I am dismanteling an old apartment that was in my basement (before I owned my house). My house was built in 1905 and has concrete walls with lots of stones, about the size of my hand, mixed in the cement. As we were taking the old drywall down I could here rocks falling from the walls. The concrete seems to be sand-like and soft. There is a 5 to 7 inch divet that is about 3 feet long. I am assuming that the wall decayed before the drywall was put up (20 years ago) because there were no piles of stone or cement between the drywall and basement wall. I have never experienced water leaks. Could it be the age of the cement or dampness that has been dorment within the concrete for years. How should I approach this problem? I am attempting to just make the basement into a basement with painted cement walls and floors. The walls are not sagging and the house has typical settling (it is balloon framed). The exterior basement walls are in very solid shape and look great. What should I do to repair this wall?