Whatever You Do—Don't Screw Metal Roofing Into OSB

We can't stress this enough: metal roofing fasteners should never be screwed directly into OSB.

We're currently replacing a roof that was done this way about 16 years ago. The screws? Some are finger-loose. Others have backed right out. The result? Leaks into the attic space. And while these homeowners caught the issue early — before it led to rot or mold — it easily could have been a much bigger, much more expensive problem.

Why does this happen?

Because OSB (Oriented Strand Board) simply doesn't hold fasteners well over time — especially when you've got exposed fasteners like most metal roofs use. Snow loads, freeze/thaw cycles, and temperature shifts all work those screws loose, and once they are, water finds a way in.

The Fix

What we're doing on this project is the proper fix: installing 2x4 horizontal purlins, then reattaching the metal panels using new screws and washers. Now, those fasteners are biting into solid lumber — not flimsy sheeting. That's how it should be done from the start.

Metal roofing screws are designed to go into structural material — 2x4s, 2x6s, etc. — not just OSB. If you install into OSB only, it's not a matter of if you'll have problems, but when. Especially in climates with snow and cold weather.

Want your metal roof to last? Make sure it's fastened right.