Introduction
Substantial footing supports of reinforced concrete are needed for buildings that have external or internal masonry walls - solid brick, cavity wall, brick veneer, or concrete blocks and earthwall or stonewall. Reinforced concrete footings are commonly called 'strip footings' and are usually continuous around the entire perimeter of the building.
Strip footings require a minimum specified depth of concrete to ensure that the footings have adequate strength. This depth is called the 'overall depth' of strip footing. It has the symbol Df.