• A basement foundation can serve as storage, living space, and appliance housing.Jupiterimages/Comstock/Getty Images
  
  Your home's foundation is important for keeping a solid structure beneath your house. A solid foundation prevents shifting within the building above, which prevents damage. It can also prevent contamination of your home by dangerous substances such as radon gas. Each type of foundation has options and advantages, as well as drawbacks.
  
  

Slab Foundation

• A slab foundation is, as its name suggests, a flat concrete flooring placed directly beneath the home. A thickened-edge slab, also known as a combined slab and foundation, is a cost-effective option in warmer areas where there is no concern of frost penetration. An independent concrete slab with foundation walls is preferable in cooler climates and is built with walls that extend below the frostline. These walls are supported below ground by piers that lead to solid bearings.
  
  

Crawlspace Foundation

• A crawlspace is a narrow opening between the ground and the lowest floor of the home. This opening is at least 18 inches high and can house wiring and plumbing. Crawlspaces are useful in areas in which termites and other pests are common because they elevate the house above the pests' homes in the ground below. They are also less expensive to lay than are full-basement foundations.
  
  

Basement Foundation

• A basement foundation extends below the ground and creates room for additional living space or storage below the house. Basement foundations are more common in colder climates where frost extends deep into the ground during winter. The basement floor extends below the frostline to prevent shifting below as the ground expands and contracts from temperature change. A basement can be finished and treated as an additional livable level of the home or left with exposed concrete. Basements are more vulnerable to radon accumulation than are crawlspaces and should have a radon detection and mitigation system built into them.