I am remodeling my basement and when I took down the sheetrock under a window that obviously had been leaking for years, I found the concrete under it crumbling and coming apart. I bought some quikrete to patch it but now the wall is very lumpy. I would like to know the best way to smooth out the wall to use furring strips to reinstall new wallboard. Thanks for any suggestions.

The correct way to finish a basement is to build a 2x4 wall laying on the floor, Then raise the wall vertically, square it, level it and secure to floor and joists. The bottom board, floor plate, should be pressure treated lumber. I would wait to make sure that the crumbling is truly fixed and dry. I would also coat the concrete walls with a sealer made for blocking moisture in cement.