condensation on cold water main pipe 1

[mark14]

would be grateful for some advice on this one. Have a 15mm cold main (domestic) entering property on ground floor it runs through a stud partition, there were complaits of wall paper bubbling and severe damp, on inspection found that the double skin of plaster board was saturated and so was the cavity insulation. found cold main (which is insulated) and it was dripping wet. thought at first it was a leak but after futher inspection found it to be condensation,(found pipe in other locations and wetness is uniform arcoss pipe work. I wiped down pipe work and 5 minutes later water is forming again. it seems to be okay from 1st floor upwards( no sign of damp) i can replace the copper pipework with double barrier plastic pipe to solve problem but it would mean hard wood floors coming up, holes in walls, you get the picture and it ain't pretty! any body know any other way?

 

[Latexman]

What kind of insulation is it? Apparently it does not have good vapor barrier properties. The insulation system must prevent water *vapor* from permeating into the cold pipe where it is condensing. Then, it just gets saturated with water and leaks out.

Idea 2: Tear out the existing insulation system. Re-insulate the pipe on 1st floor with a superior vapor barrier system. It has to be perfectly sealed (every seam) from water vapor.

Idea 2: Dehumidify the 1st floor?


Good luck,
Latexman

 

[Latexman]

By the way, when you put the good insulation system on the 1st floor, you may push your condensation problem up to the next floor, so I'd re-insulate the second floor too.

Good luck,
Latexman

 

[mk3223]

try cold temperature insulation material to separate the worm air contact the cold pipe wall. The condensate formed because the cold pipe sweat by contacting the warm air.

 

[thermcool]

The normal rubber based insulation for the piping like the one used in the car radiators may be handy and helpful in this case.

 

[KenRad]

Your best bet is to go with a closed-cell insulation product, like foam rubber.

http://www.armacell.com

As was stated above, there can be no gaps in the insulation joints. If there is any way for the high- dewpoint room air to get to the cold pipe, condensation will result. You have to be meticulous about gluing all joints. I'm guessing that this is not a problem in colder, dryer weather, when the dewpoint is lower than the water temperature. Dehumidification is only an option if you can drop the room dewpoint to less than the cold water temperature.

---KenRad

 

[mark14]

Thanks for all the suggestions, but either way I am going to have to expose all the affeced pipework, Lucky me!!

 

[ApC2Kp]

mark14,
You might avoid ripping up the walls and floors, if the cold water pipe can be warmed to a point where little or no condenstion would occur, maybe 55-60 deg F.
If there is a warm room in basement, where heat is from equipment or hot water boiler, then heat would be 'free'. Run the cold water pipe through the equipment room for 30 to 40 feet. You will have to judge whether the condensation will be a nuisance in the equipment room.