Franklin, TN Accessory Structures: Garage Conversions (2026)

A garage-to-living-space conversion is a structural alteration and a change of occupancy classification (U to R-3) under the 2018 International Residential Code as adopted by Tennessee under T.C.A. § 68-120-101 and administered through Franklin Building & Neighborhood Services. A building permit is required, and an electrical permit is required for any new or modified wiring. The converted space must meet code minimums for ceiling height (7 ft minimum), light and ventilation (8% glazing area), egress windows from sleeping rooms (5.7 sq ft net openable, 24 in min height, 20 in min width, 44 in max sill), smoke alarms in each sleeping area and hallway, carbon monoxide alarms outside sleeping areas, and energy code insulation. If the conversion includes cooking facilities and a separate entrance, it becomes an Accessory Dwelling under Franklin Zoning Ordinance § 5.2.7: the unit may not exceed 50 percent of the principal building footprint, only one accessory dwelling is permitted per lot, the owner must permanently occupy either the principal dwelling or the accessory dwelling, parking must comply with § 10.2, and exterior doors/windows must face the principal building, alley, street, or lot interior. A garage converted to non-dwelling habitable space (home office, family room, hobby room with no kitchen/separate entrance) still requires a building permit but is not subject to the Accessory Dwelling rules. If the conversion eliminates required off-street parking, replacement parking must be added per § 10.2 — most R1–R6 zones require 2 spaces for the principal dwelling regardless of the conversion.