The tables do not apply directly to plywood having a single span.
Plywood roof sheathing maximum span.
The span rating on sheathing span panels appears as two numbers separated by a slash e g 32 16 or 48 24.
Span is permitted to be 24 inches on center where 3 4 inch wood strip flooring is installed at right angles to joist.
This video may depict some work practices that do not meet current safety standards.
For face grain parallel to supports tables are based on three spans for spans of 16 and less and two spans for 24.
Always ensure your work site is compliant with current osha regulations.
Use the two span condition for support spacing greater than 16 inches but no greater than 24 inches on center.
For 1 2 inch panel maximum span shall be 24 inches.
Panels and lap siding with a span rating of 16 oc may be applied direct to studs spaced 16 inches on center.
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.
The second number is the maximum o c.
All rated siding panels may be applied horizontally direct to studs 16 or 24 inches on center provided horizontal joints are blocked.
Avoid roof complaints with proper framing sheathing and roofing techniques.
For face grain across supports and spans of 32 and less three spans are assumed and two spans for spans greater than 32.
Loads will vary with the pitch of the roof.
A 4 8 sheet of plywood is 32 ft 2.
A panel marked 32 16 may be used for roof sheathing over supports spaced up to 32 inches o c.
Panels and lap siding bearing a span rating of 24 oc may be used direct to studs 24 inches on center.
So dividing the area of the roof by 32 will give you the number of sheets needed.
For sanded plywood panels see table 3.
The first number is the maximum on center o c support spacing in inches for roof sheathing.
That will suffice on a roof with rafters set 16 inches apart with minimal roof loads.
Table 1d applies to apa rated plywood structural i sturd i floor.
For example if your roof is 1 500 ft 2 then it will take 47 sheets of plywood to sheath it.
The values given in tables 1 and 2 represent the maximum allowable loads for plywood or osb.
1 500 32 46 875 sheets.
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.
