I've just pulled a small wardrobe type cupboard away from he wall to clean behind it at my Dads place and the wall is dripping wet. There was a problem with damp a few years back, (tumble drier vents into the room), but using a dehumidifier seemed to have cured this. Is the fact that this cupboard is against the wall, (about 2cm clearance), trapping the damp and preventing the dehumidifier doing its job? Or could it be a leak from the roof or wall? The wall in question is completely tiled and the room is an extension on the side of his bungalow.
TIA, Drew.