"Andrew Barnes" wrote in message
...
I have a cellar which has damp wall, not wet, just damp. The existing
white
paint is coming off in places and there is a white powdery deposit.

I would like to make it into a pleasant room, so need to tank the cellar.

Can anybody recommend any systems?

Get to the problem at source. Dig up around the foundations in stages, and
fill with hardcore. This keeps the water away from the walls . While you
are at it put insulation against the walls to eliminate heat loss to the
ground. Around the walls have concrete on ground sloping away from the
walls. This stops water getting under the ground near the walls and takes
water away from the walls when drained. If you cannot ring the house with
concrete, put thick poly sheeting under ground from the walls slanting away
from the walls (do this as a matter of course anyhow). This will drain top
water away from the walls. In the US some put insulation about a foot under
the ground slanting away form the walls, about to as far as you can go.
This keeps the ground under very warm, and les influenced from the cold
surface earth colled by the cold air above.

Then paint the cellar walls with about 2 to 3 coats of Sythaproof. You
should be fine for ever after that. You may want top install a heat
recovery and vent system to permanently vent the place. There are a few web
sites around explaining this. One is a council in North Wales, either Clywd
or Powys.

The materials are not expensive, but the labour is and doing it yourself a
little time and patience is needed. Well worth it to basically add on an
extra habitable floor, as that is what you are doing. Far cheaper than an
extension and a large cold bridge is eliminated making the house cheaper to
heat. You could do it all in a summer and then have an extra floor to your
house. Try doing an extention floor to the top of your house in your spare
time during a summer.