nog wrote in message .. .
We have a basement below about one-third of the house and its usefulness
for storage is limited by damp, and resulting mould spores.
We've tried to combat this by using a de-humidifier but I suspect the net
result of this is to accelerate the rate at which water is vapourising
through the walls.
Would we have more success by installing one or more extractor fans to pull
air through? The floor area in question is about 45 square metres, split
between two rooms, with a ceiling height of about 2 metres. The remaining
space under the house is just crawl space, although fairly generous in
headroom. The house was built around 1910.

TIA,

Peter

It is best to eliminate the damp at source. If it is coming through
the walls and floor, get it tanked. I read in a building magazine a
number of years ago, that it is feasible to build stud frame walls and
floors that do not touch the walls. Any part of the frame that does
must have poly damp course behind and only stainless steel screws used
to fix anything against the walls and floors.

The only down side was that the surrounding earth would give warmth or
make it cool in summer.

There are other methods, like digging around the house and pouring
hard core, or poly on top the surrounding earth that diverts the rain
water away from the walls.

The external work are the more long lasting. The internal stud walls
makes the place nice.