In this photo, you can see how each of the wooden subfloor supports has extensive mold growth. In addition, you can see how the supports are warped from the moisture absorbing into them. This has lead the kitchen floor above to feel spongy and creak often. The homeowners have also noted that the oven in the kitchen is not level any longer. The last time that they baked a cake, the batter flowed over one side of the pan and was too low on the opposite side--the things that you never think of with sagging floors, right?!