Damp Bedroom Wall

[jod72]

We've had an issue with our bedroom wall for years, it's at the gable end, has a chimney (which is not in use, has a small opening, but apparently is blocked off with a slate (not an airbrick) at the top.

There is sometimes a large area that is dark (anything from a sqm to a few sqm) The gable end ws repointed about 10 years ago and the chimney repointed a few months ago.

Would this be from condensation caused by the chimney being blocked off or does it sound more like a leak somewhere?
Thanks J

 

[ree]

Use the search button and read back posts on this issue.

Thro ventilation in swept flues is essential. Unventilated soot turns to acids, and comes thro the chimney breast, often showing as damp stains on the decorated surface.

Have you checked the chimney breast in the loft?

Pics of inside and outside and the stack would help.

Any professional who goes onto the roof should supply you with before and after pics.