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Shower Leak in Cavity Wall and Mould

Joined
27 Oct 2025
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United Kingdom
Hey everyone,

We recently discovered a leak which had happened in the pipe leading to our en-suite shower, behind a cavity wall and behind a wardrobe. It'd be going on a while and we only noticed it when the carpet at the front of the wardrobe started to feel damp.

We originally looked for the leak by going through the garage (underneath the en-suite) ceiling. That was soaked, with insulation being sopping wet. We have let that dry for 2 weeks now and have let the bedroom carpet dry for about a week using dehumidifiers.

We have since fixed the leak, but now have to work out what to do with the black mould. At the moment we're sleeping in the bedroom which I think is probably bad, so need to get it fixed asap. Would appreciate any advice on this, here is some info and some questions and pictures.

I think we basically need to remove and treat all the mould before sealing it all back up. Is that right?




In the bedroom we have opened up the wall to dry it out and fix the pipe. We've moved one part of the wardrobe out and as you'll see the carpet is pretty bad. We still need to move the other parts of the wardrobe to see what the carpet is like under those. Is this carpet in anyway salvageable? My guess is we need to rip it up and look under it as it's likely based on what's going on in the garage below that it's soaked all the way through?



Looking into the wall cavity there's black there, as you can see there are joists on the side, do you think the mould will have spread to the other side of the joists / do we need to open up more of the wall to get to that to clean it?

In the garage we obviously need to replace the insulation and ceiling bits we ripped out. As you'll see there's quite a bit of mould there. Is this just a case of cleaning, treating and spraying?



Thanks in advance for all advice.
 

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Get a mould spray and treat it.
Not easy to wash that but a good mould will kill it.
Maybe a couple of goes at it to do the best you can.
HG make a good one.
Just be mindful that mould spray needs to be used with care so follow instructions.
 

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