Ways to level the floors in a house include installing leveling strips and pouring leveling compound. For uneven floors caused by a sagging structure, solutions include repairing floor joists and installing new support beams.
The appropriate floor-leveling solution depends on the home. If rotting or sagging joists have caused uneven surfaces, the homeowner must repair the joists to level the floors. A contractor might reinforce either side of the joist with plywood strips or bolt a new joist to the original joist. For increased stability, the contractor can bolt a metal plate between the two joists.
If rotting or sinking support beams are to blame, the contractor can install new beams. This process usually requires the homeowner to lift the floor with a hydraulic jack. The contractor uses the jack to lift the sinking part of the floor slightly, and allows time for the house to settle before lifting again. Once the floor is even, the contractor must install new support beams. A jack may also be required for joist repair.
In homes with a structurally sound frame, leveling a floor is less expensive. The homeowner can remove the flooring and subfloor, and install small, wedge-shaped leveling strips in the lower section. Alternatively, the homeowner can pour leveling compound into the sagging section of the floor. For both methods, a plywood subfloor usually lays over the strips or cured compound.