Harrison County, MS Accessory Structures: Garage Conversions (2026)

Harrison County regulates garage conversions through local building and zoning ordinances under MS Code Ann. §17-1-1 and the adopted Mississippi Building Code (based on IBC/IRC). Converting a garage to living space requires a building permit from the local jurisdiction (Gulfport, Biloxi, D'Iberville, Long Beach, Pass Christian, or unincorporated Harrison County). The conversion must comply with residential building codes for habitable rooms: minimum 7-foot ceiling height (IRC R305), egress window in each sleeping room (minimum 5.7 sq ft openable area, 24-inch min height, 20-inch min width per IRC R310), insulation (IECC compliance), electrical upgrades to current National Electrical Code, and HVAC extension to cover the new living space. The conversion must NOT reduce off-street parking below the zoning minimum (typically 2 spaces per dwelling unit). Replacement parking may need to be provided through driveway expansion or new carport construction, which itself may trigger setback and lot coverage issues. Fire separation between the converted space and any remaining garage area must meet code (5/8-inch Type X gypsum typical). Harrison County's coastal location adds major complications: properties in FEMA AE/VE flood zones face elevation requirements. Garage conversions below BFE are generally NOT allowed for habitable space under NFIP rules. Post-Katrina, many homeowners converted garages informally for displaced family members; Harrison County code enforcement is now systematically addressing these unpermitted conversions. Historic districts in Biloxi (Point Cadet, West Beach) have additional design review requirements.