In a recent underfloor excursion I noticed a massive difference in the dampness of the subfloor between our lounge - which is on one of the open sides of the house - and study, which is effectively in the centre of the house with minimal ventilation. In fact the study was cinder-dry and just covered me in dust, whilst the subfloor in the lounge was earthy and clammy. On a previous visit both rooms were equally dry.
As well as seeming a bit damp underfloor, the lounge has always been extremely cold. There are two sizeable radiators, but also an open fireplace which must remove a lot of warm air. In fact, sometimes the carpet feels a bit wet on the surface,as if condensation is forming.
Is it generally advisable to insulate the underside of the wooden floor? There is nothing at present. Will this have a detrimental effect on the already-poor ventilation, which is presumably the root of the dampness?
I also noticed that two airbricks at the rear are actually placed level with the floorboards, i.e. only the bottom half of the brick is below floor level. Not surprisingly, my coathanger doesn't get very far in the top half. Even in the bottom half I would say only 10-20% or so of the airbrick is clear.
Any advice is welcome, both on the potential damp situation and on warming the room up as autumn draws in.