I mentioned this in the past and I can't remember if you used OSB or plywood under you metal roof but I would not recommend the practice to anyone. We got a down burst 65 to 80 mph wind yesterday afternoon and our neighbors house across the road had their metal roof peal off for the third time in the past 5 years. They used OSB big mistake.
roof sheathing = 5/8" CDX plywood, based on an 11th hour recommendation by my engineer pal down in TX.
