The footing is what's actually in contact with the ground, while the foundation is the structure that transfers the load to the earth. A simple way to visualize the difference when comparing it to the human body would be to view the footing as the actual feet of the legs and the foundation being the legs themselves.
As its name implies, the main floor of a home is raised above the plane of the lot's soil. To create the raised slab foundation, a base structure of footings is constructed, and a perimeter wall is built upon the footings.
The purpose of a footing is to make sure the house does not move due do earth movement. But there are houses all over the world that have dirt floors and no footings. If you have a building department or building codes a footing will be a requirement. But it can be done.
Essentially, footings create an additional load-bearing point between the structure and the ground. This is especially helpful when building with shallower foundations. As a result, they help transfer weight into the ground so that the structure doesn't bear as much weight.
The Difference Between Foundations and Footings
The foundation of a building transfers gravity loads below the ground from the superstructure, whereas the footing is in contact with the ground (not below it). A foundation directly connects with soil and transfers it to the ground.
The footing must be level and must extend past the edges of the hole so that it can support the weight of the building. After the footing has been created, the foundation walls can be built. The foundation walls are usually made of concrete, but they can also be made of stone, brick, or wood.
As the name suggests, footings are in contact with the ground, reinforcing support to individual columns. Foundations, on the other hand, can be thought of as the leg of a building, transferring the load between the footing and whatever structure sits above it.
The footings are designed for both a maximum total load and a minimum dead load. This tries to insure that if the soil heaves, it heaves around the foundation rather than picking up the foundation.
A minimum of 12”inches deep for all footings and the width will be determined by the amount of stories, 12” inches for a single story, 15” inches for a two story and 23” inches for a three story. This is based on a soil bearing capacity of 1500(psf).
A permanent foundation means permanent masonry, concrete, or locally approved footing or foundation, to which a manufactured or more home may be affixed.
Without rebar, the concrete may be prone to cracking, collapsing, or failing under heavy loads. This can compromise the safety and stability of the structure.
Bottom of the Footings
The preference for the bottom of the footing is that it is level. Exception: If building on a sloped grade, you can step the footing by as much as one unit vertical per 10 units horizontal (or a 10% slope).
Footings typically must extend below the frost line to prevent shifting during freeze-thaw cycles. Dig footing holes about 6 inches deeper than required. Fill the bottom of the hole with 6 inches of gravel and compact the gravel with a 2x4 or wood post.
Contractors regularly look at the basic U.S. residential concrete foundation as being a three-day process. Excavation, footing forming and concrete placement on day one; wall forming and concrete placement on day two; and form stripping, clean-up and waterproofing on day three.
Once the footings are set and pass inspection, a contractor will pour the concrete into the home's overall foundation. This could entail anything from a slab to crawl space to a full basement. The foundation is the backbone to everything else we discuss below, which essentially rests on top of it.
For every 2 feet of adjustment to the width of the house, add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).
The footing depth, on the other hand, is typically determined by the soil type and the extent to which you must dig before striking undisturbed soil. Still, we recommend that the depth of the footing extends to a minimum of 12 inches after you've hit undisturbed soil.
Footings shall be a minimum of 8 inches by 24 inches (203 mm by 610 mm) for houses two and one-half stories and less. The footings for a three-story building shall be 10 inches by 24 inches (254 mm by 610 mm).
Poured concrete is the strongest type of foundation for a house. Concrete is incredibly strong and durable, and it can be poured into any shape. This makes it ideal for supporting the weight of a house. Block foundations are also very strong, but they are not as flexible as poured concrete.
It's "footing" not "footer," but...it's kind or a regional thing. I learned to build in Virginia, and everyone said footer. So what's a footing/footer? It's the "foot" at the bottom of a foundation wall that increases bearing surface.
Required Footing Sizes
In most cases, a house should have a minimum footing of 12 inches wide by 12 inches deep, with foundations that are 8 to 10 inches thick. This should be enough to support house weight and resist lateral soil and water pressure.
Can you pour a slab without footings? 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.
A multi-purpose concrete that is used on a wide range of commercial and domestic construction sites. C25 is often used as a foundation concrete mix when pouring foundations (footings). It is also the ideal concrete for domestic slab foundations for house and bungalow floors.
The average cost to install concrete footings is $750, though the price can range between $250 and $3,600. Concrete footings cost anywhere from $1.50 to $24 per linear foot, depending on width. Heavier homes and homes with multiple stories require wider concrete footings.