We have a longstanding issue with a strange re-occurrence of damp spots either side of a chimney breast in an internal party wall of our semi detached Victorian house.
One patch about a foot square just above the skirting, another on the other side about 6" square about 18" higher, and a small patch at the corner of the chimney breast at floor level.
I've dealt with bigger issues before and have an understanding of damp proof courses, condensation, ventilation etc., I cleared the base of chimney breast of soot deposits when upgrading the fire from coal to gas, both areas have been re-plastered at some stage and treated with damp proofing paint prior to papering.
There is no obvious damp, no horror film photos of mould etc., and it takes many months, a year or more before the paper starts to part company with the wall and for dark patches to appear but they always come back.
It transpires that our adjoining neighbour has similar issues and like us are scratching their heads.
Any suggestions/advice welcomed?
One patch about a foot square just above the skirting, another on the other side about 6" square about 18" higher, and a small patch at the corner of the chimney breast at floor level.
I've dealt with bigger issues before and have an understanding of damp proof courses, condensation, ventilation etc., I cleared the base of chimney breast of soot deposits when upgrading the fire from coal to gas, both areas have been re-plastered at some stage and treated with damp proofing paint prior to papering.
There is no obvious damp, no horror film photos of mould etc., and it takes many months, a year or more before the paper starts to part company with the wall and for dark patches to appear but they always come back.
It transpires that our adjoining neighbour has similar issues and like us are scratching their heads.
Any suggestions/advice welcomed?