I have a gable wall in hallway running through to under stairs cupboard that is showing damp (wet) patches. These can come and go depending on hall humidity. It has reached a point where action is needed as I am unable to decorate. There appears to be no obvious external signs of a problem eg leaking gutters, downspouts or render problems. Attached are a few pics showing the problem. I also have damp/wet problem on one internal wall in the front lounge - see pic. Without opening up a debate on DPCs and existence of rising damp, is there any circumstance where you would hack off all plaster to 1m and install chemical (cream) DPC? In my circumstance I can’t see an alternative, the plaster is shot. I am at a loss what to do and do not want to waste up to £1k if not necessary. I have had similar quotes and advice from 3 companies. All said rising damp and all suggested same approach to remedy the problem – hack off/chem DPC etc. Any advice appreciated.