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April 21, 2026 / Commercial Metal Roof Coatings

Why Metal Roofs Leak at the Screws (and How to Fix It)

Loose fasteners and dried out washers cause most metal roof leaks. Here is why it happens and how a coating system fixes it without replacing panels.

Thermal movement works screws loose

Metal expands when it heats up and contracts when it cools. On a sunny day, a metal roof can go from cold in the morning to very hot by afternoon, then cool again overnight. Every cycle pulls on the screws that hold the panels down.

Over years, that movement enlarges the screw holes and backs fasteners out. In the Mountain West, where temperatures can swing widely between day and night, this happens faster.

The washers give out

Each exposed fastener has a rubber or neoprene washer under the head that seals the hole. Sun and weather dry those washers out until they crack and shrink. Once they do, water runs straight down the screw into the building.

Why re-screwing alone is not enough

Replacing loose screws with larger ones helps, but it does not address the thousands of other fasteners that are aging at the same rate, or the seams and laps that are opening up. It becomes a cycle of chasing leaks.

How a coating system fixes it

A metal roof coating system starts by replacing or tightening failed fasteners, then sealing every fastener head and reinforcing seams and laps. An elastomeric coating is then applied over the entire roof, covering the fasteners and seams in one continuous membrane that flexes as the metal moves.

Instead of thousands of individual leak points, the roof has one seamless surface.

Catch it before rust spreads

Water that gets in at the screws also starts rust around the holes. The sooner the roof is sealed, the more panels stay coatable instead of needing replacement.

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