hi, ive got a problem with damp appearing through just above my skirting board and under a window. this wall had a dpc fitted about 3 years ago before i moved in. the damp showed up on the survey, the then owners got the company back in who said it needed the outside adjoining wall capping and longrr to dry out. basically i went one step further and had the wall built, but still getting damp. dont know who the company was that installed the dpc. this room/ wall never sees thr sun so is always cool, so i was maybe thinking it is condensation problem as it is more noticable when the washing is drying out. also getting powder build up in some points (efflorescence?) and the plaster is hollow now in the damp patches. will plaster need hacking off and how do i cure problem? cheers in advance
p.s sorry about any bad spelling this wss wrote on my phone