We've been noticing a band of damp for some time now about 12ins high across the whole wall area (about 3 foot). The wall is the hall & kitchen, but only damp on the hall side. The right side continues into a cupboard under the stairs so does eventually lean against the outside wall. However the whole of the wall thats in the cupboard is dry. I couldn't be 100% sure but I would say it is worse on a wet day. The bathroom is indirectly above as are some water pipes (all checked) but the top of the wall is bone dry, as is the bottom its just this strange band that is piuzzling us. Any ideas or tips would be greatly appreciated.