"Christian McArdle" wrote in message .net...
As the work will cost £300, I just wanted to double check here with
the experts, that an moisture triggered extractor fan in one room,
will sort out the problem for the whole house.

It may or may not. Assuming that penetrating and rising damp is definitely
not a problem, then the basic problem is that the downstairs entrance hall
has cold, wet air. The extractor fan will hopefully reduce the moisture, but
the real difference between that part of the flat and the rest is that there
is no heating.

As the wet air tumbles down the stairs, it gets progressively colder. Cold
air can't hold moisture, so it condenses out onto the walls.

It is certainly a very good idea to have a kitchen extractor anyway. I would
be inclined to see if it helped before determining if another cause is
indicated, as you should have one anyway.

Other things you should be checking are that you do not have flueless gas
heating and that you don't dry clothes by putting on a radiator, or use a
vented tumble dryer with no vent.

Christian.

Hi Christian,

Thank you for your response.

I had a Valiant Gas Boiler installed recently, which I guess is
properly vented - it certainly has a vent to the exterior wall.

I do indeed dry clothes in the hall, not by putting them on a
radiator, but by using a Victorian clothes dryer. I suppose this
cannot help. I also have a washer/dryer (a Bosch Classixx Wash and
Dry) with no apparent external vent. Combining this with a
dishwasher, and cooking, I guess that (as you say) an external kitchen
extractor would be no bad thing, so think I will go ahead and get that
fitted, and see whether the downstairs mustiness goes away.

I guess it might not, but I suppose that it may be general consequence
of the poor design of what is a converted house rather than a purpose
built flat.

Thank you again.

Robin.