Hi, we live in 3 storey terraced house. The old part of the house is 3 storey (200 year old, sandstone, probably sitting on sandstone bed), The front of the basement opens road level, the rear is earth under the extension.
To the rear of the of the property we have a 70's 2 storey extension, to the upper two floors of the old house. So I cannot treat any basement issues from it's outside walls.
To the rear of the 2 storey extension we have just built a single storey extension, of which it's foundations had to go all the way down to bedrock (I guess the same level as basement floor) because of neighbouring issues.
So, the issues - general dampness in the basement - I have been using a dehumidifier as a temporary solution - but need a longer term fix. There is no "running" water on the back wall of the extension but certainly damp - do we need to have tanking membrane - how would moisture escape, or would a tanking slurry/paint on solution work?
We also have dampness on the bottom of the walls on the first floor, these are the old house rear walls that are now internal - will this need treating with an injection cream?
One other point is because of our new extension all rainwater from the gutters now go to a soak away to comply with building reg, rather than into mains drainage as it was. Are we going to see an increase in dampness in the basement (there has been no great evidence of this as yet, it is downhill (thats the way the sandstone bedrock is running) from the soak away. I didn't think about the basement when we put the soak away in.
Any advice welcome as I plan to DIY it.
many thanks
Matt