damp in chimney

[Steve]

When I moved into my new house I knew it had a "bit of damp" on the chimney, and I also knew the flashing is dodgy around the chimney up top.

The chimney breast had a bit of discolouration on it in the lounge. Nothing too bad. However, we have since stripped the walls to bare plaster.

What we have found looks worrying, but I hope is only this bad due to the recent rain and the bad flashing.

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First photo shows the front of the breast with a large damp patch just above the fireplace, and also a little bit up near the ceiling (9ft up).

Second photo shows the bottom of the breast, below the arch to the left (arch is brick and support the chimney upstairs where it serves both bedrooms - no breast in the kitchen adjoining). Both sides are damp like this, but this side is worse, probably due to it being more central to the chimney pots.

What I want to know I guess is how long this will take to dry up after the flashing is corrected. Will I need dehumidifyers? Heaters? Or will running the gas fire at the bottom dry it out?

The floor is concrete, by the way. Im not sure where the updraught for the chimney comes from.

 

[CortinaV8]

Once the flashing is corrected I would imagine it would take around a week for the plaster to dry out, maybe run a dehumidifier, but don't try and bake it dry with heat.

The actual brickwork must be saturated to cause that much damp, I would expect that to take months to fully dry out.

 

[hotrod]

Christ Steve, that second piccy is soaking wet isn't it. Is that the 1st floor breast? I'm trying to think why a defective flashing would cause it to soak it that damp at that localised area. That plaster may have been soaked beyond repair. That skim may well dry back "soft". You'll have to suck it and see. Got any pics of the chimney stack / flashing?