Why are my pipes wet?

[RegB]

We've just removed some kitchen cabinets to expose a 22mm cold water pipe behind. They're all insulated with the usual foam tubing or lagging strips on some bends. The weird thing is that when the insulation is removed, the pipe is wet. Not just here and there but all along its length (about 3m), including a 2 metre vertical section. The lagging strips (horsehair or something) are actually wet to the touch. There's also mould starting on the walls. I can't find any obvious leaks so I'm baffled as to what's causing this dampness. Condensation is an an obvious possibility but I thought the insulation was supposed to prevent that. Does anyone have any ideas?

 

[terryplumb]

Condensation ,and useless insulation.

 

[KenGMac]

RegB, good evening.

The horse hair lagging is seriously flawed in that the insulation is porous and over time with a cols pipe in a warm moist kitchen especially in winter, condensation is a probability,

To prevent a re-occurrence, use the foam insulation, but make sure that the bends, sometimes considered to be the difficult bit is covered with the foam a 45 degree junction at this area works well.

 

[dilalio]

Wipe it off and if it appears again in beads with no obvious upstream trace, it will be condensation, formed by water in the pipe, being at a lower temp than the climate in which the pipe travels through.

 

[RegB]

Thanks very much for those replies guys. I guess it's just back to the drawing board and redo the insulation thoroughly in the ways you suggest. I'll get the stuff tomorrow. Thanks very much again.

 

[KenGMac]

To "Guild the Lilley" get a small roll of metallic foil adhesive tape, and wrap this tape around all / any joints.

If you think about it, the mains water is coming at [about?] 7 degrees, into a warm, very humid Kitchen with a temperature of 18 / 20 degrees and a humidity of 60% RH [as a guess]