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HomeMy WebLinkAbout09260_GYPSUM BOARD ASSEMBLIES.pdfMarch 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 1 Record Document SECTION 09260 - PART 1 - GENERAL GYPSUM BOARD ASSEMBLIES 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 1 Specification Sections, apply to this Section. 1.2 SUMMARY A. This Section includes the following: 1. Interior gypsum wallboard. 2. Tile backing panels. 3. Non-load-bearing steel framing. B. Related Sections include the following: 1. Division 7 Section "Building Insulation" for insulation and vapor retarders installed in gypsum board assemblies. 2. Division 9 Section "Gypsum Board Shaft-Wall Assemblies" for framing, gypsum panels, and other components of shaft wall assemblies. 1.3 DEFINITIONS A. Gypsum Board Terminology: Refer to ASTM C 11 for definitions of terms for gypsum board assemblies not defined in this Section or in other referenced standards. 1.4 SUBMITTALS A. Product Data: For each type of product indicated. B. Shop Drawings: Show locations, fabrication, and installation of control and expansion joints including plans, elevations, sections, details of components, and attachments to other units of Work. 1.5 QUALITY ASSURANCE A. Fire-Test-Response Characteristics: For gypsum board assemblies with fire-resistance ratings, provide materials and construction identical to those tested in assembly indicated according to ASTM E 119 by an independent testing and inspecting agency acceptable to authorities having jurisdiction. 1. Fire-Resistance-Rated Assemblies: Indicated by design designations from UL's "Fire Resistance Directory". March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 2 Record Document B. Sound Transmission Characteristics: For gypsum board assemblies with STC ratings, provide materials and construction identical to those tested in assembly indicated according to ASTM E 90 and classified according to ASTM E 413 by a qualified independent testing agency. 1. STC-Rated Assemblies: Indicated by design designations from GA-600, "Fire Resistance Design Manual". 1.6 DELIVERY, STORAGE, AND HANDLING A. Deliver materials in original packages, containers, or bundles bearing brand name and identification of manufacturer or supplier. B. Store materials inside under cover and keep them dry and protected against damage from weather, direct sunlight, surface contamination, corrosion, construction traffic, and other causes. Stack gypsum panels flat to prevent sagging. 1.7 PROJECT CONDITIONS A. Environmental Limitations: Comply with ASTM C 840 requirements or gypsum board manufacturer's written recommendations, whichever are more stringent. PART 2 - PRODUCTS 2.1 MANUFACTURERS A. Available Manufacturers: Subject to compliance with requirements, manufacturers offering products that may be incorporated into the Work include, but are not limited to, the following: 1. Steel Framing and Furring: a. Clark Steel Framing Systems. b. Consolidated Systems, Inc. c. Dietrich Industries, Inc. d. National Gypsum Company. e. Scafco Corporation. f. Unimast, Inc. 2. Gypsum Board and Related Products: a. G-P Gypsum Corp. b. National Gypsum Company. c. United States Gypsum Co. 2.2 STEEL SUSPENDED CEILING AND SOFFIT FRAMING A. Components, General: Comply with ASTM C 754 for conditions indicated. B. Tie Wire: ASTM A 641/A 641M, Class 1 zinc coating, soft temper, 0.0625-inch- diameter wire, or double strand of 0.0475-inch- diameter wire. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 3 Record Document C. Hanger Attachments to Concrete: As follows: 1. Powder-Actuated Fasteners: Suitable for application indicated, fabricated from corrosion- resistant materials, with clips or other devices for attaching hangers of type indicated, and capable of sustaining, without failure, a load equal to 10 times that imposed by construction as determined by testing according to ASTM E 1190 by a qualified independent testing agency. D. Hangers: As follows: 1. Wire Hangers: ASTM A 641/A 641M, Class 1 zinc coating, soft temper, 0.162-inch E. Carrying Channels: Cold-rolled, commercial-steel sheet with a base metal thickness of diameter. 0.0538 inch, a minimum 1/2-inch- 1. Depth: Per manufacturer’s written recommendations for application, wide flange, with manufacturer's standard corrosion-resistant zinc coating. 1-1/2 inches F. Furring Channels (Furring Members): Commercial-steel sheet with manufacturer's standard corrosion-resistant zinc coating. . 1. Hat-Shaped, Rigid Furring Channels: ASTM C 645, 7/8 inch a. Minimum Base Metal Thickness: Per manufacturer’s written recommendations for application, deep. 0.0312 inch minimum G. Grid Suspension System for Interior Ceilings: ASTM C 645, direct-hung system composed of main beams and cross-furring members that interlock. . 1. Available Products: Subject to compliance with requirements, products that may be incorporated into the Work include, but are not limited to, the following: a. Armstrong World Industries, Inc.; Furring Systems/Drywall. b. Chicago Metallic Corporation; Drywall Suspension System. c. USG Interiors, Inc.; Drywall Suspension System. 2.3 STEEL PARTITION AND SOFFIT FRAMING A. Components, General: As follows: 1. Comply with ASTM C 754 for conditions indicated. 2. Steel Sheet Components: Complying with ASTM C 645 requirements for metal and with manufacturer's standard corrosion-resistant zinc coating. B. Steel Studs and Runners: ASTM C 645. 1. Minimum Base Metal Thickness: Per manufacturers written recommendations for application, 0.0179-inch minimum. 2. Depth: As indicated. C. Deep-Leg Deflection Track: ASTM C 645 top runner with 2-inch- deep flanges. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 4 Record Document D. Proprietary Deflection Track: Steel sheet top runner manufactured to prevent cracking of gypsum board applied to interior partitions resulting from deflection of structure above; in thickness indicated for studs and in width to accommodate depth of studs. 1. Available Product: Subject to compliance with requirements, products that may be incorporated into the Work include, but are not limited to, the following: a. Delta Star, Inc., Superior Metal Trim; Superior Flex Track System (SFT). b. Metal-Lite, Inc.; Slotted Track. E. Proprietary Firestop Track: Top runner manufactured to allow partition heads to expand and contract with movement of the structure while maintaining continuity of fire-resistance-rated assembly indicated; in thickness not less than indicated for studs and in width to accommodate depth of studs. 1. Available Product: Subject to compliance with requirements, products that may be incorporated into the Work include, but are not limited to, the following: a. Fire Trak Corp.; Fire Trak attached to studs with Fire Trak Slip Clip. b. Metal-Lite, Inc.; The System. F. Flat Strap and Backing Plate: Steel sheet for blocking and bracing in length and width indicated. 1. Minimum Base Metal Thickness: 0.0312 inch G. Cold-Rolled Channel Bridging: minimum. 0.0538-inch bare steel thickness, with minimum 1/2-inch- 1. Depth: wide flange. 1-1/2 inches 2. Clip Angle: . 1-1/2 by 1-1/2 inch, 0.068-inch- H. Hat-Shaped, Rigid Furring Channels: ASTM C 645. thick, galvanized steel. 1. Minimum Base Metal Thickness: Per manufacturers written recommendations for application, 0.0179 inch minimum 2. Depth: . 7/8 inch I. Resilient Furring Channels: unless otherwise indicated. 1/2-inch- 1. Configuration: Asymmetrical, with face attached to single flange by a slotted leg (web). deep, steel sheet members designed to reduce sound transmission. J. Z-Shaped Furring: With slotted or nonslotted web, face flange of 1-1/4 inches, wall attachment flange of 7/8 inch, minimum bare metal thickness of 0.0179 inch K. Fasteners for Metal Framing: Of type, material, size, corrosion resistance, holding power, and other properties required to fasten steel members to substrates. , and depth required to fit 2” thick rigid insulation as indicated. 2.4 INTERIOR GYPSUM WALLBOARD A. Panel Size: Provide in maximum lengths and widths available that will minimize joints in each area and correspond with support system indicated. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 5 Record Document B. Gypsum Wallboard: ASTM C 1396. 1. Regular Type: a. Thickness: 5/8-inch b. Long Edges: Tapered. , unless otherwise indicated. c. Location: As indicated. 2. Type X: a. Thickness: 5/8 inch b. Long Edges: Tapered. . c. Location: Where required for fire-resistance-rated assembly. C. Flexible Gypsum Wallboard: ASTM C 1396, manufactured to bend to fit tight radii and to be more flexible than standard regular-type panels of the same thickness. 1. Thickness: 1/4 inch 2. Long Edges: Tapered. . 3. Location: Apply in double layer at curved assemblies. 2.5 TILE BACKING PANELS A. Panel Size: Provide in maximum lengths and widths available that will minimize joints in each area and correspond with support system indicated. B. Cementitious Backing Board: ASTM C 1396/C 1396M as back-up to hard tile areas. 1. Core: 5/8 inch C. Water-Resistant Gypsum Backing Board: ASTM C 1396/C 1396M at “wet areas” not receiving tile. . 1. Core: 5/8 inch. 2.6 TRIM ACCESSORIES A. Interior Trim: ASTM C 1047. 1. Material: Galvanized or aluminum-coated steel sheet or rolled zinc. 2. Shapes: a. Cornerbead: Use at outside corners[, unless otherwise indicated]. 2.7 JOINT TREATMENT MATERIALS A. General: Comply with ASTM C 475. B. Joint Tape: 1. Interior Gypsum Wallboard: Paper. 2. Tile Backing Panels: As recommended by panel manufacturer. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 6 Record Document C. Joint Compound for Interior Gypsum Wallboard: For each coat use formulation that is compatible with other compounds applied on previous or for successive coats. 1. Prefilling: At open joints, rounded or beveled panel edges, and damaged surface areas, use setting-type taping compound. 2. Embedding and First Coat: For embedding tape and first coat on joints, fasteners, and trim flanges, use drying-type, all-purpose compound. 3. Fill Coat: For second coat, use drying-type, all-purpose compound. 4. Finish Coat: For third coat, use drying-type, all-purpose compound. 5. Skim Coat: For final coat of Level 5 finish, use drying-type, all-purpose compound. D. Joint Compound for Tile Backing Panels: 1. Water-Resistant Gypsum Backing Board: Use setting-type taping and setting-type, sandable topping compounds. 2.8 ACOUSTICAL SEALANT A. Available Products: Subject to compliance with requirements, products that may be incorporated into the Work include, but are not limited to, the following: 1. Acoustical Sealant for Exposed and Concealed Joints: a. Pecora Corp.; AC-20 FTR Acoustical and Insulation Sealant. b. United States Gypsum Co.; SHEETROCK Acoustical Sealant. 2. Acoustical Sealant for Concealed Joints: a. Ohio Sealants, Inc.; Pro-Series SC-170 Rubber Base Sound Sealant. b. Pecora Corp.; BA-98. c. Tremco, Inc.; Tremco Acoustical Sealant. B. Acoustical Sealant for Exposed and Concealed Joints: Nonsag, paintable, nonstaining, latex sealant complying with ASTM C 834 that effectively reduces airborne sound transmission through perimeter joints and openings in building construction as demonstrated by testing representative assemblies according to ASTM E 90. C. Acoustical Sealant for Concealed Joints: Nondrying, nonhardening, nonskinning, nonstaining, gunnable, synthetic-rubber sealant recommended for sealing interior concealed joints to reduce airborne sound transmission. 2.9 AUXILIARY MATERIALS A. General: Provide auxiliary materials that comply with referenced installation standards and manufacturer's written recommendations. B. Laminating Adhesive: Adhesive or joint compound recommended for directly adhering gypsum panels to continuous substrate. C. Steel Drill Screws: ASTM C 1002, unless otherwise indicated. 1. Use screws complying with ASTM C 954 for fastening panels to steel members from 0.033 to 0.112 inch thick. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 7 Record Document D. Isolation Strip at Exterior Walls: 1. Asphalt-Saturated Organic Felt: ASTM D 226, Type I (No. 15 asphalt felt), nonperforated. 2. Foam Gasket: Adhesive-backed, closed-cell vinyl foam strips that allow fastener penetration without foam displacement, 1/8 inch E. Sound Attenuation Blankets: ASTM C 665, Type I (blankets without membrane facing) produced by combining thermosetting resins with mineral fibers manufactured from glass, slag wool, or rock wool. thick, in width to suit steel stud size. 1. Fire-Resistance-Rated Assemblies: Comply with mineral-fiber requirements of assembly. F. Thermal Insulation: As specified in Division 7 Section "Building Insulation." PART 3 - EXECUTION 3.1 EXAMINATION A. Examine areas and substrates, with Installer present, and including welded hollow-metal frames, cast-in anchors, and structural framing, for compliance with requirements and other conditions affecting performance. Proceed with installation only after unsatisfactory conditions have been corrected. 3.2 PREPARATION A. Suspended Ceilings: Coordinate installation of ceiling suspension systems with installation of overhead structure to ensure that inserts and other provisions for anchorages to building structure have been installed to receive ceiling hangers at spacing required to support ceilings and that hangers will develop their full strength. 1. Furnish concrete inserts and other devises indicated to other trades for installation in advance of time needed for coordination and construction. B. Coordination with Sprayed Fire-Resistive Materials: 1. Before sprayed fire-resistive materials are applied, attach offset anchor plates or ceiling runners (tracks) to surfaces indicated to receive sprayed-on fire-resistive materials. Where offset anchor plates are required, provide continuous plates fastened to building structure not more than 24 inches 2. After sprayed fire-resistive materials are applied, remove them only to extent necessary for installation of gypsum board assemblies and without reducing the fire-resistive material thickness below that which is required to obtain fire-resistance rating indicated. Protect remaining fire-resistive materials from damage. o.c. 3.3 INSTALLING STEEL FRAMING, GENERAL A. Installation Standards: ASTM C 754, and ASTM C 840 requirements that apply to framing installation. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 8 Record Document B. Install supplementary framing, blocking, and bracing at terminations in gypsum board assemblies to support fixtures, equipment services, heavy trim, grab bars, toilet accessories, furnishings, or similar construction. Comply with details indicated and with gypsum board manufacturer's written recommendations or, if none available, with United States Gypsum's "Gypsum Construction Handbook." C. Isolate steel framing from building structure at locations indicated to prevent transfer of loading imposed by structural movement. 1. Isolate ceiling assemblies where they abut or are penetrated by building structure. 2. Isolate partition framing and wall furring where it abuts structure, except at floor. Install slip-type joints at head of assemblies that avoid axial loading of assembly and laterally support assembly. a. Use deep-leg deflection track, proprietary deflection track, or proprietary firestop track, where indicated. D. Do not bridge building control and expansion joints with steel framing or furring members. Frame both sides of joints independently. 3.4 INSTALLING STEEL SUSPENDED CEILING AND SOFFIT FRAMING A. Suspend ceiling hangers from building structure as follows: 1. Install hangers plumb and free from contact with insulation or other objects within ceiling plenum that are not part of supporting structural or ceiling suspension system. Splay hangers only where required to miss obstructions and offset resulting horizontal forces by bracing, countersplaying, or other equally effective means. 2. Where width of ducts and other construction within ceiling plenum produces hanger spacings that interfere with the location of hangers required to support standard suspension system members, install supplemental suspension members and hangers in form of trapezes or equivalent devices. Size supplemental suspension members and hangers to support ceiling loads within performance limits established by referenced standards. 3. Secure wire hangers by looping and wire-tying, either directly to structures or to inserts, eyescrews, or other devices and fasteners that are secure and appropriate for substrate, and in a manner that will not cause them to deteriorate or otherwise fail. 4. Do not support ceilings directly from permanent metal forms. Furnish cast-in-place hanger inserts that extend through forms. 5. Do not attach hangers to steel deck tabs. 6. Do not attach hangers to steel roof deck. Attach hangers to structural members. 7. Do not connect or suspend steel framing from ducts, pipes, or conduit. B. Installation Tolerances: Install steel framing components for suspended ceilings so members for panel attachment are level to within 1/8 inch in 12 feet C. Wire-tie or clip furring channels to supports, as required to comply with requirements for assemblies indicated. measured lengthwise on each member and transversely between parallel members. D. Install suspended steel framing components in sizes and spacings indicated, but not less than that required by the referenced steel framing and installation standards. 1. Hangers: 48 inches o.c., maximum. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 9 Record Document 2. Carrying Channels (Main Runners): 48 inches 3. Furring Channels (Furring Members): o.c., maximum. 16 inches E. Grid Suspension System: Attach perimeter wall track or angle where grid suspension system meets vertical surfaces. Mechanically join main beam and cross-furring members to each other and butt-cut to fit into wall track. o.c., maximum. 3.5 INSTALLING STEEL PARTITION AND SOFFIT FRAMING A. Install tracks (runners) at floors, ceilings, and structural walls and columns where gypsum board assemblies abut other construction. 1. Where studs are installed directly against exterior walls, install asphalt-felt or foam-gasket isolation strip between studs and wall. B. Installation Tolerance: Install each steel framing and furring member so fastening surfaces vary not more than 1/8 inch C. Extend partition framing full height to structural supports or substrates above suspended ceilings, except where partitions are indicated to terminate at suspended ceilings. Continue framing over frames for doors and openings and frame around ducts penetrating partitions above ceiling to provide support for gypsum board. from the plane formed by the faces of adjacent framing. 1. Cut studs 1/2 inch 2. For fire-resistance-rated and STC-rated partitions that extend to the underside of floor/roof slabs and decks or other continuous solid-structure surfaces to obtain ratings, install framing around structural and other members extending below floor/roof slabs and decks, as needed to support gypsum board closures and to make partitions continuous from floor to underside of solid structure. short of full height to provide perimeter relief. a. Terminate partition framing at suspended ceilings where indicated. D. Install steel studs and furring at the following spacings: 1. Single-Layer Construction: 16 inches 2. Multilayer Construction: o.c., unless otherwise indicated. 16 inches E. Install steel studs so flanges point in the same direction and leading edge or end of each panel can be attached to open (unsupported) edges of stud flanges first. o.c., unless otherwise indicated. F. Frame door openings to comply with GA-600 and with gypsum board manufacturer's applicable written recommendations, unless otherwise indicated. Screw vertical studs at jambs to jamb anchor clips on door frames; install runner track section (for cripple studs) at head and secure to jamb studs. 1. Install two studs at each jamb, unless otherwise indicated. 2. Install cripple studs at head adjacent to each jamb stud, with a minimum 1/2-inch 3. Extend jamb studs through suspended ceilings and attach to underside of floor or roof structure above. clearance from jamb stud to allow for installation of control joint, where indicated. G. Frame openings other than door openings the same as required for door openings, unless otherwise indicated. Install framing below sills of openings to match framing required above door heads. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 10 Record Document H. Z-Furring Members: 1. Erect insulation vertically and hold in place with Z-furring members spaced 24 inches 2. Except at exterior corners, securely attach narrow flanges of furring members to wall with concrete stub nails, screws designed for masonry attachment, or powder-driven fasteners spaced o.c., unless otherwise indicated. 24 inches 3. At exterior corners, attach wide flange of furring members to wall with short flange extending beyond corner; on adjacent wall surface, screw-attach short flange of furring channel to web of attached channel. At interior corners, space second member no more than o.c. 12 inches 3.6 APPLYING AND FINISHING PANELS, GENERAL from corner and cut insulation to fit. A. Gypsum Board Application and Finishing Standards: ASTM C 840 and GA-216. B. Install sound attenuation blankets before installing gypsum panels, unless blankets are readily installed after panels have been installed on one side. C. Install ceiling board panels across framing to minimize the number of abutting end joints and to avoid abutting end joints in the central area of each ceiling. Stagger abutting end joints of adjacent panels not less than one framing member. D. Install gypsum panels with face side out. Butt panels together for a light contact at edges and ends with not more than 1/16 inch E. Locate edge and end joints over supports, except in ceiling applications where intermediate supports or gypsum board back-blocking is provided behind end joints. Do not place tapered edges against cut edges or ends. Stagger vertical joints on opposite sides of partitions. Do not make joints other than control joints at corners of framed openings. of open space between panels. Do not force into place. F. Attach gypsum panels to steel studs so leading edge or end of each panel is attached to open (unsupported) edges of stud flanges first. G. Attach gypsum panels to framing provided at openings and cutouts. H. Form control and expansion joints with space between edges of adjoining gypsum panels. I. Cover both faces of steel stud partition framing with gypsum panels in concealed spaces (above ceilings, etc.), except in chases braced internally. 1. Unless concealed application is indicated or required for sound, fire, air, or smoke ratings, coverage may be accomplished with scraps of not less than 8 sq. ft. 2. Fit gypsum panels around ducts, pipes, and conduits. in area. 3. Where partitions intersect open concrete coffers, concrete joists, and other structural members projecting below underside of floor/roof slabs and decks, cut gypsum panels to fit profile formed by coffers, joists, and other structural members; allow 1/4- to 3/8-inch- J. Isolate perimeter of non-load-bearing gypsum board partitions at structural abutments, except floors. Provide wide joints to install sealant. 1/4- to 1/2-inch- wide spaces at these locations, and trim edges with U-bead edge trim where edges of gypsum panels are exposed. Seal joints between edges and abutting structural surfaces with acoustical sealant. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 11 Record Document K. STC-Rated Assemblies: Seal construction at perimeters, behind control and expansion joints, and at openings and penetrations with a continuous bead of acoustical sealant. Install acoustical sealant at both faces of partitions at perimeters and through penetrations. Comply with ASTM C 919 and manufacturer's written recommendations for locating edge trim and closing off sound-flanking paths around or through gypsum board assemblies, including sealing partitions above acoustical ceilings. L. Space fasteners in gypsum panels according to referenced gypsum board application and finishing standard and manufacturer's written recommendations. 1. Space screws a maximum of 12 inches M. Space fasteners in panels that are tile substrates a maximum of o.c. for vertical applications. 8 inches 3.7 PANEL APPLICATION METHODS o.c. A. Single-Layer Application: 1. On ceilings, apply gypsum panels before wall/partition board application to the greatest extent possible and at right angles to framing, unless otherwise indicated. 2. On partitions/walls, apply gypsum panels vertically (parallel to framing) or horizontally (perpendicular to framing), unless otherwise indicated or required by fire-resistance-rated assembly, and minimize end joints. a. Stagger abutting end joints not less than one framing member in alternate courses of board. b. At stairwells and other high walls, install panels horizontally, unless otherwise indicated or required by fire-resistance-rated assembly. 3. On Z-furring members, apply gypsum panels vertically (parallel to framing) with no end joints. Locate edge joints over furring members. B. Multilayer Application on Ceilings: Apply gypsum board indicated for base layers before applying base layers on walls/partitions; apply face layers in same sequence. Apply base layers at right angles to framing members and offset face-layer joints 1 framing member, 16 inches C. Multilayer Application on Partitions/Walls: Apply gypsum board indicated for base layers and face layers vertically (parallel to framing) with joints of base layers located over stud or furring member and face-layer joints offset at least one stud or furring member with base-layer joints, unless otherwise indicated or required by fire-resistance-rated assembly. Stagger joints on opposite sides of partitions. minimum, from parallel base-layer joints, unless otherwise indicated or required by fire- resistance-rated assembly. 1. Z-Furring Members: Apply base layer vertically (parallel to framing) and face layer either vertically (parallel to framing) or horizontally (perpendicular to framing) with vertical joints offset at least one furring member. Locate edge joints of base layer over furring members. D. Single-Layer Fastening Methods: Apply gypsum panels to supports with steel drill screws. E. Multilayer Fastening Methods: Fasten base layers and face layers separately to supports with screws. March 10, 2005 513-6976-00 GYPSUM BOARD ASSEMBLIES 09260 - 12 Record Document F. Laminating to Substrate: Where gypsum panels are indicated as directly adhered to a substrate (other than studs, joists, furring members, or base layer of gypsum board), comply with gypsum board manufacturer's written recommendations and temporarily brace or fasten gypsum panels until fastening adhesive has set. G. Tile Backing Panels: 1. Cementitious Backing Board: Install at showers, toilet room wet walls, and where indicated. Install with 1/4-inch 2. Where tile backing panels abut other types of panels in the same plane, shim surfaces to produce a uniform plane across panel surfaces. gap where panels abut other construction or penetrations. 3.8 INSTALLING TRIM ACCESSORIES A. General: For trim with back flanges intended for fasteners, attach to framing with same fasteners used for panels. Otherwise, attach trim according to manufacturer's written instructions. B. Control Joints: Install control joints at locations indicated on Drawings, but not less than requirements according to ASTM C 840 and in specific locations approved by Architect for visual effect. 3.9 FINISHING GYPSUM BOARD ASSEMBLIES A. General: Treat gypsum board joints, interior angles, edge trim, control joints, penetrations, fastener heads, surface defects, and elsewhere as required to prepare gypsum board surfaces for decoration. Promptly remove residual joint compound from adjacent surfaces. B. Prefill open joints, rounded or beveled edges, and damaged surface areas. C. Apply joint tape over gypsum board joints, except those with trim having flanges not intended for tape. D. Gypsum Board Finish Levels: Finish panels to levels indicated below, according to ASTM C 840, for locations indicated: 1. Level 1: Embed tape at joints in ceiling plenum areas, concealed areas, and where indicated, unless a higher level of finish is required for fire-resistance-rated assemblies and sound-rated assemblies. 2. Level 2: Embed tape and apply separate first coat of joint compound to tape, fasteners, and trim flanges where panels are substrate for tile. 3. Level 4: Embed tape and apply separate first, fill, and finish coats of joint compound to tape, fasteners, and trim flanges at panel surfaces that will be exposed to view, unless otherwise indicated. 4. Level 5: Embed tape and apply separate first, fill, and finish coats of joint compound to tape, fasteners, and trim flanges, and apply skim coat of joint compound over entire surface at curved walls and where indicated. END OF SECTION 09260 F:\DOI 2/99 Copyright: Little