Requesting Advice on Returning Damp/Cold Spots on Internal Wall Backing onto Chimney Damp can be a major issue in the home. Find answers to questions or post your own here.

[SteveReds117]

Hi,

I’ve been having a re-occurring damp problem in one of the bedrooms in our house despite following advice given from a variety of sources but still notices signs of it. Right now, I’m kind of at a loss as to what to do next, what to do to prevent the root cause etc. so any advice would be very gratefully received.

So a brief bit of background – we bought our house about 2 years ago, and noticed the damp problem straight away. It is in the bedroom at the top of the wall (so not rising damp), it’s on an internal wall, though the wall is on our chimney. We have a wood-burning fire which was installed before we bought the house, so the chimney is in use.

When we bought the house, it seemed that the previous owner had some broken lead flashing around the top of the chimney which she hadn’t bothered fixing as she was selling the house. We had a roofer round who fixed this problem immediately, and we were advised by him and a plasterer I spoke to at the time, to strip bedroom wall to allow the wall to dry out. I spoke to two plasterers around this time, both advised that by leaving the wall to dry out, as long as I’d sorted the cause of the problem (which appeared to be the lead flashing) that the wall should be fine to plaster eventually as the brickwork will eventually dry due to the porous nature of the bricks. So I followed this advice, stripped the wall and left for 10 months for the wall to dry out.

In this time, I’ve used a de-humidifier to assist with drying the wall. I’ve also had the roofer back on an annual check of our roof – I’d asked him to double check the flashing and ensure there is no way water can be getting in, which he has done and assured me that there is no leak. After the 10 months, I had the room plastered and following that we painted a huge area around where the damp patch was with Damp Seal paint. Once dry this was followed by a mist coat and then painting the walls to finish the decorating.

This was about 4-5 months ago and just recently we’ve started to notice a few damp/cold spots re-appearing on the wall. There are only a few and these are quite small, a couple of cm’s in diameter. But this looks like early signs that the damp is re-appearing.

Having followed the advice of a number of people, I’m not quite sure where I’ve gone wrong – the root cause is apparently fixed, I’ve treated the walls as I’ve been advised to do but it’s still re-occurring. Have I been given some advice that is not quite correct somewhere along the line? Can anyone advise what I should do from here – can I fix this by adding any further treatment to the walls or is it a case of having to start again?

I’d really appreciate any advice you can offer as I’ve no idea where to go from here.

Many thanks.

[SteveReds117]

I've also taken a few photos which I've attached here in case that helps. The wall with the damp is against the chimney, the chimney itself runs through the centre of the house so isn't an external wall.

Any advice would be very gratefully received. Many thanks.

[Grantx]

Get into the loft space and checks for leaks or rips in the roof felt.

[LawnMower]

Has your chimney got a cowl on top of it (Stops the water running down the inside of chimney but lets smoke out)

Does your wood burner have a metal ribbed flu pipe running down the inside of the chimney (these can actually be installed upside down and also needs a metal cowl on the top)

Does your chimney have an air vent? ( This I would suspect is your problem, the chimney needs to be able to breath and condensation builds up inside.) However do not vent it if you don't have the metal flu running from the stove to the chimney top, otherwise you could suffer carbon monoxide poisoning)