I have a terrace house and it has had problems with damp, the damp course has been patched up under gaurantee many times.....but now the damp has subsided salt is coming through......little hand held machines have been held to wall and show no damp, so how do i stop the salt coming out the brick thro the plaster and spoiling the walls, (all walls are painted due to fed up of re papering after dampcourse failed)