When to use: Quick sizing of an isolated shallow (spread) footing using presumptive allowable bearing pressures from IBC Table 1806.2 — no geotechnical report required for preliminary work. The required bearing area is A = P / qallow, and for a square footing the side dimension is B = √A. Compaction targets are expressed as a percent of maximum Proctor dry density: structural fill is typically ≥95%, pavement subgrade 95–98%, and non-structural fill ~90%.