Indiana Building Codes

Indiana has NO mandatory statewide residential building code. Code adoption is entirely LOCAL - individual cities, towns, and counties choose whether to adopt codes and which editions. Class 1 structures (1-2 family dwellings) are locally regulated. Class 2 structures (commercial, multifamily 3+) regulated by state. Urban areas (Indianapolis, Fort Wayne, Evansville, South Bend) typically have IRC 2018/2021 with amendments. Many rural counties have LIMITED or NO code enforcement in unincorporated areas. EXCEPTION: Indiana Energy Conservation Code applies STATEWIDE (IECC-based with amendments) regardless of local building code adoption. Climate Zones: 4A (southern IN - Ohio River valley), 5A (northern/central IN - most of state). Ice barrier required STATEWIDE (Zones 4A/5A). Frost depth varies 24-42" (deeper in north, shallower in south). Snow loads 15-35 psf (lake effect in northwest increases to 30-35 psf). Karst terrain in southern IN (Monroe, Lawrence, Orange, Crawford counties) - sinkholes/caves. Mine subsidence in southwest coal region (Gibson, Pike, Warrick counties). Lake Michigan shoreline (Lake, Porter, LaPorte counties). Indianapolis/Marion County consolidated (Unigov). No statewide GC/roofing contractor license (local licensing varies). 92 counties.; Updated 2026-03: IN uses IRC 2018 statewide (was incorrectly marked custom)