Tiny cavity solutions?

SWMBO

We're renovating our kitchen and on removing a window have discovered that one wall only has about 1cm cavity between the inner and outer brick. There was a damp patch on the wall beneath the window, next to the washing machine, which could have penetrated from outside or be condensation due to being a colder wall than the others which have proper cavities. There was no extractor fan, so the only ventilation was opening a window.

Is this likely to have been sorted by pointing outside and moving the washing machine? Builders have suggested dry lining with plasterboard with a waterproof membrane. The wall was exposed to the room, but will have kitchen units along when we're done. We'd like to avoid taking too much off the room, and of course unnecessary expense, but also don't want to have to take out a new kitchen if there's a problem in the future.

Doozergirl

Dry lining doesn't really stop a problem, it blocks the symptoms of it showing internally.

If the wall needed pointing, then it's quite likely that you had a bit of penetrating damp. The under side of a window will be a weak spot as far as penetrating damp is concerned.

How bad was it? A patch doesn't sound like a major problem.

SWMBO

The whole wall has been repointed, and the window bricked up, so hopefully shouldn't be any opportunity for damp to get in from the outside now, but I don't know if that was the source of the problem or if it was condensation from the inside due to inadequate ventilation and the lack of a decent cavity making it a cold wall.

I'm just concerned that if we don't deal with it now and just go ahead and fit a new kitchen, we might have to take it out again to sort it out.

Editing to add: small patch around 2ft across, basically the width of the exposed patch of wall, causing the paint to flake off but no black mold.