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Damp Proofing

Damp in upstairs chimney breast of old fishermens cottage

I am in Bognor and have damp issues in the upstairs chimney breasts.

I had the local roofers in who thought the problem was 99% to do with the lead flashing, so these were replaced. However, when they did this work they said they thought there was an insufficient overlap in the slate tiles and recommended that the roof should be re-tiled, and one of the redundant chimney stacks was removed. The work was completed May 2014.

Despite the exceptional summer the damp still appears to be in both chimney breast (they have brought a damp meter to confirm this). The chimney breast which remains has a gas fire fitted downstairs and an ornamental cast iron fireplace in the bedroom which is not used. The roofers came to inspect the interior of the chimney the other morning and said that there was a very high amount of water (condensation) in the chimney. I have read that use of a gas or log fire may cause fumes that will give problems with condensation, but the gas fire has not been used since the roofing works had been completed, so cannot understand this could be why there would be condensation. The heating had not been on that week, so the only air going up the chimney was ambient temperature from within the house. They did the inspection around 7:30am following a dry night.

From your experience is there anything else to consider? Could the fitted gas fire have any effect despite not being used since the roof repair??

The house is around 1870 and is an old fishermens cottage. The chimney is rendered and they have even applied a damp proof solution to the render. The roofers are a reputable local company, but are struggling to come up with an answer. They were going to speak to a local company who supply and install gas fires, and have suggested a vent in the roof over the taken away chimney stack.

Damp proof specialist have suggested a tanking option to the breast.

Many thanks in anticipation of your advice.


1 Answer from a MyBuilder Damp Proofing Specialist

Best Answer

Hi Kevin,
Possibly your chimney does not have a dpc installed due to the age of the property. I dont think it would be due to the gas fire , I would not recommend tanking chimney breast as this can cause condensation, you may have already stopped the problem ie the leak, possibly the plaster is spored and acting as a sponge to any air-bourne moisture,, This then will not dry out without the removal of internal plaster to chimney breast, and re-plastering with waterproof additive. I hope this may be of some help to you.

Kind Regards
Steve Newton


Answered 15th Jun 2015

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