You got it right. OSB and Plywood perform similarly. There are concerns with
OSB from outside the Structural Board Association and APA, but most of the
concerns have most to do with usage and exposure of OSB. Properly handled
and installed, OSB will be less expensive to use and perform equally well as
comparable grades of Plywood. My only concern is the problem with over
nailing. In five-ply panels, the over nailing problem is minimized as the
loss of one ply generally provides similar results as a 4-ply panel. APA
publishes a standard for allowable over nailing in panels. I don't see the
comparative value with OSB as over nailing tends to crush the edge of the
panel. I would not mind hearing from others on any major concern with OSB
and over nailing.
> -----Original Message-----
> From: Bill Polhemus [mailto:bill(--nospam--at)polhemus.cc]
> Sent: Sunday, April 15, 2001 11:35 PM
> To: Aec-Residential@Polhemus. Cc; SEAINT
> Subject: Q: OSB vs. Plywood
> As some of you may know, we recently moved in to our new home.
> The roof and
> floor decking, as well as the wall sheathing, were OSB.
> I had assumed that OSB had its own tables available, similar to UBC Table
> 23-II-H or Tables 3.1A/B of NDS.
> Since I'm updating my structural notes on the current project I'm working
> on, I decided to acquaint myself with this topic a bit, and went to the
> APA's website and downloaded several of their PDFs on this topic. I also
> checked out the website at the Structural Board Association which
> appears to
> be the trade industry group specific to OSB.
> ToWell, it LOOKS like they have "performance standards" that in a
> way, "compare" the structural capabilities of OSB with plywood,
> and that you
> would still use the same panel grade designation, and the same
> shear values,
> for OSB as for plywood.
> Am I missing something here, or did I get that right?
> William L. Polhemus, Jr., P.E.
> Polhemus Engineering Company
> Katy, Texas
> Phone 281-492-2251
> Fax 281-492-8203
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