Damp from small cracks in render?

1 Dec 2019
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United Kingdom
Hello all,

I’m investigating the source of some damp in gable end of a bedroom and I’m wondering if it’s some small hairline cracks I’ve noticed on the external render. There’s one small horizontal crack and then in the corner around the chimney Brest some cracks running upwards. This is the ground floor of a four story tenement.

I think this is concrete render over sandstone but I could be wrong! Anyone have any ideas? Would it be a case of just filling in these small cracks? The render is pretty heavy duty. I’ve posted a pic too of the damp on the internal wall.

Any ideas would be massively appreciated! Oh and the render does not look to be blown. These are the only cracks I can see on the whole building.


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Its more likely to be the chimney breast than the Render.
Is there a vent on the wall where the fire place used to be?
Thanks for your comments.

Nope there’s absolutely no vents at all which does seem really strange. Would it be a big job to install vents do you think? There’s apparently some damp in the living room around the other chimney breast too.
Simple enough job to install a vent on the chimney breast, cut an opening to required size of vent then screw the vent on.
Make sure the flue is capped and vented on the chimney..
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Thanks! Hopefully that is the cause and it can easily be fixed with some ventilation.
after removing any blocking the view furniture, larger context photo's of the bedroom wall, & pics of damp signs anywhere on the gable wall would help?
do you have open or sealed fireplace openings?
photos of the other chimney breasts and fireplaces will also help?

moisture could be getting through to the masonry background - stone is shown at the corner of the elevation, is the main part of the elevation stone or something else?
simply rake out the cracks and fill with Polyurethane cartridge sealant.

simply venting a dirty, sooty flue might not be enough.
all active and redundant flues need sweeping.

its possible that neighbour's on the upper floors have similar problems? you might have to club together to have the chimney stacks and terminals inspected?

why not read Related Threads below?

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