Damp patch at base of wall

[fortnite]

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[fortnite]

No John, no water meter. I know it seems logical to think that it's being caused by a water mains leak but I really don't think it is.

 

[foxhole]

Have you checked roof level for problems , render will hold in any moisture and allow it to fall thru to ground where it hits dpc and takes line of least resistance , into the property .

 

[fortnite]

Yes, that's a good place to look but new roof and guttering were only put on about a year or two ago also and all good there, no problems. It's an odd one.

 

[tell80]

Still no pic of the inside?
As my above: you blend in the new render to the old render.
The higher extension render is looking very cloudy suggesting damp.

 

[fortnite]

Sorry tell80, there are no water stains on the inside wall, therefore there's no point in showing any inside pic. The inside wall had insulated plasterboard applied, which will have a vapour barrier, so it likely wouldn't show through anyhow, even if there was any damp on the inside wall.

The higher extension render accidentally had building sand used in the plaster rather than plastering sand. There was a bag of each sitting there and the plasterer decided to use the closest one, even though I mentioned there was a bag of each. He had that wall done before I got back, so advised him to use the other bag to finish it. I think that's what may be causing the cloudy look on the higher extension render - it's also a bit of a rougher finish and I'm surprised he didn't realise. He had the bottom part done using building sand too, which may not be helping the issue?

 

[fortnite]

If a bellcast is applied and newly plastered up to (and just above it)... would the lower part of the wall plaster below the Bell Cast, always remain damp and look damp right up to the bottom of the Bell Cast? Is there any way to stop it from looking damp, or retaining damp?

Also as an alternative quick and cheap fix, might it be possible just to cut a slot along the wall at dpc level and seal it with polysulphide mastic? Then paint it all over (Plaster and mastic) to blend it all in a bit better. Admittedly may not look exactly brilliant but it would cheaply allow me to test if it solves the issue and might actually be acceptable if it works?