Most Common Types of Foundations in Building Construction
Whether constructing single-family homes, skyscrapers, or superstructures, choosing the proper foundation is essential. The foundation of any building serves two main purposes – distribute the weight from load-bearing walls to the soil or bedrock beneath and keep groundwater or soil moisture out.
Builders choose foundations based on the home’s location and climate, soil conditions and area humidity, and of course, the budget.
TYPES OF FOUNDATIONS
1. BASEMENT FOUNDATION
A full basement foundation begins with a hole of at least eight feet deep to accommodate an underground living space whose floor space matches most or all of the home’s ground level. You will place structural foundation walls on concrete footings that run the perimeter of the basement. A basement provides extra storage space, and it can even be finished, adding more living space to a home (maybe an extra bedroom, storage area, small kitchen etc.). The clay composition in the soil can also determine whether a basement is a viable option or not.
2. CRAWL SPACE STEM WALLS
Short foundation walls on concrete footings, or stem walls, form the foundations of houses with crawl spaces. They form a space that is exactly as it sounds: a slightly elevated space below a house through which you can crawl, and often provides enough room for storage, a furnace, and other equipment.
A major advantage of crawl space foundations is the protection of the home. By lifting the base of the house, its walls are protected from flooding and other environmental hazards. The space allows easy access to plumbing, wiring, and other mechanical systems. And raising the base of a house elevates the entire home, which can result in a more aesthetically pleasing house. It is also a less expensive option than digging a full basement. While crawl space foundations are more resistant to termites because of their elevation from the ground, they are prone to mold and mildew because of the moisture that can accumulate below them.
3. CONCRETE SLAB FOUNDATIONS
Concrete slab foundations (or “Slab on Grade”) are one of the easiest types of foundation to build. During construction, concrete footers are poured approximately two feet below the finish grade. The soil behind must be a leveled, compacted piece of ground. From there, two or more layers of concrete blocks are placed over the footers. Internal pipes are installed and rock fillers are added before a concrete layer of 4-6 inches thick is poured on top.
A property poured concrete slab will not have weak points that could crumble over time and cause costly foundation repair issues. But you won’t usually find them in cold climates: As the ground freezes and thaws, cracks can form in the concrete and it can shift.
One notable downside of the slab construction is that sewer and drainage pipes are put in place before the concrete is poured. In case of a sewage or plumbing problem, you will have to cut into the slab to access the pipes.
4. WOOD FOUNDATIONS
Wood might seem like an unusual choice for a foundation, but it became a popular choice in the 1960s. Builders will use preservative-treated wood that is resistant to decay and easy to install. Because they don’t require concrete pouring or labor-intensive masonry work, wood foundations are faster and less expensive to install.
Builders can also insulate these foundations and create a warmer crawlspace—and a less drafty house. Fun fact for those who doubt the durability of wood construction in the right climate: Archaeologists have found beams made of Cyprus wood in Egyptian pyramids that are over 6000 years old.
Certain woods, such as cypress, redwood, and cedar are impervious to insects and mold, but since they are costly, the lumber industry has created ways of treating other lumber to give it similar characteristics. Still, they may not last as long as concrete foundations and can only be used in completely dry soil.
5. FOOTING AND STEM WALL CONSTRUCTION
This is one of the common foundation types, particularly when it comes to homes built in the last 50 years. One of the reasons this type of foundation is so popular is that it provides options. With this type of foundation, it is possible to build a basement, but you can opt for a crawl space as well.
Although this is a popular foundation type, it is also an expensive choice. In order to build the footing, the ground must be excavated, and the stem wall must be constructed with care. This is an excellent choice for homes in many areas.