Comparing the 5 Types of Foundations

The five most common house foundation types are basement, crawlspace and concrete slab, as well as wood foundations and pier and beam designs. The most common building foundation materials include concrete slab, concrete masonry units (CMUs) and pressure-treated lumber.

Basement foundations are the deepest type of home foundation and support the house with structural walls that extend underground. Basement walls are usually at least 7 feet high.

There are two types of basements.

• Full basements feature foundation walls that run along the perimeter of the ground floor. For example, if a ground floor has 900 square feet, a full basement will also be 900 square feet.
• Partial basements, also called daylight basements, feature some walls below ground and some entirely or partially above ground, to allow daylight. These can only be designed in homes built on slopes.

Finished basements are popular choices because they can significantly increase a home’s living space. Unfinished basements offer convenient locations for furnaces, water heaters and other storage options.

Basement foundations are usually the most expensive of the home foundations, ranging from $10,000-$175,000. They can be more costly if the home is built on bedrock that requires major excavation or removal by blasting.
The average cost to finish an unfinished basement in the United States is $18,395, or $25 per square foot.

Basement foundations can have high maintenance requirements, frequently involving leaks and other water damage. They are not recommended for areas that have a high water table.

Crawlspace foundations are built on stem walls, or short structural walls on footings. Crawlspace stem walls are usually 4 feet or less. Unlike basement foundations, crawlspace foundations are too low for conversion to living space.

Crawlspace foundations are less expensive than full basements, ranging in price from $8,000-$21,000. They are preferable for sloped lots over slab foundations because crawlspaces require less excavation.

Features of crawlspace foundations include easier access to electrical wiring and plumbing systems. Their design allows ventilation to control the build-up of moisture below the house.

Considerations for crawlspace foundations include that they lack heating and can be difficult to move through.

Concrete slab or slab-on-grade foundations are solid concrete foundations that rest on the ground and usually have mesh or rebar reinforcement. They are usually 4-6 inches thick and are more effective on level ground or minimal slope.

Concrete slab foundations are the least expensive of the house foundation types, ranging from $4,500-$21,000. They are impervious to termites and other insects.

Considerations with concrete slabs are that they make plumbing and electrical systems less accessible and more expensive to repair. They also lack the storage or living space options of basements or crawlspaces.

Concrete slab foundations are best in moderate climates. They are not recommended for climates with temperature extremes, as they can crack when the ground repeatedly freezes and thaws.

Wood foundations, despite the name, are usually built of both wood and concrete. Wood foundations consist of pressure-treated wood walls below grade, usually on a base of concrete slab that provides the floor of the basement. Wood foundations were popular in the 1960s but are not common in contemporary builds.

Wood foundations are quicker to install than other types of foundations. They can save up to $15,000 compared to concrete foundations, depending on the type of wood and location of the home in the United States.

The foundation lumber is chemically treated to resist rot, mold and termites. These foundations also offer more accessibility to plumbing and wiring.

Wood foundations are less durable, more susceptible to water damage and do not last as long as masonry foundations.

Pier and beam foundations, also called pile or pier and post foundations, are a specialized type of foundation that resembles a crawlspace foundation. This design features concrete piers that support a grid of beams and leave a crawlspace beneath the house.

In some areas with sand or unstable soil, pier and beam foundations use long pillars of concrete or treated wood that are sunk into the ground until they reach load-bearing soil. In some cases, the structural poles can be 15 yards or more depending on sand or soil conditions.

Pier and beam foundations are common in homes built along coasts or in areas prone to significant flooding or storm surges.

Pier and beam foundations are simple to build and less expensive than basement foundations. A 2,000 square foot foundation will range from $16,000-$30,000.

The following are the most common types of building foundation materials.

• Poured concrete walls are the most durable for use below ground. They resist breaking and cracking and keep out water and earth better than concrete blocks.
• Concrete masonry units (or CMUs), including cinder blocks, are blocks made of concrete or aggregate. They require assembly with mortar and waterproofing.
• Precast concrete panels offer similar advantages to poured concrete while eliminating the time spent waiting for concrete to cure. Installation can be complex, often requiring a crane.
• Pressure treated lumber is cheaper and easier to install than poured concrete.
• Steel is lighter and more durable than lumber when used for framing. (See our guide Metal Studs vs. Wood Studs.)
• Stone is prone to chipping or cracking and is no longer a common material in foundations but can be found in older homes. Homes with stone basements use a combination of stone and mortar.

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