Does a Crawl Space Have a Concrete Foundation?

Post and Beam

• The post and beam method of creating a foundation primarily exists to keep wooden floors and support beams off and away from the soil. This might be because the soil is terminally wet or acidic. The result is that beach houses and homes in very wet areas often have foundations created in the post and beam style, and therefore often have crawl spaces.

Post Crawl Spaces

• Post and beam construction utilizes a concrete footer buried deep into the ground, usually below 12 inches. The footer is normally buried under the “frost line,” or in that depth of the soil not affected by winter freezing. The pier is built from the footer and is almost always made of concrete. Atop this is the post, which then supports the floor joists. This automatically creates a crawl space. It is built into the foundation method. The crawl space is then based on concrete piers and footers, but has a “roof” made of wood.

Shallow Foundations

• Since the 1960s, even in colder countries, homes have utilized methods of creating crawl spaces with normal foundations. This is called the “shallow foundation” and it is used to save money in foundation building, design and repair. A crawl space is created with a regular concrete block or poured foundation, normally associated with a basement. This is still fairly rare in the United States. Usually, the colder the region, the deeper the concrete foundation.

Concrete Crawl Spaces

• Shallow foundations in Scandinavia, Iceland and, increasingly, in the northern United States are using newer forms of insulation and drainage systems to permit a foundation that is not as susceptible to frost damage. If the shallow basement or crawl space is properly insulated and heated, then the frost around the structure will partially melt, permitting a shallower basement. Therefore, while the crawl space is normally associated with the post and beam construction, recent adaptations in heating and insulating technology have permitted crawl spaces to be used in shallow foundation construction.