Oklahoma City, OK Accessory Structures: Garage Conversions (2026)

Oklahoma City addresses garage conversions through two chapters of the Municipal Code. Construction work is governed by Chapter 13, which adopts the 2018 International Residential Code (IRC) with State of Oklahoma and Oklahoma City amendments under the authority of Title 11 of the Oklahoma Statutes (Oklahoma Municipal Code) and 59 O.S. relating to building code commissions. A garage being converted to habitable space requires building, electrical, mechanical, and plumbing permits issued by the Development Services Department, and plans must comply with the IRC for ceiling height, egress windows, light and ventilation, smoke and carbon monoxide alarms, energy code (insulation), and electrical and mechanical work. Zoning compliance flows from Chapter 59 (Zoning and Planning Code). If the converted space is used as a separate dwelling unit (with its own kitchen, bath, and sleeping area), it is treated as an Accessory Dwelling, regulated by use standards adopted in 2025 under Ordinance No. 27,847. Under that ordinance, the total floor area of an Accessory Dwelling may not exceed 950 square feet, only one Accessory Dwelling is permitted per parcel, and a building permit is required when an existing structure (such as a detached garage) is converted to an Accessory Dwelling. Detached Accessory Dwellings must be located in the rear yard and meet the setback requirements applicable to the underlying zoning district. Where an Accessory Dwelling is converted within an existing permitted structure, the existing structure's footprint and height generally control. Off-street parking for the principal dwelling under Chapter 59 must continue to be met after the conversion, and one off-street space is generally required for the Accessory Dwelling unless an exception applies (for example, where the paved street frontage is at least 26 feet curb-to-curb). Accessory Dwellings may be used for short-term rental only when the host's primary residence is on the same parcel and is occupied by the host at the time of rental. Accessory Dwellings are exempt from the standard Section 59-12200 accessory-structure rules but must comply with their own use standards in Chapter 59.