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Damp on walls - how to deal with it?

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zico
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Damp on walls - how to deal with it?

#473586

Postby zico » January 16th, 2022, 6:02 pm

My father's bungalow has noticeable discoloured patches on the wall over where the chimney used to be, and some peeling wallpaper, presumably caused by damp.
What's the best way to go about dealing with this - does he need a builder/roofer to identify and eliminate the source of damp into the property, then replaster, or is there a simpler way?

DrFfybes
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Re: Damp on walls - how to deal with it?

#473591

Postby DrFfybes » January 16th, 2022, 6:07 pm

No.

You need to work out where it is coming from, and stop it coming in. If an old chimney then if there is anything left on the roof that is where to start. If it is a chimney in the middle of the property (rather than on a party wall) it might be best to take it down to below roof level and then re-tyle the gap.

THEN you can start to look at repairing the damage. Any other approach will just mean the damp spreads behind the cover up and emerges elsewhere. Of course if he is moving, you can slap 6 coats of damp proof paint and paper over it and hope the surveyor doesn't spot it. DAMHIK :(

Paul

malakoffee
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Re: Damp on walls - how to deal with it?

#473593

Postby malakoffee » January 16th, 2022, 6:11 pm

? Residual compounds of combustion ? which may be impossible to remove and difficult to mask.
If so they may be hygroscopic leading to enduring damp on adjacent surfaces.

However, that^ is just speculation . . .. It's difficult to say really without a detailed description ( & photo ).

Mike4
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Re: Damp on walls - how to deal with it?

#473617

Postby Mike4 » January 16th, 2022, 7:49 pm

malakoffee wrote:? Residual compounds of combustion ? which may be impossible to remove and difficult to mask.
If so they may be hygroscopic leading to enduring damp on adjacent surfaces.

However, that^ is just speculation . . .. It's difficult to say really without a detailed description ( & photo ).


That nice Mr Occam thinks it is nothing more complicated than rain coming down the chimney.

AsleepInYorkshire
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Re: Damp on walls - how to deal with it?

#473627

Postby AsleepInYorkshire » January 16th, 2022, 8:42 pm

zico wrote:My father's bungalow has noticeable discoloured patches on the wall over where the chimney used to be, and some peeling wallpaper, presumably caused by damp.
What's the best way to go about dealing with this - does he need a builder/roofer to identify and eliminate the source of damp into the property, then replaster, or is there a simpler way?

When was the chimney removed?

Has the chimney been removed completely or down to a height? What height?

Is it on the side elevation or the middle of the roof?

Has anyone done any work to attached houses or is it a detached home?

Photo's would help to identify the issue and thus sort a solution

AiY(D)

zico
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Re: Damp on walls - how to deal with it?

#473659

Postby zico » January 16th, 2022, 11:44 pm

Just to clarify, the chimney wasn't removed, it just hasn't been in use for many years (there's just a gas fire there). The damp is just around and above the fireplace.

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Re: Damp on walls - how to deal with it?

#473660

Postby monabri » January 17th, 2022, 12:08 am


Mike4
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Re: Damp on walls - how to deal with it?

#473671

Postby Mike4 » January 17th, 2022, 7:27 am

zico wrote:Just to clarify, the chimney wasn't removed, it just hasn't been in use for many years (there's just a gas fire there). The damp is just around and above the fireplace.


As there is a gas fire there, may we surmise it is still in use? Or has it fallen into disuse?

If it is never used, the first thing to do to address the damp problem is to cap the chimney to stop rain ingress. If your father wants to continue using the gas fire then probably a flue liner needs installing to start with.

Then if necessary, treat the chimney breast as though hygroscopic salts are the cause, as suggested in the link provided by monarbi.

88V8
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Re: Damp on walls - how to deal with it?

#473727

Postby 88V8 » January 17th, 2022, 10:31 am

So is the gas fire just venting up the old flue, or is there a liner?

If the gas fire is disused and it's the old flue with an open clay pot on top, that needs an elephant's foot cap, or a half tile cap like this https://www.belowstairs.co.uk/acatalog/Antique%20Modern%20Terracotta%20Chimney%20Cap%20CP139.jpg - any builders' merchant.

If the gas fire is still in use, I would prefer the half-tile version as it has a greater open area, but as Mike says, a flue liner is better.

If there is already a liner with a gas terminal then the water is getting in through degraded pointing or flaunching or missing or defective flashings. Pop up there and take a look.

Once you have stopped the water getting in leave it a year to dry out, then remove the wallpaper and cover the offending area with Foildamp, then re-paper over it.

Foildamp will stop the soot stains leaching through. They can otherwise be very persistent.
https://www.brewers.co.uk/product/FA1405E

V8


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