Exposure Ratings. The grade/trademark stamp
lists the exposure durability classification for plywood.
There are two basic types or ratings: exterior and
interim. The exterior type has a 100-percent waterproof
glue line, and the interior type has a highly
moisture-resistant glue line. However, panels can be
manufactured in three exposure durability
classifications: Exterior, Exposure 1, and Exposure 2.
Panels marked Exterior can be used where there
is continual exposure to weather and moisture. Panels
marked Exposure 1 can withstand moisture during
extended periods, but they should be used only
indoors. Panels marked Exposure 2 can be used in
protected locations. They may be subjected to some
water leakage or high humidity but generally should
be protected from weather.
Most plywood is made with
glue. However, interior panels
intermediate or interior glue.
Hardwood Plywood Grades
may be made with
Hardwood plywood panels are primarily used for
door skins, cabinets, and wall paneling. The
Hardwood Plywood Manufacturers Association has
established a grading system with the following
grades: premium (A), good grade (1), sound grade
(2), utility grade (3), and backing grade (4). For
example, an A-3 grade hardwood plywood would
have a premium face and a utility back. A 1-1 grade
would have a good face and a good back.
Figure 3-40.-Planing and squaring to dimensions.