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Is 1/2" plywood sufficient for a standing seam roof...a 1.75" snap lock? In other words, will it offer the clips enough wood to screw into if 18" on center?
I hope so because I have 50 sheets of 1/2" stacked up at my job site. However, if 5/8" is unanimously recommended, I will try to sell my 1/2" and replace it with 5/8".
My area's wind Exposure is “B” with a 115 mph gust velocity wind speed. We get a fair bit of wind but rarely anything serious. My place has a decent wind break with trees as well.
1/2" or even nominal 1/2" is pretty standard as far as decking that manufacturers have done their uplift testing on. Ultimately, I'd refer you back to your metal roofing manufacturer and suggest you ask them this question but I think you will be okay.
Thanks, Todd. I did ask the metal manufacturer. They didn't provide any engineering specs but said 1/2" was often used in their area. That said, they did tell me their local code just changed which requires builders in that area to use 5/8". However, they are 3 hours from me and in a completely different environment. They are in the mountains with severe winter weather.
Normally a manufacturer of metal roofing will be able to reference what thickness of decking they used in their uplift tests, so that confuses me. Are you in an area where a building code is enforced? If so, I would suggest contacting the building inspection department and asking what the decking requirement is. This question is very much one of local code requirements plus the requirements of the product manufacturer.
Yes, code is enforced here, though it is pretty lax. My plans were approved with the 1/2" plywood but that doesn't mean much here. Everyone uses 1/2" or 7/16". I'm going to try to pin the roofing manufacturer down and see just what they tested for.
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