I recently bought an inter terrace house where the previous owners obviously painted over the damp patch on the lounge wall. I have had the flashings resealed and still the damp gets worse. I also have mushrooms growing in one spot. The specialists concluded it is my neighbours tiled on top of concrete roof that is leaking and the water is tracking down and finding its way on to my wall. The neighbour has refused to pay as they do not have any problems. The proposal is to cut a hole into my ceiling and spray at 45 degrees a chemical solution which will allegedly travel up through the brick wall about 1.5m reach the top (covered by flashing) and then turn right and head into the neighbours concrete roof. Is this realistic, it does not sound logical to me.