Chimney fixed but damp still spreading?

6 Mar 2024
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United Kingdom
Hi all!

We've had a steadily growing damp patch for a while on a 1st floor chimney breast (disused) of our 1930s semi-detached. Had a damp survey - definitely water ingress from the chimney stack. Had the flashing redone, and the chimney repointed. We might need a new flaunch, but our roofer said it was fine.

We've had a dehumidifier in the room for about 3 weeks since the chimney fix, the air moisture level is about 40 or so. We know it'll take a while for the chimney breast to fully dry out, as it'd been in a not great state for a while, but the damp patch is still slightly growing here and there. Is that to be expected? I've attached two pics from 5 days apart - the damp patch is very spotty and only growing spot by spot, it seems. But we're just trying to figure out if that suggests the chimney isn't fixed, or if it's normal while the chimney breast is drying out?

Appreciate any advice or thoughts!


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Inane, your FF chimney breast will probably have two flues in it - the bedroom fireplace flue, and a flue from a GF fireplace.
Is either fireplace blocked off - pics please? When did you last have your c/flues swept?
Have you been in the loft and examined the loft chimney breast? Pics of any wet brickwork or rafters would help.

Pics of your: - chimney stack - the flaunching - & the stack flashing - will definitely help.
Why not read the Similar threads below?

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