Document LgdvEZDmMkDvgJBgQB8X2K84X

GYPSUM ASSOCIATION SPECIFICATIONS COVERING EXISTING INTERIOR WALLS AND CEILINGS WITH GYPSUMBOARD PRODUCTS GA- 650-71 GEORGIA- PACIFIC THE GROWTH COMPANY SGP 0025591 SPECIFICATIONS FOR COVERING EXISTING INTERIOR WALLS AND CEILINGS WITH GYPSUMBOARD PRODUCTS I. Introduction This specification is intended to provide methods for covering interior wall and ceiling surfaces which have been decorated with lead-based paints Prior to World War II lead-based paints were commonly used for in terior decoration The purpose of covering these surfaces is to minimize the potential lead poisoning hazard to children who eat paint from wood trim, such as window sills, and paint peeling from walls and ceilings In addition to walls and ceilings, all lead-based paint on the following surfaces shal1 be removed or made in" cessible a All trim and moldings including base shoe, base, casings, chair rail, wainscot, doors, door jambs, win dow sills, sash and trim, b All kitchen cabinets, pantry cabinets and shelving, fireplaces, sinks and bathtubs c All electrical cable, conduit, fixtures, wall plates, receptacles and switches d All exposed gas and water piping e Any other surfaces, such as floors If the paint on the above cannot be removed or covered, then these items shall be removed II. Covering Lead-Base Painted Surfaces. Section II describes two methods of covering wall and ceiling surfaces, i e . (1) direct attachment, and (2) furring attachment Suspended ceiling systems are described in Section III. Characteristics, properties or performance of materials or sys tems herein described are based on data obtained under con trolled test conditions The Gypsum Association makes no warranties or other representations as to their characteristics, properties or performance under any variation from such con ditions in actual construction Test condition details will be furnished by the Gypsum Association on request 2 A. Material. Any of the following gypsumboard products, with appropriate accessories, may be used for accom plishing the work described in this specification Board Type Finish Regular tapered edge or special bead resistant edge Joints taped and fin ished Regular bevel edged or square edged Edges butted and painted or covered with battens and painted (Board applied verti cally) Predecorated bevel edged or square edged Veneer plaster base Water resistant gypsum backing board Edges butted or edges butted and covered with matefung or contrasting batten (Board applied vertically) Edges butted and fin ished with tape and gypsum veneer plaster Edges and corners butted and treated to provide a water resis tant base for wall tile in wet areas Gypsum lay-in ceiling panels Solid (plain or predec orated) 1/4" thick gypsumboard is recommended only for direct application where the base wall is sound, without holes or void spaces, and is flat and level 3/8" thick gypsumboard requires support not exceeding 16" o c 1/2" or 5/8" thick gypsumboard requires support not exceeding 24" o.c B. Preparation for Application-- Direct Attachment, 1 When gypsumboard products are applied directly over existing walls, all loose plaster and wall paper shall be removed When wall surfaces are extremely uneven or unsound, it may be neces sary to remove entire wall surfaces SGP 0025592 2 Void areas, resulting from removal of loose plas ter. shall be shimmed with material of the same thickness as the plaster in order to provide uni form backing support to the gypsumboard See Figure 1. LOOSE PLASTER REMOVED GYPSUM ASSOCIATION SPECIFICATIONS Note: Figure 1--Treatment of Large Voids in Plaster. To maintain fire resistive characteristics of walls be tween adjacent living units or public corridors, void areas shall be treated as follows: (1) When 3/8" thick gypsumboard is being used, voids not exceeding 16" shall be filled with plaster or other suitable noncombustible material. (2) When voids exceed 16", 1/2" or 5/8" gypsumboard shall be used and shimmed as illustrated. 3 Minimum width of wood shims shall be 1-1/2" Minimum width of gypsumboard shims shall be 2" Care must be taken to make the strips equal in thickness to the surrounding plaster Shims shall be applied to the exposed framing or wood lath with nails or screws spaced no more than 6" on center See Figure 1 4 Shims may also be secured to wood lath or masonry with adhesives or masonry nails If the base is gypsum lath or metal lath, toggle bolts or other approved fasteners can be used C. Direct Attachment of Gypsumboard Products to Existing Walls and Ceilings. Gypsumboard products used over the existing wall and ceiling surfaces shall bo applied with me chanical fasteners, suefi as nails or screws into framing, or with adhesives in combination with nails or screws See Figure 2. 1 Attachment by Nailing or Screws Gypsum wallboard may be attached directly over sound wall and ceiling surfaces by nailing or power driven screw application Framing mem bers must be sound, rigid and aligned, and shall not exceed 16" oc for 3/8" thick board or 24" Note: For furred attachment apply new gypsumboard to full wall height. oc for 1/2" and 5/8" board Drywall nails shall be of sufficient length to penetrate into framing 7/8" plus the thickness of the wallboard and plaster or shims Power driven drywall screws must penetrate into framing at least 5/8" Fas tener spacing shall be 8" o c maximum for walls and 7" oc maximum for ceilings and not less than 3/8" from board edges and ends 2 Attachment Using Adhesives a Testing for strength When an adhesive is to be used, a test should be made to insure that frond to ttie wall sur face will be adequate Loose paint or wall paper must be removed from the plaster so that the adhesive can be applied directly to a sound surface Apply a single 3/8" by 3" long bead of drywall adhesive to an 8" square sample of gypsum wallboard and press the sample to the wall Repeat tins in several widely separated areas Allow sufficient setting time, according to the manufacturer's directions Adhesive bond is tested by pulling tire sample away from the wall Bond is adequate if the gypsum wall board paper surface is torn from the wallboard sample SGP 0025593 3 GYPSUM ASSOCIATION SPECIFICATIONS b. Application. When it has been determined that bond strength is adequate, wallboard application can proceed as follows: Board Product Regular tapered edge or special bead resistant edge Adhesive NailOn Application R-1 Water resistant gypsum backing board R-1 Prefinished (vinyl faced) * R-2 Prefinished (paper faced)* R-2 Modified Contact Adhesive Application R-1 3 3 R-2 KEY: R -- 3/8" diameter dry wall adhesive beads maxi mum 16" o.c. applied to back face of boards. 1 -- Fasteners maximum 24" o.c. throughout (Type G or Type S drywall screws). 2-- Fasteners maximum 16" o.c. top and bottom edge (Type G or Type S drywall screws or nails to plates). 3---Not recommended. * -- Intended for walls only, but can be applied to ceilings, if desired. NOTE: (a) Nails shall penetrate framing 7/8" minimum. Screws shall penetrate framing 5/8" mini mum. (b) Firm contact shall be maintained with fas teners, braces, or temporary fasteners until the adhesive sets. Wallboard edges are to be snugly butted and squarely aligned. D. Furring Attachment of Gypsumboard Products Over Existing Walls and Ceilings When walls and ceilings are not acceptable for direct application as described in IIC, the use of furring is recommended 1 1 rim need not bo removed if it is not covered with lead based paint, or if the walls are to be furred so that trim would tie covered by the new' surface finishing materials 2 Where furring strips cannot be pulled tight against the surface, because of bulging plaster, remove the bulges so the furring is level across the wall or ceiling 4 3 The minimum width of the face of the wood furring to which gypsumboard is attached shall be 1-1/2" 4 The minimum thickness of wood furring attached over other than solid surfaces shall be 1-1/2" 5 Steel furring channels are available and may be used if desired 6 Ttie use of furring strips or channels can elimi nate the need fo.r removal of painted woodwork Wood trim can be utilized as nailer strips along floor and door and window openings Furring strips are fastened horizontally to base framing 16" or 24" oc with drywall screws or common nails Furring fasteners must be long enough to penetrate into the framing members a minimum of 3/4" Use two nails at each framing inter section for wood furring Screws through steel furring channels shall be applied alternately from top to bottom through flanges at each framing member intersection Stop furring 6 inches short of any trim member If trim and furring are not equally thick, slums can be used to level out differences Decorative moldings around doors and windows that protect beyond face of the trim should be removed or cut back 7 Gypsumboard can be applied using adhesives when installed over wood furring Apply 3/8" diameter beads full length on each furring strip Supplemental fastening is required Adhesives are not recommended for installations over metal furring channels 8 Nail, screw and steel furring channel standards are listed in Section IV References E. Corner and Edge Treatment. 1 Exterior Corners When installations are treated with tape and joint compound. 1-1/8" by 1-1/8" steel corner beads shall be attached by nailing or by crimping the flanges into the gypsumboard at intervals not exceeding 12" Paper backed metal corner beads may be used with the paper flanges bedded in joint compound Predecorated wallboard joints should be covered with an ap propriate wood batten or other suitable molding 2 Interior Corners- Interior corners may be fin ished with tape and joint compound or wood moldings Moldings may be used for predoco rated or bevel edged boards 3 Trim Edges- If gypsumboard edges are exposed around door and window openings, edges should be trimmed with a suitable drywall casing bead or wood molding to hide tfie cut edges Nail the SGP 0025594 casing or molding into framing or abutting wood base or trim Trim, routed out along the back edge to fit boards, may be used over plain or predecorated wallboard If intersection gaps are 3/16" or less, a permanent type of resilient caulking compound can be used as filler See Figure 3, GYPSUM ASSOCIATION SPECIFICATIONS nels on 16" or 24" centers Gypsumboard is at tached with 1" type S drywall screws at 12" maxi mum spacing Figure 3--Door Framing Details--Direct Lamination. 4 When trim is not removed, and is used instead as a nailing surface, the wall may be finished as shown in Figures 4, 5 and 6 Suspended Ceilings. Older dwellings often have high ceilings, ten feet or more If ceilings are high, and in poor condition, it can be advantageous to use a suspended system which will permit covering the old ceding without removal of ceil ing material The suspension system can be planned so that the new ceiling is 7-1/2 to 8 feet high Aside from avoiding the mess of tearing down an old ceiling, the decreased height can result in other advantages, such as reduced heating costs and reduced sound trans mission between floors Four suspended ceiling systems are described A. Suspended Wood Furring Suspend 2" x 4" wood furring members by hanger wire attached to the ceiling joists Gypsum wall board panels are applied across the 2 x 4's and at tached with drywall screws spaced at 1 2" maximum B. Suspended Metal Channels Suspend 1 1/2" carrying channels from hanger wires attached to screw eyes fastened into the sides of framing members Steel screw furring channels are clipped or wire-tied to the 1-1/2 carrying chan FOLDING DOOR Figure 4--Door Framing Detail with Corner Bead. METAL FURRING NEW JAMB METAL FURRING NEW JAMB SGP 0025595 5 GYPSUM ASSOCIATION SPECIFICATIONS METAL FURRING CHANNEL OR I 5/q" TRACK (ALTERNATE C. Suspended Steel Screw Studs Suspend steel screw studs on 16 or 24" centers using stud clips suspended from hanger wires Ah ternately the screw studs may be attached to 1-1/2" steel screw furring channels suspended by hanger wires attached to ceiling framing For details see Figure 7. D. Suspended Gypsumboard Grid Ceiling System Lay-in panels in 24" square or 24" by 48" sizes are supported in a grid system suspended from the sup porting framing by hanger wires Lay-in panels are non perforated to prevent paint on old ceilings from falling through Detailed installation instructions are normally available from the material supplier, manu facturer, or described in AST M Standard C 636 Common to all the ceiling covering methods is the necessity to arrange for adjustment of ceiling elec trical fixtures and heating or ventilating ducts, if present Relocation or adjustment work should be accomplished prior to ceiling installation IV. References 1 American National Standard Institute Standard Specifications ANSI A97 1 for "The Application and Finishing of Wallboard " 2 American Society for Testing and Materials ASTM Designation C 636, "Recommended Practice for Installation of Metal Ceiling Suspension Systems for Acoustical Tile and Lay-In Panels " 3 American Society for Testing and Materials ASTM Designation C b14, "Specifications for Nails for the Application of Gypsum Wallboard 4 American Society for Testing and Materials ASTM Designation C 645, "Nonload-Bearing Steel Studs for Screw Application of Gypsum Wallboard, Runners and Rigid Furring Channels 5 American Society for Testing and Materials ASTM Designation C 646, "Specifications for Steel Drill Screws for the Application of Gypsum Sheet Ma terial to Light-Gage Steel Studs ' 6 Gypsum Association Specifications, "Application of Gypsum Base for Gypsum Veneer Plasters and Ap plication of Gypsum Veneer Plaster ' 7 Gypsum Association Manual "Using Gypsumboaid for Walls and Ceilings " 8 "Lead-Based Paint Poisoning Prevention Act Public Law 91-695. 91st Congress. HR 19172, January 13, 1971 SGP 0025596 6 NOTES SGP 0025597 GYPSUM ASSOCIATION MEMBERS THE CELOTEX CORPORATION THE FLINTKOTE COMPANY GEORGIA-PACIFIC CORPORATION. GYPSUM DIVISION GRAND RAPIDS GYPSUM COMPANY KAISER CEMENT & GYPSUM CORPORATION NATIONAL GYPSUM COMPANY TEXAS GYPSUM COMPANY. INC. UNITED STATES GYPSUM COMPANY PRINTED IN U S A SGP 0025598