Damp issues

[WilsonandNoodles]

HI, looking for advice as we are having damp issues. I've just decorated the bedroom and with one wall we have really struggled to get the paint to dry and stay on the wall. We now have condensation pouring down the wall taking off the paint and mould growing in a matter of days. It's an outside wall, brick on the outer surface, 1960s ex council house and as far as I know nothing has been done to the wall since. The other outside wall is fine. We always got the odd bit of damp on this wall behind furniture in winter but the last wallpaper laster 7 years so nothing like this. Any suggestions of the problem or advice as to who were get round to come and help us identify the problem!

An obvious question but is your extractor fan working properly ? Or possibly your bathroom doesn't even have one ?
We bought a 1930's property that didn't even have one and both the bathroom and the room next to it suffered from mould and condensation. We had an extractor installed and over a period of 3 or so months of it being fitted the problem completely dissappeard. It runs every time the bathroom light is on and continues for about 5 mins after the light is off. The decent ones are about silent and have valve flaps to stop any heat loss during the majority of non running time.

Could it be a problem with guttering / a downpipe outside? I'm thinking that as it appears to be quite concentrated on one wall, it is more likely to be related to a leak than general condensation, although it's definitely a good idea to ensure sufficient ventilation. Do you have a dehumidifier?

NB the problem may have been there for some time. Many are saying that due to the exceptionally wet weather over the summer and into winter, houses are suffering from damp more than usual, so any issues will be magnified.

That patch under the socket looks like there's some sort of bridging across the cavity between the external wall and internal finish. What is your house built of?

The bathroom doesn't have a fan, the window is just left open when showering and for half an hour afterwards. So could definitely be a contribution although we have lived in the house for 10 years and we haven't had the water pouring on the walls before.

No guttering on that side of the house. We do have a dehumidifier have had it running plenty but not convinced it's the best one, although doesn't explain why that wall is a problem but the other outside wall is fine.

We were lucky? to not have an exceptionally wet summer. We live in the North West, it's rarely not wet!

The patches are from re- wiring and plastering to cover up the holes. When first painted you couldn't tell but the new plaster bits seem to be getting wetter and mouldy quicker.
The house is standard brick built but I don't know if there's anything in the cavity as far as insulation etc. Sorry, my buying knowledge is pretty much zero!

You need to get a builder to look at it and determine the cause. Likely this has been a problem for years but the paper has masked the problem. Don't get a damp specialist as they are out to sell products, a recommended general builder will be able to help diagnose the source. Go and look outside whilst it's wet for any leakage, again once dry for any damp patches. Is this up or downstairs, are there any other rooms on the same face of the house, any damages guttering elsewhere might be directing water inappropriately.

I'm wondering if there's inappropriate cavity wall insulation in the cavity, definitely something for a builder to check.

The patches are from re- wiring and plastering to cover up the holes. When first painted you couldn't tell but the new plaster bits seem to be getting wetter and mouldy quicker.

Plaster didn't dry out enough prior to painting ?

Thr re- wiring was 6 years ago, we just patched up the paper and have only got around to re-decorating now!

OK so a general builder should be able to identify the cause, that's useful to know.
I don't think it's a guttering problem. Its the gable end wall so no guttering and water drains other ways.
It's an upstairs bedroom. Bathroom is next door and fully tiled so can't compare. Below is living room. No obvious issue in there. Below bathroom is downstairs loo. We get water on the wall in there but have always blamed the lack of heating and it being off the utility so clothes drying etc.

Possibly the wrong kind of plaster. Was the original plaster lime? If so, it really ought to have been patched with lime, and painted with claypaint. But I'd imagine that the house is a bit too modern for lime.

I think a hefty extractor in the bathroom would be a good idea.

When you decorated, did you scrub all the paste residue off the wall before painting? If not, the paste could be sucking up and holding damp. Unless a builder comes up with something obvious, try sanding off the paint back to the plaster in an area where the damp is and paint with claypaint ( you could get a sample pot) and see if it stays dry. That would at least get you a little further in fact-finding without a lot of expense.

My guess is would be that it is condensation, and that it's worse where the new plaster is for some reason to do with the plaster. Did you seal the new plaster with PVA (or anything else except claypaint or thinned-down matt emulsion) by any chance? If you did, you're going to need to sand that off.

I'd want an extractor fan in the downstairs loo too, though. Possibly on a humidistat.

No idea on the type of plaster. It was quite possibly the original plaster but the builder who did the work when we got re-wired was a neighbour who new the houses well and is on the more experienced side (of the 65+ variety) so would hopefully have used appropriate plaster. We just sealed the new plaster with waterered down paint.
Paste was washed off as well as any of the other walls that we don't have any issues with.
Extractor fans are on the to do list but so is an extension, moving the downstairs loo and redoing the bathroom which is why it's not happened. Might have to pay up and get the bathroom one done anyway.

I'm a bit out of ideas, then, you seem to have done everything by the book. But it's odd about the damp being worse on the new plaster.

We had a bit of the same with our rewire, they used gypsum (pink stuff) because I didn't know then it ought to have been lime really, I painted with claypaint because the rest of the wall was lime, and it did dry out on the new bits as well, and stayed dry. But we also increased the ventilation, etc. But a house your house's age would not usually be lime.