Last Spring I got water in my finished basement due to an exterior surface water (not ground water) problem that has since been corrected. The problem is I still get some musty odors especially when the outside hunidity level is high. I live in a raised ranch so about 3.5 feet of the basement is below grade. I noticed when I was cleaning up the water that when they built the basement they used some type of backerboard as insulation behing the baseboard radiators. This backerboard (like the kind you would use behind exterior shingles) remained damp for a long time. I also noticed that the basement walls were not insulated. My question is should I take off the wooden ledge and get behind the lower walls and try to remove some of this "backerboard" and insulate the walls with foam panels? Should I also try to use something like drylok to treat the walls to lower the moisture levels or will the foam panels help in that regard?