General Construction Specifications
SECTION 09220
PORTLAND CEMENT PLASTER
PART 1 - GENERAL
1.01 SECTION INCLUDES
A. Metal furring and lathing.
B. Portland cement plaster system.
1.02 PRODUCTS INSTALLED BUT NOT FURNISHED UNDER THIS SECTION
A. Section 08305 - Access Doors: Metal access panels integral with Portland cement plaster.
1.03 RELATED SECTIONS
A. Section 09307 - Wall Tile: Wall substrate surface.
B. Section 06112 - Framing and Sheathing: Wood studs.
C. Section 07900 - Joint Sealers.
D. Section 08305 - Access Doors: Access panels.
1.04 REFERENCES
A. ASTM C91 - Masonry Cement.
B. ASTM C150 - Portland Cement.
C. ASTM C206 - Finishing Hydrated Lime.
D. ASTM C207 - Hydrated Lime for Masonry Purposes.
E. ASTM C631 - Bonding Compounds for Interior Plastering.
F. ASTM C926 - Application of Portland Cement Based Plaster.
G. ASTM E119 - Methods for Fire Tests of Building Construction and Materials.
H. NTMA - National Tile and Marble Association.
1.05 SYSTEM DESCRIPTION
A. Install Portland Cement Plaster scratch and leveling coats behind ceramic tile work.
1.06 SUBMITTALS
A. Submit under provisions of Section 01300.
B. Product Data: Provide data on plaster materials, characteristics and limitations of products specified.
1.07 QUALITY ASSURANCE
A. Perform Work in accordance with ASTM C926.
1.08 QUALIFICATIONS
A. Applicator: Company specializing in performing the work of this section with minimum five years experience.
1.09 ENVIRONMENTAL REQUIREMENTS
A. Do not apply plaster when substrate or ambient air temperature is less than 50 degrees F (10 degrees C) nor more than 80 degrees F (27 degrees C).
B. Maintain minimum ambient temperature of 50 degrees F (10 degrees C) during installation of plaster and until cured.
PART 2 - PRODUCTS
2.01 MANUFACTURERS
A. United States Gypsum Company.
B. Thoro.
C. Substitutions: Under provisions of Section 01600.
2.02 PLASTER BASE MATERIALS
A. Premixed Base Coat:
B. Water: Clean, fresh, potable and free of mineral or organic matter which can affect plaster.
C. Bonding Agent: ASTM C631; type recommended for bonding plaster to concrete masonry surfaces.
2.03 CEMENT PLASTER MIXES
A. Mix and proportion cement plaster in accordance with manufacturer's instructions.
B. Mix only as much plaster as can be used prior to initial set.
C. Mix materials dry, to uniform color and consistency, before adding water.
D. Protect mixtures from freezing, frost, contamination, and evaporation.
E. Do not retemper mixes after initial set has occurred.
PART 3 - EXECUTION
3.01 EXAMINATION
A. Verify surfaces and site conditions under provisions of Section 01039.
B. Masonry: Verify joints are cut flush and surface is ready to receive work of this Section. Verify no bituminous or water repellent coatings exist on masonry surface.
C. Concrete: Verify surfaces are flat, honeycomb is filled flush, and surface is ready to receive work of this Section. Verify no bituminous, water repellent, or form release agents exist on concrete surface that are detrimental to plaster.
3.02 PREPARATION
A. Dampen masonry surfaces to reduce excessive suction.
B. Clean concrete surfaces of foreign matter. Clean surfaces using acid solutions, solvents, or detergents. Wash surfaces with clean water.
C. Roughen smooth concrete surfaces and apply bonding agent. Apply in accordance with manufacturer's instructions.
3.03 PLASTERING
A. Apply plaster in accordance with manufacturer's instructions.
B. Apply scratch coat to a nominal thickness of 3/8 inch and a finish coat to a nominal thickness of 1/8 inch over masonry surfaces.
C. After curing, dampen base coat prior to applying finish coat.
D. Apply finish coat to a smooth and consistent finish.
E. Avoid excessive working of surface. Delay troweling as long as possible to avoid drawing excess fines to surface.
3.04 TOLERANCES
A. Maximum Variation from True Flatness: 1/8 inch in 10 feet.
END OF SECTION
