[slowzuki]

I'll say I went with the no OSB with the metal right onto the purlins. If I had to do it over I'd put the OSB down only because we live in the house and the stiffness of the stressed skin of OSB really tightens up a house to cut down on creaks.

The other think I would change is I would not use the full length sheets. We had the steel company cut the sheets to match our roof.

Now when the sun comes out and goes away, the top and bottom fasteners on the building get a heck of a workout and its noisy inside. If we had used three rows of 8 ft sheets it would have been much less movement. Also, we had some ice damage to a vent pipe (slab of ice came down the roof and ripped the steel as it took the vent pipe down hill) and depending on the location in the sheet, it can be hard to repair. If I could have just removed and replaced a sheet I would have been happier.