If a stroll across your living room floor feels like crossing the deck of a ship on the high seas, it's time for leveling. Out-of-level floors are not only a nuisance but sometimes a safety hazard as well. Such floors will likely result in cracks over windows and doors, or doors and windows that stick and that are at least difficult to operate.
Most homes have floors that are out of level to some extent. Some of the causes are plain old settlement, poorly compacted soil, excessively damp soil, excessively dry soil and support posts under the floor that dry out and shrink.
Homes constructed on a hillside, on expansive soil or in earthquake country will probably require the services of a licensed soils engineer and structural engineer, although some of the following remedies may apply.
If you've visited the crawl space below your home, you're familiar with the foundation at its perimeter and the various concrete piers scattered about the area. Atop these piers (they vary in depth from home to home) are support posts. These support posts are attached to a wood block or a steel bracket embedded into the concrete pier at the bottom and connected at the top to a floor support beam.
Over time these piers may either sink or rise depending upon the moisture content of the soil in which they are embedded. If there happens to be irrigation on one side of the home, and none on the other side, water will attack only part of the area and some of the piers may rise causing unevenness in the floor above. Conversely, soil at one side of the home may be extremely dry due a drought conditions, causing a sunken pier.
In either case there is something you can do. Start your floor-leveling project with a six-foot level and a Sherlock Holmes mentality.
Walk the floors of your home and identify the general areas that appear out of level. Place the level over the floor in various directions and locations. Doing this will reveal where the high and low spots are.
Working under the house can be dirty and dark so wear coveralls, carry a drop light and all the tools you'll need. It helps to have an assistant above. Also, you'll need a few feet of replacement post material, a couple of lengths of 2 by 6, a handful of 16-penny nails, a circular saw, a hydraulic jack and lots of patience.
At the locations where the floor is HIGH, place the floor jack over a block of wood directly under the floor beam and a couple of feet from the pier. Using a short piece of post material, jack the floor up slightly, just enough to relieve any pressure on the existing support post, and knock out the existing post. Cut a new support post shorter than the one removed (by the amount calculated with your level) and place it between the top of the pier and the beam. Slowly lower the jack until the beam and new post rest firmly on the pier. Re-attach the new post to the pier and the beam. Be sure to use a connection that is approved by your local building department.
At the locations where the floor is LOW, the process is the same with one exception. The new support post will need to be cut longer (by the amount calculated with your level). Either that or the shims can be used to increase its height.
In severe cases where the condition has existed for a long time, a deep saw cut may be required at the underside of the support beam, in one or more locations, to make the timber yield to accommodate vertical movement of the floor. Short pieces of 2 by 6 should be nailed onto either side of the support beam in those locations to offer additional strength.
If you live in an area where the soil is expansive and is subject to regular movement, there is an alternative to the conventional wood support post. An adjustable floor jack or "screw jack" is a metal device that is useful when there is frequent movement because adjustments can be made with little effort and without getting into all of the work outlined above.
Don't be surprised if a few of your doors and windows that were previously sticking operate well after your floor-leveling project.
