A footing is a concrete pad that spreads a foundation's load over soil. It is wider than the wall or column it supports. That width reduces the pressure on the soil. If the pressure is too high, the soil settles, and the building cracks. The footing is the interface between the building and the ground. It is buried below the frost line to prevent heaving. It is reinforced with rebar to resist bending. It is one of the most important parts of the structure, and it is never seen.

Footings come in several types. A spread footing is a continuous strip under a wall. A pad footing is a square or rectangular pad under a column. A combined footing supports two or more columns. A mat or raft foundation is a thick slab that covers the entire footprint. A pile cap sits on top of piles. The type depends on the soil, the load, and the building. A geotechnical engineer tests the soil and recommends the design.

Footing construction requires excavation, formwork, rebar, and concrete. The soil must be compacted and level. The forms must be set to the right dimensions. The rebar must be placed and tied. The concrete must be poured and cured. The footing must be inspected before the concrete is placed. If the footing fails, the building fails. It is the foundation of the foundation. It is the first thing built and the last thing seen.