The footing is the base of a structure and the first step in a foundation. It is a mass of concrete supporting the foundation of the house.
The concrete footing is the most important part of the steps above and is the most important part of the house.
If it is built on unstable soil, the house will settle and the foundation will crack. If the footing settles or moves, so will your house.
Local building inspectors usually check the location, depth, width, and soil suitability of foundation footings before the concrete is poured to make certain that the footings will be deep enough and be resting on undisturbed stable earth.
If the inspector is not satisfied with any facet of the footing parameters, he or she can demand that you employ either a structural engineer or a geotechnical engineer, or both to determine a course of action.
If it is not done according to the dimensions of your plans, you will have to change the plans to accommodate the footing or do the footing over.
House footings can be poured into wooden forms or into trenches.
Foundation footings must be below the frost line, or they will heave when the ground thaws and freezes.
In the northern states and higher elevations of any area, this frost line may be 4 or more feet below grade level.
That is one reason why basement foundations are more prevalent in colder climates.
The footing inspection is the most critical inspection that any building inspection department can make.
If additional expenses are incurred at this stage to be sure the footings are done right, don't complain.
It could save you, the home owner, thousands of dollars if it means that you will avoid some future foundation settling problems.
If you plan on doing this critical backbreaking work yourself, or if you at least plan on ordering your own concrete, here's a concrete calculator from Concrete Network.
Hire a professional foundation contractor for the footings.
Do it right, do it once. Carl Heldmann.