Plywood Roof Sheathing Span Rating

The span rating on apa rated sturd i floor underlayment and apa rated siding panels appears as a single number.

Plywood roof sheathing span rating.

Typical size is 4 ft x 8 ft but other sizes may also be produced. 2 4 common performance categories and corresponding span ratings performance category span rating 3 8 24 0 7 16 24 16. All rated siding panels may be applied horizontally direct to studs 16 or 24 inches on center provided horizontal joints are blocked. Panels and lap siding bearing a span rating of 24 oc may be used direct to studs 24 inches on center.

Panels and lap siding with a span rating of 16 oc may be applied direct to studs spaced 16 inches on center. Commonly square edge but may be produced with tongue and groove edges. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads. Allowable uniform load based on deflection of 1 360 of span is 100 pounds per square foot except the span rating of 48 inches on center is based on a total load of 65 pounds per square foot.

Uniform loads psf on apa rated plywood sheathing. Allowable load at maximum span. Uniform loads psf on unsanded span rated plywood panels multi span normal duration of load dry conditions face grain parallel to supports span load face grain across supports span center to center rating governed span center to center of supports inches of supports inches by 12 16 19 2 24 30 32 36 40 48 60 12 16 24 l 360 92 37 21 10 8 3. Multi span normal duration of load dry conditions panels 24 inches or wider span rating b load governed by c strength axis a perpendicular to supports span center to center of supports inches parallel to supports span center to center of supports inches 12 16 19 2 24 30 32 36 40 48 60 12 16 24.

Most roofs will be sheathed in plywood at least 3 8 inch thick. Sheathing panels 3 8 category may be installed perpendicular or parallel to supports spaced a maximum of 16 o c and will support a 30 psf live load without exceeding a deflection limit of 1 180. Apa rated sheathing panels are produced as plywood or oriented strand board osb.