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

The UDC defines "coverage" at Sec. 64-8-2 as "the percentage of a property that is covered by buildings and other roofed structures," clarifying that the term refers to building coverage unless the code says otherwise. For the R-A (Residential Agriculture) district, Sec. E's dimensional standards table sets coverage at a maximum of 35 percent, alongside a 1-acre minimum lot area, 1 dwelling per lot density cap, 35-foot height limit, 25-foot minimum front yard, and 10-foot minimum side and rear yards. Coverage limits vary by district: the adjoining Sec.

E table for Single-Family Residential (R-1) sets coverage at 50 percent in the R-1 Urban sub-district, 35 percent in R-1 Suburban, and up to 75 percent per individual dwelling lot in R-1 Conservation, which trades a higher footprint allowance for smaller minimum lot sizes and clustered open space. A structure or site that already exceeds its district's coverage cap is treated as a nonconforming structure or nonconforming site under Article 6: Sec. 64-6-2 lets it stand and be occupied if kept in good repair, but any expansion must conform to current district requirements, and an expansion exceeding 50 percent of the existing footprint must bring the whole property, not just the addition, into compliance.

Sec. 64-6-3 applies the same 50-percent trigger to nonconforming site features generally. Building or expanding past the coverage cap without an approved variance is not simply flagged at inspection; it blocks future permitting on the property until corrected.