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RE: OSB vs Plywood

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RE:  OSB vs. plywood

If the contractor is using a nail gun, over-driving should not be your only
concern.  Commonly used pneumatic nails have only 73% of the shear
resistance of "common" nails.  If they use staples instead of nails, the
orientation of the staple is important also.  For more information you can
visit the Structural Engineering Consultants of British Columbia web site at
http://www.dwg.com/vseg/secbc/Woodframe-Committee/Nailsta.html.  I would
also suggest getting a copy  of National Evalluation Report NER-272, it
gives information on several tested brands of nails and staples.

Roger Davis
SDS Architects, Inc
205 N. Dewey Street
Eau Claire, WI 54703
715-832-1605
rdavis(--nospam--at)sdsarch.com




I suggest contacting APA(American Plywood Assoc.) their web address is:
www.apawood.org.  Or call the local technical rep in your area.
Most plywood/OSB or wood structural panel roofs are nailed with nail guns
and nailing plywood or OSB is not a problem except when the gun drives the
nail head below the surface of the plywood.  Nail heads
should be driven flush with the plywood surface.
I believe, the moisture problem occured initially when OSB was first
introduced.  The problem was the panels would swell and expand causing the
sheets to buckle.  This problem has been solved.  The glue formulation was
changed to reduce or mitigate this problem.  APA can better answer this
question.
Plywood can also buckle & delaminate when exposed to weather.  Plywood/OSB
can buckle when the 1/8-inch gap between sheets is not maintained.
Expansion due to thermal conditions can cause the panels to buckle.
Carpenters like to butt the joints tight and this can cause problems.
Regards,
Tom Jakaby, SE
Jakaby Engineering
San Jose, CA