Damp Proofing

Damp on the internal wall behind chimney breast in 1950s concrete building

Anonymous user 09/03/2024 - 3.16 PM

We recently bought a 1950s Cornish style house which was originally made from concrete but had the outside walls replaced in the 1980. We took the wallpaper off the wall behind the chimney breast (internal wall, centre of the house) and there is damp and mould over the bottom four inches of the wall, only directly behind the chimney breast and nowhere else in the room. There is a strong smell of damp although the black mould wiped straight off and the plaster is solid. However, there does appear to be a wetter line around the damp and some salt marks. We have looked at the chimney and it appears to be capped off but there are cracks in the pot and we have also found that there seems to be water coming into the master bedroom through the ceiling and that this is from the chimney too. Any suggestions about the likely cause and treatment? With it being in such a confined area, is it more likely to be connected to the chimney or is it full on rising damp?