Plywood Roof Sheathing Maximum Span

For face grain across supports and spans of 32 and less three spans are assumed and two spans for spans greater than 32.

Plywood roof sheathing maximum span.

Always ensure your work site is compliant with current osha regulations. 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 with a span rating of 16 oc may be applied direct to studs spaced 16 inches on center. Loads will vary with the pitch of the roof.

Span is permitted to be 24 inches on center for floors where 1 1 2 inches of cellular or lightweight concrete is applied over the panels. Most roofs will be sheathed in plywood at least 3 8 inch thick. 1 500 32 46 875 sheets. For sanded plywood panels see table 3.

When the panel strength axis is placed parallel to framing supports the three span condition is used for support spacing up to and including 16 inches on center. A 4 8 sheet of plywood is 32 ft 2. This video may depict some work practices that do not meet current safety standards. Span is permitted to be 24 inches on center where 3 4 inch wood strip flooring is installed at right angles to joist.

Produced by apa the engineered wood association formerly the american plywood association in 1989. Use the two span condition for support spacing greater than 16 inches but no greater than 24 inches on center. A panel marked 32 16 may be used for roof sheathing over supports spaced up to 32 inches o c. Tables 2a through 2c apply to apa rated osb sheathing apa rated osb structural i sheathing and apa rated osb sturd i floor respectively.

Support spacing when the panel is used for subflooring. Panels and lap siding bearing a span rating of 24 oc may be used direct to studs 24 inches on center. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads. For example if your roof is 1 500 ft 2 then it will take 47 sheets of plywood to sheath it.

The second number is the maximum o c. So dividing the area of the roof by 32 will give you the number of sheets needed. The first number is the maximum on center o c support spacing in inches for roof sheathing. The values given in tables 1 and 2 represent the maximum allowable loads for plywood or osb.

Table 1d applies to apa rated plywood structural i sturd i floor. For 1 2 inch panel maximum span shall be 24 inches. Avoid roof complaints with proper framing sheathing and roofing techniques.