How can I attach corrugated roofing to osb to ensure no water will get under the metal? I was going to just put a small dab of caulk over the nails, but I'd like something more permanent and reliable. I was thinking about a sandwich of neoprene washers, but I am not sure it would be water tight. I'll also be using my framing nailer, so it might be hard to shoot a nail right through a small washer. What about marking nailing points on both sides of the roof and putting the caulk between the metal and osb? Any ideas? Thanks.