12 inches wide shall be bridged with furring channels spaced 300 mm 12
inches on centers. Openings 300 mm 12 inches wide and less do not need to
be bridged. Lath shall extend 75 mm 3 inches beyond the edges of opening.
Lath shall be securely fastened by nailing or tying. Lath shall be
securely fastened with nails, screws or wire ties.
3.7.5
Installation of Gypsum Lath
Gypsum lath shall be installed in accordance with ASTM C 841. Spring clips
or floating-wall-type attachment may be used in lieu of nails. Lath shall
be cut and fitted to allow slight clearance around openings. Horizontal or
vertical joints are not acceptable at corners of openings. End joints
shall be made over supports. Where clip systems are approved, end joints
shall be staggered in alternate courses. End joints shall not coincide
with ceiling joints, and shall not occur in the same course on opposite
side of support. Internal corners shall be reinforced with cornerites, and
external corners shall be reinforced with corner beads. Internal corners
of unrestrained ceilings shall not be reinforced with cornerites.
3.8
INSTALLATION OF GYPSUM BASE TO RECEIVE VENEER PLASTER
Gypsum base shall be installed in accordance with ASTM C 844. Base shall
be cut and fitted to allow slight clearance around openings. Horizontal or
vertical joints are not acceptable at corners of openings. End joints
shall be made over supports. Where clip systems are approved, end joints
shall be staggered in alternate courses. End joints shall not coincide
with ceiling joints, and shall not occur in the same course on opposite
side of support. Internal corners shall be reinforced with cornerites, and
external corners shall be reinforced with corner beads. Internal corners
of unrestrained ceilings shall not be reinforced with cornerites.
3.9
OPENINGS
Reinforcement shall be provided at corners of openings in plastered areas
extending 300 mm 12 inches or more in any dimension by securing striplath
diagonally at corners. Striplath shall be at least 150 mm 6 inches wide by
400 mm 16 inches long. Shorter lengths shall be used to preclude lapping
striplath. Striplath shall be secured to lathing without extending
fastenings into or around supporting members. Where plaster is applied
directly to concrete or masonry surfaces, striplath shall be secured to the
concrete or masonry.
3.9.1
Steel Frames
Steel frames shall be securely attached through built-in anchors to the
nearest stud on each side of opening with tie wire, bolts, screws, or
welding or bracing where bracing is specified. Steel frames shall be
grouted solid with plaster grout and a groove shall be formed within the
frame returns to receive lath and plaster.
3.9.2
Wood Frames
Wood frames shall be securely attached to the nearest stud in frame
partitions and to wood bucks built into the solid partition. Sizes shall
be as indicated for each type and size of wall or partition.
3.9.3
Ceiling Openings
Framing shall be provided for ceiling openings and supplemental supporting
SECTION 09200A
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