I had a damp problem in my kitchen, cause unknown but contributing
factors may have been:
1. House empty for 2 years.
2. No heating, ventilation for 2 years
3. Kitchen is above a cellar which had become very damp with
4. Kitchen floor is stone flags, which seems to have soaked up moisture
from the damp cellar
5. The plaster on the kitchen walls went right own to the floor, the
stone flags and was therefore able to soak up moisture.
6. The was also a dodgy water stop tap under the sink.
The steps I have taken to address this are:
1. Opened up the cellar windows (after fixing metal gauze to prevent
vermin entry) to get some ventilation.
2. Hacked off two inches of plaster in the kitchen at the foot of the
walls to break the plaster's contact with the stone flags.
3. Switched on the heating and opened some more windows
4. Got a dehumidifier in.
In 5 weeks this has made a big difference, with the kitchen walls now
almost completely dry.
On one part of the wall, I hacked off some loose top layer plaster to
leave the browning undercoat. The undercoat was also damp, but dry now.
I have however noticed on this now dry browning a white powdery deposit,
and I'm not sure how to read this. Is it a sign of fungal rotting, or is
it something harmless that can just be swept away?