When should you replace the screws on a metal roof?
Short answer. Replace metal roof screws when their rubber washers are cracked, flattened or missing, when screws have backed out or rusted, or when leaks show up along screw lines. On exposed-fastener roofs this often comes up somewhere in the second decade, sooner on sun-baked slopes, so it pays to check the screws every year or two.
Signs the screws are done
- Washers cracked, brittle or squeezed out from UV and heat, or from being overdriven at installation.
- Screws backed out after years of the panels expanding and contracting.
- Rust streaks running down from the screw heads.
- Leaks or stains in the attic or ceiling below screw lines.
- Stripped holes where a screw spins without tightening.
How replacement is done
- Remove each old screw and check the hole.
- Install a new screw with a new washer, often one size larger in diameter where holes are enlarged or stripped.
- Drive it snug so the washer just compresses; overtightening crushes the washer, and undertightening leaves a gap.
- Reseal or replace trim screws, ridge closures and flashing sealant while you are up there.
Many roofers replace every exposed screw at once rather than chasing individual leaks, because the washers all age together.
Safety and timing
Metal roofs are slippery, especially with morning dew or spring pollen, and panels dent where you step between the supports. Walk only over the framing lines, or hire the job out. Mild weather keeps the panels from being too hot to handle.