Been in our house for 25 years but moved to Thailand 3 years ago. Came back to find a tide mark around 6" high above skirting in the dining room where the old fireplace would have been (chimney breast removed upstairs and down) and damp patches around the size of a dinner plate in the bedroom directly above.
Chimney capping had broken away so we had both repointed, flashing reset and flaunching made good. Patches are still there. They get noticably worse after heavy rain. This is a semi and its on the wall between us and the neighbours. They also had their chimney breast out and say they haven't noticed damp, but they have fitted wardrobes so wouldn't really see if it were there.
Had suggestions for new flashing, remove chimney stack, new roof and getting a damp expert. Any ideas if this is likely to be salt damp patches or penetrating damp?