Diagnosis
Why is my chimney breast damp?
Damp chimney breasts have a handful of common causes — and salts often keep them looking damp.
Water from above
Defective flashings, a cracked or missing pot, failed flaunching or a damaged cowl can let rain into the stack, which then shows on the breast internally.
Redundant flues
A capped flue with no ventilation can trap moisture. Combined with historic soot and salt deposits, this often produces persistent staining.
Hygroscopic salts
Salts absorbed into the masonry over decades attract moisture from the air, so a chimney breast can appear damp even after the original source is resolved. Specified replastering may be needed.
Related service
Penetrating Damp in Bedford