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Re: [SEAOC] Re: Substitution of OSB for plywood sheathing

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>In a message dated 96-03-07 13:42:54 EST, you write:
>
>>After evaluating around a hundred or so homes with OSB sheathing whos roofs
>>failed after hurricane Andrew, I would not consider using it as roof
>>sheathing. Wall sheathing mabey, but never for a roof.
>
>Why, John?
>
>Did it *all* fail? Or just certain types of installations or grades? Was it
>from a controlled manufacturing process? There are a bunch of questions to
>answer before sweeping generalizations are made. 
>
>Mark Deardorff, SE
>...
>Mark, 

My firm specializes in investigation of failures of structures and
components of structures, and over 2000 investigations have concerned single
faimly homes that were damaged in hurricanes Hugo, Andrew, Erin and Opal,
with most of them being in Andrew since my office is in Miami.

We found that OSB did not preform well when wet, to the point that the South
Floirda Building Code has banned its use as roof sheating.

I made a similar recommendation after reviewing damage in South Carolina in
hurricane Hugo for both NSPE and the Army Corps of Engineers, Charleston
District.

No, it did not *all* fail, but most did when wet. Additionally, since the
magnitude of hurricane Andrew's damage precluded quick repairs in many
thousands of homes, we were able to obsrve the performance of OSB board and
plywood over a long period of time. The plywood held together for months,
and the OSB fell apart.

I consider my level of experience with the product sufficent to provide my
fellow engineers with an opinoin that includes a "sweeping generalization".

I leave it to them to judge for themselves.

Kind regards, 

John Pepper
The Pepper Engineering Group, Inc.
20895 East Dixie Highway
Aventura, FL 33180

<A HREF="mailto:pepper(--nospam--at)netrunner.net">

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