stripped my walls a couple of weeks ago and was preparing to plasterboard and plaster,but i noticed a discolored area running about 12" above the skirting a few days ago .It wasn't a massive area so i borrowed a damp tester, placed it on the wall let a it let out a loud squeak ..So i tested all the walls and it ranged from high squeaking to some thing that sounded like morse code .asked me old fella wot was goin on and he said the dpc had failed thats why it was squeaking.
can anybody offer any advice pls what i could do to remedy this