AskCodeMan

Hi Jerry,
My question concerns repairing rotted structural siding specifically T1-11 over wood framed walls.
Does the building code or the APA have specifications for replacing damaged structural sheathing? Can you zip off the bottom 2 feet and put in a piece?
Will doing so affect the structural integrity of the wall?

I believe with roof sheathing your allowed half sheet pieces but no smaller

David

David,

Both the code and APA E30 specify, when used on roofs, that the design rating are only applicable when (see note b):
- (b) Applies to APA RATED SHEATHING and APA RATED STURD-I-FLOOR panels 24 inches or wider applied over two or more spans.

When used for roofs, and when smaller pieces are used, the contractor needs to either: a) have an engineer sign off on the non-compliant installation; b) replace the smaller pieces so the installation complies.

For APA Rated structural panel wall sheathing and APA Rate Siding panels, none of the charts I have found specify anything for minimum size of panels, which may indicate that only full panels are permitted when the charts are used. It may also indicate that tiny 1 inch wide pieces installed over one span and only two supports may be used ... however, that seems highly unlikely. The solution, then, it for the contractor to either: a) provide documentation from APA which specifies a minimum acceptable width and the number of spans and supports; b) have an engineer sign off on the complete siding installation.

Would it be reasonable to presume that the minimum acceptable wall sheathing and siding panel size might also be 24 inches width and over two spans on three supports? Maybe, but I have not found anything which says that, so ... back to the APA or engineer options.