5 county-level rules, plus city-specific rules for 4 cities in Franklin County, Ohio.
Verified from official government sources
Columbus legalized accessory dwelling units citywide in 2024 under the Zone In Columbus code update. ADUs of up to 800 sq ft are permitted on most single-family lots with a single-family permit, an owner-occupancy requirement, and standard setbacks. Suburban Franklin County cities have varying rules; many still prohibit ADUs.
Sheds in Franklin County under 200 sq ft are exempt from building permits under the Ohio Residential Code, but still must meet zoning setbacks. Columbus requires a zoning clearance for any shed; most suburbs require building permits above 200 sq ft. Typical setback is 3 ft side and rear.
Garage conversions to habitable space are permitted in Franklin County but require building permits to verify insulation, egress, ceiling height, and life-safety standards. Columbus allows conversions and they may count as ADUs under the 2024 Zone In rules. Parking-replacement is required.
Carports in Franklin County must comply with the same zoning setback and permit rules as accessory structures. Columbus requires a zoning permit regardless of size; building permits are required for anchored structures. Front-yard carports are generally prohibited in most residential zones.
Tiny homes on permanent foundations are legal in Franklin County if they meet the Ohio Residential Code minimum floor area and habitable space standards. Tiny houses on wheels are generally not permitted as permanent dwellings under Columbus zoning; they are treated as RVs or trailers and subject to RV parking rules.
4 cities in Franklin County have their own accessory structures rules. Each link goes to that city's dedicated page with code citations.
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Franklin County Ordinance Hub →