We live in an old house that has a stone basement foundation. Because the wall surface is irregular, we can’t install rigid foam panels to insulate the basement. What other methods should we consider?
If your aim is to finish the basement, a good approach would be to have a spray foam contractor apply a coating of 2-part, closed-cell spray foam against the rock walls from inside your basement. Make the final thickness of the foam between 1 in. and 3 in. Once the walls are coated with spray foam, frame new walls about 2 in. to 4 in. from the foam-covered walls, using steel studs. Unlike wood studs, steel versions can’t absorb and hold moisture or attract mold, so they’re definitely better in the basement. Your new walls can now be finished by fastening mold-resistant wallboard against the steel framing.