How do you patch a hole in a metal roof?
Short answer. Patch a metal roof hole based on its size: an empty screw hole gets a slightly larger gasketed screw or a dab of compatible sealant, a small hole or crack gets a cleaned surface and a sealant-backed patch, and a larger hole gets a piece of matching metal cut a few inches bigger than the damage, bedded in sealant or butyl tape and fastened around the edge with stitch screws or sealed rivets. Clean, dry metal and compatible materials are what make a patch last.
Prep, whatever the size
- Work on a dry, mild day from a safe position; metal is slick when wet or dusty.
- Wire brush any rust back to clean metal, then clean the area with a cleaner the panel maker approves.
- Figure out what made the hole: old fasteners, a dropped tool, hail, a fallen limb, or rust from debris sitting on the panel.
By size
- Empty or stripped screw holes: fill with the next size up gasketed screw into solid framing, or seal with a compatible sealant if no screw belongs there.
- Pinholes and short cracks: a butyl or sealant-backed repair patch that overlaps the damage well on every side, pressed down firmly.
- Holes larger than a coin: cut a patch from the same metal and finish, a few inches larger than the hole on all sides, round its corners, bed it in butyl tape or sealant, and fasten the perimeter with stitch screws or sealed rivets. Seal the uphill edge carefully, since water hits it first.
- Rusted-through areas or long tears: replacing the panel is usually better than patching.
What to avoid
- Roofing tar or asphalt cement, which cracks and does not suit most panel finishes.
- Patches of a different metal, which can corrode the panel.
- Silicone over rust or dirt, which peels away.
- Patching only the visible hole when hail or a limb also damaged nearby seams and fasteners.
If the holes came from hail or a falling limb, photograph them before patching, since storm damage may be covered depending on your policy. See metal roofing in Georgia and common roof leak causes.