I've got an external wall following on from the boundary wall. When the (brick) wall and (block) extension was built about 4 years ago the builder put in a DPM in the extension wall at the same level as the boundary wall, but left a bit sticking out and cement/sand plastered over it. Now there is a crack along (about 4 metres long) where the DPM sticks out on the extension. Water has seeped in through the crack and what looks like salty deposits has appeared on the internal plaster.
Whats the best way to fix the problem on the outside and inside of the extension wall?
Whats the best way to fix the problem on the outside and inside of the extension wall?