applied during cold weather, longer curing periods are necessary. In freezing weather, do not apply ORIENTAL Exterior Stucco unless special precautions are taken to keep the materials at a temperature above 50F. dur ing mixing and for at least 48 hours after application. FUNCTION AND UTILITY FACTORY PREPARED--Uniformity in formulation insures endurance under all weather conditions. Avoids possibility of job-mixing errors. INTEGRAL COLORING--Prevents variations possible where colors are added at site. DECORATION--Requires none. ADAPTABLE to any texture. SCOPE Unless otherwise shown on drawings, all exterior walls shall be finished as herein described. MATERIALS Exterior finish coat shall be ORIENTAL Exterior'colored finish as manufactured by the United States Gypsum Com pany. Color and texture to be designated and approved by the architect or his representative. LIMITATIONS 1. Not designed for use as a smooth trowel finish. 2. Requires a portland cement-lime basecoat. Page 14 MIXING AND APPLICATION ORIENTAL Exterior colored finish shall be mixed and applied in strict accordance with the manufacturer's directions. *Trademark Reg U. S. Pat. Off. t ( r r r ( c V.. r V V f- < v_ v' kci^ A EXTERIOR STUCCO BASECOAT DESCRIPTION Exterior stucco basccoat is prepared on the job from portland cement, lime, sand and water and is the basccoat that receives the ORIENTAL* Exterior (colored) Finish. FUNCTION AND UTILITY Exterior stucco basccoat is used for the scratch (first coat) and brown (second coat) over cement block or clay tile, or over sheathing to which STL'GCO MESH or self-furring metal lath has been properly applied. FIRE RESISTANT--Made from portland cement, lime and sand, it will not support combustion. WEATHER RESISTANT--Suitable for normal exposure to climatic variations. STRONG--Properly mixed and cured, it provides a dense, hard base that will withstand normal wear and usage. ECONOMICAL--L'sc of standard, readily available materials provides a low cost basccoat. LIMITATIONS OF USE 1. Because of the use of portland cement, each coat required curing with water after set. 2. Must not be applied in freezing weather or over bases con taining frost. 3. Must not be used on smooth, dense surfaces or over old, un sound stucco unless stucco mesh reinforcement is first properly applied. SPECIFICATIONS (.Vole to Architect: The following specifications may be adapted to your requirements for interior portland cement-lime plaster.) SCOPE Unless otherwise specified or shown on the drawings, all ex terior walls shall have a portland cement-lime stucco basccoat. MATERIALS Reinforcing mesh (where required) shall be USG STUCCO MESH applied with stucco furring nails or USG 3.4 lb. SelfFurring Diamond Mesh Metal Lath, applied with l}o" 11 gauge galvanized roofing nails. Nails to be spaced not over 6* on center vertically and 16* on center horizontally. PORTLAND CEMENT--Shall comply with A.S.T.M. Desig nation C150-47. LIME--Shall bcMORTASEALor REDTOPMasons Hydrate Lime or Quicklime as manufactured by the United States Gypsum Company. SAND--Shall be clean and sharp and shall meet the require ments of American Standards Association specifications A-12-2. WATER--Shall be clean, free from harmful quantities of or ganic matter and fit for domestic consumption. FINISH--Shall be ORIENTAL Exterior (colored) Finish as manufactured by the United States Gypsum Companv. MIXING OF BASECOATS The scratch (first coat) shall be mixed in the proportion of one bag of portland cement (one cubic foot); two bags of MORTASEAL (or two cubic feet of RED TOP Masons Lime Puttv) and seven and one-half cubic feet of sand (approxiinatelv 45 No. 2 shovels). For application over stucco mesh or sclf-Airrinc metal lath, approximately two pounds of fiber or hair shall be added to each mix of the above proportions. The brown coat (second coat) shall be mixed in the proportion of one bag of portland cement, two bags of MORTASEAL (or two cubic feet of RED TOP Masons Lime Putty) and nine cubic feet of sand (approximately 55 No. 2 shovels). APPLICATION Scratch coat shall be applied in a full J-g" coat, with sufficient pressure to form a good bond with masonry surfaces or to force it through and completely embed the stucco mesh. Cross scratch and, after set, damp cure for not less than 48 hours. Brown coat shall be applied over the dampened scratch coat in a full coat with sufficient pressure to form a good bond, rodded level and left rough, using a broom if nccessarv. After set, damp cure for at least 48 hours before applying the finish (third) coat. CURING Damp curing of each coat shall be accomplished by applying water in a fine, fog spray. Apply only as much water as is readily absorbed. The frequency of spraying required will de pend on the weather exposure, more frequent applications being required during hot, dry and windy weather. Page 15 BB018 1*62 -'S > STATES GYPSUM ( r ( ( ( ( ( ( ( < ( ( < < < w G) a o !-* 00