Figure 6-5.-Grain direction in a sheet of plywood.
Dry from the mill, plywood is never “green.”
From ovendry to complete moisture saturation,
Figure 6-3.-Laminated and sawed lumber or plywood
a plywood panel swells across or along the grain
beam.
only about 0.2 of 1 percent and considerably less
with normal exposures.
There is probably no building material as
versatile as plywood. It is used for concrete forms,
wall and roof sheathing, flooring, box beams,
soffits, stressed-skin panels, paneling, partitions,
doors, furniture, shelving, cabinets, crates, signs,
and many other purposes.
Sizes
Plywood is generally available in panel widths
of 36, 48, and 60 in. and in panel lengths ranging
from 60 to 144 in. in 12-in. increments. Other sizes
are also available on special order. Panels 48 in.
wide by 96 in. long (4 by 8 ft), and 48 in. wide
by 120 in. long (4 by 10 ft), are most commonly
available. The 4 by 8 ft and larger sizes simplify
construction, saving time and labor.
Nominal thicknesses of sanded panels range
from 1/4 to 1 1/4 in. or greater, generally in
1/8-in. increments. Unsanded panels are available
in nominal thicknesses of 5/16 to 1 1/4 in. or
greater, in increments of 1/8 in. for thicknesses
over 3/8 in. Under 3/8 in., thicknesses are in
1/16-in, increments.
Types
Plywood is classified by type as INTERIOR
or EXTERIOR. Made of high-quality veneers and
more durable adhesives, exterior plywood is
better than interior at withstanding exposure to
Figure 6-4.-Scarf joints.
the elements. Even when wetted and dried
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