Ohio Building Codes

Ohio operates under a statewide mandatory adoption model through the Board of Building Standards (BBS). The state enforces uniform codes for 88 counties across IECC Climate Zones 4A (southern) and 5A (northern/central). Residential Code of Ohio (RCO 2019) is based on IRC 2018. Commercial codes (OBC 2024) based on 2021 I-Codes effective March 2024. Fire code (OFC 2025) based on IFC 2021 effective November 2025. Electrical follows NEC 2023. Local building departments must be certified by BBS. Charter cities have home rule authority. Ice barrier required statewide. Agricultural buildings exempt.