Damp / Wetness internal wall

[Craig24]

Hi all,

I have a 1895 built terrace. On the internal wall between the living room and dining room (highlighted yellow), I have damp, cold, almost wet feeling patch along the middle of the wall, around 4ft up, just above the dado rail -

I have tried drying it out and no luck, the other side of the wall has no signs of damp. I drilled a hole in the wall and the bricks feel dry. Its a single skin internal wall. This wall has has damp injection in the past and looks like its also had the 1 meter high type render than all the damp "specialists" do.

The other side of the wall has nothing up against it and there is no pipe work in the wall or anywhere near above the wall upstairs.

I'm at a loss how to treat the issue?

 

[mrrusty]

At some point in it's life, your house will have had coal fires. It's quite likely the walls are salt poisoned to some extent caused by reactions between combustion gases, lime and water , and once in the plaster they draw moisture out of the room air. Where were the original chimney breasts in your rooms? Some info here https://www.tracebasementsystems.co.uk/post/guide-to-damp-related-salts-in-buildings and https://www.tracebasementsystems.co.uk/post/damp-chimney-breasts

Best cure. Strip the wall, and plasterboard again isolating the plasterboard from the masonry by using foam adhesive not wet dabs. A "maybe" cure is to sand back to bare plaster and paint with a damp seal paint, and then paint over. The damp seal paint will help to keep the moist room air away from the salts. I have had reasonable success doing this. Quick cure. Keep some paint to hand and just paint over it from time to time....