Concrete Foundation Footings

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    Concrete foundations used in home and commercial construction come in many different configurations and are made up of many different parts. The four basic types of foundations used in residential construction include: Slab, Kneewall, full basements and post and pier. Each of these require some type of footing. The main reason for a foundation is to support the structure and to provide a level starting point for building. The main function of the footing is to provide a stable base to build the rest of the foundation.

    To allow the foundation to support the home correctly excavators must dig away topsoil until they reach a gravel soil mixture that has no organic material. This is because organic material will continue to decompose and over time this could lead to weakness or voids below the foundation. Frost line depth and soil compaction quality are other factors that must also be considered. If the building will have a basement then additional digging must occur to lower the floor height of the basement so that after grading and landscaping has been performed the first floor door thresholds will be just above finished grade level.

    As you can see we are pouring a footing to support a full basement wall.

    The concrete truck to the rear of the site is at finished grade level and the footing to support the basement walls has been dug about 12″ below the floor height of the basement.

    Various lengths of 2×10 lumber have been used to build the form for the footing and stakes have been driven flush with the form board to support it from the outside.

    Wire fastened 1/2″ Rebar Rods have been placed within the footing and are supported so they will remain mid-height or in the center of the pour as concrete flows around it.

    A 2×4 screed board is scrapped along the top of the form to level the surface of the footing.

    Before the Footing hardens three foot long rebar will be placed vertically every 6 feet in the center of the footing and when the walls are poured they will tie the foundation walls to the footing.

    Many factors are considered when defining the exact placement, size or depth of a footing and your architect or structural engineer will provide a complete plan and spec sheet for you to follow.

    There are many other projects that require a footing. In our other HowTos you will see examples in our deck / porch construction and other home building projects.

    Because of the high level of skill and the specialized equipment needed home foundations should be performed by a professional that only works in concrete but smaller projects like decks, sheds or even some additions can be completed by a owner-builder or a conventional contractor.

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