[Help] Damp wall.

Jam The Man said:

Hi all - I’m a total diy novice, so apologies for my ignorance!

My downstairs bedroom wall has a relatively minor (I think) damp problem. It has 3 exterior walls and the issue is in the corners of two of the walls.
The outside of these walls has a soffit covering it.
My question is, if I pumped expanding foam into the soffit, would it ease the damp problem?

Any other suggestions gratefully received - thanks.

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CheeseRolls said:

Is the damp caused by water ingress or by condensation?

If it is the latter, you might be better off with an air dehumidifier. Cavity wall insulation may also be helpful.

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banjo said:

A picture of the problem might help.

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Cheshire Cat said:

Probably not.

Where is the damp patch?

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Jam The Man said:

Hi all - I’m a total diy novice, so apologies for my ignorance!

My downstairs bedroom wall has a relatively minor (I think) damp problem. It has 3 exterior walls and the issue is in the corners of two of the walls.
The outside of these walls has a soffit covering it.
My question is, if I pumped expanding foam into the soffit, would it ease the damp problem?

Any other suggestions gratefully received - thanks.

Click to expand...

PeterOut said:

As others have suggested, understanding the cause is critical, otherwise you are just spending money to treat the wrong problem.

See https://www.which.co.uk/reviews/damp/article/dealing-with-damp/faqs-dealing-with-damp-aJUGV5Z9wjtg then follow the links ref how to deal with the different types of damp.

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banjo said:

Is the room getting aired, most modern double glazing have trickle vents fitted. If not might be worth just opening the fan light open slightly for an hour or so during the day. Trouble with damp could be anything, even a broken wall tie allow damp to pass through outside skin to the inside walls. A cracked tile above the soffit.

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Harry Wilson's tackle said:

Sounds similar to me. In one room upstairs there is plaster direct on to brick (work done by a fool), and the two layers of brick are separated by a cavity too narrow (and doubtless compromised by debris) for cavity wall insulation. Many years ago I was offered this for free via the council, along with new loft insulation, but they couldn't do the former. My house was built in the 1880s.

To add to that, horizontal rain got under the roof 10 years ago (there was no soffit or fascia and the gutter was simply attached to the wall - now all fixed) and it ran down the small cavity and settled on a horizontal wooden beam in the cavity and brickwork (don't ask - I said it was an old house), soaking the beam, leaving a line of wet wall that took 4 years to dry out. Owing to that I mistook condensation for penetrating damp, which we don't have (but would get if we put in cavity wall insulation).

The remaining problem is that in cold weather condensation forms on the bedroom walls. We rather foolishly put in a bespoke fitted wardrobe before realising the nature of the problem, and the cold walls and lack of circulating air has created a condenser.

We had a similar problem in another room (less marked, less warm breath as not a bedroom) but getting it replastered with modern 'insulating' plaster seems to have done the trick. So the new wardrobe will probably all have to come out so the wall can be replastered properly, with an insulating layer.

Meanwhile, yes, dehumidifier, wiping condensation off the windows (which are double glazed, but...), and putting a small oil/electric radiator in the wardrobe, seem to help. But we don't like radiators on at night (prefer a cool room) so can't decide whether to leave cupboard doors open or shut at night.

We have thought about some form of (ahem) cladding, but this is a sodding conservation area, and local planning is run by tossers, as I discovered when we built an extension.

Good luck with yours

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*Gullsworth* said:

Dehumidifier sounds like the way to go. You will be gobsmacked how much moisture is extracted from the air in a very short time.

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LamieRobertson said:

I never knew you had been a plasterer

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