I am decorating my bedroom. My house is a 1930s semi. I ripped uo old floor covering and there is a wet patches on the floorboards running along the internal dividing wall of my house and my neighbours. There is also a wet patch on the floorboards on the external wall which adjoins the internal dividing wall. The wall just above the skirting on the external wall feels damp and the wet is along the floorboards. The wet patch is not continuous, just sporadic along the skirting. ANY HELP PLEASE.....