It's 3"iso 3/4 air space 1/2' osb screwed to metal deck dryin with I&W .Now I'm thinkin it will eazy nailin threw the osb but also ifin the wind was to lift the slate it could pull out the copper nails just as eazy what do you think?
( real slater plezzs dont yell at me :laugh: )>>>
The OSB wood not be my preferred choice but its what I got .I am thinking I'll try my own lift test when get to the end of the project if there is material left over.>>>
Slate doesn't NEED underlayment, but it is a good idea to install it anyway. If a slate breaks as they do occasionally, they are easy to repair and the underlayment will keep things dry until that is done. At least it is easy to replace them! A solid decking will last longer thatn the OSB's and plywoods of the world. It will hold the nails better too.>>>
Do they make copper toggle bolts? That might be stronger then nails. :laugh:>>>
I'm no fan of osb, I always buy plywood. But I have done a little comparative research and like I said, the nail resistance is the same, FNRFR's example is in essence a stress (SIP) panel over a metal deck, so impact strength wouldn't be an issue. The only way the osb would ever become unsuitable for the slate would be if it ever got wet. We know that would never happen because from what I hear, slate don't even need underlayment.>>>
You tell him Frank!>>>
Ring shank copper nails are much weaker than smooth. Not to mention, an OSB deck is completely unsuitable for a slate roof. Might as well use shingles and the life would be about the same.>>>
The nail resistance between the two is about the same. I'd use ringshank copper just the same. Where you lose using osb is impact resistance (might not be an issue with your specs)and the speed of degradation if it ever gets wet.>>>