I have just bought a flat on the top floor, the bathroom is in the middle with no windows. The fan is ducted into the roof space but after the fan has been on for a few minutes there is a terrible smell of damp. What could this be.
I went to a house to do a PIR. The builder had just installed a fan in the bathroom ceiling but not ducted anywhere (must have been to get the building inspectors OK).
Loft insulation had been laid over top of fan so the fan did nothing.
Have checked all that was suggested, it is vented through an outside wall and there does not seen to be any dips although it goes a long way to the outside. Took the cover off the fan and is very clogged inside. Do you think buying a new unit will help.