1/4″ plywood wall sheathing instead of 7/16 OSB?
Hi. I have a bunch of 1/4″ plywood available and thought: why not use it for exterior wall sheathing instead of my original plan of 7/16 OSB?
I am in zone 4a.
I will be covering it with 2″ foam, housewrap, 1x verticals for rain screen, and lap siding.
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All structural sheathing panels have an APA rating: https://www.apawood.org/Data/Sites/1/documents/product-support/rated-sheathing-datasheet.pdf.
I suppose that even a 1/4-inch plywood panel has shear contribution but note that the APA referenced above has a table that STARTS at 3/3-inch thickness.
The first place to start is y0ur building code. Ours wouldn't allow 1/4" as sheathing.
On a practical level 1/4" yields several difficulties.
- I'm not sure an air-nailer will fasten it to the studs without overdriving,
- The resulting sheathing, even with 16"0c backing, will be quite wavy. That's a problem in particular if you intend to tape the seams.
- You can't nail trim or anything else to it and expect it to stay put.