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.

So 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.