How to Figure Concrete Footer Sizes

Everyone knows that houses rest on some type of foundation, but many people do not realize that foundations are built on footers. The footer, or footing, typically is made from concrete and is poured to give the structure a solid base. This prevents the home from shifting, which would damage the building's integrity. There are many factors to consider when determining the size of a footer; it is important to make sure you give the home a strong enough base to stay standing.

Local building code books
Soil samples

Instructions

- 1
  Refer to your local code book for size requirements for footers poured in your area. Codes vary from town to town and state to state, so be sure to check both sets of guidelines. The code will tell you how deep you need to dig and whether a footer is necessary at all.
- 2
  Refer to the plans drawn up by the architect or project engineer to determine how heavy your structure will be. A three-story home will require a larger footer than a single-story home.
- 3
  Determine the soil's load-bearing capacity. This number depends on the soil type and varies significantly across the country. A soft, sandy soil will require a wider footer than a strong, hard-packed soil.
- 4
  Determine which type of footer system you will be using. Typical footer options include continuous spread footings, grade beam footings, and spot footings. The width will be the same for each footing options, but they amount of concrete used will vary.
- 5
  Refer to the guide in the references for further assistance. The minimum width of a footing should be 12-inches, the table will help you determine when you need a bigger footer.

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