Central heating leak under concrete floor - best approach

13 Dec 2004
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United Kingdom

My central heating has sprung a leak somewhere as yet unknown. The carpet is very damp (and hot) around the bottom of one of my doorframes, and the plasterwork and skirting woodwork near the site is also showing signs of excessive dampness.

I had a plumber round who did a bit of exploration around the door frame (i.e. chiseled away a hole about 6-8 inches round and deep) but couldn't find either a pipe or a source of a leak. On inspection, it appears that the pipes from the nearest radiator are running in the opposite direction from the damp spot.

As this is a concrete floor (no floorboards to lift) it seems to me that maybe the pipe is leaking somewhere remote from the damp spot, and that the water is seeping along somehow. The concrete floor has a thick blue plastic membrane a couple of inches down so my guess is that the water has found its way along this membrane to a low point, where it comes up through the concrete/carpet.

Does anyone have any ideas of a good approach for finding the source of the leak, other than just randomly digging up the floor? Is it possible to detect copper pipes that may be buried under an inch or two of concrete?

Note that I have no idea where the pipes run as it was all put in before I bought the flat.

Many thanks in advance.
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urmm 2 choices here...................cut the pipework and surface mount it, or quite simply get DIGGING !!!

You can usually find it with a thermal imaging camera.

Otherwise, an infra red thermostat will often indicate the heat source by scanning across the floor.

Copper pipes can be found with a treasure detector about £24 upwards in Maplins.

You might find a damp test meter would help but thats not what I would ever use.

The most common place to leak is the elbow under the rad valve.


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