I live in the North East, I see a new build house going up down the road, they have installed what looks like 5/8 OSB board roofing material. The joists are 16". I though you needed to install 3/4 for roofing? Would plywood have been better then OSB at least for the roof?
roofing questions
Jan 07, 2006
5 Replies
Depending on the rafter spacing and roof loads, 1/2" is standard for
16" OC rafters. There's one village around here that still requires 3/4" roof sheathing. They're dinosaurs with lots of stupid code provisions. I've never seen 3/4" sheathing on new construction anywhere else. RMost structural panels are "span rated". Given that, conditions specific to site, load, and frame must be considered. TB
3/4" means that one can walk on the roof without that vague feeling of = being asea. =20
I have the 5/8 on my roof (code is really the minimum acceptable) and it = sinks beneath my feet. =20
OSB vs. plywood is 6 of one and half a dozen of the other. It just = depends on how much one is willing to pay for roofing.
--=20 PDQ
OSB used to be a lot cheaper than plywood. Not so much any more. The only places ply wood is used where I live is the edges of the roof. They will install a 2-foot wide piece on the ends where exposed to the elements. The rest is OSB.
Wander about on your roof much? ;) I've seen 300 pound guys on 1/2" ply on 16" centers. They didn't fall through.
Deflection is expected with load. If the sheathing was made up of 2x material it would still deflect. There's the balance (especially important on a roof!) one tries to achieve between structural strength and cost. Adding more weight, and cost, doesn't necessarily make it a better structure.
Exactly.
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