VA 09 23 00-2011 GYPSUM PLASTERING.pdf

1、10-11 09 23 00 - 1 SECTION 09 23 00 GYPSUM PLASTERING SPEC WRITER NOTE: Delete between /-/ if not applicable to project. Also delete any other item or paragraph not applicable in the section and renumber the paragraphs. PART 1 - GENERAL 1.1 DESCRIPTION This section specifies metal and gypsum lathing

2、 and gypsum plaster. 1.2 RELATED WORK A. Steel framing members for attachment of plaster bases: Section 05 40 00, COLD-FORMED METAL FRAMING, and Section 09 22 16, NON-STRUCTURAL METAL FRAMING. B. Room finish schedule: Section 09 06 00, SCHEDULE FOR FINISHESS. C. Cement plaster: Section 09 24 00, POR

3、TLAND CEMENT PLASTERING. D. Veneer plaster: Section 09 26 00, VENEER PLASTERING. E. Lead lined lath: Section 13 49 00, RADIATION PROTECTION. 1.3 TERMINOLOGY A. Definitions and description of terms shall be in accordance with ASTM C11, C841, and C842 and as specified. B. Underside of Structure Overhe

4、ad: In spaces where steel trusses or bar joists are shown, the underside of structure overhead is the underside of the floor or roof construction supported by beams, trusses, and bar joists. C. Self-furring Lath: Metal plastering bases having dimples or crimps designed to hold the plane of the back

5、of the lath 6 to 10 mm (1/4 to 3/8 inch) away from the plane of the solid backing. D. Solid Backing or Solid Bases: Concrete, masonry, sheathing, rigid insulation, and similar materials to which plaster is directly applied. E. Wet Areas: Areas of a building where cyclic or continuous exposure to ver

6、y humid or wet conditions, or in which a dew point condition may occur in the plaster. Dew point conditions occur frequently in such areas as laundries, natatoriums, cart and dish washing spaces, hydrotherapy, kitchens, bathing or shower rooms and similar areas. 1.4 SUBMITTALS A. Submit in accordanc

7、e with Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND SAMPLES. B. Shop Drawings: 1. Details of floating interior angle unrestrained construction. 2. Details of assembly and anchorage of lath and accessories. Provided by IHSNot for ResaleNo reproduction or networking permitted without license fro

8、m IHS-,-,-10-11 09 23 00 - 2 C. Manufacturers Literature and Data: 1. Accessories for plaster, each type. 2. Metal plaster bases, each type. 3. Fasteners. 4. Bonding compounds, including application instructions. 5. Admixtures, including mixing and application instructions. D. Manufacturers certific

9、ates: 1. Gypsum plaster. 2. Keenes cement. E. Samples: Accessories for plaster, each type, not less than 150 mm (six inches) long. SPEC WRITER NOTE: Request plaster sample where color is specified or special finish is required, and where required to match existing special finish conditions. Specify

10、a size to suit requirements, 150 by 300 mm (6 by 12 inches) minimum. Panel showing finish coat, _ by _ mm (inches). 1.5 DELIVERY, STORAGE, AND PROTECTION ASTM C841 and C842. 1.6 PROJECT CONDITIONS Maintain work areas at a minimum temperature of 13C (55F) for not less than one week prior to applicati

11、on of plaster, during application of plaster and until plaster is completely dry. 1.7 APPLICABLE PUBLICATIONS A. The publications listed below form a part of this specification to the extent referenced. The publications are referenced in the text by basic designation only. B. American Society for Te

12、sting And Materials (ASTM): A641-09 Zinc-Coated (Galvanized) Carbon Steel Wire C11-10 . Terminology Relating to Gypsum and Related Building Materials and Systems. C28-10 . Gypsum Plasters C35-01 (R2009) . Inorganic Aggregates For Use in Gypsum Plaster C61-00(R2006) Gypsum Keenes Cement C206-03(R2009

13、) . Finishing Hydrated Lime C472-99(R2009) . Physical Testing of Gypsum, Gypsum Plaster and Gypsum Concrete C631-09 Bonding Compounds for Interior Gypsum Plastering C841-03(R2008) . Installation of Interior Lathing and Furring C842-05(R2010) . Application of Interior Gypsum Plaster C847-10 Metal Lat

14、h Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10-11 09 23 00 - 3 C1002-07 . Steel Self-Piercing Tapping Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Wood Studs or Steel Studs D3678-97(R2008) Rigid Poly (Vinyl Chlo

15、ride) (PVC) Interior-Profile Extrusions C. Commercial Item Description (CID): A-A-55615 Shield, Expansion; (Wood Screw and Log Bolt Self Threading Anchor) PART 2 - PRODUCTS SPEC WRITER NOTE: Make material requirements agree with applicable requirements specified in the referenced Applicable Publicat

16、ions. Update and specify only that which applies to the project. 2.1 PLASTERING BASES (LATH) A. Expanded Metal: ASTM C847, except as modified by ASTM C841 and this specification. B. Gypsum Lath: 1. 10 mm (3/8 inch) thick. 2. Type X for fire rated assemblies. 2.2 GYPSUM PLASTERS A. Base and Finish co

17、ats ASTM C28 and ASTM C842, except as otherwise specified. 1. Compressive strength of base coat for high-strength gypsum and Keenes cement finish coat plaster; 25 Mpa (2800 psi) when tested in accordance with ASTM C472. 2. Compressive strength of finish coat (when fully dry) of high-strength gypsum

18、plaster; 35 Mpa (5,000 psi) when tested in accordance with ASTM C472. B. Keenes Cement for Finish Coats: ASTM C61. 2.3 LIME ASTM C206, Type S. 2.4 AGGREGATES A. ASTM C35, natural sand, except grade aggregates in accordance with “TABLE 1“, except sand for Keenes Cement Finish Coat, 100 percent passin

19、g a No. 30 sieve. B. Vermiculite and perlite aggregates are not permitted, except where required for fire rated assemblies. 2.5 BONDING COMPOUND (FOR INTERIOR WORK) ASTM C631, except water re-emulsifiable compound is prohibited. Provided by IHSNot for ResaleNo reproduction or networking permitted wi

20、thout license from IHS-,-,-10-11 09 23 00 - 4 2.6 ACCESSORIES FOR GYPSUM PLASTER ASTM C841. 2.7 FASTENERS A. Tie wire, screws, clips, and other fasteners ASTM C841, except as otherwise specified. B. Fasteners for securing metal plastering bases shall have heads, or be through washers large enough to

21、 engage two strands of the metal plastering base. C. For fire rated construction type and size as used in fire rated test. D. Screws: ASTM C1002. E. Expansion Shields: CID A-A-55615, of the Type and Class applicable. SPEC WRITER NOTE: Coordinate with Section 09 30 13, CERAMIC TILING for type of sett

22、ing bed required for ceramic tile. Generally in wet areas glass fiber reinforced concrete backer board is used and is mandatory for showers. Gypsum plaster or gypsum board may be used for adhesive applied ceramic tile in areas not considered wet. Coordinate with Sections 09 06 00, SCHEDULE FOR FINIS

23、HES, Section 09 22 16, NON-STRUCTURAL METAL FRAMING and Section 09 30 13, CERAMIC TILING to clearly define substrate for ceramic tile finish. Portland cement plaster is required for walls and ceilings above ceramic wall tile in showers and similar wet areas. PART 3 EXECUTION 3.1 APPLYING LATH BASES

24、A. In accordance with ASTM C841, except as otherwise specified or shown. B. Use metal plastering bases where plaster is required on partitions, ceilings and furring /, where required for setting ceramic title in adhesive on gypsum plaster / and for light troughs, beams and other curved or irregular

25、surfaces. 1. Where plaster is required on solid bases, metal plastering bases are not required, unless shown on the drawings. 2. Form true surfaces, straight or in fair curves where shown, without sags or buckles and with long dimension of lath at right angles to direction of supports. 3. Shape lath

26、ing to within 19 mm (3/4 inch) of finished profiles of irregular surfaces. 4. Lath for ceiling construction shall terminate at casing bead (Floating Angle Construction) where butting into or penetrated by walls, columns, beams, and similar elements. Provided by IHSNot for ResaleNo reproduction or ne

27、tworking permitted without license from IHS-,-,-10-11 09 23 00 - 5 C. Gypsum lath may be used in lieu of metal lath for gypsum plaster only on straight flat surfaces of partitions and walls, and on furring, except for lathing in wet areas and as a base for marble finishes. D. Installing Metal Plaste

28、ring Bases: 1. Select type of metal plastering base to conform to Table 1 of ASTM C841, except as otherwise specified. 2. Where metal plastering bases are required over solid backing, use self-furring, zinc-coated (galvanized) metal plastering base, with vapor permeable backing. 3. Attach self-furri

29、ng metal lath directly to masonry and concrete with hardened nails, power actuated drive pins, or other approved fasteners. Locate fasteners at the dimples or crimps only. 4. Where metal plastering bases are required over steel columns, use self-furring, diamond mesh, expanded metal lath. 5. Rib lat

30、h shall not be used, except 10 mm (3/8 inch) rib lath may be used above ceramic title wainscots where the finish above the wainscot is required to finish flush with the tile face. 6. Metal plastering bases shall not be continuous through expansion and control joints, but shall terminate at each side

31、 of the joint. 3.2 SURFACE PREPARATION OF SOLID BASES A. Prepare and condition in accordance with ASTM C842, except as otherwise specified. SPEC WRITER NOTE: Read ASTM C842 regarding Conditioning of Surfaces, Monolithic Surfaces. Check concrete spec to see that finish specified will receive plaster.

32、 New concrete should not need preparation other than that specified in 3.2, B, C and D. Examine condition of existing surfaces to receive plaster and specify only one of following methods for each condition. Where more than one kind of surface preparation is required, list areas where each is applic

33、able. B. Surface of masonry and concrete shall be straight and true so that maximum variation in plane does not exceed 6 mm (1/4 inch), 3 mm (1/8 inch) plus, 3 mm (1/8 inch) minus), in 3 m (10 feet), non-accumulative. C. Form ties and other metal projections shall be cut back to slightly below the s

34、urface. D. Projections shall be removed and depressions, holes, cracks and similar voids shall be filled flush with patching compound compatible with the substrate and plaster, within the tolerance, specified in ASTM C842. E. Clean existing concrete surfaces specified to receive plaster to ensure me

35、chanical key as specified in ASTM C842. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10-11 09 23 00 - 6 F. Condition new or existing concrete surfaces specified to receive plaster by applying bonding compound as specified in ASTM C842. G. Conditio

36、n / existing / new / concrete / masonry / surfaces (solid backing) specified to receive plaster by applying metal plastering base as specified in ASTM C842. 3.3 INSTALLING PLASTERING ACCESSORIES A. Install accessories in accordance with ASTM C841, except as follows: 1. Set plastering accessories plu

37、mb, level and true to line, neatly mitered at corners and intersections, and securely attach to supporting surfaces as specified for metal lath. 2. Install in one piece, within the limits of the longest commercially available lengths. 3. Wood plugs are not acceptable anchorage for fasteners. B. Corn

38、er Beads: Install at all vertical and horizontal external plaster corners, as required to establish grounds, and where shown. C. Strip Lath: 1. Install metal lath strips centered over joints between dissimilar materials, such as clay tile, brick, concrete masonry units, concrete, and metal / and gyp

39、sum / lath, where both such surfaces are required to be plastered and are in contact with each other in same plane, except where expansion joints and casing beads are required. 2. Wire tie, staple, screw, or nail strip lath to base along both edges at not over 150 mm (6 inches) on centers. 3. Reinfo

40、rce gypsum lath at corners of openings, at internal corners, and at chases and similar breaks in continuity in accordance with ASTM C841. D. Casing Beads: 1. Install casing beads at locations where plaster terminates against other materials. 2. Where shown. 3. Where plaster terminates against trim o

41、f steel frames and trim of other materials and equipment, except where trim overlaps plaster. 4. Where plaster for new walls or furring (vertical or horizontal) terminates against existing construction. 5. Around perimeter of openings for recessed casework and equipment, except where edge is covered

42、 by flanges. Locate to conform to dimensions shown on approved shop drawings. 6. Both sides of expansion and control joints, unless shown otherwise. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10-11 09 23 00 - 7 7. Install casing beads where ceil

43、ings butt into or are penetrated by walls, columns, beams, and similar elements so as to provide floating angle (unrestrained) construction in accordance with ASTM C841. E. Cornerites: 1. Install at interior corners of walls, partitions, and other vertical surfaces to be plastered, except where meta

44、l lath is carried around angle. 2. Fasten only as necessary to retain position during plastering. 3. Omit cornerites at junction of new plastered walls with existing plastered walls. 4. Where metal plastering bases are specified not to be carried around internal angles, and at locations where casing

45、 beads are specified and shown. SPEC WRITER NOTE: 1. Show and clearly define on drawings locations of control joints. 2. Detail control joints. 3. See ASTM C841 for design criteria. F. Control Joints: 1. Where control joints are placed paralleled to framing members, install joints within 100 mm (4 i

46、nches) of framing member. 2. Install control joints only to the edges of abutting sheets of lath so that the latch is not continuous or tied across joint. 3. Extend control joints the full width and height of the wall or length of soffit/ceiling plaster membrane. 3.4 GYPSUM PLASTER APPLICATION A. Pr

47、oportion, mix, and apply plaster in accordance with ASTM C842. B. Thickness of Plaster: ASTM C842, except as follows: 1. Where greater thickness is shown. 2. Where thickness is required to match existing. 3. On metal plaster base 19 mm (3/4 inch), except where greater thickness is required for fire

48、rated construction /4. As required on ceilings having radiant heating piping embedded therein to provide a minimum 10 mm (3/8 inch) cover over piping./ 5. Apply finish coats to a uniform thickness of approximately 2 mm (1/16 inch) with not more than 3 mm (1/8 inch) thickness at any point. SPEC WRITE

49、R NOTE: Check drawings and omit following subparagraph, if casing beads are shown at door frames. Coordinate with specification requirements for casing beads at door frames. C. Cut 2 mm (1/16 inch) deep V-joint in finish coat of plaster adjacent to metal door frames and wherever plaster finishes flush with other Provided by IHSNot for ResaleNo reproduction or networking permitted without l