I have minor sagging of my roof plywood, 3/8" thick, placed on trusses 24" apart. Is there an amount of sag that is technically okay? I could not find anything on the APA website. I am not worried about cosmetic appearance of the sagging, but wondering what my limits are for structural integrity.
Wood – How much sag on a roof is acceptable
plywoodroofroofing
Best Answer
Courtesy of @lsiunsuex in chat: http://www.tecotested.com/techtips/pdf/tt_plywooddesigncapacities
Max Live Load Deflection = span/240, Max Total Deflection = span/180.
So for a 24 inch span, the deflection should be < ~1/8 of an inch. (2.1333 sixteenths)