Damp Patch on External Wall

[diynoob]

Hi,

This section of the wall always seems to look damp. Any idea what it is or what I should do?

It hasnt rained at all today when I took the pictures.

Thanks

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• diynoob
• 7 Mar 2015
• 1

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• diynoob
• 7 Mar 2015
• 1

 

[HERTS P&D]

What's on the inside of that wall? Radiator?

Andy

 

[Burnerman]

It looks like its damp both above and below DPC.....if thats the DPC just below that junction box.
Is the wall actually damp, or just coloured somehow? No moss is visible that I can see.
John

 

[diynoob]

Hi,

The kitchen is on the other side of the wall so yes there is a radiator, sink, dishwasher etc. But note the height difference. The window sills in picture 1 are waist height when you stand in the kitchen. So the damp patch is below the floor and the floor is concrete.

Also note in picture 2 the black bobbly stuff. Is that a damp membrane?

Thanks

 

[diynoob]

Burnerman, not sure where the DPC is but I think its the black line 3 bricks higher than the juntions box rather than below the junction box.

 

[dave1953]

That bobbly stuff is your bitumous Dpc which, though a bit high, seems to be holding the damp beneath it. Could be you have an internal kitchen pipe issue which has breached the Dpm and saturated the brick work to that area, are your hot/cold pipes buried in the floor screed in that area?

 

[HERTS P&D]

I'm going for a leaking pipe/joint on the rising main to the kitchen sink.

Andy

 

[diynoob]

Here's a picture of the kitchen whilst it was being renovated. The pipework is above the concrete in the picture but goes into the concrete just out of shot on the right.

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• diynoob
• 30 Jul 2013
• 2

 

[dave1953]

I would take out a couple of external bricks beneath the Dpc to the left of your kitchen window and see whats going on, if it's saturated in the cavity you may well have a pipe work issue.

 

[diynoob]

I read the meter this morning and it was on 607.0296 and not moving. Ran the tap for a few seconds and the meter started to move and went up to 607.0302

I waited 1 hour and the reading hadn't moved, so if its a leak its a very small one.

 

[diynoob]

Hmm looks damp near the dishwasher.

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• diynoob
• 9 Mar 2015
• 1

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• diynoob
• 9 Mar 2015
• 1

 

[Burnerman]

Bottom pic......what are those pipes that disappear under the floor?
Sure looks ominous......copper pipes in contact with wet concrete are a big no no!
John

 

[diynoob]

They are the central heating pipes. They are in the concrete floor throughout the house apart from a small section in the kitchen where they are above the floor. You can see those pipes better during the renovation 3 posts above.

I'll turn off the supply to the FE tank which should prove one way or the other if theres a leak in the CH pipes.

 

[Burnerman]

I think I'd be inclined to do some excavation anyhow....does the floor seem loose at that point? (Apologies - small screen to look at here).
It will take a wee while for the loft tank to show what's happening - surface tension and all that .....I would think you are on the right track though.
John

 

[diynoob]

OK whilst the meter isnt visibly moving, if I record the thousandths dial I can see there is a leak. A thousandth is 1 litre I would think.

With the house stop cock off there is no loss at all.

With the supply on I lost 1 litre in 21 minutes.

With the FE tank supply off I lost 1 litre in 22 minutes.

So its not the CH thank god, that would involve taking up a lot of floor.