Hi

I'm in the process of buying a Georgian terrace in E1 (london) and the
survey has recommended that the basement rooms (originally the
kitchen, but now the bedroom) are tanked as there is extensive damp.

I'm currently trying to get some quotes for how much this work would
cost, but as I have no experience of this, I don't want to get stung
for work which won't fix the problem or cost a fortune!

The front and back walls are not earth-retaining as there is a little
under-the-pavement room out the front which can only be accessed by a
door from the bedroom (which doesn't fit well, but I'm planning to
replace) and the side walls are part of the terrace. Both rooms also
have windows. From what I've read about tanking, I'm not sure that it
can be done to rooms with windows and/or doors. Is this true?

Also, I went back to the property at the weekend and couldn't see any
evidence of the damp on the walls (survey done in August) and the
survey didn't say where the water was coming from, so I'm beginning to
wonder how bad it is.
The only thing I spotted was that the drain for the outside cellar
room appears to be blocked - is this likely to be causing the damp?

Thanks in advance for any advice or help.
Nicky