We have recently bought a house a 1940’s cottage, in one of the rooms (which is an extension onto main original part) it had a suspended wooden floor which was damp and rotten which has since been replaced with dpc insulation and screed. There was a leaking pipe for rad underneath the floor which was replaced with pex piping. There was yellowing on a solid wall in the room which was painted last week but the wall appears to be damp from the bottom up to about 800mm in places. The wall in question is original stone wall, with plaster on it. This wall contains the chimney stack. Does anyone have any suggestions as to what I can do to remedy the damp. I’ve done the usual and checked drains etc