Birmingham, AL Building Setbacks & Zoning: Lot Coverage Limits (2026)

3 sets the district's cap on maximum manmade impervious surfaces, defined as roof top, paved parking, and like surfaces, as a percentage tied to the use on the parcel rather than a single citywide number. Retail sales or services and light industrial or warehousing uses can cover up to 80 percent of their site with impervious surface, office or research uses are held to 65 percent, and every other use in the district, including most residential development, is capped at 50 percent. For attached single-family dwellings, the ordinance clarifies that the ratio applies to the composite site as a whole rather than to each individual parcel, so a row of attached homes is measured together rather than lot by lot.

The section gives the director of the Department of Planning, Engineering and Permits authority to interpret how a given use fits into these categories, with any appeal of that interpretation going to the Zoning Board of Adjustment rather than the courts in the first instance. This impervious-surface limit sits inside the same Subsection 6 that also fixes required open space (a minimum 15 percent of gross land area at the conceptual-plan stage) and required civic-use dedication (3 percent for MXD/R and MXD/E subareas, 5 percent for MXD/VC), so a developer proposing an MXD project has to satisfy the coverage cap, the open-space minimum, and the civic-use dedication together, not any one requirement in isolation.