What is this dark patch on my chimney breast?!

[philkiel]

Hi, about 2 years ago we had the whole house re-plastered and painted when we moved in, however this one single patch has refused to dry and the paint has flaked off. It's on the left hand side of my fireplace and I haven't a clue what's causing it!

Can anyone help identify it? It doesn't smell like damp or have any mouldy patches, it just refuses to dry properly.

Thanks

 

[roy c]

It looks like someone has had a blow lamp on it !!! Or one of the candles has burnt it!!

 

[roughcaster]

I reckon that's damp, maybe not to the touch, but something's coming through. Nothing shows up damp/salts, etc more than gypsum plaster. Was there an old firepace there when you moved in?

 

[foxhole]

Damp , check roof ,chimney, flashing etc.

 

[scruffybiker]

Most probably salts left behind from when fire was in use. I get it in my property. Salt staining on chimneys & one exterior wall in lounge. It flares up when humid/cooking or raining.

 

[ree]

scruffybiker,

the OP appears to have disappeared from his own post. But, FWIW, if you are having difficulties with soot penetration from a flue(s) then why not open a separate thread describing your difficulties on here or in the building forum?