Wood structural panels that are used for wall sheathing are permitted to be installed with the strength axis either perpendicular or parallel to the studs. Panels rated for wall spans, such as Wall-16, must be installed over studs spaced no farther apart than the span rating. When panels rated for roof spans are used for wall sheathing, the maximum stud spacing is 16 inches for panels with span ratings of 16 and 20 inches, and 24 inches for 24 inch and greater span ratings. For example, a panel with a 20/0 span rating could be applied as wall sheathing when studs are spaced at 12 or 16 inches, but not 24 inches.
Building codes often require that wall sheathing be at least 1/2 inch thick when stucco is to be applied (unless the lathe is fastened directly to the wall studs). Sheathing rated as Structural 1 has greater cross-panel load carrying capacity and is ideal in shear wall and diaphragm applications.
To prevent problems associated with expansion of panels due to an increase in moisture content, wall sheathing should be installed with 1/8-inch gaps at panel ends and edges and around window and door openings, unless specific spacing recommendations are provided by the panel manufacturer.
Panels identified with an Exposure 1 bond classification are not intended for permanent exposure to the weather and need to be covered by an exterior wall covering complying with the applicable code.
Figure 1
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