to drpepe

[ree]

stuart45 gave the answer to your difficulties: use a sand and lime render to 300mm above the signs of damp. Remove skirtings before knocking off the damp plaster.

You've not responded with answers so its difficult to advise you further.

But if you suspect that damp is penetrating behind the stair stringer then knock off the plaster behind the stringer (feel behind it for fungal damage), and merely render up to it - and try to render behind as best you can.

i suspect that you have a cavity and if you do then open it up for bridging rubble inspection.

 

[theprinceofdarkness]

You have a complicated arrangement. You have to work out if you and your neighbour have cavity walls. Look at the front walls, what is between his house and yours, do his bricks interlock with yours? do your damp courses join? (they should). Did they just build the 30s house of your house wall (cash might changed hands ).
As others have said, my Victorian house (1894) was built with proper cavities, which were filled higher then the damp course in places with sand, which I cleared to cure damp. This replastering, what the DPC companies are really worried about is that hydroscopic salts might have come up with the old rising damp, so when the damp is cured, the salts constantly absorb moisture from the air and so remain damp. So the undercoat is a preventative measure against moist air getting to the bricks with their salts.
Leaking water pipe?, they normally run in a bee line from the road to the kitchen, do they run under the stairs? Lift a floor board to check.
Frank

 

[drpepe]

Thanks for the comments guys - I didn't see these responses until now, and I've just posted up the old thread and some extra info and pics.