When thinking of the system that supports houses or commercial buildings, most people think it begins with the foundation. But even a foundation system needs a foundation, so the very first element when preparing the vertical support scheme is the foundation footer. While not all footings require reinforced concrete, we’ll concentrate on two types that do: grade beam and spread footings.
FoundationsWhen the building goal includes fortitude and longevity, then you can’t forgo the expense of a foundation, especially in areas frequently attacked by high winds, earthquakes or flooding. Together with the footings, foundations also fight differential settlement, where the the building settles at different rates and not all vertically. In addition to avoiding the cracks and structural damage that occur from extreme differential settlement, foundations also:
- transfer loads to the footing or directly to the earth
- anchor the structure to resist wind, floods and earthquakes
- keep the basement dry
- separate moisture-averse building materials from the ground
FootingsFootings offer several primary benefits for foundations.
- They provide a level surface upon which to build the foundation.
- Also, they provide resistance to the upward-acting forces of the soil opposing the downward-acting forces of the weight above.
- With widths greater than the foundation itself, footings serve to distribute the building load to the soil.
- Footings add strength to the foundation system in weak or expanding soils. Shifting soils push on foundation walls above the footing and laterally.
- Footings can help absorb the pressure and shore up the foundation against unstable earth.
- Footings allow the foundation to be sunk far enough below grade to avoid frost depths where heaving and thawing also cause uneven settlement.