I've got a 4' by 10' room in my basement that is cinder block on all 4 walls. It has a interior door into it. In the past, the door was very tight to the carpet. There is no heat, nor return. We use it for storage, but it has had some water issues from time-to-time so I haven't insulated it. I think I have the water issue resolved now, so I'm thinking of insulating it. If not, should I have an exterior door to the room. If I use an interior door, should I leave a gap to get air flow. I don't want the room to cause musty smell to the rest of the basement.