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Wet insulation on a cold-water pipe keeps coming back
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What’s a sensible way to tell ordinary condensation from a small leak before putting pipe insulation back on? Moisture spread across the pipe surface seems different from dampness concentrated around a joint, but I’m not sure how dependable that clue is.
Would drying the pipe and watching it when it’s cold, especially during humid weather, be useful? What safe checks can help distinguish sweating from a leak, and when is it better to have a plumber investigate rather than keep drying and monitoring?
2 replies
A wet spot at a joint isn’t conclusive; condensation can collect there too, since fittings have more surface area than straight pipe. After drying both, you could place separate dry tissue strips at the joint and on nearby pipe, then watch as moisture returns. If the joint strip gets wet first, that’s a reason to investigate the connection, not proof of a leak.
I’d be cautious about treating “not using the water” as a leak test by itself. Dry the pipe, then see whether moisture returns while the surface is still cold and the surrounding air is dry; condensation can still form if humid air meets a cold pipe. If moisture keeps returning when the air is dry, or you can’t tell what’s causing it, I’d stop monitoring and have a plumber investigate before putting the insulation back.
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