Hi, I have a very slight damp patch on a wall which separates my terraced house from my neighbours. I assume it is where their chimney breast is/was. I applied Ronseal anti damp paint and a couple of coats of emulsion but I now have darker, greasy looking stains penetrating through the emulsion. Could this be the oil based damp paint penetrating through the water based emulsion and has anybody any solution how to solve this problem without hacking off newly painted plaster?
Any suggestions would be greatly appreciated.