Problem 8.15
Span ratings
Sheathing grades
Unsanded sheathing grade for wall, roof, subflooring, and industrial applications and for engineering design, with proper stresses. Manufactured with intermediate and exterior glue. (from Plywood Design Specification - APA)
Span Ratings appear as two numbers separated by a slash, such as 32/16, 48/24, etc. The left-hand number denotes the maximum recommended spacing of supports when the panel is used for roof sheathing with the long dimension or strength axis of the panel across three or more supports. The righthand number indicates the maximum recommended spacing of supports when the panel is used for subflooring with the long dimension or strength axis of the panel across three or more supports. A panel marked 32/16, for example, may be used for roof sheathing over supports 32 inches on center or for subflooring over supports 16 inches on center. (from Grades and Specifications - APA)
APA rated Sturd-I-Floor
For combination subfloor-underlayment. Provides smooth surface for application of carpet and pad. Possesses high concentrated and impact load resistance during construction and occupancy. Manufactured with intermediate and exterior glue. Touch-sanded. Available with tongue-and-groove edges. (from Plywood Design Specification - APA)
Panels are designed specifically for single-floor (combined subfloor-underlayment) applications under carpet and pad, and are manufactured with Span Ratings of 16, 20, 24, 32 and 48 inches. These, like those for APA Rated Sheathing, are based on application of the panel with the long dimension or strength axis across three or more supports. (from Grades and Specifications - APA)
APA rated 303 siding
Panels are produced with Span Ratings of 16 and 24 inches. Panels and lap siding may be used direct to studs or over nonstructural wall sheathing (Sturd-I-Wall construction), or over nailable panel or lumber sheathing (double-wall construction). Panels and lap siding with a Span Rating of 16 inches may be applied direct to studs spaced 16 inches on center. Panels and lap siding bearing a Span Rating of 24 inches may be used direct to studs 24 inches on center. When used over nailable structural sheathing, the Span Rating of Rated Siding panels refers to the maximum recommended spacing of vertical rows of nails rather than to stud spacing. (from Grades and Specifications - APA)