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*3eorgia-f^cific jf%. MARCH 1972 ORDER NUMBER 1. 2. 3. 4. 5. 6. 7. 8. TITLE AND DESCRIPTION A Story of Human Enterprise Booklet reviewing Georgia-Pacific history and policy, with color photographs, revised October 1971. Suitable for plant tour visitors and civic clubs, schools, etc., in connection with appearance of G-P representative on program. Free in limited quantities: 250 or more, 10 cents each. Annual Report Company sales, earnings, assets, manufacturing, timber, re search, etc. Current issues available in limited quantities. Vital Statistics Insert for Annual Report containing Company sales, earnings, assets, location of plants and mills, etc. Interim Financial Report Company sales, earnings, assets, etc. Specify month and year. Growth Magazine Company magazine. Current and back issues available in limit ed quantities. Specify month and year. Oregon Saw-Buck Describes the forest products industry's contribution to Oregon's economy. Keep America's Symbol of Freedom Flying High Eagle protection posters, 9 x 12", and 10 x 17". Seed Packets Douglas fir or redwood available in limited quantities. 250 or more, 10 cents each. (Longleaf pine, loblolly pine and yellow poplar available from PR Manager, Augusta, Georgia.) SGP 0025848 2- - ORDER NUMBER 9. 10. GENERAL CORPORATE LITERATURE CONTINUED TITLE AND DESCRIPTION Hunting Maps Current hunting maps available for Springfield, Toledo and Coos Bay, Oregon divisions showing areas open to hunters by Georgia-Pacific. Building Products Catalog A catalog of building products manufactured by G-P with 5 categories. (A) Sheathing, underlayment and concrete forms. (B) Siding. (C) Interior paneling. (D/E) Gypsum Wallboard, Lath and Plaster. (H) Doors. Limited quantities only. Order by category. CONSUMER LITERATURE .11 Imagination Package The right way to use wood paneling for dining rooms, recre ation rooms, kitchen and family rooms, living rooms and foyers, bedrooms and dressing rooms, and storage areas. Package of six folders. 12. How to install G-P Factory Finished Paneling How to measure, pre-installation instructions, accessory materials, care and maintenance, design and decorating tips. With charts to show the amateur and possibly help the pro fessional . 13. The Great Divide How to build fences, patio decks, storage areas out of wood. With dimensions and framing details. 14 . Saw-textured Redwood Booklet illustrated with color photographs, showing the uses for saw-textured siding/paneling. The board with new faces for a multitude of uses. 15. Reddi-Deck From Georgia-Pacific, ready-to-install redwood decks take the guesswork out. Complete instructions, illustrations and charts. SGP 0025849 -3- RECREATION AND ENVIRONMENT (Also sec Pulp and Paper) ORDER NUMBER 16. 17 . 18. 19. 20. 21. 22. 23. 24 . 25. TITLE AND DESCRIPTION G-P Recreation Areas In Oregon Map of recreation areas in Oregon and listing of facilities at each location. Two pages, 8-1/2 x 11". Public Outdoor Recreation AFI survey results, 1968. 4 x 9", 8 pages. Welcome to G-P Demonstration Forest Guide to G-P Demonstration Forest near Trinidad, California, 4 x 9", 8 pages. An Invitation to Recreation In The Redwoods Illustrated folder, 4 x 8", issued by Redwood Industries Recreation Areas. Georgia-Pacific and the Environment A report on G-P air and water quality programs, reprinted from February 1972 GROWTH MAGAZINE. The Gift Six page folder covering gift of Van Duzen Redwood Groves to the public by Georgia-Pacific in 1969. Boning Out Your Deer Oregon State University Bulletin Number 819, 16 pages. Georgia-Pacific Redwood Land Use Policy One page, 8-1/2 x 13". Politics, Paperwork and Pollution Control An address by Matthew Gould, G-P Environmental Control Director, before the national conference of The National Environmental Health Association at Portland, Oregon, June 1971. Industry Speaks Up On Pollution Reprinted from INDUSTRY WEEK, April 1971. Remarks by Matthew Gould, G-P Environmental Control Director. SGP 0025850 -4- ORDER NUMBER 26. 27. RECREATION AND ENVIRONMENT CONTINUED TITLE AND DESCRIPTION Beware: Witchdoctors in the Woods Speech reprint of address by W. H. Hunt, President, G-P, at 62nd Pacific Logging Congress, Portland, Oregon, November 3, 1971, in which he points out that environmentalists who proceed without knowledge, particularly in field of forest management, can do more harm than good. We Live Here Too Explains relationship of gypsum industry to the environment. Produced by the Gypsum Association. FORESTRY AND TIMBER 28. 29. 30. 31. 32. 33. 34. 35 . Better Environment Through Forestry Four pages, 4 x 9", IFA. Patch From the Blue Six pages, 3-1/2 x 8-1/2", clearcutting, WWPA. Clearcutting--Instant Plunder or Resource Renewal Six pages, 3-1/2 x 8-1/2", AFI. The Go d Lord's Made all the Land He's Going to Make Eight iges, 4 x 9", WWPA. Conservation for Whom? Sixteen pages, 3-1/2 x 8-1/2", talk by Dean Zivnuska, RRCC. Want to be a Certified West Coast Tree Farmer? Four pages, 4 x 9", IFA. Emotions Aside, Clearcutting is Silvaculturally Sound Concept Four page reprint of W. D. Hagenstein talk, from FOREST INDUSTRIES MAGAZINE, December 1970. A Vital Aspect to Forest Ecology Color pamphlet, WWPA. SGP 0025851 -5FORESTRY AND TIMBER CONTINUED ORDER NUMBER 36. 37 . 38. 39. 40. TITLE AND DESCRIPTION Unwinding A Tree. . .The Story of Plywood Color booklet, 8-1/2 x 11", APA. Facts About Western Woods Gives history, botany, uses of western trees, WWPA. Excellent as teachers aid and for college students. ABC's of Even-Aged Management Article provides understanding of even-aged forest rr anagement in the United States with particular attention to clearcutting practices, 8-1/2 x 11", reprinted with permission of The American Forestry Association from AMERICAN FORESTS, August 1971. Multiple Use of Our Forests Pamphlet produced by AFI, explaining term "multiple use," 3-1/2 x 8-1/2". Forests USA Report on the American forest and what this unique, renewable resource means to man and his environment, AFI, color, 18 pages, 8-1/2 x 11". Excellent source material for answers to questions about the forest products industry. 1971. PULP AND PAPER 41. 42 . Environmental Protection Pamphlet describing air and water quality control programs of Northwest pulp and paper mills, NWP&PA. Meeting the Challenge Report on pollution control by NWP&PA. SGP 0025852 6- CAREER INFORMATION ORDER NUMBER 43. 44. 45. TITLE AND DESCRIPTION The Challenge of the Forest. . .Youth Looks to the Future in Wood Illustrated, color booklet by NFPA. 0 Paper and Opportunity Twelve pages, 8-1/2 x 11", illustrated, APA. Schools 6c Colleges offering technical and Vocational Education Programs for Careers in the Forest Products Industries Schools and colleges offering technical and vocational programs in preparation for careers in the forest products industries are listed, color, NFPA. SCHOOL INFORMATION 46. 47 . 48. A Forest Products Community The City of Crossett, Arkansas, and G-P operations located there are featured in this new textbook for second graders. Prepared by the Social Science Staff of the Educational Research Council of America. Copies may be obtained from the publisher, Allyn & Bacon, Inc., Ralston Park, Belmont, California 94002, at a cost of $1.20 each. Aids to Learning Pamphlet describing teaching aids that can be ordered to assist teachers in presenting basic understanding of forest management. AFI. Teaching aids include tree charts, illustrated story booklets and audio tapes. Learn to Love Trees Pamphlet which teaches children that forests are important and why, color, illustrated, AFI. SGP 0025853 -7- REDWOODS (Also sec redwood publications under Recreation) ORDER NUMBER 49. 50. The Redwoods TITLE AND DESCRIPTION Paperback pocket book, 176 pages, illustrated, CRA. The Story of the Redwood Forest Eight page brochure, 4 x 9", CRA. 0- - AFI--American Forest Institute 1619 Massachusetts Avenue, N. W. Washington, D. C. 20036 Phone: (202) 667-7807 APA--American Plywood Association 1119 "A" Street Tacoma, Washington 98401 Phone: (206) 272-2283 CRA--California Redwood Association 617 Montgomery Street San Francisco, California 94111 Phone: (415) 392-7880 IFA--Industrial Forestry Association 1410 S. W. Morrison Portland, Oregon 97205 Phone: (503) 222-9508 NFPA--National Forest Products Association 1619 Massachusetts Avenue, N. W. Washington, D. C. 20036 Phone: (202) 332-1050 NWP&PA--Northwest Pulp & Paper Association 2633 Eastlake East Seattle, Washington 98102 Phone: (206) EA5-3277 RRCC--Redwood Region Conservation Council 224 Rosenberg Building Santa Rosa, California 95404 Phone: (707) 545-9531 WWPA--Western Wood Products Association 700 Yeon Building Portland, Oregon 97204 Phone: (503) 224-3930 SGP 0025854 8- - 1TEMS ORDERED DIRECT AS INDICATED Redwood Vacation homes A booklet for three types of people: beach, mountain and fresh water. Photographs of homes fashioned by thoughtful architects for comfort, beauty and permanence. And all built of redwood. (Order direct from: California Redwood Association, 617 Montgomery Street, San Francisco, California 94111.) Vacation Homes A booklet showing 12 views and plans for vacation homes, and featuring Western Wood. You may order plans or blueprints by using order forms on the inside back cover. (Order direct from: Western Wood Products Association, 700 Yeon Build ing, Portland, Oregon 97204.) A Bookful of Ideas for Your New Home Beautifully illustrated with color photographs, showing the many uses for plywood--siding, paneling, built-ins, and a section on "Hidden Values." (Order direct from: American Plywood Association, 1119 "A" Street, Tacoma, Washington 98401.) SGP 0025855 March 1972 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12 . ORDER FORM Order by order number and quantity wanted from: Media Service Center 609 N. E. Schuyler Portland, Oregon 97212 13. 25 . 37 . 49. 14. 26. 38. 50. 15. 27. 39. 51. 16. 28. 40. 52. 17. 29. 41. 53. 18. 30. 42. 54. 19. 31. 43. 55. 20. 32. 44. 56. 21. 33. 45. 57 . 22 . 34. 46. 58. 23. 35. 47 . 59. 24. 36. 48. 60. SHIP TO: ____________________________________ (NAME OF PERSON ORDERING) DATE NEEDED: ___________________________________________ (ALLOW TWO WEEKS FOR DELIVERY) SGP 0025856 USING * GYPSUM BOARD WALLS AND CEILINGS GA-201 -71 MEMBERS THE CELOTEX CORPORATION THE FLINTKOTE COMPANY GEORGIA-PACIFIC CORPORATION GRAND RAPIDS GYPSUM COMPANY KAISER CEMENT AND GYPSUM CORPORATION NATIONAL GYPSUM COMPANY TEXAS GYPSUM COMPANY, INC. UNITED STATES GYPSUM COMPANY SGP 0025858 GYPSUM ASSOCIATION 201 North Wells Street Chicago, Illinois 60606 1800 North Highland Avenue Hollywood, California 90028 Copyright 1970 by the Gypsum Association. All rights reserved. USING GYPSUMBOARD FOR WALLS AND CEILINGS (VCVCVCV If) lO 10 IO IS N ^0) 0) O O O T- r- t- n n TABLE OF CONTENTS I GYPSUMBOARD CONSTRUCTION WHAT IS GYPSUMBOARD? GLOSSARY ADVANTAGES OF GYPSUMBOARD CONSTRUCTION Fire Resistance...................................................... Sound Isolation.................................................... Durability ................................................................ Economy.................................................................. TYPES OF GYPSUMBOARD Gypsum Wallboard............................................. Gypsum Backing Board................................... Gypsum Coreboard........................................... Type X Gypsum Board...................................... Water Resistant Gypsum Backing Board Other Gypsumboard Products..................... APPLICATION OF GYPSUMBOARD Sing e vs. Multi-Ply............................................. Job Site Preparation.......................................... Cutting and Fitting Precautions.................. 1 i II SUPPORTING CONSTRUCTION WOOD FRAMING Furring........................................................................................................................................................ Studs............................................................................................................................................................1 Ceilings....................................................................................................................................................... 1 METAL STUDPARTITIONS AND CEILING SYSTEMS 1 Studs............................................................................................................................................................1 Joists............................................................................................................................................................1 Channels.................................................................................................................................................... 1 MASONRY SUPPORTS 1 ATTACHMENTS ANDFASTENERS 1 Nail'.............................................................................................................................................................. 1 Scr *rs.........................................................................................................................................................1 Stai les.........................................................................................................................................................15 Adt sives...................................................................................................................................................15 III SINGLE-PLY APPLICATION NAIL ATTACHMENT 16 L^,,se Attachment................................................................................................................................. 16 Loose Nails................................................................................................................................................ 16 Facepaper Fractures.............................................................................................................................16 SCREW ATTACHMENT 17 ADHESIVE-NAIL ATTACHMENT 18 Stud Adhesives....................................................................................................................................... 18 Bracing ....................................................................................................................................................... 19 METAL FRAMING CONCRETE AND MASONRY 19 19 PREVENTING DEFECTS Nailpopping.......................................................... 0025859 UUZOOO 19 ............... 19 Cracking.................................................................. 20 Ridging....................................................................................................................................................... 20 TABLE OF CONTENTS (Continued) IV MULTI PLY APPLICATION BASE PLY ATTACHMENT 23 WOOD FRAMING AND FURRING 23 METAL FRAMING AND FURRING 24 FACE PLY ATTACHMENT 24 NAIL AND SCREW ATTACHMENT 24 ADHESIVE ATTACHMENT 25 Temporary Fasteners........................................................................................... 25 Permanent Fasteners........................................................................................... 25 SELF SUPPORTING GYPSUM PARTITIONS 26 Semi-Solid Partitions........................................................................................... 26 Solid Partitions.................................................................................................... 28 RESURFACING EXISTING CONSTRUCTION 28 V JOINT AND FASTENER TREATMENT JOINT TREATMENT PRODUCTS 30 Taping Compound................................................................................................31 Topping Compound............................................................................................. 31 All Purpose Compound....................... 31 TAPING AND FINISHING 32 FLUSH JOINTS 32 INTERIOR CORNER JOINTS 33 EDGE AND CORNER TRIM 33 FASTENER TREATMENT 34 REMEDYING DAMAGE 34 Nail Popping........................................................................................................ 34 Ridging................................................................................................................ 34 Shadowing.......................................................................................................... 34 Cracking....................................................................................................... .......34 VI DECORATING Regular Gypsum Wallboard................................................................................. 35 Predecorated Wallboard.................................................................................... ..35 VII SPECIAL CONSTRUCTION SOUND ISOLATING CONSTRUCTIONS 39 Separated Construction...................................................................................... 39 Resilient Mounting.............................................................................................. 39 Sound Deadening Board..................................................................................... 40 Sound Absorbing Materials................................................................................. 40 FIRE RESISTANT CONSTRUCTION 41 THERMAL INSULATING CONSTRUCTION 42 MOISTURE RESISTANT CONSTRUCTION 42 Exterior Locations............................................................................................... 42 Interior Locations................................................................................................ 43 Bath-Shower Areas............................................................................................. 43 ELECTRIC PANEL HEATING 44 Wiring.................................................................................................................. 44 Filling................................................................................................................... 44 VIII SUMMARY A GUIDE FOR HIGH QUALITY 46 SGP 0025860 Characteristics, properties or performance of materials or systems herein described are based on data obtained under controlled test conditions. The Gypsum Association and the member companies make no warranties or other representations as to their characterics, properties or performance under any variation from such conditions in actual construction. I GYPSUMBOARD CONSTRUCTION WHAT IS GYPSUMBOARD? GLOSSARY Adhesive, Contact. Bonds layers of gypsumboard. It forms a strong instantaneous bond after the two surfaces are brought in contact. Adhesive, Laminating. Bonds one gypsumboard to another in multiple-layer construc tion, or it bonds gypsumboard to suitable masonry or concrete sur faces. The bond generally devel ops slowly as the adhesive dries. Adhesive, Stud. Used for attaching single-ply gypsumboard to framing. Back Blocking. A single ply installation proce dure for reinforcing joints that fall between framing members with strips of gypsumboard. This helps prevent surface imperfections such as cracking and joint ridging. Beading. See Ridging. Butt Joint. Joints in which board ends with the core exposed are butted to gether. Corner Cracking. Cracks occuring in the joint of inside corners, betwc n intersect ing walls or at walls and ceilings. Corner-Floating. See Floating Angle*. Crimping. A method of fastening corner beads in place or fixing metal studs in runners by pinching and deforming the metal using a spe cial tool. Cross Furring. Furring members installed across, or at right angles to, fram ing members or runners. Crown, Joint. The maximum height above the surface to which treating compound is applied over the wallboard joint. Edges. Paper bound edges which usual ly run the long dimension of the board. (Fig. 1). Ends. Mill or job-cut edges which ex pose the gypsum core. They us ually run the short dimension of the board. (Fig. 1). Gypsumboard construction for walls and ceilings is commonly called drywall construction be cause little or no moisture is re quired for application. Sometimes plywood, hardboard, and fiber- board are also called "drywall", but the term generally refers to gypsumboard. The major dif ference between gypsumboard and the various other "drywall" boards is that the gypsum prod uct is noncombustible and fire resistant. Gypsumboard products are flat panels which have a fire-proof gypsum core between surfaces of paper or other sheet material. Some boards also have a surface layer of plastic nr aluminum foil laminated on ont face. Gypsum is a rock. It is a crys talline form of calcium sulfate combined with two molecules of water, known as hydrous calcium sulfate, Ca(SO )-2H 20. Thus, 100 pounds of gypsum rock contains about 21 pounds, or 10 quarts, of WOOD STUDS Fig. 1 Horizontally applied wallboard shows paper bound edges at right angles to framing members. Field, perimeter, edges, and ends are also shown. 1 GLOSSARY (Cont.) Feather Edging. (Feathering.) Tapering joint compound to a very thin edge to blend with the adjacent wallboard surface Fastener Treatment. Concealing fasteners which are set below the surface of the drywall by successive application of joint compound until a smooth surface is achieved Field. The surface of the board ex clusive of the perimeter. (Fig. 1). Floating Angles. Mechanical fasteners at interior angles are omitted to relieve stresses that might otherwise cause cracking and nail popping. Framing. The supporting members such as wall studs, ceiling joists, and roof trusses. They may or may not bear part of the load of the building. Furring. Wood or metal members used to provide properly spaced, rigid, and even support for gypsumboard. These are fastened over or at tached to underlying construction of framing, concrete, or masonry which is not in suitable condition for application of gypsumboard. Fire Rating. The time in hours that a wall, ceiling, beam, column, or roof deck will contain a fire when tested in conformance with re quirements of ASTM Standard El 19. Gypsumboard. The name for a family of non combustible sheet products con sisting of a gypsum core between paper surfaces. The core may be regular, water resistant, special fire resistant, or a combination of these. Horizontal Application. Horizontally applied boards have the edges at right angles to the framing members. (Fig. 1). Joint Beading. See Ridging. Joint Compound. A material used to conceal fas tenor. , joints, and surface indenta tions m gypsum drywall construc tion Joint Treatment. The method of concealing wall- board joints with tape and layers of joint compound. Nail Popping. A protrusion of nailhead and com pound directly over the nailhead, caused by outward movement of the nail relative to the gypsum board. Nails, Drywall. Nails suitable for drywall appli cation. (See page 14.) Nail Spotting. See Fastener Treatment. Perimeter. Surface of the board near the edges and ends (Fig 1). Ridging. A linear surface protrusion along the treated joints. (See page 20.) 2 chemically combined water. In processing gypsum, the rock is mined or quarried, and then crushed and ground to a powder. This is heated to about 325 F, which removes about 3/4 of the chemically combined water. The resulting material is known as calcined gypsum or hemihydrate and is also sometimes called "stuc co" or "plaster of Paris." This product is used to make plaster, gypsum lath, and gypsumboard. To make gypsumboard, the cal cined gypsum is mixed with water and additives and spread between sheets of paper. The calcium sul fate then takes on the water and recrystallizes to form gypsum rock as the core of the gypsumboard. ADVANTAGES OF GYPSUMBOARD CONSTRUCTION Gypsumboard walls and ceilings have a number of outstanding advantages: Some of these are: 1. Fire resistance 2. Sound isolation 3. Durability 4. Economy Fire Resistance: Gypsumboard is an excellent fire barrier, not only because it is noncombustible, hut also be cause it has combined water in the gypsum core. When gypsum is ex posed to fire, the water of crystall ization is slowly released as steam, and this effectively retards heat transfer. Gypsumboard walls and ceilings will retard a fire for a number of hours depending on the assembly chosen (Fig. 2). Sound Isolation: Specially designed gypsumhoard wall and ceiling systems control sound transmission be tween rooms. Experience shows that sound isolation cannot be adequately provided by the use of either very light, combustible panelling or acoustical surfacing materials. Thin, low-density pan els transmit annoying amounts of noise. Acoustical materials re duce the reflection of sound and the noise levels in a room, but they do not greatly reduce the noise that goes through them to the next room. Gypsumboard walls and ceilings are effective sound barriers and are comparatively lightweight. Excellent sound isolation is ob tained by techniques (Fig. 3) such as: (1) separate framing of the two sides of the wall, (2) resil ient channel mounting for the gypsumboard, (3) fastening the wallboard over a sound control material, such as another gypsum board, and (4) including sound ab sorbing materials in the wall cavity. Durability Gypsumboard makes strong high-quality walls and ceilings with good dimensional stability. The surfaces may be easily decor ated and refinished during their long life. Economy Gypsumboard products are readily available and relatively easy to apply. They are the least expensive wall surfacing mater ials available which offer a struc turally sound, fire-resistant inte rior finish. If predecorated board is used, even the cost of decorating may be saved. GLOSSARY (Cont.) Screws, Drywall. Screws developed for wallboard application. (See page 14.) Sheet Lamination. Multi ply construction with ad hesives applied to the entire sur face to be bonded. (See Adhesive, Laminating.) Strip Lamination. Multi-ply construction with ad hesive applied in parallel strips usually spaced 16 in. or 24 in. apart, Sound Transmission Class (STC) Numbers used by engineers and architects to rate resistance to air borne sound transmission. Taping. Embedding tape in joint com pound in the process of joint treatment. Vertical Application. Vertically applied boards have the edges parallel to framing members. SGP 0025862 How Gypsum Retards Heat Transmission TWO-HOUR EXPOSURE Vertical line represents plane of calcination at depth of about 2". Temperature never greatly exceeds 212F. behind plane of calcination. Temperature of exposed surface 1900F. Temperature 1" from exposed face = 950F. Temperature 2" from exposed face -- 220F. Temperature 4" from exposed face -- 180F. Temperature at back surface -- 130F. (Data from Underwriters' Laboratories, Inc.) Fig. 2 Diagram of a six-inch thick block after two-hour fire test shows how gypsum fights fire. Fig. 3 Sound isolating techniques improve the sound transmission class (STC) and noise reduction of gypsumboard walls Fig 3a Adding sound absorbing mineral wool increases the STC four points in this wall. Fig. 3b Staggered studs provide par tially separated framing for wall surfaces and increase STC about eight points from wall in Fig. 3a. Addition of sound absorbing material raises STC another 3 points to the 48 50 range. SGP 0025863 Fig 3c Resilient mounting of gypsum board surfaces raises STC about 12 points above that of wall in Fig. 3a. Fig. 3d Two-ply construction increases the weight of the wall surfaces and helps provide high sound resistance of wall with STC of 53-55. 3 TYPES OF GYPSUMBOARD PRODUCTS There are a number of types of gypsumboard. One of the earliest types was gypsum wallboard, and many people still refer to all gypsumboard by that term. Today however, it prevents confusion if each type is called by its correct name. Gypsum Wallboard Gypsum wallboard is used for the surface layer on interior walls and ceilings. Regular gypsum wallboard (Fig. 4) has gray liner paper on the back, but on the facing side and the edges, it has a special paper covering, general ly cream colored, that provides a smooth, even surface suitable for decoration. Insulating gypsum wallboard has a sheet of brightfinished aluminum foil bonded to the gray liner paper on the back. wall and ceiling sur faces. 3, 8-in. -- Principally used as the outer face in two-layer wall systems. 1/2-in. -- Used in single layer wall and ceiling sys tems in new construc tion. 5/8-in. -- Used for best quality single layer wall sys tems. The greater thick ness provides additional fire resistance and greater control of sound transmission. Standard gypsum wallboard is 4 ft. wide and 8, 10, 12, or 14 ft. long. The width complements the standard distances between studs or joists of 16 and 24 in. The standard edges on gyp sumboard used for walls and ceilings are rounded, beveled, ta pered, square (Fig. 6) or com binations thereof. Rounded Beveled the wall. It is surfaced with gray liner paper on both sides. Insulating backing board (Fig. 8) has a sheet of bright-finished aluminum foil bonded to the back face, which serves as a vapor barrier and reflective thermal in sulation. Fig. 8 Insulating backing board has an aluminum foil liner on one side. Gypsum Coreboard Gypsum coreboard is used as a base in space saving self-support ing gypsum walls erected without framing, and in demountable walls. Coreboard is made'as one in. thick solid gypsum backing board (Fig. 9), or it is factory laminated from two layers of 1/2-in. thick gypsum backing board. Fig 4 Regular gypsum wallboard is shown with wallboard surface paper and both tapered and square edges. Fig 5 Predecorated gypsumboard is available with a variety of surface finishes Tapered A. Square Edge Fig. 6 Four standard edges used on gypsumboard are shown. Gypsum Backing Board Gypsum backing board (Fig. 7) is used as a base layer where multiple plys of gypsumboard are required for extra fire resistance, sound isolation, and strength in Fig 9 One-inch thick coreboard shown here is solid, although coreboard may also be laminated from two sheets of backing board. Type X Gypsumboard Type X gypsumboard (Fig. 10) is similar in all respects to the previously mentioned boards, ex- Predecorated gypsum wallboard (Fig. 5) litis a decorative vinyl or paper sheet bonded to the front (exposed) surface which does not require further decorative treat ment. The various thicknesses of gyp sum wallboard tire used as follows: 1 4-in. -- A low cost wallboard designed for covering and rehabilitation of old 4 Fig. 7 Backing board has square edges and gray liner paper on both sides. i Fig. 10 Type X gypsumboards have the same appearance as other boards, such as regular wallboard here, but the core has added fire resistance. SGP 0025864 cept that the core has been made more fire resistant by the addition of glass fiber reinforcement and other materials. It may be wallboard, backing board, predecor ated, or other types. Type "X" hoards are used in most fireresistance rated assemblies. Water-Resistant Gypsum Backing Board Water-resistant gypsum back ing board has a water-resistant gypsum core and water repellent face paper. It is much more re sistant to absorption of water than untreated gypsumboard. It serves as a base for application of wall tile in baths, showers, and other wet areas. Other Gypsumboard Products There are other gypsumboard products besides those used for interior drywall construction. These include: Gypsum lath -- used as a base for regular gypsum plaster. Gypsum veneer base -- used as abase for thin coats of very hard, high-strength, gypsum veneer plaster. Gypsum sheathing -- used to stiffen exterior frame walls against the forces of wind and vibration, and to provide fire resistance. This is covered with an exterior finish, such as siding. APPLICATION OF GYPSUMBOARD Gypsumboard can be applied over any firm, flat (Figs. 11 and 12) base such as wood or metal framing (wall studs, ceiling joists, and roof trusses) or furring (wood strips or metal channels supported by underlying construction). Wallboard can also be applied directly to masonry or concrete, but usual ly, furring is required to separate the wallboard from possible damp ness in masonry walls. Self-sup porting solid or semi-solid gyp sumboard partitions are also built and attached to floor and ceilings by runners.1 The most common gypsumboard used in residential construction is regular gypsum wallboard. Joints between panels and at interior corners are covered with paper tape. Exterior corners and ex posed edges are reinforced or trimmed with metal or plastic bead. Joint compound is then used to hide the fasteners, tape, and trim and to give the wall or ceil ing a smooth, unbroken surface. Final decoration may be com pleted with paint, wallpaper, tile, or panelling. A portion of the gypsumboard used is predecorated wallboard. This requires no paint or other decoration after installation. Joints are sometimes covered with special mouldings or battens, but often they are left exposed to give a featured joint or plank effect. Also, they may be concealed with the decorative material. Special instructions for installation of pre decorated gypsum wallboard are given later under "Predecorated Wallboard Finishes." Single vs. Multi-ply Single-ply gypsumboard sys tems (Fig. 11) are commonly used in light commercial and residential construction. Generally, they are adequate to meet fire and sound resistance requirements.2 'The proper, recognized methods of in stalling gypsumboard and finishes are set forth in: American National Standard Specifi cation for the Application and Finisftiny of Gypsum Wallboard, ANSI A97.1 2 Single-ply gypsumboard systems achieve sound ratings from 30 to 50 ST(\ Fire ratings are generally limited to one hour for partitions. Single Ply Application Fire-Block gypsumboard -- used under combustible roof cov erings to protect rafters and the rest of the structure from fires started on the roof. It also serves as additional protection against fires within the structure. Gypsum formboard -- used as a support and permanent form to hold gypsum concrete in poured gypsum roof decks. Miscellancous -- additional gyp sumboard products that may be mentioned include gypsum soffit boards for exterior ceilings, and gypsum planks for floor-ceiling assemblies. New products for spe cial needs appear regularly. Gypsumboard is attached to framing or furring members by mechanical fasteners suchasnails, screws, clips, or staples, or by special adhesives. CCIUNG JOISTS - 1/2 OR 5/8 GYPSUM WALLBOARD (Honionlol oppheotton) __ J 1/2 OR 5/8 gypsum WALLBOARD* ' (VtriKol application) JOINT TftfATMfNT (All foiftti and torntn) BASE BOARD fI 4 f -7 ... A.. 2* * 4* WOOD FRAMING STUDS Fig. 1 1 Wood stud framing provides a firm, level, plumb, and even base for single-ply gypsumboard application. All joints are treated before decorating. SGP 0025865 5 Double Ply Application Fig 12 Double layer multi ply system has laminated surface layer of gypsum wallboard and base layer of gypsum backing board for greater fire resistance, sound control, and durability. Multi-ply systems (Fig. 12) have two or more layers of gypsumboard and produce increased sound isolation and fire resis tance.1 They also provide better surface quality because face layers are often laminated and have few er fasteners in the surface and be cause the surface joints are rein forced by the continuous backing layer of gypsumboard. Therefore, they are inherently resistant to problems such as nail popping and ridging, and they can provide a good finish with less perfectly aligned supports. A high-quality job can be as sured with either single-ply or multi-ply assemblies by requiring proper: 1. framing details (evenness, spacing) 2. job conditions under which the board is applied. 8. application of the board. 4. joint and fastener treatment, and 5. special requirements for sound isolation, fire resistance,therm al properties, or moisture re sistance. 'Multi-ply K.vpsumiioard systems achieve sound ratings up to (if ST(\ Three hour fire ratings are possible. 6 Jobsite Preparations Job conditions such as temper ature and humidity affect the performance of joint treating ma terials, the quality of the joint; and sometimes the adhesive bond. During the winter season, when the temperature is less than 55 F, interior finishes should not be in stalled unless the building has a controlled heat of at least 55 F. This temperature should be main tained for 24 hours before installa tion, a.id until a permanent heat ing system is in operation. During warm months, the build ing need not be completely glazed, but all materials and the installa tion should be protected from the weather. Ventilation should be provided if humidity is excessive. In glazed buildings, windows should be kept open to provide air circulation. In enclosed areas without natural ventilation, fans should be used. When drying is slow, additional drying time between coats of joint compound should be allowed. Dur ing hot dry weather, or in large, open areas, drafts should be avoid ed so that joint compound will not dry too rapidly. Both lumber and gypsumboard can be affected if they get wet at the job site. Excess moisture in lumber will cause wood shrink age and nail popping. Lumber shrinks across the grain as it dries, and it tends to ex pose the shanks of nails driven into the edge (Fig. 13). If shrink age is substantial and nails are too long, separation between the gypsumboard and its framing lum ber can result. This can happen with excessively long screws al so. A separation as small as 1/32 in. can result in an objec tionable nail pop (protrusion of the nail head from the surface). Therefore, lumber must be kept dry during storage and installa tion, and nail lengths should not exceed those recommended for specific applications. Green lum ber should not be used for fram ing and furring. Moisture content should not exceed 19 per cent. Delivery of gypsumboard should coincide closely with the installation schedule. Boards should be stored flat and under cover at the site. Stacking long lengths on short lengths should be avoided to prevent the longer boards from breaking. Setting boards vertically against the framing with the long edges horizontal is not recommended and is sometimes a dangerous SGP 0025866 J1/0" SHRINKAGE 19% r 10% MOISTURE MOISTURE f; CONTENT CONTENT T bits -t I .1 lDi J ft l/l$* SRACC ^8" SHRINKAGE I >0% MOISTURE CONTENT ft 1/8 SPACC Fig. 13 Studs shrink as they dry out, and separation may occur between the stud and the gypsumboard in a wall. As studs shrink, separation may be as much as 1 / 1 6 in. when nails penetrate one in. or 1/8 in. with two in. pen etration. Fig. 1 5 Gypsumboard applied horizontally provides a stiffer surface finish. Meas urements at each corner of framing and gypsumboard must be made carefully to assure close fit around openings. practice unless safety precau tions are taken. All materials should remain in their wrappings or containers until ready for use. When hoards are used on the job, they should be carried, not dragged, so that the edges are not abused. trim components such as cover plates, registers and grilles. Hoards should span the entire length of ceilings and walls if possible, to avoid butt-end joints which are difficult to finish. Buttend joints that do occur should be staggered; and they should be irregularity in framing and fur ring so that corrections can be made or allowances made in cut ting. Straight line cuts across the full length or width of gypsum board are made by scoring through the face paper into the core (Fig. Cutting and Fitting Precautions located as far from the center of 16). The core of the board is | 3 Gypsumboard installations should be carefully planned. Win dow and door frames should be of appropriate depth for the intended wall thickness. When installing mechanical and electrical equip ment, consideration should be the walls and ceilings as possible. Then, they will be less conspicu ous. Except in face layers of two-ply construction, board ends and edges parallel to supporting members should fall on these mem bers to reinforce the joint. then snapped and the back paper is cut (Fig. 17). Ragged cut ends should be smoothed with a rasp or sandpaper, or trimmed with given to the thickness of the It is preferred that wallboard be gypsumboard finish and design of nstalled at right angles to sup porting members because a stiffer surface finish results, and there are usually less joints to treat. On long walls, boards of maxi mum practical length should be used to minimize the number of end joints. Scored, scratched, broken, or otherwise damaged board should not be used. Proper measuring, cutting, and fittings are very important for successful application of gypsum board finishes. Measurements should be taken Fig. 14 A boom truck delivers gypsum board economically to upper stories. accurately at the correct ceiling or wall location for each edge or end of the board (Fig. 15). Accur ate measuring will usually reveal Fig. 16 Gypsumboard can be cut by scoring and breaking. Here, a drywall applicator scores a measured length using a straightedge as a guide. SGP 0025867 7 Fig. 1 7 Completes the break by snapping the gypsumboard away from the scored surface (left) and running a knife through the uncut paper (right). Usually, gypsumboard will be snapped as well as cut while standing as shown at the right. a sharp knife; otherwise, burrs on the ends will form a visible ridge in the finished surface. Paper-bound edges that have been severely damaged--so that the gypsum core is fractured--should be cut back to sound board. Badly broken edges are susceptible to ridging after joint treatment is applied. Gypsumboard can be sawn, if necessary, by making the cut from the face side to preserve a smooth paper edge. When gypsumboard is installed, ceiling panels should be installed first, and then the walls. All panels should be cut so that they fit easily into place. Joints should be loosely butted; boards should be in contact but should not be forced into position. Tapered edges should be placed next to tapered edges, and square cut ends should be loosely butted to square ends. Square ends should not be placed next to tapered edges because the resulting ridge is very difficult to conceal. 8 SGP 0025868 II SUPPORTING CONSTRUCTION WOOD FRAMING All wood framing and furring must be accurately aligned in the same plane so that the gypsumboard fits flat against it at all points (Fig. 18). Fastening sur faces should not vary more than 1/8 in. from the plane of ad jacent supports. Furthermore, the spacing of framing should not exceed the maximum recommend ed for the wallboard thickness as shown in Table 1 for single-ply and multiple-ply construction. This support spacing provides the ne cessary strength and rigidity for a durable finish. Warped or crooked studs and joists should be removed and re placed with straight lumber. F,xcessive moisture in wood can cause warping as the wood dries and that will have an effect on the finished surface. Therefore, the moisture content should never ex ceed 19 per cent. Supports for gypsumboard should be rigid to maintain the good appearance of the finish. Headers or lintels should be pro vided over openings to support structural loads and special con struction should be provided TABLE I MAXIMUM FRAMING SPACING FOR APPLICATION OF GYPSUMBOARD IMPROPER FRAMING UN-EVEN TOP PLATE TWISTED STUD STUD NOT ALIGNED Fig. 18 Framing that is not accurately aligned can cause loose board attach ment and problems in finished surfaces GYPSUMBOARD THICKNESS BASE LAYER FACE LAYER LOCATION APPLICATION MAXIMUM SPACING TWO LAYERS ONE LAYER ONLY FASTENERS ONLY ADHESIVE BETWEEN LAYERS %" Ceilings Horizontal 16" o.c. 16" o.c. 16" o.c. %" %' Ceilings Horizontal NA 16" o.c. 16" o.c. %" %" Ceilings Vertical NA NR 16" o.c. Vt" Ceilings Horizontal 24" o.c. 24" o.c. 24" o.c. Vi" Ceilings Vertical 16" o.c. 16" o.c. 16" o.c. Vi" %" Ceilings Horizontal NA 16" o.c. 24" o.c. Vi" %" Ceilings Vertical NA NR 24" o.c. Vi" Vi" Ceilings Horizontal NA 24" o.c. 24" o.c. Vi" Vi" Ceilings Vertical NA 16" o.c. 24" o.c. %" Ceilings Horizontal 24" o.c. 24" o.c. 24" o.c. %" Ceilings Vertical 16" o.c. 16" o.c. 24" o.c. %" %" Ceilings Horizontal NA 16" o.c. 24" o.c. %" %" Ceilings Vertical NA NR 24" o.c. %" Vi" or %" Ceilings Horizontal NA 24" o.c. 24" o.c. %" Vi" or %" Ceilings Vertical NA 16" o.c. 24" o.c. V>" V," W' %" %" Vi" or %" W' or Vt" %" Vi" or W %" or Vi" or %" Is" or Vi" or %" Walls Walls Wails Walls Walls Walls Walls Vertical NR Horizontal or Vertical Horizontal or Vertical Horizontal or Vertical Horizontal or Vertical Horizontal or Vertical NR NA NA 16" o.c. NA 24" o.c. NA 16" o.c. NR 16" o.c. 16" o.c. 16" o.c. 24" o.c. 24" o.c. 16" o.c. NR 16" o.c. 24" o.c. 24" o.c. 24" o.c. 24" o.c. NA--Not Applicable NR--Not Recommended 1 Framing spacing for two-ply, 3/8 adhesive is used between plys. in. gypsumboard wall may be 24 in. o.c. if where required to support wallhung equipment and fixtures. Furring When the spacing between framing mer lers exceeds the maximum recommended for a par ticular board thickness, or when the surface of the framing mem bers is not sufficiently flat, fur ring should used. The furring surface bearing against the gyp sumboard must be at least 1-1/2 in. wide for wood members and 1-1/4 in. wide for metal furring at joints of abutting edges or ends. The wood furring strips or met al channels can be directly at tached to the underlying framing or to a concrete or masonry wall. Gypsumboard is attached to the furring members. Wood furring to which gypsum board is to be nailed must be SGP 0025869 9 rigid enough to provide firm sup port during the nailing. This re quires at least a nominal 2 in. x 2 in. wood strip. Where screws are used, wood furring can be a minimum of 1 in. x 3 in. nominal size, and where the furring is backed by solid construction, such as masonry, wood furring strips can be as small as 5/8 in. x 1-1/2 in. Furring on wood-framed walls is usually metal sound control (resilient) channels, and the gypsumboard is attached with screws. The maximum spacing between furring strips should be the same as shown for framing members in Table I. sometimes are finished before in terior partitions are erected and finished. When this method is used, the roofing and all other construction elements which in crease roof loads should be in stalled before interior partitions are erected. If substantial roof loads are introduced after par titions are installed, the ceiling may be forced down against the partitions and may be distorted as the roof trusses deflect (Fig. 20). Studs Wood studs in load-bearing par titions should be nominal 2 in. x 4 in. or larger. In nonload-bear ing partitions, 2 in. x 3 in. wood studs may be used. Studs in staggered stud, load-bearing par titions rated for one hour fire resistance may be 2 in. x 3 in. at 16 in. o.c. and staggered 8 in. o.c. in opposite rows one inch apart. For two hour fire resistance in the same type of wall, 2 in. x 4 in. studs must be used. Back-up or extra support mem bers should be provided at all interior corners for support or as a nailing base for the gypsumboard. Fig. 19 Slightly crooked or bowed joists may be corrected by nailing stringers approximately at the mid spans. 2 in. x 4 in. stringers, laid flat, regulate spacing, and other stringers, set on edge, accomplish some leveling. TRUSS CHORDS ijJ DISTORTED CEILING - - -J. 1 WALL STUDS Ceilings Ceiling joists to which gypsumboard will be attached should be evenly si aced with all bottom faces aligned in a level plane. Ex cessively bowed or crooked joists should not be used. Joists with a slight crown may be used if they are installed with the crown up. Slightly crooked or bowed joists can be aligned by nailing bracing members across the joists approxi mately at mid span (Fig. 19). Wood ti-usses to which a ceiling must be attached may have irreg ularities in spacing and leveling. When wide variances are found, cross furring generally is recom mended to provide a plane sur face for supportinggypsumboard. With truss roof construction, the exterior walls and the ceilings Fig. 20 Ceiling distortion can result unde truss roofs where the weight of the roof forces the ceiling down and the interior partitions hold it up. Partitions may be installed only after truss roofs and ceilings are completed and the roof cover ing is finished. METAL STUD PARTITIONS AND CEILING SYSTEMS Metal stud partition systems are common in high-rise residen tial and other commercial build ings where noncombustible con struction is required (Fig. 21), and it is becoming a factor in home building. Nonload-bearing partitions usually are framed with metal studs; ceilings usually are framed with metal furring secured to or suspended from open-web joists or light beams. 1 There are a variety of metal framing systems. Many are de- signed for ease of erection and demountability with a minimum of waste. Many others are de signed to meet requirements for sound isolation and fire resistance. The fire resistance classification and sound transmission class of 1 Detailed specifications for metal framing are given in Gypsum Association Sjteeifications for the Installation of Screw-Type Steel FYaming Members to Receive Gyp sumboard. 10 SGP 0025870 several hundred systems are shown in Design Data-Fire Re sistance/Sound Control, published by the Gypsum Association. The advantages of metal fram ing are noncombustibility, stable price, freedom from rot, ease of erection, and freedom from prob lems caused by moisture content and nonuniformity. The elements of the system are manufactured to fit. The spacing for metal framing to receive gypsumboard should not exceed the maximum spans recom mended for single and multi-ply construction which are shown in Table 1. Studs Typically, metal studs in non load-bearing partition framing are "C" shaped, 25 gauge coldformed steel, electrogalvanized, hot-dip galvanized, or painted to resist corrosion (Fig. 22). This gauge is suitable for use with most drywall screws used for fastening gypsumboard to metal studs. Joists Open-web joists generally are not designed to receive wallboard directly, and they often are spaced more than 24 in. o.c. Hence, it is necessary to provide suitable fur ring or suspension systems at ap propriate spacing for attaching the wallboard ceiling (Fig. 23). Channels Metal furring members may be either cold-rolled channels, drywall furring channels, resilient fur-ring channels, or drywall steel studs (Fig. 24). Metal furring is used in noncombustible assemblies Fig. 22 "C" shaped steel studs placed in metal runners support this multi ply, sound insulating partition. and for extra sound isolation in wood-framed assemblies. Fig. 21 Metal studs go up quickly in this office building. Fig. 23 Open web joists are furred with a cold rolled and drywall channel suspension system to hold gypsum board in this floor ceiling assembly. SGP 0025871 11 screw or a 5d nail, and to metal framing with wire ties or clips at each support. Drywall furring channels over masonry or concrete surfaces may be installed horizontally or ver tically, whichever is more con venient. Metal studs may also be used. The spacing should be as shown in Table I. Masonry and concrete walls or dinarily use plain furring chan nels because resilient mounting does not substantially improve the sound isolation qualities. How ever, most drywall channels are used in ceiling assemblies to sup port the wallboard (Fig. 25). If sound or vibration isolation is de sired , a suspended ceiling of gyp- clean and flat. Above-grade, ex terior cavity walls also may be suitable for direct lamination if the cavity is properly insulated to pre vent condensation. However, ad hesive application directly to exterior masonry walls is not recommended. Also, predecorated gypsumboard with a surface which is highly resistant to water vapor generally should not be laminated directly to concrete or masonry. Moisture may become trapped within the gypsum core of the board. The base surface should be made as flat as possible. Rough or protruding edges should be removed and large depressions may be filled with mortar. Excess mortar in joints should be trimmed ceiling attachments roucjli or finished cciling metal trim Fig 24 Plain drywall channel (top) has a hat shaped cross section, while re silient drywall channels (center four) come in several designs All are of galvanised steel. Cold rolled channels (bottom two) are "C" shaped and gen erally of 16 gauge black asphaltum painted steel. Cold-rolled channels may be used in furred partitions and in most types of suspended ceiling assemblies. Ordinarily, they are wire-tied in place with the furring channels tied or clipped to them. These channels usually are of 16 gauge steel with either a galvan ized or black asphaltum finish. They are available in sizes rang ing from 3/4 to 2 in. wide in lengths up to 20 ft. Drywall furring channels (or plain furring channels) are cold rolled from 25 gauge electrogalvanized or hot-dip galvanized steel and are generally "hat" shaped. Standard drywall chan nels are designed for wallboard attachment with self-drilling and self-tapping gypsum drywall screws. The channels should he installed at right angles to fram ing supports. They are fastened to wood framing with a 1-1/4 in. 12 Fig. 25 In suspended gypsumboard ceil ings, drywall channels are clipped to suspended cold-rolled channels rather than to framing members. Various clips are used. sumboard is attached to drywall channels clipped or tied to a grid of cold-rolled channel) supported by wire hangers. Resilient furring channels are used over both metal and wood framing to provide a sound ab sorbing spring mounting for a gypsumboard surface. They not only improve sound isolation, but they also help to isolate the gyp sumboard from structural move ment, and help minimize the possibility of cracking. MASONRY SUPPORTS In addition to attachment to wood or metal framing or furring, wallboard finishes can be lamin ated directly to above-grade, in terior masonry and concrete if the surface is sufficiently dry, smooth. furring channel l/4" - min. ?-1/4" - max 3/4" - c.r. channel wire tie furring bracket floor attachments adjustable wall furring Fig. 26 Adjustable brackets make in stallation of furring easy over irregular masonry walls. SGP 0025872 Fig 27 Nails properly driven with a crown headed hammer show a slight depression, or "dimple", around the nailhead. flush with the face of the wall. Base surfaces should be cleaned of form oils, curing compounds, loose particles, dust, or grease to assure adequate bond. It is es sential that concrete be allowed to cure for at least 28 days be fore wallboard is laminated di rectly to it. Exterior and below-grade walls, horizontal surfaces subject to moisture or excessive heat loss, or any surface which cannot be prepared readily for adhesive lam ination should be furred to pro vide a suitable base for attaching the gypsumboard. A variety of clips, runners, and adjustable brackets are available with engineered furring systems to facilitate rapid erection over irregular masonry walls. When special clips are used, manufac turers specific recommendations for installation should be followed. ATTACHMENTS AND FASTENERS Nails and screws are commonly used to attach gypsumboard in both single and multi-ply instal lations; clips and staples are used only to attach the base layer in multi-ply construction. Special drywall adhesives can be used to secure single-ply gyp sumboard to framing and furring, masonry and concrete, or to lam inate a face ply to a base layer of gypsumboard, sound deadening board, or rigid foam insulation. Adhesives generally are supple mented with mechanical fasteners. Mechanical application of gyp sumboard requires special nails, staples, and screws. Ordinary wood screws, sheet metal screws, or common nails should not be used. They are not designed to hold the board tightly and to countersink neatly. Fasteners should be placed at least 3/8 in. from board edges and ends. Fastening should start in the middle of the board and proceed outward toward the edges. Fasteners should be driven as nearly perpendicular as pos sible while the board is held firm ly against the supporting con struction. Nails should be driven with a crown headed hammer which forms a uniform depres sion or 'dimple" not more than 1,32 in. dee]) around the nail head (Fig. 27). Particular care should be taken not to break the face paper or crush the core with too heavy a blow. SGP 0025873 13 f or Apphc otiori o* O'F'SUf/ WALLROAW) GWB 54 098 pauge l`/`or 1 Vi tong Hal, slight'/ countersunk head, annular ringed, slight taper t cl C onipr T ype Nan ( I '/, lung! r-' Concave Head Nail {Proprietary) 1 4 .igi- l Vo Color Hm Ml * per lh ) 1 f Ml Mr,*! Ralrhct Nail (?b7 [XU lb ) II gauge 1Galvanized Ruotmg Nail vuin flat head I 189 [H't lb ) " either aod elched or cement coated to mciease holding power Fig 28 Nails used in drywall construc tion have thin, 1/4 in. diameter heads. Small headed nails shown are color pins for use with predecorated wallboard. These are used according to instructions of the manufacturers Nails Samples of nails for gypsumboard application are shown in Fig. 28.*1 Preferably, the nails should have heads that are flat oi- slightly concave and thin at the rim. The heads should be at least 14 in. diameter and not more than 5; 16 in. diameter to provide adequate holding power 'Nails suitable for frypsumlioard application should conform to ASTM C-5M, Standard Specifications For Naiht For the Applica tion of Gi/psum Wallboard, although some fire rated constructions require special nails as recommended by the manufacturer. 14 without cutting the face paper when the nail is dimpled. Casing nails and common nails have heads too small in relation to the shank; they easily cut into the face paper and should not be used. Nail heads that are too large are also likely to cut the paper surface if the nail is driven incorrectly at a slight angle. Nails should be long enough to go through the wallboard lay ers and far enough into support ing construction to provide ade quate holding power. Nail pene tration into the framing member should be 7/8 in. for smooth shank nails, but only 3/4 in. for annular ringed nails which pro vide more withdrawal resistance and require less penetration. Screws Drywall screws are used to attach gypsumboard to wood or steel framing or to other gypsumboards. They have cupped Phillips heads designed for use with a drywall power screwdriver. These screws pull the board tight ly to the supports without damag ing the board, and this minimizes fastener/surface defects due to loose boards. The specially con toured head makes a uniform de pression free of ragged edges and fuzz if properly driven. The three basic types of drywall screw,f, Type W for wood, Type S for sheetmetal, and Type G for solid gypsum construction, are shown in (Fig. 29) with their recommended penetrations into the framing members. Also shown are properly designed screws available for attaching wood or metal trim and Type S-12 screws for attaching wallboard to heavy gauge, load-bearing metal studs. Type W gypsu m drywall screws are designed for fastening gyp sumboard to wood framing or furring. Diamond-shaped points on Type W screws provide ef ficient drilling action through both gypsum and wood, and a specially designed thread gives quick pen etration and increased holding power. Recommended minimum penetration into supporting con struction is 5/8 in. However, in two-ply construction where the face layer is screw attached, ad ditional holding power is devel oped in the base ply which permits reducing penetration into supports to 1/2 in. Type W screws are available in several lengths. However, if the right length cannot be found, drywall sheetmetal screws, more readily available in longer sizes, may be substituted in two-ply construction. Type S gypsum drywall screws are designed for fastening gyp sumboard to metal studs or fur ring. They are self-drilling; they have a self-tapping thread and generally a mill-slot or hardened drill point designed to penetrate sheet metal with little pressure. Easy penetration is important because steel studs often are flexible and tend to bend away from the screws. Type S screws are made available in several lengths, from 7/8 in. to 2-1/4 in. Sc row*. for Application of GYF'SUM WAL L HOARD I yi><' S Huglr T y t S I'.in Iyp< b I? Ihlglr lyin' b P.in 1 ype G Hugh' Ty[>< W (P.glr I yr>,- S Inm N, . 0 ft.is.' S' ,rw Fig. 29 Type S screws shown should penetrate at least 3/8 in beyond gyp suntboard surface to bold metal framing tightly. Type G screws should penetrate at least 3/8 in. into supporting layers of gypsumboard to hold tightly, andType W screws should penetrate at least 5/8 in. into wood framing under gypsum board. SGP 0025874 Corrected Page 15 For Using Gypsum Board For Walls And Ceilings Type G gypsum drywall screws are used for fastening gypsumboard panels to gypsum backing boards. Type G are similar to Type W screws, but they have a deeper special thread design. They generally arc 1-1 /2 in. long, but other lengths are available. Gypsum drywall screws require penetration of at least 5/8 in. of the threaded portion into the framing members. Gypsum drywall screws should not be used to attach wallboard to 3,8 in. backing board because sufficient holding strength is not available. Nails or longer screws should be driven through both the surface layer and the 3/8 in. base ply to give the proper penetration in supporting wood or metal con struction. Staples Staples are recommended only for attaching base ply to wood members in multi-ply construc tion. They should be 16 gauge, flattened, galvanized wire with a minimum 7/16 in. wide crown and spreading points. Staples should provide a minimum of 5/8 in. penetration into supports. Adhesives Adhesives are used to bond single layers of gypsutnboard di rectly to framing, furring, ma sonry, or concrete. They can also be used to laminate wallboard to base layers of backing board, sound deadening board, rigid foam, or other insulation. They generally are used in combination with nails or screws which provide supplemental support. Adhesives for applying wallboard finishes are classed: 1. stud adhesives: 2. laminating adhesives; and 3. contact or modified adhesives. Stud adhesives are specially pre pared to attach single-ply wallboard to steel or wood supports. 1'hey should be of caulking con sistency so that they bridge fram ing irregularities. Also they should meet rigid standards for strength, bridging ability, aging, and other qualities necessary for longterm performance.1 They are applied with a gun (Fig. 30) in a continuous or semi-continuous bead. Solvent-base stud adhesives should not be used near an open flame, in poorly ventilated areas, or for lamination of predecorated gypsumboard. Laminating adhesives generally are casein-base compounds in pow der form to which water is added. They are used to laminate gypsumboards to each other and to suitable masonry or concrete sur faces. They are not intended for adhesive bonding to wood framming or furring. Although some stud adhesives and contact ad hesives also can be used for lam inating, they should not be so used unless recommended by the manufacturer. Only as much laminating ad hesive should be mixed as can be used within the working time specified by the manufacturer. Water used should be at room temperature and clean enough to drink. The adhesive may be applied over the entire board area with a suitable spreader, or it may be spaced in parallel ribbons or a pattern of spots as recommended by the manufac turer. Face boards require tem porary support or supplemental fasteners until the adhesive de velops sufficient bond strength. Contact adhesives have a syn thetic rubber base, sometimes with resins added. Contact ad hesives are used to laminate gypsumboards to each other or to bond wallboard to metal studs. The adhesive is applied by roller, spray gun, or brush, in a thin, uniform coating to both surfaces to be bonded. For most contact adhesives, some drying time us ually is required before surfaces can be joined and bond can be developed. To assure proper ad hesion between mating surfaces, the face board should be im pacted over its entire surface with a suitable tool, such as a rubber mallet. 'ASTM C-557 Tentative S)>ecification for Adhesives to Fasten Gypsum Wallboard to Wood Framing. Fig. 30 Adhesive applicators (guns) are loaded with material pumped from a container. Contact adhesives give the ad vantages of immediate bond, ex cellent long-term strength, and resistance to fatigue. Also, no temporary supports are needed while the adhesive sets and the bond forms. One disadvantage is their inability to fill in irregu larities between surfaces, which leaves areas without adhesive bond. Another disadvantage is that most of these adhesives do not permit moving the boards once contact between surfaces has been made. A sheet of poly ethylene film or tough building paper can be slipped between the surfaces so that gradual bonding of surfaces will occur as the slip sheet is withdrawn. Extra care and judgment should be taken when contact adhesives are used. Manufacturer's recom mendations should be followed. Modified contact adhesives pro vide a longer placement time. They have an open time of up to 1/2 hour during which the board can be repositioned if necessary. They combine good long-term strength with sufficient immediiate bond to permit erection with a minimum of temporary fasten ers. In addition, the adhesive has bridging ability. Modified contact adhesive is intended for attaching wallboard to all kinds of supporting construc tion, including framing, solid walls, other gypsumboard, and various insulating boards. SGP 0025875 15 Type G gypsum drywall screws are used for fastening gypsum- board panels to gypsum backing boards. Type G are similar to Type W screws, but they have a deeper special thread design. They generally are 1-1 /2 in. long, but other lengths are available. Gypsum drywall screws require penetration of at least 5/8 in. of the threaded portion into the framing members. Gypsum drywall screws should not be used to attach wallboard to 3/8 in. backing board because sufficient holding strength is not available. Nails or longer screws should be driven through both the surface layer and the 3/8 in. base ply to give the proper penetration in supporting wood or metal con struction. Staples Staples are recommended only for attaching base ply to wood members in multi-ply construc tion. They should be 16 gauge, flattened, galvanized wire with a minimum 7/16 in. wide crown and spreading points. Staples should provide a minimum of 5/8 in. penetration into supports. Adhesives Adhesives are used to bond single layers of gypsumboard di rectly to framing, furring, ma sonry, or concrete. They can also be used to laminate wallboard to base layers of backing board, sound deadening board, rigid foam, or other insulation. They generally are used in combination with nails or screws which provide supplemental support. Adhesives for applying wallboard finishes are classed: 1. stud adhesives; 2. laminating adhesives; and 3. contact or modified adhesives. Stud adhesives are specially pre pared to attach single-ply wallboard to steel oi' wood supports. They should be of caulking con sistency so that they bridge fram ing irregularities. Also they should meet rigid standards for strength, bridging ability, aging, and other qualities necessary for long term performance.1 They are applied with a gun (Fig. 30) in a continuous or semi-continuous bead. Solvent-base stud adhesives not be used near an open in poorly ventilated areas, lamination of predecorated nboard. inating adhesives generally ein-base compounds in pow der iorm to which water is added. They are used to laminate gypsumboards to each other and to suitable masonr" or concrete sur faces. They are not intended for adhesive bonding to wood framming or furring. Although some stud adhesives and contact ad hesives also can be used for lam inating, they should not be so used unless recommended by the manufacturer. Only as much laminating ad hesive should be mixed as can be used within the working time specified by the manufacturer. Water used should be at room temperature and clean enough to drink. The adhesive may be applied over the entire board area with a suitable spreader, or it may be spaced in parallel ribbons or a pattern of spots as recommended by the manufac turer. Face boards require tem porary support or supplemental fasteners until the adhesive de velops sufficient bond strength. Contact adhesives have a syn thetic rubber base, sometimes with resins added. Contact ad hesives are used to laminate gypsumboards to each other or to bond wallboard to metal studs. The adhesive is applied by roller, spray gun, or brush, in a thin, uniform coating to both surfaces to be bonded. For most contact adhesives, some drying time us ually is required before surfaces can be joined and bond can be developed. To assure proper ad hesion between mating surfaces, the face board should be im pacted over its entire surface with a suitable tool, such as a rubber mallet. 'ASTM C-557 Tentative Specification for Adhesives to Fasten Gypsum Wallboard to Wood Framing. Fig. 30 Adhesive applicators (guns) are loaded with material pumped from a container. Contact adhesives give the ad vantages of immedia e bond, ex cellent long-term strength, and resistance to fatigue. Also, no temporary supports are needed while the adhesive sets and the bond forms. One disadvantage is their inability to fill in irregu larities between surfaces, which leaves areas without adhesive bond. Another disadvantage is that most of these adhesives do not permit moving the boards once contact between surfaces has been made. A sheet of poly ethylene film or tough building paper can be slipped between the surfaces so that gradual bonding of surfaces will occur as the slip sheet is withdrawn. Extra care and jud lent should be taken when contai t adhesives are used. Manufactu t's recom mendations should be followed. Modified contact adhesives pro vide a longer placement time. They have an open time of up to 1/2 hour during wh.eh the board can be repositioned if necessary. They combine good long-term strength with sufficient immediiate bond to permit erection with a minimum of temporary fasten ers. In addition, the adhesive has bridging ability. Modified contact adhesive is intended for attaching wallboard to all kinds of supporting construc tion, including framing, solid walls, other gypsumboard, and various insulating boards. SGP 0025876 15 Ill SINGLE-PLY APPLICATION The quality of single-ply fin ishes is largely dependent on ac curately aligned, solid supports. Before single-ply gypsumboard is applied, the framing or furring members should be checked for firmness and alignment in the same plane (Fig. 18). NAIL ATTACHMENT Wallboard can be attached by either a single-nailing or doublenailing method. In general, space between nails is determined by re quirements for fire resistance and for firmness of board-to-stud con tact necessary to reduce possible surface defects. It is less depend ent on the load imposed. Single nails should be spaced 7 in. o.c. on ceilings and 8 in. o.c. on walls along supports (Fig. 31). Double nai. ig can produce tighter board-to-stud contact and fewer loose be ards than single nailing. In double nailing, a first seti of nails is driven 12 in. o.c. in the middle of the panel, and then a second set is driven 2 in. from each of the nails first applied. After the second set of nails is driven, the board is held tighter than before, and the first nails driven should be given an extra blow to reseat them firmly. Edges and ends falling over supports should be single-nailed 7 in. o.c. on ceilings and 8 in o.c. on walls (Fig. 32). Loose Attachment Loose attachment of gypsum board will result in objectionable Fig. 31 In single nailed gypsumboard, nails are spaced 7 to 8 in. apart along supports and not less than 3/8 in. from edges and ends. Nails are first driven in the middle area of the board and then out toward the edges and ends. ir nail pops. The board must be drawn tig itly against framing or furring members so that it cannot move on the nail shank. Even when substantial pressure is applied properly, it still may not be possible to produce snug con tact between board and support ing members. This will happen if a board is cut too large to fit and must be forced into place or if nailing is stalled at the peri meter (ends or edges) and finished inward. To prevent loose boards, panels should be cut to fit easily into place, pressure should be ap plied while nailing (Fig. 33), and the correct nailing sequence from the middle of the panel outward should be observed. Loose NaiD Loose na is also cause loose gypsumboardf Loose nails can result when nails jither miss the under lying construction or enter it at an angle near the edge (Fig. 34). These nails may eventually work loose from vibration until they protrude beyond thefinishsurface. To guard against loose nails: 1) the location of supporting mem bers should be marked carefully on the wallboard prior to nailing; 2) nails should be driven perpen dicular to the surface and into the member; 3) nails which do miss the supports should be removed promptly, and their holes should be dimpled and treated with compound. Face Paper Fractures Face paper fractures can cause loose boards and nail popping. SGP 0025877 Fig 32 In double nailing, first nails, represented by black dots, are driven starting with row 1, then row 2 and 2A, working out toward the ends. Second nails, represented by the circles, are then driven in the same sequence. This defect can be caused by im proper nailhead design, nails driven at an angle (Fig. 35), or excessive and repeated impact during nailing. The gypsum core is easily crushed where the paper is punctured, and it offers less resistance to loosening from nor mal impact and vibration. Fractures caused by over driving of nails should be cor rected by driving a new nail 2 in. away from the fracture to provide firm attachment. Other common causes of face paper fractures are misaligned or twisted supporting members and projections of improperly in stalled blocking or bracing (Fig. 18). These framing faults prevent solid contact between wallboard and supporting members, and hammer impact causes the board to rebound in a manner that often ruptures the paper. Defective sup ports should be corrected before the wallboard is erected. Pro truding supporting members should be trimmed off or re installed. Shims can be used if necessary for receding pieces. The use of screws, adhesives, or two-ply construction will mini mize problems resulting from these defects. SCREW ATTACHMENT Because fewer fasteners are required when screws are used to attach wallboard, the number to be treated and possible defects are reduced. Screws should be spaced 12 in. o.c. on ceilings and 16 in. o.c. on walls where framing members are 16 in. o.c. Screws should be spaced a maximum of 12 in. o.c. on walls and ceilings where framing mem bers are 24 in. o.c.1 The neces sary penetration for screws is given in Fig. 29. 'For fire-rated construction, spacing may differ according to test requirements. Fig. 33 Gypsumboard applicator lifts board into place with a foot lever and leans against board with his forearm to hold it firmly while nailing. Fig 35 Nails driven in loose board will probably fracture the face paper (top) Nails driven at an angle also usually fracture the face paper (center). Properly Fig. 34 Loose nails are caused by poor fit of gypsumboard to framing surface driven nails produce tight attachment (left) or by nails missing the framing members when driven (right). with a slight, uniform dimple (bottom). SGP 0025878 17 ADHESIVE NAIL-ON ATTACHMENT Compared to conventional nail ing, adhesive nail-on attachment has the advantage of reducing the number of nails in the middle of the panel by at least 50 per cent. The tight bond between the wallboard and its supports results in a stronger, stiffer assembly with fewer fastener defects. Screws can be used in place of nails, but their use is not common because good board-to-stud con tact is assured by the adhesive and the number of face fasteners is already reduced to a minimum. Stud Adhesives not required for wallboard sup port, such as diagonal bracing, blocking and plates. The number and spacing of supplemental nails (or screws) varies, depending on the adhesive properties. Stud adhesives require only per imeter fasteners for wall applica tion.1 The fasteners should be spaced 16 in. o.c. along edges or ends that fall on parallel supports, and then should be placed at each point where edges or ends cross perpendicular supports. For ceil ing application, the perimeter is nailed as for walls, but additional fasteners spaced 24 in. o.c. are required in the field (Fig. 87). Some stud adhesives, such as those for use with metal framing, require fasteners on intermediate supports as well as at the peri meter of panels. Fastener spacing varies according to type of fasten er, support spacing, and loadbearing conditions as shown in Table II. 'These adhesives conform to ASTM C-557. See footnote, page 15. Stud adhesive should be applied with a caulking gun in accordance with the manufacturer's recom mendations. A straight bead, ap proximately 1/4 in. diameter, is applied to the face of supports in the field of the panel (Fig. 36). Where two adjacent panels join over a supporting member, a serpentine or zig-zag bead should be applied if the joint is to be treated (Fig. 36). When a pre decorated wallboard joint is to be left untreated, two parallel VERTICAL APPLICATION FIELD FASTENERS ON CEILINGS ONLY PERIMETER SPACING SAME FOR WALLS AND CEILINGS SUPPORT SPACING 1 6 in OR 24 m 0 C - Fig. 37 Single-ply gypsumboard systems attached with stud adhesives require supplemental fasteners on the perimeter. Spacing is the same whether board edges are perpendicular or parallel to supports. Ceiling installations require supple mental fasteners in the field as well as the perimeter. Fig 36 Beads of stud adhesive are applied (left) straight under the field of a board, (center) zig zag under |omts to be taped, and (right) parallel under predecorated joints. beads of adhesive should be ap plied, one near each edge of the member (Fig. 36). Enough ad hesive should be in the bead so that, when the wallboard is pressed on, the bead will spread to an average width of 1 in. at least 1/16 in. thick. Not so much adhesive should be applied that it will squeeze out at the joints. It should not be applied to members which are 18 adhesives after it is applied. SGP 0025879 Bracing Predecorated wallboard with bevelled or square edges often does not require joint treatment, and therefore, it is desirable to avoid fasteners at the joints. The board should he applied with ad hesive, and prebowing, temporary bracing, or some other means should he used to ensure contact between hoard and adhesive until the bond develops full strength. Plain wallboard may also be at tached vertically with adhesives without using fasteners at the edges if temporary nailing or bracing is used. Temporary sup ports for adhesive attachments should be allowed to remain in place for at least 24 hours (Fig. 39). METAL FRAMING TABLE II SPACING FOR FASTENERS USED WITH STUD ADHESIVES. LOCATION Ceiling Load-bearing Walls SUPPORT SPACING 16 in. o.c. 24 in. o.c. 16 in. o.c. 24 in. o.c. FASTENER SPACING NAILS SCREWS 1 6 in. o.c. 1 2 in. o.c. 1 6 in. o.c. 16 in. o c. 1 2 in. o.c. 24 in. o.c. 1 6 in o.c. Nonload-bearing Walls 1 6 in. o.c. 24 in. o.c. 24 in. o.c. 16 in. o.c. 24 in. o.c. PREVENTING DEFECTS Nail Popping Nail popping is caused by wood shrinkage or warping, improper framing, improper nailing or any conditions that lead to loose gypsumboards. These conditions have been shown in Fig. 13, 18, 34 Wallboards should be attached to metal framing and furring with Type S screws, spaced not more than 12 in. o.c. along sup ports for both walls and ceilings.1 These screw spacings are appro priate also when wallboard is mounted on resilient furring chan nels over wood framing. CONCRETE AND MASONRY Some laminating adhesives and stud adhesives are suitable for laminating wallboard directly to concrete and masonry, but indi vidual manufacturer's recommen dations vary and should be con sulted to ensure proper selection and application. While adhesive is setting, temporary support should be provided for the wallboard. Temporary bracing, threaded stub nails, or cut nails may be used. 1 For fire and sound-rated construction, screw spacing must follow that of the system tested. Fig. 39 Temporary bracing holds gypsumboard against supporting framing until adhesive bond develops. SGP 0025880 19 VERTICAL CEILING APPLICATION single nailing described above. A source of cracking in non bearing walls is the modern trend toward less rigid structures. Larg er deflections in structural mem bers and greater expansion and contraction of exterior columns can impose unexpected loads on nonbearing walls, and this may cause cracking. Detail designs for perimeter relief of nonbearing partitions are available to improve this condition. Several designs may be used with fire rated and sound rated partitions. One ex ample is relief runners used to attach nonbearing walls to ceiling and column members (Fig. 41). Fig. 40 Floating angle construction helps eliminate nail popping and corner crack ing. Fasteners at the intersection of walls or ceilings are omitted. and 85. Maintaining good job site storage conditions, making sure that framing is in line, and using proper nails and attachment pro cedures will help avoid the prob lem. Floating angle construction (see below) will also help avoid nailpopping caused by stresses at inside corners. Cracking Corner cracking may result from structural stresses at inside corners where walls and ceiling meet, although it may also result from improper joint treatment. Floating angle construction is in tended to minimize damage from structural stresses. It consists of omitting some fasteners at inte rior cornel's (Fig. 40). Wallboard should be applied to the ceiling first. It should befitted snugly at the wall-to-wall and 20 ceiling-to-wall intersections. Framing members or blocking should be used at corners to pro vide solid backing, even though they may not be required to hold fasteners. Where walls meet ceilings, the last row of fasteners on the wall should be omitted so that nails start 8 in. from the intersection. On ceilings where the joists are parallel to the intersection with a wall, nailing should start at the intersection; where joists are per pendicular, nails should start 7 in. from the intersection (Fig. 40). For interior corners at the meet ing of walls, the last row of fasteners is omitted from the board first applied only; the over lapping board on the other wall is nailed in the conventional man ner. When double nailing, the same nail-free clearances at corn ers should be maintained as for Ridging Joint ridging may occur when joints are treated during cold or humid weather. It occurs more frequently when joint compound is not properly applied. Joint treat ment is discussed in a later section. The most effective preventive is to use a multi-ply gypsumboard system which reinforces the sur face joints. Other preventives are to use back blocking or strip rein forcing to reinforce joints and to prevent the stresses that cause ridging. Special edged boards, pro duced specifically to overcome ridging problems, are available from most gypsumboard manu facturers. Back blocking is used when gypsumboard ends are located midway between framing mem bers on walls or ceilings. Gyp sumboard back-blocks spanning the distance between supports are laminated to the back of the sur face wallboard to reinforce the joints and prevent flexing or movement. Joints between square ends need a high crown and wide feathering which may cause ridg ing when they are treated under adverse weather conditions. A procedure which reduces the need for high crowns is end joint taper ing, shown in Fig. 42. Used in conjunction with back blocking, end joint tapering produces a shallow depression which is easier to treat than the square end joint. Back blocking and associated constructions are used most often SGP 0025881 r STEEL STUD PARTITION SOLID CORE GYPSUM PARTITION SOLID OR LAMINATED GYPSUM CORE PARTITION STEEL ANGLE WITH 1 3/i" LEGS WALLBOARD UNACCESSIBLE SHAFT OR CHASE SIDE SECTION AT HEAD OR END DOUBLE STEEL ANGLE SINGLE CHANNEL OR RUNNER WITH l'V LEGS GYPSUM COREBOARD . CONCRETE 20 GA STEEL CHANNEL OR DOUBLE ANGLE WITH l'/*" LEGS >/," INSULATION 25 GA. STEEL CHANNEL OR DOUBLE ANGLE WITH 1 V* " LEGS SECTION AT HEAD OR END 3/i" OR V?" GYPSUM WALLBOARD SEMI-SOLID GYPSUM CORE PARTITION CONCRETE CAULK BEHIND RUNNEf FOR SOUND CONDITIONED CONSTRUCTION l/?" GYPSUM WALLBOARD SCREWS STEEL RUNNER WITH l1," LEGS. 24"T0NCERS STEEL CHANNEL WITH I'/*" LEGS ALTERNATE SECTION AT HEAD DOUBLE WALL GYPSUM STUD PARTITION CAULKING^urr TRIM SCREWS MAX .20 GA STEEL CHANNEL WITH I ; " LEGS; FASTENERS 24" 0 C 25 GA STEEL RUNNER WITH I V LEGS OR 1 " WOOD RUNNER Vi" INSULATION SECTION AT HEAD OR END DOUBLE WALL Fig. 41 Detail designs show fire-rated perimeter relief systems to eliminate stress cracking m gypsumboard. on ceilings because imperfections are more conspicuous on such large, unobstructed, obliquely lighted surfaces. Strip reinforcing offers many of the advantages of two-ply con struction at reduced cost. Com bining adhesive lamination with mechanical fastening reduces the number of nails in the face-ply. Although it results in thicker as semblies than does back blocking, strip reinforcing accomplishes the same results positively and in less time. Strips of 3/8 in. backing board or scrap wallboard, 8 in. wide, are installed 24 in. o.e. perpen dicular to framing members in the same way as cross furring. Strips should be 4 in. wide along the base of the partition and along the partition-ceiling intersection. This cross stripping supports the edges and provides intermediate support in the field. To support the butt ends, ad ditional short strips are secured directly over the supporting mem bers between the cross-stripping. All strips except those parallel to studs are nailed about 1 in. from the edge. Laminating adhesive is applied to the strips with a strip-lamin ating head in parallel beads. Wallboard should be 1/2 in. or thicker and must be installed perpendi cular to framing members so that long edges fall on the cross stripping and ends are supported on the short intermediate strips. SGP 0025882 21 Workman use double-headed nails m temporary bracing for end joint tapering. Backing blocks, 8 in wide and long enough to fit loosely between joists, are placed along the boated ends of a ceiling wallboard. Top cross section shows how wood strip along joint and temporary (traces depress the end joint while adhesive bond sets Bottom shows joint after removal of strip and braces. Fig 4 2 Back blocking and taperin putt joints on ceilings reduces the need for high crowns and strengthens the joint against ridging After wood strips are removed, tapered joint remains depressed. When supporting members in walls are spaced 16 in. o.c., 1-1,2 in. Type G drywall gypsum screws are required through the surface layer to the gypsumboard strips midway between framing members for both walls and ceil ings. Appropriate drywall nails providing generally recommended penetration are used to attach both stripping and wallboard to the framing. Special-edged wallboards are one widely recommended solution for the problem of joint ridging in single-ply finishes proposed by manufacturers today. These have beveled or rounded tapered edges specifically developed to overcome joint ridging. A special fast-set ting joint compound is used to prefill the joints. ---------------------------- SGP 0025883 IV MULTI PLY APPLICATION Multi-ply constructions have two or more layers of gypsumboard. Face layers usually are laminated to a base layer of wallboard, backing board, or sound deadening board. Only a limited number of fasteners are used to assure adhesive bond. Multi-ply construction is used on ceilings, framed wall assemblies, and selfsupporting all-gypsum partitions. The maximum support spacing for multi-ply finishes depends mainly on the base-ply thickness and placement. It is the same for both wood and metal framing and furring, and it is shown in Table I. BASE-PLY ATTACHMENT The base-ply of gypsumboard multi-ply systems may be wallboard, but more often, backing board is used for economy. Spe cial gypsumboard is used for in creased sound isolation, and other sound deadening boards are also found as a base ply. Nails, staples, or screws are used to attach the base-ply to supporting framing or furring. Fastener spacing is shown in Table III. WOOD FRAMING AND FURRING When a multi-ply system with a laminated face layer is to be used oven wood supports, the base ply should be single-nailed as recom mended for single-ply eonstruc- tion. Double nailing is not used because nailheads wil. be covered by the face ply a d fastener treatment is not a a nsideration. TABLE III BASE PLY FASTENER SPACING ON WOOD FRAMING 1 Location Walls Ceilings NAIL SPACING Laminated Face Ply 8 in. o.c. 7 in. o.c. Nailed Face Ply 1 6 in. o.c. 16 in. o.c. SCREW SPACING Laminated Face Ply 2 1 6 in. o.c. Screwed Face Ply 24 in. o.c. 1 6 in. o.c. 24 in. o.c. STAPLE SPACING Laminated Face Ply 7 in. o.c Nailed or Screwed Face Ply 16 in, o.c 7 in. o.c 16 in. o.c Fastener size and spacing for applying sound deadening boards vary for different fire and sound-rated constructions. The man ufacturer's recommendations should be followed. 1 2 in. o.c. for both ceilings and walls when supports are spaced 24 in. o.c. SGP 0025884 23 edges where the face-ply will he laminated, and 1G in. o.c. through out when the face ply will be attached with screws. is preferred. However, predecor ated wallboard that is to be left with joints untreated or wallboard that is to he trimmed with battens is installed vertically. Fig 43 Floating angle construction for multi ply systems has overlapping side of base ply only nailed at interior corner FACE PLY ATTACHMENT Joints in the face-ply should be offset from joints in the base-ply by at least 10 in. Wallboard can be applied either horizontally or vertically, whichever results in the least waste of materials. On walls, horizontal application usually re sults in fewer joints and therefore NAIL AND SCREW ATTACHMENT When the face-ply is attached with mechanical fasteners and there is no adhesive between plys, the maximum spacing and mini mum penetration recommended for nails and screws should he the same as for single-ply ap- The base-ply on multi-ply fin ished walls may he installed par allel or at right an gles to framing members. Support spacings are given in Table I. On ceilings, it is preferred that the base-ply be perpendicular to the framing members. At inside cornel's, it is recom mended that only the overlapping base ply he nailed or screwed and that fasteners be omitted from the face ply. The floating cornei s created arc more capable of resisting structural stress (Fig. 43). The base ply generally does not need fasteners at exterior corners because support will be provided when the face ply and corner trim is added. Staples used o fasien base plys should be driven with the crown perpendicular to the edges of the hoard, exi cpt that where edges fall over supports, they should he driven parallel to the edges (Fig. 44). Crowns of driven staples should bear tightly against the hoard without breaking the face paper. VERTICAL APPLICATION S' At 1 FS Sf'*M t i) , I\ i- c ( HH\'A s t f' suppF'EH"c VP. v,A-. t HORIZONTAL APPLICATION Fig. 44 Staples are driven with crowns perpendicular to gypsumboard edges ex cept where edges fall along supporting members. METAL FRAMING AND FURRING Base layers of multi-ply con struction on metal framing or furring are attached with Type S dry wall sheet metal screws. Screw spacing in the base-ply should he 12 in. o.c. in the field and at Fig. 45 Notched spreaders apply adhesive for sheet lamination. SGP 0025885 plication. These have been given ter under "Nail Attachment" and in the Single Ply Application chap- "Screw Attachment". ADHESIVE ATTACHMENT Typical multi-ply construction may employ sheet lamination, strip lamination, or spot lamin ation to attach the face-ply to the base-lily. Sheet lamination involves cov ering the entil e back of the face- ply with laminating adhesive from a notched spreader, box spreader, or other suitable tool (Fig. Jo). Size and spacing of the notches varies with the adhesive. The wallboard should be erected using moderate pressure, and any ad hesive squeezed out at the joints should be promptly removed. Sti'ip lamination and spot lamination are preferred to sheet lamination in sound rated parti tions because the sound control is improved. In strip lamination, adhesive is applied with a special spreader in ribbons normally spaced 16 in. to 24 in. o.c. (Fig. 46). In spot lamination, spots of adhesive (Fig. 47) are brushed or daubed on in a pattern. ply of fire-rated assemblies. Nail spacing varies depending on the tested assembly construction and is not related to whether adhesive is used between plys. The spacing is given in the report of the fire tests and is available either in the manufacturer's literature or Gypsum Association literature. In sound-rated partitions where fire resistance is not a consider ation, the most common practice is to attach the face ply vertically over sound deadening board or other board with permanent me chanical fasteners at the top and bottom. Intermediate fasteners are omitted along vertical joints and in the field, and temporary bracing is provided until adhesive has developed sufficient bond strength. Temporary Fasteners Supplemental mechanical fas teners or temporary bracing (Fig. 69) are required to hold the face ply against the base ply, and to assure satisfactory adhesive bond. Temporary fasteners may be used to hold a face ply in place while the adhesive sets if a fire rating is not required. These fas tener's may be double-headed nails (Fig. 48), stucco furring nails, or drywall nails, generally spaced approximately 24 in. o.c. in each direction. Drywall nails should be driven through gypsumboard washer's or other rigid material for easy removal without damage to the face ply. After nails are removed, nail holes should be dimpled and finished with com pound, like permanent nails. Fig. 46 Strips of adhesive for lamin ating can be applied to base ply on the wall or to the back of gypsumboard to be mounted. Some permanent mechanical fasteners should be used in each laminated gypsumboard panel, particularly on ceilings. On side walls these can be placed at the perimeter of the board where they will be concealed by joint treatment or trim. Permanent Fasteners Permanent fasteners generally are required in the field as well as in the perimeter of the face SGP 0025886 25 Semi-Solid Partitions Semi-solid partitions provide vertical interior passages for me chanical services. They consist of single or two-ply faces of gypsumboard separated by vertical gyp sum ribs, 6 in. wide and preferably 1-5/8 in. thick.1 The panels are set vertically in place (Fig. 49). In single-faced partitions, the face ply is attached directly to the ribs. Partitions with two-ply faces consist of gypsum ribs, a backingboard base ply and wallboard face ply. Semi-solid walls may be pre laminated or laminated in place. Gypsum ribs, cut 6 in. shorter than wallboard, are laminated to the face ply on one side of the par tition either before or after it is erected. (Edges of door and win dow openings should be reinforced with wood or steel). Adhesive is spread on the erected face ply or on the ribs, keeping it 1 in. from the rib edges, and the rib is pressed in place. The rib-rein forced panels are secured to wood or metal runners at top and bot tom with appropriate drywall screws spaced 12 in. o.c. The ribs on the erected panels then are spread with adhesive, and facing panels are installed by Fig. 48 Double headed temporary nails are easily removed. A metal plate is used to protect the wallboard surface. ________ 'If one in. thick ribs are used, care must be taken to make sure proper outlet boxes are used. SELF-SUPPORTING GYPSUM PARTITIONS These are nonload-bearing, non combustible, multi-ply partitions. They are fabricated on the job, almost entirely from gypsumboard. Inner plys are backing board ribs or sheets, and wallboard face plys are laminated to these. Unlike the framed ceiling and wall assemblies which depend on wood, metal or other construc tion to support the surface finish, gypsum partitions are entirely self-supporting, and they require only floor and ceiling runners to stabilize the partition. Runners should be attached securely to ceilings and floors with fasteners 26 spaced not over 24 in. o.c. Self-supporting gypsum parti tions are classed as: 1. semi-solid, utilizing backingboard ribs between face plies, 2. solid with a coreboard (thicker backing board) inner ply, or 8. double solid and triple solid, with two or three solid walls placed parallel to provide in creased fire resistance and sound control. All gypsumboard components such as ribs, coreboard, backing board and wallboard are installed in ver tical position. Fig. 49 A workman mounts prelaminated semi-solid partition panels on floor and ceiling runners. SGP 0025887 JOB LAMINATING OF PANEL ASSEMBLIES Fig. 50 An efficient method of attaching gypsum ribs to face panels for semi-solid partitions is: STEP 1 - Place two pieces (one bundle) of face layers (plain or piedecorated gypsum wallboard) with finish surfaces together on a smooth, level surface; STEP 2 - Spread adhesive on one side each of two gypsum ribs, using a spreader; STEP 3 - Place one rib, adhesive face down, in the middle of the top face sheet about 3 in. from each end, STEP 4 - Set the second rib flush with the edge, adhesive side up, about 3 in. from each end; STEP 5 - Place a second bundle on top of the ribs with the edge flush with the edge of the uncoated stud a9a'n spread two ribs with adhesive and repeat the procedure until the required number of panels are laminated Place an extra bundle on the top assembly to provide pressure while the adhesive dries. SGP 0025888 screw-attaching them to the run ners with screws spaced 12 in. o.c. Adequate bond to the ribs is assured by 1-1/2 in. Type G dry- wall gypsum screws placed along each rib 12 in. from the top and bottom and spaced not more than 36 in. o.c. A more rapid method for ad hering ribs to panels is shown in Fig. 50. After this procedure is carried out, panels with ribs attached are erected with ad hesive spread on the outer face of the ribs. The erected panel edges are kept in contact with the ribs by temporary fasteners until the adhesive dries. 27 I Fig. 51 Double solid gypsumboard partitions have parallel courses attached to two runners separated try an air space. Courses are coreboard faced with wallboard Fig. 52 Triple-solid gypsumboard partitions have three parallel courses and provide superior sound control when a mineral wool or glass fiber blanket is added. For partitions with two-ply faces, the ribs and backingboard base plies are assembled and installed as previously men tioned. The face plies are sheet laminated as described for twoply supported partitions using supplemental drywall gypsum screws. (Screw spacing should be according to manufacturer's recommendations for fire rated partitions.) Separated rib construction to improve sound isolating effective ness can be provided in either single or two-ply ribbed partitions. Installation is essentially the same as for ordinary ribbed partitions, but twice as many ribs are re quired. These are spaced 12 in. o.c. and staggered on opposite sides of the partition. Solid Partitions Solid gypsum partitions have wallboard faces laminated to each side of a coreboard. Vertical joints in the face ply should be offset at least 3 in. from joints in the coreboard. The face ply typically is attached by sheet lamination with supplemental drywall gyp sum screws. Double and triple solid partitions separated by air spaces are shown in Figs. 51 and 52. RESURFACING EXISTING CONSTRUCTION Wallboard may be used to pro vide a new finish on existing walls and ceilings of wood, plaster, masonry or wallboard. If the existing surface is structurally sound and provides a sufficiently smooth and solid backing without shimming, 1/4 in. wallboard can be applied with adhesives, nails or screws. Existing surfaces which are too irregular to receive wallboard should be furred and shimmed to provide a suitable base. Minimum wallboard thickness for various support spacings and installation methods should be as recom mended for new construction over furring. Surface trim for mechanical and electrical equipment such as switch plates, outlet covers, and ventil ating grilles should be removed and saved for reinstallation. Elec trical boxes should be reset prior to the installation of new wallboard . I' SGP 0025889 28 V JOINT AND FASTENER TREATMENT After wallboard is erected, it is and protection. Both taped and necessary to make joints either trimmed areas, as well as fas inconspicuous or decorative to give teners, require finishing with com the wall or ceiling a desirable pound to achieve a smooth, mono appearance (Fig. 53). Panel joints lithic look. t in the same plane and interior SGP 0025890 corners are usually covered with paper tape and joint compound.1 Exterior corners and exposed edges require metal or other corn er and edge trim for appearance 'Joint tape and joint compound used to produce a smooth finish should conform to ASTM C-475 Joint Treatment Materials for Gypsum Wallboard Construction. 29 Where joints are decorated in stead oi taped, battens or mould ings are generally used (Fig. 54). JOINT TREATMET T PRODUCTS Tape used for joint reinforce ment typically is strong-fibered paper with feathered edges. The special paper used resists tensile stresses across the joint as well as longitudinally. Joint treatment products in clude: 1. Taping or joint compound for embedding and bonding the joint tape; 2. topping or finishing compound for final smoothing and level ing over joints and fasteners; and 3. all-purpose compound, which combines features of both ta ping and topping compounds. 30 These compounds either are packaged in powder form to be mixed with water on the job, or ctre premixed by the manufac turer. Dry, powdered compounds gen erally are casein products which shrink as they dry. They require several applications to cover prop erly, but each application must be thoroughly dry before the suc ceeding coat is applied. Dry, pow dered, vinyl-resin compounds are also available. When mixed with water, these have working char acteristics very similar to factory premixed material. Most joint compounds harden by evaporation of the water. They have a long wet, or working, life, and they can be kept as wet mixes for several days. They should be covered with a moist cloth or a film of water to pre vent drying, and they should be protected against freezing during storage. Preservatives have been added to prevent putrefying. There are also setting types of dry, powdered compound which can be used for filling joints, for embedding tape, or for both. Set ting compounds generally have a gypsum base that sets in a fixed position and holds it when dry. Setting compounds have a short wet life; they must be used within the time limits marked on the container. SGP 0025891 Fig. 55 Reinforcing joints with tape prevents cracks from appearing at filled gypsumboard joints. The joint fill and first coat may be joint compound or all purpose compound. The second and third coats should be finishing compound or all-purpose compound. Regular casein or vinyl resin based compounds may be used as second or final topping coats over setting compounds. How ever, setting compounds and dry ing compounds must be kept separated until they are applied. They must be mixed in clean containers and applied with clean tools. If the materials are acci dentally mixed, they will set too fast to be used properly. Taping Compound Taping or joint compounds fill depressions, bond tape over joints, and serve as a first coat for concealing fasteners and edge and corner trim. These materials are sometimes referred to as "em bedding" compounds. Usually, taping compound requires at least overnight drying before following coats can be applied. Setting com pounds, discussed above, harden in two to four hours, These permit up to three applications of com pound in one day. Topping Compound Topping or finishing compound is primarily a surface filler used to conceal and smooth over em bedded tape, fasteners, and trim. It is a ready-mixed or powder for mulation that bonds well with taping compound, gypsumboard, and fasteners. Also, it sands easily and provides a surface with suf ficient "tooth" and "suction" for painting. Do not use topping compounds as laminating adhesives. All Purpose Compound All-purpose com) mnd, avail able from some m nufacturers, serves as both tapin.; and topping material. This conv oient formu lation is available .1 powder or ready-mixed form, in either a machine or hand-tool consistency. All-purpose compound can be used for embedding tape topping over tape, finishing over metal trim, and concealing fasteners. It may also be used to texture surfaces. However, it should not be used for laminating gypsumboard. TAPING AND FINISHING SGP 0025892 At least three coats of joint compound are recommended for all taped joints-- an embedding coat to bond the tape and two finishing or topping coats over the tape. Each coat should be allowed to dry thoroughly before the next coat is added so that it can com plete its maximum shrinkage be fore it is covered. 31 t Fco'9m- p5o6unFd,illin(gligahnt)d tTaappineg aisre ctehnetefirresdt stoevpesr inthefinijsohinint ganadgyspmsouomthbeodardanjdoinptr,es(lseefdt) iTnhtoe tdheeDrcessinn,, ,ur ' int 'S filled Wl,h smoothed over'the tape and feathered out with a wide knife. ne conlPOLind. Excess compound is Depending on atmospheric con ditions, joint compound may need 12 to 24 hours for each successive coat to dry unless a setting com pound is used. Temperature and ventilation at t-he job site should be controlled as discussed under "job site preparations". feathered Fig 57 Top coat edges are flush with out till the treatment appears of wider the walII surface. The u knives helps in feathering e top coats. FLUSH JOINTS To treat a flush joint, taping compound is spread into the de pression formed by the tapered edges of adjacent boards and over all butt-end joints. Then tape is centered over the joint and smoothed to avoid wrinkling. The tape is pressed into the compound by drawing a broad knife along the joint with enough pressure to squeeze out excess compound. If too much compound is forced out, ridging can occur. The excess should be redistributed as a skim coat over the tape (Fig. 56). When the embedding coat is dry, it may be sanded if the surface is too rough. Then a second coat of compound is ap plied and the dges are feather ed 2 in. to 4 i. beyond the tape edges. After his coat dries, it * SGP 0025893 Fig. 59 An automatic treating machine rapidly dispenses an even top coat of compound and does most of the leveling. 112 METAL ACCESSORIES Cornerbead - (Numbers indicate width of flanges i.e. -- 118 is 1-1/8 in. W. Flange) ANSI-CB- 1 x 1 ANSI-CB- 1 18 x 118 ANSI-CB 1 1 4 x 114 ANSI-CB- 1x114 ANSI-CB-PF (Paper Flange, Steel corner bead) "U" Bead (Numbers indicate thickness of board to be used) "S" indicates square nose, "B" Bull or Round Nose) (.V/////I ANSI-US-38, UB-38 ANSI-US-1 2, UB-12 777////////ZZZ77/ZZZ/Za ANSI-US-58, UB-58 ANSI-US-34, UB-34 "L" Bead -- (Number indicate thickness of board to be used) ("S" indicates square nose, "B" Bull or Round Nose) ANSI-LS-38, LB-38 ANSI-LS-1 2, LB-12 ANSI-LS-58, LB-58 n ANSI-LS-34, LB-34 'LK" Bead- (For use with Kerfed jamb) ("S" indicates square nose, "B" Bull or Round Nose) ANSI-LK-S ANSI-LK-B y? 'LC'' Bead - (Numbers indicate board to be used) ANSI-LC-38 ANSI-LC-1 2 ANSI-LC-58 ANSI-LC-34 thickness of Fig. 60 Cornerbeads, CB, protect outside corners of gypsumboard walls. UL, LK, and LC beads are used where boards end at door and window frames. Flared angles at corners provide space for joint treating compound. is sanded if necessary, and a third coat of compound is spread with edges feathered 2 in. to 4 in. beyond the second coat to blend smoothly with the wallboard surface (Fig. 57). When joint treatment is done skillfully, sanding of successive coats is unnecessary. If sanding is done, care should * -c taken to avoid scratching the base paper be cause this raises the fibers and contributes U poor appearance after decorating. Figs. 58 and 59 show auto matic taping and treating ma chines that can speed joint treatment. INTERIOR CORNER JOINTS At interior corners, compound is applied to both sides of the joint; then tape is folded along the center- crease and embedded snugly in the corner to form a right angle. Fxcess compound is removed, and the surfaces are finished as described for flush joints. Hand tools or machines can be used for corner finishing. EDGE AND CORNER TRIM Exposed wallboard corners need the protection of wood or metal trim. Wood casings are often used for decorative effect at window and door- frames, and a baseboard is used to protect wallboard edges at the floor. Metal trim, such as corner beads and casing beads, is used when inconspicuous edge protection is desired. The standard shapes for metal trim1 are illustrated in Fig. 60. On outside corners, metal corner- beads protect the wallboard from damage and provide neat, slightly rounded corners which are dif ficult to obtain with tape and joint compound alone. Metal flanged beads such as CB, L. LC, and LK generally are nailed or screwed to supporting con struction approximately 6 in. o.c. (CB can also be crimped for at tachment as in Fig. 61). All trim shapes except metal Ubead are installed after the wallboard is erected. Trim shapes require at least three-coat finish ing with joint compound to obtain a smooth surface and to conceal fasteners. SGP 0025894 i 'Taken from American National Standard Specifications for the Application and Fin ishing of Gypsum Wallboard, ANSI A97.1. Fig. 61 Various tools are used to crimp cornerbead at the outside corner of gyp sumboard facings on a column. 83 strong sidelight will show whether the ridge has been eliminated or whether additional coats of com pound are necessary. When the repair is satisfactory, redecorate. Unlike other trims, U-bead is fastened through the back flange first, then the wallboard is erect ed, with edges inserted in the trim. Finishing with compound is not required because fasteners are concealed. The drywall ap plicator must make sure that the U-bead is in /dace before the wallboard is fastened down, or the board will have to be removed and replaced. Also, if LC bead is used, the board edges to be protected should not be fastened until the bead is in place. Fig 62 The dimpled depressions from fasteners must be treated with compound before gypsumboard is decorated. More than one coat is often necessary. FASTENER TREATMENT Joint compound usually is ap plied over fastener heads at the same time joints are taped. Fas teners may be treated (spotted) using an automatic spotter or a finishing knife (Fig. 62) to fill in depressions or to blend in pro trusions. The knife should be pressed against the surface to make the finish level and to re move excess compound. Second and third coats of compound gen erally are applied over fasteners when similar coats are applied to taped joints, edges and corners. The procedure is the same as previously described under "Joint Taping and Finishing". REMEDYING DAMAGE The prevention of surface dam age to gypsumboard finishes has been discussed. Prevention is more effective than repair because these problems cannot always be corrected by finish treatment. Nevertheless, if problems do oc cur, there are some remedies available. Nailpopping The usual repair for a nail pop (Fig. 63) is to drive a new nail of the proper size about 1-12 in. from the popped nail, while holding the board tight against the framing. Then the popped nail is reseated and again treated with joint compound. If punctured facepaper is the rea son for the loose attachment and nail [topping, the board should be 34 nailed tight or screws should be used 1-1/2 in. from the defective fastenings. The old nail should be removed from the broken area, and the damaged part should be filled smoothly with compound. Ridging If ridging occurs due to strains caused by expansion and contrac tion of the framing, let the con dition develop fully before making repairs. Six months or one heating season should be sufficient. Sand ridges down to the rein forcing tape without cutting through the tape, and fill the concave areas on both sides of the ridges with topping compound. After the fill is dry, blend in the repaired area with a light film of topping compound. After the repair is made, a Shadowing Fastener head shadowing is simply a surface discoloration, but it may appear similar to nail popping when viewed at a dis tance. Shadowing is an accumula tion of dust or dirt caused by increased thermal conductivity and moisture condensation over the fastener head. It occurs com monly on roof/ceiling or exterior wall assemblies in regions with great indoor-outdoor temperature variations. Shadowing can be rem edied by periodic washing or dec orating; it can be avoided by installing adequate insulation and using laminated, two-ply construc tion. Where a permanent ventila ting system is employed, air filtration and humidity control will be helpful. Joint shadowing is the joint showing darker when viewed from an angle. Texture variation or low or high joints are the causes. Cracking Cracks may be filled, but if they are caused by excessive movement in the framing, they will have to be refilled and redecorated per iodically. Fig. 63 Nail pops are repaired by either driving the protruding nail beneath the surface or removing it entirely and using additional fasteners, 1-1/2 inches away, to securely hold the board if necessary. The damaged area and the additional fastener heads are then treated with compound and redecorated. SGP 0025895 VI DECORATING Regular Gypsum Wallboard Gypsum wallboard finishes should be reinspected prior to decorating, particularly at joints and fasteners. Any imperfections should be sanded or repaired. Be fore the decoration is applied, joint compound must be thorough ly dry. Dependingontemperature and humidity, 24 hours or more of good drying time is generally required. Wallboard surfaces can be dec orated with emulsion or oil-base paints or with paper, fabide, or vinyl wall coverings. Always seal or prime the wallboard surface before decorating. An emulsion sealer will block the pores and lay the fibers in the paper surface so that suction and texture differ ences between paper and joint compound will be equalized. A good primer will provide uniform texture and conceal color or sur face variations. Some coatings both seal and prime with one application. For best results when decora ting with oil-base paints, lacquers, and enamels, wallboard should b( sealed. Also, sealers are used under wall coverings so that the coverings can be later removed without marring the surface and an adequate base will be left for redecorating. Most emulsion paints such as latex, resin, and casein do not raise the fibers in the face paper. High quality latex paints often have inherently good sealing and priming properties and require no special preparation of the wallboard. A pigmented emulsion seal er applied as a first coat or at least two coats of emulsion paint will be durable and attractive if the wallboard has been properly installed and treated. Glue size, shellac, and varnish are not suit able sealers or primers. Predecorated Wallboard Patterns or colors on some kinds of predecorated gypsum wallboard may vary slightly from lot to lot. All the board used in a room should be from the same lot, but when this is not possible, the joint between two different lots should be in a corner. Care should be taken to match the patterns on adjacent pieces of predecorated wallboard. One pro cedure is to simply stand the boards in the places they are to occupy. Boards that do not match well are shifted. If joints are to be covered with metal trim, plan the layout of walls and ceilings in advance so that a balanced layout of joints is obtained. Avoid the appearance of two metal trim med joints close together in a corner. If the stud spacing is not proper to allow an attractive ar rangement of joints, furring strips may be necessary so that joint locations may be shifted. SGP 0025896 35 Out edges that are to be cov ered with trim (moldings or bat tens--see Fig. 64) can be sawed oi' scored and snapped the same as regular wallboard. If cut edge joints are to be exposed how ever, the face material should be cut approximately 1 in. wider than the gypsum core. The core should then be snapped and re moved from the fabric -- not the fabric from the core. The core should be trimmed straight and bevelled on the face side under the flap, and the overlapping face material should be pulled around the edges and fastened to the back with adhesive (see Fig. 65). Then when the panels are butted together, they will form a good looking joint. Other joint treatments for pre decorated board include using tape matching the face material or adhei'ing a flap of the face material from one board onto the face of the other (Fig. 66). These methods form seams much like wallpaper seams; and when they are skillfully done, the seams are well hidden. NOTE: When using ad hesives for the application of vinyl covered gypsum board, read and follow the wallboard manufacturer's instructions. Improperly applied, or incompatible adhesives, can damage vinyl finishes. Fig. 64 Screws holding predecorated wallboard are concealed with vinyl strips in battens which cover joints. Fig 65 For butt joints without covering trim, decorated surface is cut 1 inch longer than the exposed gypsum core (top) or the gypsum core is cut back 1 inch from the surface end (bottom left). Then the core is bevelled on the face side (center), and the decorative material is pulled around and adhered to the back. This gives a finished end which makes an attractive exposed butt joint. 36 SGP 0025897 Drywall applicator fills joints with quick setting compound Flaps of vinyl facing are folded out of the way. When the joint compound sets, the area is coated with wheat paste. The right hand flap is pasted down and smoothed; then the left flap is pasted over the right hand flap. Cut-off strips are removed. The over lapped right hand flap that was cut is pulled out from under the left flap. A straight-edge and a sharp wallboard knife are used to cut through both layers of the overlapping vinyl. SGP 0025898 The two flaps are now smoothed into a perfectly fitting butt joint. Rolling the joint eliminates bubbles and excess wheat paste under the vinyl covering. Finally, the excess wheat paste is sponged off, and the joint is dried. t Fig. 66 Smooth, flat and carefully butted joints in vinyl coverings on wallboard are difficult to see. 37 "NORMAL" CONSTRUCTION... Arrows show flanking paths "SELECT" CONSTRUCTION... Caulking of relief detail at perimeter of partition to prevent sound leakage "PRE-DESIGN" CONSTRUCTION ... Simulating laboratory conditions V perimeter relief & caulking to seal agamst sound leaks Through partitions - openings, outlet bones (plan) void between box and wallboard electrical box with extension ring Outlet box detail lr offset boxes minimum of one Ihrouph partitions- openings, outlet boxes (plan) Caulkmg of openings through partitions 50 STC Outlet box detail Typical partition-mullion intersection Intersection with exterior wall wood or metal stud Around flanking partition ends (plan) Intersection with interior wall Typical partition intersections Fig. 67 Plan views show typical caulking to close off flanking paths for sound transmission. 38 SGP 0025899 VII SPECIAL CONSTRUCTION Most special constructions in tended to provide improved sound, fire, moisture and thermal control require a gypsumboard assembly with complete joint treatment and panel caulking. The caulking should be a nonhardening, non shrinking, nonbleeding, nonstain ing, resilient sealant. In each case, the manufacturer's specific instal lation recommendations should be followed for individual systems. walls--through nonsound proof ceilings above them, around walls --through windows and doors ad jacent to them, or under walls-- through nonsound proof floors and crawl spaces below. SOUND ISOLATING CONSTRUCTION The first essential for airborne sound isolation by any assembly is to close off air leaks and flanking paths by which noise can go around the assembly. Hair line cracks or small holes in an assembly will reduce resistance to sound transmission by several decibels.1 Failure to observe spe cial construction and design pre cautions can destroy the effective ness of the best sound control methods that can be built into an assembly. Assemblies should be airtight. Recessed wall fixtures such as medicine cabinets, or electrical, 'A 0.14 sq. in. opening will reduce the STC of a sound harrier from 50 to 47. or from GO to 48. A 1.4 sq. in. opening will reduce an STC of 50 to 39 and an STC of 60 to 40 (I). Harris, Decibels Per Dollar). telephone, television and intercom outlets which perforate the gypsumboard surface should not be located back-to-back or in the same stud cavity. In addition, any opening for such fixtures and piping outlets should be care fully cut to proper size and caulked. The entire perimeter of a sound isolating partition should be caulked around wallboard edges and on both sides of runners to make it airtight (Fig. 67). Details of caulking needed will be given for various wall assemblies by the manufacturers of the gypsumboard used. Assemblies intended for sound isolation should not contain heat ing ventilating, or air condition ing ducts. They should be designed so that airborne sound will not go over, around, or under the as sembly. Noise can travel over Separated Construction Separated construction systems can raise the resistance to noise transmission considerably. These have the two wall surfaces on separate sets of su oorts so that vibrations are not transmitted through the framin to the other side. Studs may be taggered on the same top and bottom plates (Fig. 3b), but for best results they should be placed on separate plates with a space between the plates. Simply inc' asing the dis tance between the finished sur faces of the wall increases the Sound Transmission Class (STC). Doubling the distance between the walls can increase the STC about five points in some cases. Separated walls without fram ing are made from all-gypsum double-solid and semi-solid partitions. Resilient Mounting Resilient attachments act as "shock absorbers'' to reduce SGP 0025900 39 ness. The manufacturer's recom mendations should be followed. Resilient clips can be used to attach the base ply of two-ply finishes to wood studs, but they are not recommended for ceiling application. Special nail-on clips designed for use with auxiliary 1 in. thick wood furring are avail able for single-ply gypsumboard ceilings. Fig. 68 Paper faced isulating blankets should have flanges stapled to inside surface of studs Stud faces to receive gypsumboard should be left free. sound passage. Gypsumboard sur faces mounted on resilient chan nels or over sound deadening board are isolated from their framing, and thus transmit less er amounts of vibration. The same is true for base plies mounted with resilient clips in multi-ply walls. Resilient mounting can raise an STC rating as much as seven points. Kitchen cabinets, lavatories, ceramic tile, medicine cabinets and other fixtures should not be supported on resiliently mounted walls because the added weight 40 and fastenings may "short out" the construction acoustically. Sep arated walls are recommended. Resilient furring channels gen erally are attached across the framing members (Fig. 3c). Nails used to attach channels to wood joists in ceiling assemblies may work loose as the framing lumber dries and cause floor squeaking; therefore, screw attachment is preferred for ceilings. Some resilient channels can sup port only limited loads without losing their acoustical effective Sound Deadening Board Sound deadening board used in gypsumboard construction in cludes: 1. gypsumboard sound deaden ing panels, 2. wood or cane based organic fiber board. 3. mineral (im hiding glass) fiber board, and 4. rigid (plastic) foam board. Sound deadening boards are manufactured from 1/2 in. to 5/8 in. thick, 4 ft. wide, and 8 ft. to 12 ft. long. They are used as base layers and they are often set parallel to supporting mem bers with joints staggered on al ternate studs. Gypsum wallboard face layers are generally laminated over sound deadening board. However, if a fire rating must be obtained, nailing or screwing through the sound deadening board into the framing is required. This will reduce the sound isolating ef fectiveness ol the sound deaden ing board. Fiberboard nd foamboard can be used over ,vood construction or where noncombustible ma terials are not required. Gyp sumboard sound deadening pan els are used with metal framing where noncombustible materials are required. SGP 0025901 Sound Absorbing Materials Mineral wool or glass fiber insulating batts and blankets may be used in assembly cavities to absorb airborne sound within the cavity. The full height of the cavity should be filled, and batts or blankets should be carefully fitted behind electrical outlets, around blocking and fixtures, and around cutouts necessary for plumbing lines. Insulating batts and blankets may be faced with paper or a vapor barrier and may have flanges or be friction fit types. They are installed by stapling or fitting to the inside surfaces of studs (Fig. 68). Stapling flanges across the stud face before ap plying gypsumboard is not recom mended because it prevents prop er board-to-stud contact. In metalstud-framed and in laminated allgypsumboard partitions, the blan kets are attached to the back of the gypsumboard. Batts and blan kets without facings are required in noncombustible construction. They are installed and held by friction fit within the stud space. FIRE-RESISTANT CONSTRUCTION Fire resistance ratings of gyp sumboard assemblies can be im proved by: 1. using Type X gypsumboard, 2. increasing the gypsumboard thickness, and 3. filling the stud cavity with mineral wool or glass fiber. Unless all of the materials used in the tested assembly classify as noncombustible, the term com bustible is used after the as signed hourly classification. Nominal 2 in. x 4 in. wood stud partitions finished with 5/8 in. Type X wallboard on both sides and installed as specified, receive a one-hour rating. Wood stud partitions have been rated two-hours when two layers of 5,8 in. Type X board are fas tened on each side. Metal stud partitions receive 2 hour ratings with two-ply faces of 1 2 in. Type X board installed as recommended by the manufacturer. Wood-joist floor, ceiling assem blies with single-layer wallboard finishes generally are limited to one-hour ratings although two hour, two layer assemblies are available. Steel and concrete as semblies protected by a suspended gypsumboard ceiling generally achieve higher ratings. Details of many fire rated as semblies are given in DesignData-Fire Resistance/Sound Con trol published by the Gypsum Association. Beside the ability to Fig. 62 A steel and concrete upper floor is protected from fire by a suspended gypsumboard ceiling membrane. The workman is tying a spliced drywall channel to a suspended cold rolled channel. SGP 0025902 41 IN SUMMER INSULATION IN WINTER >/ \ \ TV TV > WITHOUT INSULATION WITH ALUMINUM FOIL INSULATION Fig. 70 Foil surfaces on gypsumboard reflect heat rays in summer and reduce radiation in winter. contain a fire, indicated by fire resistance ratings, another cri terion for fire hazard of exposed surface materials is the rate of surface flame spread. This rating for gypsumboard is under 15 based on a flame spread of 0 for as bestos-cement board and 100 for red oak. This low flame spread rating meets the requirements for most interior finishes. Rigid foam insulation is inten ded primarily for exterior and below-grade concrete or masonry walls. Insulating foam-boards are made from expanded polystyrene or polyurethane in panels 1 2 in. to 3 in. thick and up to 4 ft. wide by 12 ft. long. Foamboards are generally ad hesive-bonded to the masonry or concrete surface. (Methods and adhesives should be specifically recommended by the insulation manufacturer.) They should be fitted together so that no gaps between the boards create cold spots or allow moisture migration. Gypsumboard can then be at tached to the rigid foam insulation as recommended by the foamboard manufacturer. The use of furring channels and mechanical fasteners is recommended. Screw attachment to special channels provided with the foamboard can be used. If the gypsumboard is laminated, it should be held in place by temporary bracing or double-headed nails which can be removed after sufficient bond strength develops. SGP 0025903 THERMAL INSULATING CONSTRUCTION In certain regions of the coun try. exterior wall and ceiling as semblies may require thermal insulat'on to minimize heat gain or loss through the assembly. Typ ical means used to increase ther mal resistance of gypsumboard assemblies include: 1. flexible fiber insulation (batts and blankets), 2. loose fill insulation, 3. rigid foam insulation, 4. reflective foil insulation with 3 4 in. minimum still airspace, or 5. air spaces provided by furring over solid materials such as masonry and concrete. In addition, vapor barriers are commonly required to retard pas sage of moisture and condensation within the assembly. Vapor control can be provided as an integral part of the gyp sumboard or as part of the insu lation. Insulating (foil-backed) gypsumboard may provide some insulating value, equivalent to 1/2 in. fiber board, as well as an effective vapor barrier, and it can be used with or without other in sulation materials. It is popular in the areas where minimum in sulation is required (Fig. 70). Rigid plastic foam and reflective foil insulation are materials with very low vapor permeability and they generally do not require a separate vapor barrier. Insulating batts and blankets are available with or without vapor barriers. Ixxise fill insulation requires either a separate vapor barrier, such as foil or polyethylene film, or an integral barrier provided by in sulating gypsumboard. Vapor barriers should be lo cated on the warm side of the insulation. When reflective foil is used, it should face an air space of at least 3/4 inch to be effective. 42 MOISTURE-RESISTANT CONSTRUCTION Most gypsumboard is affected by prolonged contact with mois ture and should not be used in locations subject to direct wetting or continuous high humidity. How ever, it can be used in exterior locations such as eave soffits and porch or carport ceilings when properly protected from direct contact with water. Also, it is suitable for wet or humid interior locations when special precautions are taken. Exterior Locations Regular or water-resistant wallboard used on horizontal sur faces in exterior locations should be at least 1/2 in. thick. Facia boards protecting wallboard sof fits should have a drip edge that prevents water runoff across the wallboard (Fig. 71). In addition, edges and ends at the perimeter of the boat'd should be protected by metal edge trim or wood mould ings. Wallboard edges without metal trim or other water stop should be spaced at least 1/4 in. from abutting masonry. Exposed wallboard surfaces and metal trim should be sealed with two coats of exterior paint. Adequate venti lation of eaves, ceilings and attic spaces must be provided. Interior Locations Water-resistant gypsumboard, rather than regular gypsum wallboard is recommended for all interior areas subject to high humidity. These areas include bathrooms, laundries, and utility rooms. Water-resistant board gives definitely superior perform ance in these areas, although regular wallboard is successful when properly installed, sealed, and protected. Furthermore, insulating (foilbacked) wallboard should not be used in high-humidity interior areas. The foil backing may trap moisture in the board core. Hecause condensation is a particu lar problem where the high hu midity area is located on an exterior wall, a separate vapor barrier on the warm side of the wall and adequate insulation are necessary. Otherwise, moisture will collect in the cavity. Bath-Shower Areas Most of the wall tile installed today is applied over gypsum board. Water-resistant gypsum board is particularly recommen ded as a backing for wall tile in bath-shower areas, and proper adhesives for the service should be used with it.1 Gypsumboard around the tubs and showers should be at least 1, 2 in. thick. Stud spacing should ALTERNATE FACIA DETAILS 1 Ceramic wall tile application to gypsum board should meet American National Standard S)>icifications for Ceramic Tile Installed With Water-Resistant Organic Adhesices, ANSI A108.4-1968. The ad hesives used should meet the specifications of the American National Standard for Organic Adhesives for Installation of Cer amic Tile, ANSI Ai3G.l-19G7. ---- 1-- SGP 0025904 MASONRY WALL Fig. 71 Gypsumboard should be protected from wetting in outdoor locations by facia boards with drip edges. Gypsumboard edges should be separated from pos sible dampness by metal edge trim or by a 1/4 in. space. Spaces enclosed by gypsumboard must be adequately vented. 43 tions. The space between tile and tub trim, shower receptor, or subpan top should be caulked (Fig. 72). To prevent the caulked joint from opening as settling occurs, it is recommended that the tub be supported at the walls on metal hangers or vertical block ing nailed to the studs. Shower receptor pans or subpans should have an upstanding leg or flange. This should at least be 1 in. higher than the water dam or threshold in the entry to the shower, so that wallboard edges may be placed above the level where leakage might reach them. Fig. 72 Details show installation of wall tile on gypsumboard around tubs and showers. The gypsumboard must be separated from the tub, receptor, or pan by at least 1/4 in. gap to prevent moisture seepage. ELECTRIC PANEL HEATING not exceed 24 in. o.c.; if stud spacing exceeds 16 in. o.c., block ing should be installed not more than 4 ft. o.c. between all studs. The first row of blocking should be approximately 1 in. above the top of the tub or shower receptor. Soap dishes, hand-hold bars, and other fixtures must be backed with blocking. The gypsumboard should be applied perpendicular to fram ing members with paperbound edges parallel to the top of the tub or shower receptor. The board must not touch on the tub or re ceptor; at least 1/4 in. space should be maintained (Fig. 72). Generally, gypsumboard should be fastened with nails spaced not more than 8 in. o.c. or screws spaced not more than 12 in. o.c. However, when ceramic tile over 5,16 in. thick is intended, nails should be spaced 4 in. o.c. and screws 8 in. o.c. When water-resistant gypsum board is used, any special recom mendations made by the manufac turer of the board should be followed. All cutouts for plumbing fixtures should be sealed with water-resistant, nonhardening compound or vinyl tape before wall tile is applied, to prevent water from seeping into the core (Fig. 78). When regular wallboard is used, joints between adjacent boards, including those at corners, should be treated in the regular fashion. 44 A water-resistant sealer should be applied to the entire wallboard surface, including treated joints and corners before tile is installed. When tile adhesive is used as a sealant, the sealing coat should be spread over the entire surface and allowed to dry before the bonding coat is applied. A continuous, uniform coating, approximately 1/16 in. thick, cov ering all cut ends and all cutouts for fixtures is necessary. The tile finish should cover the area illustrated in Fig. 75. Ap plication should be according to tile manufacturers' recommenda- Fig. 73 Clear tape around cutouts helps keep moisture from soaking the board over a period of time. Electric heating panels in ceil ings can be constructed with gyp sum backing board, electric heating cables, a special, nonin sulating, nonshrinking filler ma terial, and gypsum wallboard. Wiring The backing board base layer should be attached perpendicular to supports with nails, screws, or staples spaced 7 in. o.c. Clear ance of at least 1-1/4 in. free of cable on either side of the joint centerline, and 4 to 6 in. around the perimeter of the ceiling at the walls (Fig. 76), should be maintained by the cable installer. Filling A specially formulated filler, mixed according to the manufac turer's recommendations, is used to completely embed the heating cables. It should be applied to a 1/4 in. thickness and levelled to a smooth surface ready for the finish layer. All inspection and testing of the electrical installation should be performed before the face layer is applied. Finally, a finish coat of compound or a face layer of gypsum wallboard is applied. When wallboard is used, care must be taken that the nails do not cut the cables. All filler material should be completely dry before decorating. SGP 0025905 Fig. 7 4 Regular gypsum wallboard (light area) is covered with a skim coat of adhesive (smooth area) which is allowed to dry before the bonding adhesive (ridged area) and wall tile are applied. Fig 7 5 Tile in baths and showers should be brought up to the levels shown. Proper insulation is important for economy in electric panel heating. Unfaced, friction-fit, mineral wool or glass fiber insul ating batts may be used in the ceiling above the panel heating system. Other electrical radiant heating systems with special wallboard panels are also available. The manufacturer's application rec ommendations should befollowed. SGP 0025906 TYPICAL CEILING LAYOUT PATTERN Fig. 7 6 Electric heating panel is formed from cable fastened to gypsumboard and covered with a filling compound. 45 VM( SUMMARY A GUIDE FOR HIGH QUALITY Before gypsumboard is applied, check that it is the type specified for the job and in pood condition after storage. Check for any cracked or edge-damaged hoard. Check the job drawings and specifications (or manufacturer's recommendations if they are the guides). Make sure of application details such as direction (hori zontal or vertical), fasteners, and caulking required. Check the framing. Make sure it is installed as specified and firmly in place. Find and remedy uneven top plates, twisted studs, and studs out of alignment. No support for the gypsumboard should be more than 1/8 in. from the plane of the board, and no blocking or bracing should project out from the plane. Trim all projections and either use shims or reposition framing members to correct other defects. Check the moisture content of wood framing with a moisture meter. If necessary, delay gyp sumboard application until the moisture content meets the jol specifications. Check that window and doe frames and that all electrical an< other fixtures are set for th wallboard thickness used. Verif> that there is caulking beneath run ners if required. When metal framing is user1. check that all joints and splices are securely fastened and that runners are securely attached. (Details of metal framing are given in Gypsum Association Spe cifications For the Installation of Screu'-Type Steel Framing Mem bers To Receive Gypsumboard.) When inspecting a base ply, check that boards are horizontal or vertical as specified and that they are fastened as specified. Test for loose board by pushing adjacent to the fasteners. Check 46 that face paper is not broken where fasteners are driven. Check caulking for proper seal behind electrical boxes, medicine cabinets and other recessed fix tures. Make sure that required insulation is properly fitted and attached in wall cavities. In face play application, make sure exposed surfaces are free from defects. Check to see that boards are tightly attached and applied in the right direction. Joints must be correctly butted and staggered. See that specified procedures for application of ad hesive and fasteners are carried out. On single ply applications, see that backing blocks or strip reinforcing is used if specified. Suspended ceiling application should comply with component manufacturer's recommendations and job specifications. Details of grillage framing may also be ob tained from the Gypsum Assoc iation Specifications (for steel framing members) previously mentioned. Measure spacing of hangers, channels, and studs to assure compliance. Runners and Fig. 77 When applying a base ply of gypsumboard to a steel stud, grasp the flange and gypsumboard firmly to pre vent movement. furring channels should extend to within six inches of abutting walls, but they should not touch the walls. Ends should clear by at least 1 inch and sides should clear by at least 1/8 in. Certify that mechanical equip ment is independently supported and does not rest on the grillage. Also make sure that reinforced channel support is provided around light fixtures and openings. Check that furring channel clips are alternated and that furring channel splices are secure. After wallboard is applied, in spect trim at corners and around partition perimeters. It must be installed as specified and securely attached. Check that no boards are loose and that all fastener heads are seated below the surface of the wallboard. Fastener heads which have broken the face paper should be replaced. Make sure that caulking is in place and that voids are com pletely sealed. Before treating joints and fas teners, make sure that temper ature, humidity, and ventilation are proper to assure good drying of treating materials. In cold wea ther, temperatures should be maintained between 55 F. and 70 F. In hot, dry weather, drafts should be avoided. In very humid weather, ventilation may be ne cessary to provide drying. In joint treatment, use proper compounds and be certain they dry completely between coats. Avoid heavy fills. Check that finished joints and all fastener and trim coverings are smooth and dry before dec orating. Sand if necessary. Careful application and inspec tion of gypsumboard construction will assure smooth walls and ceil ings that should remain free from defects for many years. SGP 0025907 INDEX Adhesives, Contact Laminating Modified Contact Stud 15 15 15 15 Applying Gypsumboard, Cutting Fasteners General Job-sites Masonry Supports Placement Planning Single-Ply Multi-Ply 7 13 5 6 12 8 7 16 23 Attachment Single Nailing Adhesive-Nail Base Ply Base Ply, Metal Framing Base Ply, Wood Framing Bracing Concrete and Masonry Double Nailing Face Ply Loose Nailing Metal Framing Screw Stud Adhesives 16 18 23 24 23 19 19 16 24 16 19 17 18 Back Blocking 20,21 Caulking 38,39 Ceramic Tile 44 Channels Cold-rolled Plain furring Resilient 12 12 12 Concrete and Masonry Supports 12 Compounds All Purpose Taping Topping 31 31 31 Cracking 20,34 Decorating Defects, Remedying 35 Nail Popping Ridging Shadowing Drywall Exterior Locations Face Paper Fractures Fasteners Permanent T emporary T reatment Framing Metal Wood Spacing Finishing Edge and Corner Trim Interior Corners Flush joints Fire Resistance Gypsum Fire Resistance Ratings Flanking Paths Furring Gypsum Gypsumboard Backing Board Durability Economy Moisture Resistant Multi-Ply Single-Ply Special Edged Storage Tub-Shower Areas Type "X" Wallboard Water Resistant Heating Electrical Panel Humid Locations Insulation Board Mineral Fiber Organic Fiber 34 34 34 1 43 16 25 25 34 10 9 9 33 33 32 2 41 39 9 1 4 4 4 5,43 5 5 22 6 43 4 4 5,43 44 43 42 42 Rigid Foam Joint Compounds Joint Tape Joint Treatment Joists Steel Wood Lamination Sheet Spot Strip Moisture Resistance Gypsumboard Sealing Gypsumboard Nail-Popping Nails Nails, Loose Partitions, Self Supporting Semi-Solid Double Solid Solid Triple Solid Predecorated Gypsumboard Resilient Mounting Resurfacing Ridging Screws Separated Construction Sound Isolation Staples Strip Reinforcing Studs Steel Wood Taping Thermal Insulation Tile, Wall Truss Roof Construction Trusses, Wood Warping Wood Shrinkage 42 30 30 29 11 10 25 25 25 42 44,45 19,34 14 16 26 26,28 26,28 26,28 35 39 28 20,34 14 39 2 15 21 11 10 32 42 44 10 10 9 6 BIBLIOGRAPHY These Gypsum Association publications give additional details on the use of gypsumboard in walls and ceilings: Printed in U.S.A. Design Data-- Fire Resistance/Sound Control American National Standard Specifications for the Application of Gypsum Wallboard and Backing Board, Including Finishing ANSI A9 7.1 Gypsum Association Specifications for the Installation of Screw Type Steel Framing Members to Receive Gypsumboard Design Data-- Gypsum Wallboard Recommended Guide for Gypsum Drywall Construction SGP 0025908 ova REV. 10/71 USING GYPSUM BOARD WALLS AND CEILINGS ------------ ------------------------------- V GYPSUM ASSOCIATION 201 North Wells Street Chicago, Illinois 60606 SGP 0025909 LITERATURE SGP 0025847