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Damp Proofing

damp patches on chimney breast

Anonymous user 01/03/2024 - 2.48 PM

Hi. I have an end terrace house, we have had problem with damp for a year. Tradesmen so far don't want to tackle the problem as not sure they know what it is. The first lot of damp appeared on the chimney breast wall up to 2 metres spreading down the wall. Today, we noticed wet patches higher up. The cellar is dry and so is the wall in bedroom. It was suggested and decided to go ahead a few months ago to dig a trench at the side of house in case it was bridging water and causing damp. Looks as not worked as had a few rainy days and wall wet again. Builders have been up and sorted the chimney. On the adjoining wall to next terrace we got horizontal damp lines. Today we have knocked it out. What should we use to plaster the wall? Any ideas of our problems?

Are you a tradesperson and able to answer this question?

2 Answers

Trident Damp

Rating: 5 out of 5

Sidcup

Hi there Have air-bricks inserted in these areas to allow for airflow as internally there could be condensation. Also, how did they sort out the chimney at the top as this should not be sealed off but a cowling inserted to allow for air flow, as any moisture in the chimney has to come out some where. Could also be flashings around chimney but this would show only in the areas below. You need to use a water proof render which will also stop salts coming through. You also have to stop the root problem, you may need a damp survey. Regards Joseph

Answered5 July 2013

JWSurveys Ltd

Rating: 5 out of 5

Hythe

Sounds like your breast is contaminated with ammonium sulphates from fossil fuel residue. You will need to neutralise these prior to rendering with a waterproof cement idiots slurry coat and plaster. Ensure you maintain ventilation of the flue though

Answered10 July 2013