Chimney breast damp

Discussion in 'Building' started by Bethan Saunders, 24 Nov 2021.

  1. Bethan Saunders

    Bethan Saunders

    24 Nov 2021
    Thanks Received:
    United Kingdom
    Hi. First time posting and hoping I can get some help or advice.

    February 2020 I noticed a small damp patch coming from the top of my bedroom wall. The wall is the chimney breast.

    Round the houses, a few people told me my chimney was the cause, so took it down in May 2020 as I no longer had a fire.

    Winter came and the wet patch grew some more. So assumed the chimney hadn't been taken down correctly and water was still getting in.

    Fast forward to now and a roofer has been to see the problem, however no water in the attic. No light coming through so he's of the opinion. The chimney removal was done correctly... However can't explain the patch in the bedroom which has grown again this winter.

    Ive read a few places this could a hygroscopic salt problem.

    So firstly how or who would i get to test this theory?
    Secondly, how fixable is it, should it turn out to be that.

    Photos attached showing the growth of the patch

    Attached Files:

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  3. JohnD


    15 Nov 2005
    Thanks Received:
    Crossgates, Europe
    Cook Islands
    is that an external wall, or a chimneybreast? What is on the other side of that wall?

    are there any pipes or tanks in the loft?

    it does not look like salts to me, nor condensation. It looks like a leak.

    draw round it with a pencil, write the date on the line, photograph it frequently and see if it changes with weather or something else.

    Are the flues chimney ventilated at the bottom, with an airbrick or similar where each fireplace used to be?

    Is there a steamy bathroom?
  4. tell80


    30 Jun 2021
    Thanks Received:
    United Kingdom
    Are you saying the whole chimney breast and the chimney stack on the roof have been removed?

    For Hygroscopic saltss
    Where the chimney breast in the bedroom has been removed,
    was the back wall thoroughly cleaned of all soot stains?
    With the back wall its best to clean spotless and then blind with two coats of SBR.
    Next its good to use two coats of sand and lime render but dont use any gypsum plaster.

    Having said that it doesnt look like a Hygroscopic salts stain?
    You need to go in the loft and examine the wall/roof just above the stain.
    You also need pics of conditions on the roof and any remaining stack.

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