I have used OSB for a roof but I cover it in tar paper and then screw R panel to it. I have some I did 5-6 years ago and its doing fine. I think the tar paper helps to keep moisture that forms (condensation) on the bottom of the metal. I used to just screw the metal to the rafters but then it would sometimes drip on me in the stand. Tar paper is cheap and lasts a long time.


I love my country, but don't trust my government.