specs

Section 09220
Page 4
1. Space hangers so that each hanger supports a maximum area of 16 sq. ft. Wrap or saddle-tie hangers
around the runner channel to prevent twisting.
a. Under steel construction, wrap hangers around or clip or bolt hangers to a structural steel member
(not under steel deck).
b. Under bar joists, suspend hangers from top chord or from bottom chord at panel points only.
c. Under ductwork, employ trapeze system of hangers to support ceiling. Do not suspend hangers
from ducts, piping, or conduit.
2. Erect runner channels on 4’ centers or closer and locate a channel within 4” of each parallel wall. If
runner channel spans between hangers are more than 4 ft. but less than 5 ft., use 1.12 lb. 1-1/2” runner
channels. If spans between hangers are 5’ or more, used boxed 1-1/2” channels, 2” channels, or heavier as
required.
3. Erect furring channels at right angles to runner channels with joints lapped and made at hangers and
crossings only. Provide a channel next to each wall. Space ¾” furring channels on 13-1/2” centers.
Saddle-tie channels to runners with two strands of wire at each crossing.
4. Brace vertical furring channels with horizontal channels on 4’ centers where possible. Provide additional
bracing and cross-bracing to make all furring rigid and secure.
5. No part of the suspended grillage (main runners and cross furring) shall be permitted to come in contact
with abutting masonry walls and partitions.
3.02 MIXING PLASTER
A. General:
1. Except where hand mixing of small batches is approved by the Architect, mechanical mixers of an
approved type shall be used for the mixing of plaster.
2. Frozen, caked, or lumped materials shall not be used.
3. Mechanical mixers, mixing boxes, and tools shall be cleaned after mixing each batch and shall be kept free
of plaster from previous mixes.
4. Plaster shall be thoroughly mixed with the proper amount of water until uniform in color and consistency.
5. Retempering will not be permitted, and plaster which has begun to stiffen shall be discarded.
6. Plaster for scratch coats over metal lath shall be fibered.
7. Mix and proportion cement plaster in accordance with PCA Plaster (Stucco) Manual and in accordance
with manufacturer’s instructions.
8. Do not use frozen, caked, or lumpy materials. Clean mixer or mixing boxes of set or hardened materials
before materials for a new batch are loaded. Mix each batch separately. Thoroughly dry mix materials
before adding water.
9. Mix only as much plaster as can be used prior to initial set.
10. Mix materials dry, to uniform color and consistency, before adding water.
11. Protect mixtures from frost, contamination, and evaporation.
B. Portland Cement Plaster Proportions:
1. Scratch Coat (by volume) - 1 part Portland Cement, 3 parts sand, and 1/4 part lime putty.
2. Brown Coat (by volume) - 1 part Portland Cement, 3 parts sand, and 1/4 part lime putty.
3. Finish Coat – Apply finish coat with a "sand finish".Mix in accordance with
manufacturer's recommendations.
3.03 APPLICATION OF PLASTER
A. General:
1. Do no plastering until temperature of 50 degrees, is rising, and is expected to stay 50 degrees until plaster
is cured. Provide heat to avoid freezing to plaster work.
2. The thickness of the plaster, from the face of the plaster base to the finished brown coat surface, shall be
not less than 3/4", and as shown on drawings.
3. Protect finished work surfaces over which work is to be performed.
4. Staining of concrete surfaces caused by lack of proper precautions shall be removed.
5. Protect existing work and equipment of others.
6. Examine surfaces to be plastered and report to the superintendent surfaces that are not suitable for
plastering. Plastering of a surface will be construed as acceptance of the substrate and defects will be
repaired at the Contractor's expense.
NAPA CENTURY CENTER XD 12
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