If the floors in your home are sagging or bouncy, extra supports may be needed. When floors sag the drywall often cracks especially on the corners of the windows or doors. The floor can often be raised back to its proper position and held in place with stronger piers. Sometimes additional piers need to be added when the spans between them is too large. Special care needs to be taken when the floors have been tiled. When the floor is lifted the probability that the tiles will come loose is very high.