We've had the valley gutter on a metal roof patched twice now and each time it's rusty and weeping again within about a year. It's the only spot that keeps failing. Feels like we're throwing money at it, so what's the fix that actually lasts?
A detail that fails on repeat is usually a preparation and detailing problem, not bad luck. Valleys and gutters hold water and debris far longer than open roof, so any patch that goes on over residual rust, dirt or standing damp will let go quickly at the edges. A lasting result means cleaning the channel right back to a sound surface, treating the corrosion properly, and using a liquid-applied system that can be reinforced and dressed continuously into the upstands so there are no open seams for water to track behind. A reinforced coating such as Fibrecoat suits this kind of wet detail well. Given it keeps recurring, let us survey it and specify the detail correctly.
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