Problem with salting plaster?

Question

Damp proofing was carried out 5 years ago. I now experience salting plaster. Called the company and they came for a survey. The report says that the damp proofing works well but they will replaster free of charge. Doesn't sound good to me as I can see small damp stain on chimney breast just after the part that was treated. Just worried they're trying to patch up... Could it really be a plaster's problem?

Thanks in advance

Answer 1

It's not a plaster problem, it's either damp from below or from above, by above it would be coming down the chimney or condensation forming inside the flue. Good luck.

Answer 2

Damp patches due to a faulty DPC will never rise or show any higher than 1mtr above ground level

sometimes it is possible for salting to appear due to composites in the existing brick or stone work.

You say that theres a damp patch above the treated area and the company are honouring their guarantee, so no problem there then.

After 5 years I doubt the damp stain would be faulty work! if it is damp!

If its just staining and salts showing try washing it down with acetic vinegar as this can break down the chlorides, sulphates and nitrates that appear to be damp patches

You may have to do this a couple of times as these properties will remain in the plaster for some considerable time.

Answer 3

you get salting on a wall that is or was damp ..if you get a really damp wall it can take months to dry out ..even after a new dpc is inserted ..the brickwork above damp will be wet ..and if plastered while still damp it can create salts ...that does not say the dpc is not working ..its common to see staining around edge of new plaster ...but if company is doing it right they should be using limelite plaster