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Re: OSB roof and shearwalls wet from these rain

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At 10:21 AM 2/10/1998 -0800, you wrote:
>>Once the board has swollen there's not much to be done.  ALWAYS warn
>>Contractors of the danger of using OSB in, especially, exposed locations,
>>even with so-called exterior grade!!. 
>>
>Thor , It is cheaper in the USA.
>Also the "all products association " APA should have application
>specifications for the OSB.
>Norb Vony , PE
>  

It is cheaper here, too. Apart from the issue of the OSB getting
temporarily wet and drying again in sunny CA, you must consider if it will
have the opportunity to dry. If it gets wet, then the construction
continues and the wet OSB, as well as other wood components, get buried in
the wall, they may have no opportunity to dry. In this climate, the result
is mold, fungus,  even big fat mushrooms that can completely destroy the
material in a very short time. It does not have to be wet enough for
visable evidence such as swelling to occur for this rot to get going.

Before being covered,  wood should be tested for moisture content and if it
is above 19% it violates all building codes in Canada, and I would suspect
(but don't know for sure) there is  comparable code requirement or standard
in the US. 

Maura Gatensby Architect
Vancouver, Canada