Struc 1 plywood?

[vegask]

Was calling around the other day and found a lumber yard that could get me 4x10 sheets of 15/32" Fir. She stated it was "struc 1" which I assume means structural grade one or something. Anyone familiar with this and would it be ok to use for my walls? Planning on buying 4 sheets, outer wall and inner skeleton style build.

[tony.latham]

I'm not familiar with the term, "struct 1" plywood. I suspect it is CDX which may be great for sheathing a house but too many voids for teardrop building in my opinion.

I think you'll find a consensus here that 15/32" plywood is too thick (and heavy) for the sheathing parts of a sandwiched wall. I like 1/4" plywood subflooring* for the inside/outside and 3/4" AC plywood for the core of the wall. Get on the phone and ask around who has 1/4" plywood subflooring and go look at it. (Look for voids on the edges) The stuff I get here is higher in quality than 1/4" AC plywood and a bit cheaper.



Tony

* The stuff is stamped "for moist environments" and you can throw a scap in a bucket of water and it won't delaminate.

[MtnDon]

struc 1 is meant for sheathing a building wall to give structural strength. It is not pretty; meant to be covered. Many knots showing, some with voids. Much like CDX

[vegask]

Ok, back to the drawing board. If I were to find 1/4" AC 4x10 and use that for the exterior face, 3/4 AC 4x10 for the core, then 1/8 baltic birch for the interior, that would make a pretty decent wall correct?

[tony.latham]

Ok, back to the drawing board. If I were to find 1/4" AC 4x10 and use that for the exterior face, 3/4 AC 4x10 for the core, then 1/8 baltic birch for the interior, that would make a pretty decent wall correct?

Yep. That'll work just fine.

I haven't tried to order 10' long plywood here in this one-lumberyard town. What I did on my last build was spline join two pieces of 3/4" AC plywood and then cover those joints with the 1/4" subfloor. And if i have to build again, that's the way I'll do it. Spline joining 3/4" plywood with a router is easy and as long as you've got good plywood glued across the joint, it's strong.



Tony