Mobile, AL Accessory Structures: Tiny Homes (2026)

Mobile is one of the more permissive Alabama jurisdictions for small detached dwellings. The City of Mobile Unified Development Code (Chapter 64), adopted June 7, 2022, includes accessory dwelling unit provisions in its residential districts (R-1 and R-2 series). Industry guidance summarizing Mobile's ADU rules describes a maximum ADU footprint in the 800-1,000 square-foot range or roughly 40% of the primary structure (whichever is smaller), one ADU per lot, a permanent foundation, one off-street parking space, and architectural compatibility with the primary home. ADUs may not be sold separately from the main dwelling and the city has historically prohibited their use as short-term rentals. Standalone tiny houses on wheels (THOWs) are not classified as permanent dwellings under Mobile's adopted building code and generally cannot be permitted as a primary residence on a residential lot; placing a THOW long-term may require RV/manufactured-home park standards. Site-built tiny houses on permanent foundations are reviewed under the Alabama-adopted International Residential Code. Alabama has no statewide preemption forcing or prohibiting IRC Appendix Q (Tiny Houses), so adoption is left to the local jurisdiction; verify the current edition and any local amendments with Build Mobile Permitting at 251-208-5895. Floodplain and coastal wind-load standards apply throughout the city.