I am selling my house and the surveyor has been to check it over. He checked the interior wall of the living room and sucked his teeth and said the wall was 10-15% damp in places possibly caused by problems with the exterior UPVC boards. I have since checked the rest of the house myself and find most of the walls are in this range, but there is no sign of damp nor has there ever been and the house feels warm and dry so is the 10-15% figure he quoted significant? If it is what range should the interior walls and brickwork be?
many thanks