Help with Damp Chimney Breast

[pownallca]

Hi All
I wonder if you might be able to help?
We are trying to buy a 1930’s detached bungalow, had a full survey done today and they have found high damp readings in the top of the chimney breast in the living room.
The chimney has been taken off the roof and tiled over but the chimney is still in the loft and has been sealed over with lead.
It seems that water can’t be leaking from the roof, so why is the breast showing damp readings?

 

[blup]

The flue is lined with contaminants from the use of the fire, these trap and release water/moisture which causes the staining/damp readings. Worth properly ventilating the flue at top and bottom as air flow will remove/reduce the moisture.

Blup