Flint, MI Accessory Structures: Garage Conversions (2026)

Garage conversions in Flint sit at the intersection of three regulatory frameworks. First, the Michigan Single State Construction Code, adopted at MCL 125.1501 et seq. through PA 230 of 1972, makes the Michigan Residential Code applicable to one- and two-family dwellings. A change of occupancy from non-habitable garage to habitable space triggers a building permit under MCL 125.1513 and full IRC compliance, including R310 (emergency escape and rescue openings — typically minimum 5.7 sq ft net clear opening with sill no higher than 44 inches; below-grade conversions require window wells meeting R310.2), R305 (minimum 7-foot ceiling height for habitable rooms), R303 (light and ventilation), R314 (smoke alarms in every sleeping room and adjacent to sleeping areas), and R315 (carbon monoxide alarms). Second, the Flint Zoning Ordinance at Chapter 50 likely requires zoning approval to confirm that the resulting use is permitted in the underlying transect/district, that floor-area and lot-coverage limits are not exceeded, and that the loss of garage parking does not drop the property below any off-street parking minimum set in the regulating plan. Third, if the conversion creates a self-contained dwelling unit with kitchen, bathroom, and separate entrance, ADU rules apply (see adu-rules entry). Michigan has no statewide ADU preemption, so Flint's Chapter 50 rules govern. Flint's many bungalow-style and post-war ranch homes commonly have attached or detached garages that homeowners have informally converted over the years — many such conversions were never permitted and may surface during sale or insurance inspection.