Gypsum Plaster Basecoat Work

plaster, masonry and concrete bases is 16 mm 5/8 in. Total

thickness of plaster for horizontal concrete surfaces is 3 to 10 mm

1/8 to 3/8 in.

c.

Where vertical and horizontal concrete surfaces require more than

16 mm 5/8 in and 10 mm 3/8 in, to produce required lines or

surfaces, [attach metal plaster base for plaster application] [as

indicated].

3.3.2

Gypsum Plaster Basecoat Work

3.3.2.1

Gypsum Two-Coat System

Apply the first coat to cover the base with sufficient material and

pressure to form a good bond on the wall or ceiling base. Before the first

coat has set and without scratching or cracking the surface, apply a second

coat (double back) of the same material proportion as the base coat to the

screeds. Straighten to a true surface without application of water, and

cross rake or scratch to receive the finish coat.

3.3.2.2

Gypsum Three-Coat System

Apply scratch coat 5 to 6 mm 3/16 to 1/4 in thick to cover the base with

sufficient material and pressure to form a good bond on the wall or ceiling

base. Rake or scratch the surface and allow to set firm and hard. Apply

the brown coat to bring the base coat out to the screeds, compact and

straighten to a true surface without the application of water, and cross

rake or scratch to receive the finish coat.

3.3.3

Gypsum Plaster Finish Coats

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NOTE: Do not specify rough textured finishes

bathrooms, kitchens, and other similar type places,

which require a constant cleaning cycle.

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NOTE: There are six gypsum finish coat plasters,

each with a specific function:

Smooth Finishes: Gypsum-lime putty trowel finish

Keene's cement-lime putty trowel finish Prepared

gypsum trowel finish

Float Finishes: Keene's cement-lime sand float

finish Gypsum-sand float finish

Acoustical Plaster Finishes

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Moderately moisten or fog spray base coat of plaster that has become dry

before finish coat is applied. Accelerate plaster, if necessary, to

provide a setting time of not more than 4 hours from the time the plaster

is mixed.

3.3.3.1

Lime-Putty and Gypsum-Gaged Finish Coats

Apply lime-putty gypsum-gaged finish white coat or aggregated white coat

SECTION 09210

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