Please help, I have no idea what to do. We bought a 1st&2nd floor flat of a converted Edwardian house last September. There were no visible issues although the survey did pick up a slightly high damp reading on some walls which we were told by surveyors might be down to the seal between the chimney stack and roof and would cost 2k to sort so we didn't think much of it as seemed like an easy enough fix. Since moving in we started noticing damp patches, which had got bigger and bigger and started to spread across multiple areas. We had a very wet few months weather wise but it was very wet and dripping weird orange/yellow drops some mornings in the winter. We got a roofer in who sealed up the chimney and relayed some new felt as he said the previous one was looking torn and badly fitted. We have seen no improvement since and if anything, it has gotten worse.
The damp patches are on the wall next to the old/unused chimney breast (it's on the top floor right below the roof and the wall is an external one). We have also recently noticed a big orangey brown patch where it used to be all white paint (see 2nd picture) just below the roofline. Also a newer damp patch has appeared since too on the same wall but further along into the hallway.
We don't know who to call to troubleshoot. We tried calling a damp specialist and he said it sounds like an external issue and would be better off calling a roofer. But we have already had that done so what else could it be? There is no vent on the chimney which I'm pretty sure is blocked up but I can't really tell. Could it be that? We are not 'handy' people and know very little about this stuff so happy to pay someone to come and assess and tell us what needs to be done but we don't know what sort of tradesperson does this. Googling also mentioned something about rendering but again, no idea what that means and what sort of professional to come and look.
Downstairs/ground floor flat say they haven't got any damp patches so it really just seems to be one side of the top floor that's the issue.
It's been a lot dryer in the mornings since the summer but Im sure the problem will return when it gets colder and wetter again.
Any advice would be gratefully accepted.
