Materials
Metal Roof Seam Leak Repair
A mechanical failure mode — corroded gaskets and backed-out fasteners — that causes rust before it ever visibly leaks.
Metal roofing on flat or low-slope sections uses overlapping panels sealed with a gasket at each seam, held down with fasteners. Over years of thermal expansion and contraction, the neoprene or rubber washer under each fastener corrodes and deteriorates, eventually allowing water to work its way in at the fastener point.
Once water gets between the panels, it accumulates and causes rust — visible on the underside of the top panel well before it shows up as an interior leak, which is why we check metal roof seams closely even when there’s no active leak yet.
Proper repair: removing the affected fasteners, using a wire brush or angle grinder to clean rust and old sealant off the panels, installing new pan-head fasteners in fresh locations (not the same corroded holes), and sealing the full seam width — typically 2 inches on each side — with a reinforced silicone sealant and mesh. Done correctly, this stops both the rust and the leak permanently rather than just temporarily.
Not Sure What’s On Your Roof?
We identify the material and repair method during inspection.