Footing vs. Foundation: What’s the Difference?
A foundation supports a structure, while a footing usually supports the foundation
Highlights
Footings support foundations, fence posts, and smaller structures.
Foundations can sit directly on soil but often rely on footings.
Footings help distribute foundation loads further down into the ground.
Footings help avoid foundation movement from expanding and freezing soil.
When it comes to home construction, many homeowners don’t know the difference between footings versus foundations, in part because these parts of the home often aren’t visible. Understanding the difference can help you anticipate and determine foundation issues that might pop up in your home and better understand how your home gets support from underneath. In this guide, we’ll explain what footings and foundations are and how to tell the difference between the two.
What Are the Differences Between Footings and Foundations?
A foundation is a large structure under a home that provides even and level support for the house above, which is either in contact directly with the soil or sits on footings. A footing is a relatively small piece of concrete that’s set deep into the ground to distribute the load from the foundation to stable soil. Footings can serve as a small type of foundation on their own but are more often part of a larger foundation.
Foundations and footings are usually both concrete, and the term “foundation” often includes the footings that support it from underneath. Construction teams and homeowners also use footings on their own to support smaller structures, like sheds, pergolas, arbors, and fence posts.
| Type of Difference | Footings | Foundations |
|---|---|---|
| Definition | All footings are foundations | Some foundations are footings |
| Application | Can support foundations or small structures | Support large and small structures, often with the help of footings |
| Material | Concrete | Concrete |
| Relation to Soil Movement | Typically less prone to soil movement | Can be more prone to soil movement |
Footings vs. Foundations: Differences in Appearance
You can tell the difference between footings and foundations based on a few different key points. Keep reading to learn more so you can distinguish between the two.
Location
Footings are usually not visible since they reach several feet into the ground and often sit below your home’s foundation. Any concrete you see below most homes is a part of the foundation. The exception to this would be concrete piers in a pier and beam foundation, as those pieces of concrete are technically footings that are a part of the foundation system.
Some footings that aren’t a part of your home’s foundation might be visible, like those below deck posts, sheds, or fence posts.
Size
Visible footings that serve as standalone foundations for small structures—like shed footings, deck footings, patio footings, or pergola footings—are usually less than a foot in diameter. Footings that support home foundations are usually much larger, but most are fully underground and aren’t visible. The exception would be the visible concrete supports under a pier and beam foundation.
Foundations are large structures made out of concrete that usually span the entire footprint of your home. Concrete slab foundations, crawl space foundations, and basement foundations all have slabs that make up the base of the foundation, and crawl spaces and basements also have concrete foundation walls around the perimeter.
Type
There are four different kinds of footings that builders use in home construction:
Individual footings: These are the most common, and they’re also the type that appears under smaller structures, like decks and pergola posts. They consist of a single concrete pier set into the earth.
Combined footings: These are two individual footings placed adjacent to one another under particularly heavy pieces of a structure.
Raft footings: These are large slabs that sit directly on top of the soil and support the entire structure above without other footings underneath. This is what you’d see in a floating slab foundation, one of the most common shed foundation types.
Strip footings: These are like underground walls that provide continuous and even support for a wall above the ground.
There are four main types of foundations, many of which can include footings below for support:
Slab foundation: Slabs can either sit directly on the soil or on shallow or deep footings. There is no underhome area, and the structure sits directly on top of the concrete slab.
Crawl space foundation: This consists of a concrete slab, usually around 4 feet underground, and concrete block walls around the perimeter. It often includes footings below for support.
Basement foundation: A basement is similar to a crawl space but sits much deeper in the earth, often on footings. The inside of a basement is usually 7 to 10 feet in height, with concrete block walls or poured concrete walls around the perimeter.
Pier and beam foundation: It consists of concrete piers (footings) set into the earth and wooden beams that rest on them and support the structure above.
Footings vs. Foundations: Differences in Applications
In addition to the differences in appearance, you can often use the application in which the concrete appears to tell if it’s a footing or a foundation.
Home Construction
Since home construction involves a large, heavy structure, there’s usually a foundation system that involves footings. You typically won’t see a home sitting solely on footings, except in the case of a pier and beam foundation, in which the footings serve as the foundation, or with a floating slab foundation, which is uncommon in residential construction.
Outbuilding Construction
Smaller outbuildings, like sheds and detached garages, are much lighter than homes and can sometimes include footings without a complete foundation system.
You might see footings as a standalone foundation for sheds, but floating slab foundations are more popular options for larger sheds and detached garages. Floating slabs are considered footings because they deliver the load of the structure to the soil, but they’re also considered foundations since they provide even and level support to the structure above.
Other Minor Construction
Finally, you’ll almost always see footings and not complete foundation systems for things like pergolas, arbors, and fence posts. These lightweight structures typically use individual footings that distribute the load to a deep-enough level where soil expansion from freezing and moisture from runoff isn’t a major concern.
No matter the application, a concrete foundation company near you can help you decide which foundation type is best for you and will suit the climate and weather conditions in your area.
Frequently Asked Questions
A floating concrete slab is considered a footing since it distributes the weight of the structure to the soil, but not all concrete slabs are considered footings. For example, a T-shaped slab includes separate footings below the slab that support the concrete above and push the load further down into the ground. In that case, the slab would not be considered a footing.
Yes, you can pour a foundation slab without footings, in which case it’s often called a floating slab. Floating slabs don’t have separate footings poured beforehand for support, which means they’re better suited for smaller structures. Monolithic concrete slabs are another option for a slab foundation without standalone footings, although the vertical edges of the single-pour slab do act as footings.
The depth of a foundation footing can range from about 2 feet to 8 feet or more. The depth of a foundation footing depends on several factors, but the most significant one is usually the depth of the frost line. Footings distribute the load of the foundation and the structure above to soil that won’t see a lot of expansion and upward movement, which means it needs to be deep enough that the soil underneath won’t freeze or see a lot of fluctuation in moisture content.
Yes, you can pour the footings for your foundation and the foundation system itself together, in which case the footing acts as the foundation. Some common examples of a foundation where you might pour the footings simultaneously include floating slab foundations and monolithic slab foundations. Both lack traditional footings underneath the slab, so these foundation types are considered footings.