On 31/01/2020 11:16, Jimk wrote:
Wrote in message:
A cavity wall has a "tide mark" about 200mm above the floor. The wall
was originally an external wall but, as a result of building an
extension, is now an internal wall. The wall has a 1930s DPC and the
floors have modern DPMs.
I assume that the old DPC has failed so am wondering what the best
options are. At the moment I'm thinking of knocking-off the plaster to
about 300mm, coating the wall with something and then
rendering/plastering with an additive.
The question is what to put on the wall: liquid DPM? bitumen? cement
board (hardiebacker)? foil-backed plasterboard?
What does the team think?


Whats the floor construction?
Concrete, with insulation and DPM.
The wall is on the original footings.

Can you get under it? Cellar, void, whatever?