Wednesday, December 12, 2007

RE: Uplift on Roof Sheathing - "Pull Through" Resistance

Maybe screws or ring-shank nail? 

Both are pretty common and easy to install, would hold the panel more firmly below the head and I’d guess distributes uplift load to the interior plys..

 

From: Daryl Richardson [mailto:h.d.richardson@shaw.ca]
Sent: Wednesday, December 12, 2007 9:42 AM
To: seaint@seaint.org
Subject: Re: Uplift on Roof Sheathing - "Pull Through" Resistance

 

 

Jerold,

 

        I think washers would be very labor intensive.  My preference would be to use more nails.

 

Regards,

 

H. Daryl Richardson

----- Original Message -----

Sent: Wednesday, December 12, 2007 9:45 AM

Subject: Uplift on Roof Sheathing - "Pull Through" Resistance

 

I would like to ask for feedback on the design / specifying of sheathing for uplift.

 

For uplift on roof sheathing in HIGH WIND areas, is “Pull-through” a concern for the Plywood or OSB?  For Component and Cladding loading at some of the end zones, net uplifts can exceed 100 psf (for example, ASCE 7-02, V=130 mph, Exp. C, Bldg Class. III and Zone 3). 

 

APA provides design data for allowable stresses for spans and thicknesses of material, but for a situation where loading can be concentrated at the nail head “bearing” (kind of a reverse punching shear), are there special precautions I should warrant against?  Are there some type of washer that is sometimes typically used at these locations to help “spread out” the load?   

 

I have tried to find specific info on the Internet, without success, so I was hoping for some assistance from those who work with such high uplift pressures more frequently than I.

 

Thanks

 

Jerold Taylor PE

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