We are in the process of purchasing a 70 year old house. It has a fully modernized basement with 3 bedrooms, 3/4 bath and rumpus room. It also has wall to wall carpeting. Today when my wife was vacuuming, she came upon a "crunchie" spot in the carpet in the closet. After ripping off the baseboard and pulling back the carpet, we discovered that the cement is white and chrystalized and breaking down. Is this alkali and what can be done to remedy the problem?