CertainTeed Learning Center: Foundations

How many types of building foundations are there?

One of the most important features of your new house is buried underneath it. Most people don’t think too much about types of building foundations when they’re having a new house built but the foundation is as important as any other element of your structure. It's what takes all of the loads from the roof to the walls to the floors, and transfers them into your soil.

The foundation is the first piece of a home to be constructed and creates a base for the rest of a home’s components. There are three types of foundations that are commonly used in the U.S.

Full-height basements
Crawlspace
Slab on Grade

A full-height basement is an accessible space between the soil and the bottom of the first floor of a home. It usually has more headroom than a crawlspace. Full-height basement construction is predominant in cold climates where the foundation needs to be situated below the frost level.

A crawlspace is an accessible space with limited headroom, typically between the soil and the bottom of the first floor of a home. Crawlspace construction is predominant in areas where there is heavy clay content in the soil.

Slab-on-Grade is a type of foundation consisting of a structural concrete slab poured directly on the grade. No accessible space exists in slab-on-grade construction. Slab-on-grade foundations are popular in areas where there is a high water table.

All three types of building foundations are usually constructed out of poured concrete, but can also use concrete masonry units or insulated concrete forms. Poured concrete walls use removable forms that are stripped when the concrete has cured. High R-value foam panels can be integrated into this construction system to provide a code-compliant, insulated, ready-to-finish wall, without the need to frame-out the basement.

Concrete Masonry Units (CMUs) are hollow, concrete blocks. To create the foundation wall, mortar is used between blocks to hold them together, forming the wall.

Insulated Concrete Forms (ICFs) are made of rigid foam insulation forms into which concrete is poured. ICFs are common in regions in which the local building code requires the foundation to be insulated. Another benefit is that the homeowner or builder is able to finish the basement immediately, without adding studs.