A Primer on Home Foundation Types

by Murray Anderson

Depending on where you live in the country your home will likely be built on one of three types of foundation - slab, crawl space or full basement. Each has advantages and disadvantages and generally related to climate, are common in different areas of the country. Here's a quick overview of each of the different types of home foundation and some of their pros and con.

Slab foundations

Common in warmer climates where frost isn't an issue, slab foundations are popular with both builders and home owners since they minimize the amount of time needed to build a home. Without the necessity to dig a large hole for a crawl space or full basement homes built on slabs can be constructed much quicker and at significantly less cost than homes built on other types of foundations.
Slabs provide a solid, level surface for floors so homes built on slabs don't often have problems with creaking floors or doors that won't open and close as a house settles over time.
On the downside, slab foundations in general are prone to moisture and pest intrusion, since they are set literally on the ground.
However, perhaps the largest potential problem with a slab foundation is since plumbing and wiring is run through the slab, if anything breaks, it's expensive and difficult to make any repairs.

Crawl Space

Built on raised wall set on concrete footings a home with a crawl space is raised slightly above the ground (2 to 3 feet) preventing moisture and pest intrusion (the home is well above ground) while providing an open and accessible yet enclosed space to run heating ducts, plumbing and wiring.
Some downsides to crawl space foundations include the cost to dig the shallow foundation along with the time needed to pour the footings and build the perimeter wall. Also, since the home is up above ground level,, you need stairs to get into the house so accessibility can be an issue for some.

Full basement foundations

Common in colder areas of the country where the ground freezes in winter, a full basement is built in a hole dug 6 to 8 feet into the ground (below the frost line) to provide a stable foundation. Similar to crawlspace construction the foundation is built on a set of concrete footings built around the perimeter, an external perimeter wall up above ground level and commonly a concrete slab floor.
Full basements provide space for the household utilities along with the head space that allows for building full rooms below grade (building basement rooms is the least expensive floor space you can build in a home since the walls are already built).
The downsides to a full basement are similar to those of a crawl space foundation since over time the foundation will settle and floors will creak and doors may stick.
However perhaps the largest downsides to a full basement foundation is the time and cost associated with building it (digging the hole and building the perimeter walls).