A wood basement is made of wooden walls in place of concrete blocking or poured cement. Large treated timbers are used to support treated wooden planks that form the basement walls. Used mainly in the northern midwestern United States, the wood basement has proven to give a great deal of competition to masonry-type basements. Using only pressure-treated lumber, the typical wood basement is rated to last 100 years.
When building a home to sit on a wood basement, the initial preparation is the same as when using a concrete basement. The basement hole is dug and the footings are installed. With the footing is secured, the large timbers are set into position. The first rows of planking are nailed against the timbers to aid in standing them in place. Once the main frame of the wood basement is in place, the remainder of the planks are nailed into position, creating the basement walls. The wall boards are usually tongue-in-groove planking, which aids in the strength of the walls.
Once completed, the wood basement's exterior is painted with a waterproofing substance, which renders the basement watertight. In cold climates, the interior walls of a wood basement are covered with fiberglass insulation and then finished with dry wall or thin plywood. In warmer climates, many homeowners choose to fasten wooden shelving between the timbers of a wood basement, thereby providing handy storage space without sacrificing any floor space. An occasional inspection for insect or water damage is all that is required of the walls.
In a wet climate, proper drainage under and around the basement is critical to prevent water from leaking past the wooden walls of the basement. An improperly-planned water drainage system which allows water to accumulate at the base of the walls could lead to a water problem. Placement of sump pumps at high-flow corners of the basement can prevent this from occurring. Recurring water leakage can be addressed by applying waterproofing compound to the basement's interior walls.
Some wood basement construction is used with dirt floors. This is often termed a "Michigan basement" due to its prevalence in that U.S. state. In this type of basement, cement slabs are typically poured to place a furnace, hot water heater and other fixtures on the structure. In some instances, homeowners opt to use only bricks or blocks to set the appliances on. This type of basement also works well for the storage of vegetables over the winter and summer months.