Damp cold spots on plastered walls

[roy c]

I am a great believer in poly backed plaster board when dot and dabbing a non cavity wall, I live in a Victorian house with 20" walls and I have scratched them with sand and cement and applied poly backed dot and dabbed to the walls (down stair walls) which were pulling up moisture from the ground This was done a number of years ago and have had no problem since, I hasten to add that one of the rooms has become a "storage" room where most of our "odds and sods" are stored and even tho I don't put the rad on in that room there is no evidence of damp or mould, My thoughts on this is, that the water will still track up and down the wall but even tho the dabs must get wet it doesn't show thru the poly back. I know the wall behind had moisture in when I did it and still probably got moisture in it now so is the thermal value of the polyback stopping the dabs breaking down and coming away from the scratch and the poly back and keeping an even temperature between the dabs and the wall? I don't know the answer to this and I don't really dig to far into the question, but I know it is working on my house

 

[JohnD]

"rising damp" has great difficulty in climbing more than a few inches up clean brickwork, even when the wall is standing in a pool of water or a river.

In the pictures, the example in this thread certainly seems to be condensation forming on the surface of the (cold, uninsulated) wall.

I am attracted to the idea of foam slabs and cladding on the outside, because that would also protect against rainwater penetration (half-brick-thick wall) but if it is not continuously heated, I suppose it would be better to insulate the inside. Such a pity that the inside has already been lined and plastered.

It does also need ventilation to allow the moist air to escape.

 

[Aylagrace]

If there are ground salts showing this would mean it is rising damp then bridging over where the dwa is if it was condensation then it would get moldey I will say it needs chemical injection then to be on the safe Side hack off existing plaster apply a membrane to create a barrier from brick work and new plaster finish if this wall does get moldey then it is more than likely condensation so a condenser unit should be fitted this will make the air sirculate so condensation can't settle on cold spots