09 26 00.pdf

P347 Cutler ME

SECTION 09 26 00

VENEER PLASTER

08/ 16, CHG 1: 08/ 18

PART 1 GENERAL

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

ASTM INTERNATIONAL (ASTM)

ASTM C475/C475M (2017; R 2022) Standard Specification for Joint Compound and Joint Tape for Finishing Gypsum Board

ASTM C514 (2004; R 2020) Standard Specification for Nails for the Application of Gypsum Board

ASTM C587 (2004; R 2014) Gypsum Veneer Plaster

ASTM C645 (2014; E 2015) Nonstructural Steel Framing Members

ASTM C754 (2020) Standard Specification for Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products

ASTM C843 (2017) Standard Specification for Application of Gypsum Veneer Plaster

ASTM C844 (2015; R 2021; E 2021) Standard Specification for Application of Gypsum Base to Receive Gypsum Veneer Plaster

ASTM C954 (2022) Standard Specification for Steel Drill Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Steel Studs from 0.033 in. (0.84 mm) to

0.112 in. (2.84 mm) in Thickness

ASTM C1002 (2022) Standard Specification for Steel Self-Piercing Tapping Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Wood Studs or Steel Studs

ASTM C1047 (2019) Standard Specification for Accessories for Gypsum Wallboard and Gypsum Veneer Base

ASTM C1177/C1177M (2017) Standard Specification for Glass Mat Gypsum Substrate for Use as Sheathing

SECTION 09 26 00 Page 1 Pre-Final Design Submittal

ASTM D3678 (2019) Standard Specification for Rigid Poly (Vinyl Chloride) (PVC) Interior-Profile Extrusions

FM GLOBAL (FM)

FM APP GUIDE (updated on-line) Approval Guide http://www.approvalguide.com/

UNDERWRITERS LABORATORIES (UL)

UL Fire Resistance (2014) Fire Resistance Directory

1.2 GENERAL REQUIREMENTS

Except where otherwise indicated or specified, conform to ASTM C754, ASTM C843, and ASTM C844. Apply the gypsum veneer plaster as a two coat system over a special gypsum base. The veneer plaster, gypsum base, and joint reinforcement must be products of the same manufacturer. The extent and location of veneer plaster must be as shown on the drawings. Metal framing is specified herein.

1.3 SUBMITTALS

Government approval is required for submittals with a "G" or "S" classification. Submittals not having a "G" or "S" classification are for information only. When used, a code following the "G" classification identifies the office that will review the submittal for the Government.

Submit the following in accordance with Section 01 33 00 SUBMITTAL

PROCEDURES:

SD-03 Product Data

Gypsum Base

Gypsum Veneer Plaster

Descriptive data and installation instructions.

1.4 DELIVERY AND STORAGE

Deliver and store plaster materials in the manufacturer's original unopened containers. Store materials off the ground within a completely enclosed structure or enclosed within a weathertight covering. Store gypsum base and gypsum backing board flat to prevent warping and protect from excessive exposure to sunlight. Keep materials wrapped and separate from off-gassing materials, such as paint and adhesives. Do not use materials that have visible moisture or biological growth.

1.5 SCHEDULING

Commence application only after the area scheduled for veneer plaster work is completely weathertight. The heating, ventilating, and air-conditioning systems must be complete and in operation prior to application of the plaster. If the mechanical system cannot be activated before veneer plastering is begun, the plastering may proceed in accordance with an approved plan to maintain the environmental conditions

SECTION 09 26 00 Page 2 specified below. Apply plaster prior to the installation of finish flooring and acoustic ceiling.

1.6 ENVIRONMENTAL REQUIREMENTS

Do not expose the gypsum base to excessive sunlight prior to plaster application, as bond failure of the plaster may result. Maintain a continuous uniform temperature of not less than 50 degrees F and not more than 80 degrees F for at least one week prior to the application of veneer plaster, while the plastering is being done, and for at least one week after the plaster is set. Shield air supply and distribution devices to prevent any uneven flow of air across the plastered surfaces. Provide ventilation to exhaust moist air to the outside during plaster application, set, and until plaster is dry. In glazed areas, keep windows open top and bottom or side to side 3 to 4 inches . Openings can be reduced in cold weather. For enclosed areas lacking natural ventilation, provide temporary mechanical means for ventilation. In unglazed areas subjected to hot, dry winds or temperature differentials from day to night of 20 degrees F or more, screen openings with cheesecloth or similar materials. Avoid rapid drying. During periods of low indoor humidity, provide minimum air circulation following plastering and until plaster is dry.

1.7 FIRE RESISTIVE CONSTRUCTION

Comply with specified fire-rated assemblies for design numbers indicated per UL Fire Resistance or FM APP GUIDE.

PART 2 PRODUCTS

2.1 MATERIALS

Conform to the requirements specified below. Miscellaneous items not otherwise specified must be as recommended by the veneer plaster system manufacturer and approved prior to use. Powder driven fasteners may be used only when approved in writing. Material must be manufactured for use in exterior soffit and ceiling applications.

2.1.1 Steel Framing, Furring, and Related Items

ASTM C645. Provide steel framing, furring, and related items that contain a minimum of 25 percent recycled content. Provide data identifying percentage of recycled content for steel framing or furring .

2.1.2 Vapor Retarder

Foil-backed gypsum base or gypsum backing board, or 4-mil polyethylene.

2.1.3 Gypsum Backing Board

Glass mat faced gypsum sheathing ASTM C1177/C1177M . Provide boards with square edges as the first ply in two-ply application. Provide 48 inches wide boards, thickness as shown except that board used for liner panels and core plies of shaftwall construction must be the size and thickness recommended by the system manufacturer.

2.1.4 Gypsum Veneer Plaster

ASTM C587. Minimum compressive strength of finish coat plaster must be

SECTION 09 26 00 Page 3

2500 psi . Product must be manufactured specifically for Exterior soffits and ceilings. Finish system shall be a textured acrylic based system with intergal color.

2.1.5 Joint Reinforcement

ASTM C475/C475M, Mesh reinforcing strip or paper tape as recommended by the veneer plaster manufacturer.

2.1.6 Joint Compound

ASTM C475/C475M.

2.1.7 Screws

ASTM C1002or ASTM C954, type appropriate to use.

2.1.8 Nails

ASTM C514, with corrosion-resistant treatment.

2.1.9 Corner Bead, Casing Bead, and Control Joints

ASTM C1047 or ASTM D3678, Corrosion protective-coated steel, vinyl or clear anodized aluminum as recommended by the veneer plaster manufacturer. Provide flanges free of any material that would adversely affect bonding of the plaster.

PART 3 EXECUTION

3.1 STEEL FRAMING

ASTM C754. Space framing at 16 inches on center maximum. Partitions must support applied loads such as cabinets and counters without exceeding the permitted deflection.

3.1.1 Special Framing

Build framing for beams, columns, soffits, and other special items to the sizes, shapes, or forms indicated. Secure rigidly at each intersection with screws.

3.1.2 Ceiling Openings

Provide support members at ceiling openings such as required for access panels, recessed light fixtures, and for air supply or exhaust. Locate support members of not less than 1 1/2 inch main runner channels and suspension wires or straps to provide at least the minimum support specified herein for furring and wallboard attachment. Provide intermediate structural members for attachment or suspension of support members.

3.1.3 Blocking

Provide blocking when mounting equipment. Cut metal or wood blocking to fit in between the framing members. Rigidly anchor blocking to the framing members. Under no circumstances will accessories or other wall mounted equipment be anchored directly to the veneer plaster system.

SECTION 09 26 00 Page 4

3.2 APPLICATION OF GYPSUM BASE

Apply gypsum base and gypsum backing board to framing and furring members in accordance with ASTM C844 and the requirements specified herein. Gypsum wallboard may be used for the base ply in two-ply construction. Provide gypsum base and backing board of maximum practical length, using full length boards for vertical application. Install separate boards in moderate contact without forcing in place. Install boards tight against the framing so as to eliminate any offset in the face plane between adjoining boards. Stagger end joints of adjoining boards. Fit abutting end and edge joints. Cut boards as required to make close joints around openings. Gypsum base may be adhered to gypsum backing board with an adhesive, except where prohibited by fire rating. In multi-layer construction, offset joints between layers. Offset joints on opposite faces of the partition.

3.2.1 Control Joints

Control joints in ceilings and walls must be one piece manufactured products designed for use with a veneer plaster system.

3.2.2 Vapor Retarder

Install foil-backed gypsum base or gypsum backing board with the reflective surface against the framing members. Install polyethylene vapor retarder with joints over framing members, and with joints lapped the full width of the framing members.

3.3 JOINT REINFORCEMENT

Reinforce all interior angles and flat joints prior to application of the veneer plaster. Do not use self-adhering fiberglass mesh tape.

Reinforcement must be a special mesh reinforcing strip embedded in veneer plaster, or paper gypsum wallboard tape embedded in joint compound.

3.3.1 Mesh Reinforcing

Embed the mesh reinforcing strip in veneer plaster, so that embedment material is both under and covering the reinforcement. Allow areas of reinforcement to preset, and leave rough enough for proper bonding of the plaster coat. Reinforcement must be set but not dry, before the application of veneer plaster.

3.4 APPLICATION OF GYPSUM VENEER PLASTER

Apply gypsum veneer plaster in accordance with ASTM C843, and with the manufacturer's approved installation instructions where such instructions are additional to or more restrictive than the requirements of ASTM C843.

Apply plaster as a two-component base coat and finish system. Minimum plaster thickness must be as recommended by the manufacturer, but must in no case be less than 1/16 inch for base coat and 1/32 inch for finish coat of a two-component system.

3.4.1 Mixing

Clean mixer between batches to avoid accelerating the setting time. Do not add other plaster materials to modify the properties of the veneer plaster. When extreme conditions so demand, small quantities of commercial retarder or accelerator may be added to the mixing water to

SECTION 09 26 00 Page 5 adjust setting time. When used, the retarder or accelerator must conform to the veneer plaster manufacturer's recommendations.

3.4.2 Application

Trowel plaster on by hand. Apply with sufficient material and pressure to develop bond and to provide the specified component thickness.

3.4.2.1 Base Coat

Scratch in the base coat tightly, then immediately double back using material from the same batch. Fill all voids and imperfections and level the plaster to a true surface without the application of water. For good bond or adhesion, roughen the final surface for bond by brushing or cross-raking with a fine wire rake. For application of finish coat, set the base coat and partially dry. If the base coat is totally dry, dampen before finish coat application.

3.4.2.2 Finish Coat

Scratch in the finish coat tightly, then immediately double back using material from the same batch. After the plaster has been allowed to set up slightly, lightly trowel the surface without the addition of water, filling all voids and imperfections and eliminating surface irregularities. When the plaster has become firm and prior to set, smooth-trowel the surface using water sparingly. Avoid over troweling.

3.5 CLEANUP AND PATCHING

Remove plaster splashes from adjacent surfaces. Repair defects in the veneer plaster. Plaster surfaces must be smooth, clean, and in condition to receive the finishing materials that will be applied.

-- End of Section --

SECTION 09 26 00 Page 6

3.5 CLEANUP AND PATCHING