I was wondering if anyone can help me. The hallway in my ground floor flat has a slight damp problem. When we first moved in we stripped the wallpaper, had it re-plastered and once fully dried painted it. It looked great for a few weeks and then the paint started to bubble up in small areas, just on one side of the wall. We sanded it back and re-painted the area but it came back again after a few weeks. On the third attempt, it's also come back but this time I've also noticed small orange patches coming through (it looks like rust). The wall in question is an internal wall (on the other side is the communal hallway which we have also noticed has bubbling and crumbling paint). It's only in very small patches so I don't want to pay out for damp proofing. Does anyone have any quick fix solutions that they may know of? Many thanks