What nails or fasteners do you use for a metal roof?
Common fastener types
- Wood screws with EPDM washers: for panels over wood decking or purlins. A sharp point and coarse thread bite into the wood, and the bonded washer seals the hole.
- Self-drilling screws: drill their own hole in steel framing, used where panels attach to steel purlins.
- Stitch or lap screws: short screws that join metal to metal at side laps and trim.
- Pancake head screws: low-profile screws that hold standing seam clips under the panels.
- Rivets: used on trim, flashings and Z-closures where a screw would be visible or would hit a panel.
- Cap nails: only for fastening the underlayment beneath the metal.
Length and placement
Screw length must reach solidly into the wood, as the manufacturer specifies for the deck or purlin. Placement, in the flat of the panel or on the rib, also follows the manufacturer, since each profile is tested one way. Screws are driven straight and snug so the washer compresses slightly without splitting.
Match the metals
Fasteners should be coated or made from a metal compatible with the roof. Aluminum and copper roofs need stainless or matching fasteners, because mixing metals causes corrosion. Color-matched heads keep the roof looking clean.
Why plain roofing nails do not work
Every day, panels expand in the sun and shrink at night. That movement slowly works smooth nails loose, the washer lifts, and the hole leaks. Screws hold against that movement far better.
Maintenance
On exposed fastener roofs, check screws and washers every few years and after strong storms.
See metal roofing in Georgia and common causes of roof leaks.