Figure 6-6.-Plywood veneer grades.
identified. Figure 6-7 shows typical back-stamps
and edge-marks found on a standard sheet of
plywood. It shows all information needed about
the sheet, except its actual size.
Figure 6-8 shows the stamps found on the
backs of structural and standard sheathing panels.
They vary somewhat from the standard stamps.
repeatedly or otherwise subjected to the weather,
exterior plywood retains its glue bond and
withstands exposure to the elements. Interior
plywood can withstand an occasional wetting but
not permanent exposure to the elements.
Grades
The several grades within each type of
plywood are determined by the grade of the veneer
(N, A, B, C, or D) used for the face and back
of the panel (fig. 6-6). Panel grades are generally
designated by the kind of glue and by the veneer
grade on the back and face. Grading is based on
the number of defects, such as knotholes, pitch
pockets, splits, discolorations, and patches, in
each face of the plywood panel.
Identification Stamps
Stamps are
each sheet of
placed on the edges and back of
plywood so it can be properly
Figure 6-7.-Standard plywood identification symbols.
Figure 6-8.-Structural and standard sheathing identifica-
tion symbols.
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