Every building has a foundation for that building to rest upon. Basically put, a foundation is the construction that is below the house and ground that supports the weight or load of the house. The type of soil in the region where the home is being built will generally determine what foundation the house will have.
Types of House Foundation
Generally there are three different types of home foundation. The house foundation types are basement, crawl space and slab.
Generally a basement is partially underground and has a walk-out. Sometimes basements will house the garage. They will have a concrete floor and walls then have steel and wood beams supporting the house. Treated plywood and lumber can be used in constructing the joists and ceilings of the basement. Many times basements are finished into usable living space allowing a home’s living space to be expanded without having to build onto the existing structure. If a basement is not sealed properly, it can leak and create moisture. If the moisture is not tended to it can cause black mold. Basements have also been known to flood in extreme situations. In some regions the soil will not allow for a basement to be dug.
Crawl spaces are also called raised foundations. If the frost lines are not deep in the region that the house is being built, then the house will have a crawl space. Usually a crawl space will have stem walls around the perimeter and then a girder system with floor joists on top. A crawl space is about 2 feet tall; sometimes it is a little taller, around 3 feet. The flooring of a crawl space is usually gravel, however, it can be just graded dirt or thin concrete. Wood such as treated plywood and lumber can also be used when constructing a crawl space. The crawl space is needed to be able to maintain or repair the house’s mechanical systems. Flooding within the crawl space can be problematic since all the mechanical systems are located under the house within the space.
A slab of concrete is poured directly on the ground. This is used in areas where the water tables are very high and any type of deeper digging will disturb them. The area where the slab will be placed is graded so it sits fast. A footing is dug and then poured to hold the slab in place. Gravel is placed prior to the slab being poured.
This is a more cost effective and time efficient foundation. These are found in tract housing. The pouring of the slab is done all at once. Slabs are best used in places that do not generally freeze in the winter. Slabs do not do well within regions where freezing and thawing occurs on a regular basis.