Arlington Heights, IL Accessory Structures: Garage Conversions (2026)

Arlington Heights zoning ordinance requires single-family homes to maintain a minimum of two enclosed off-street parking spaces, typically provided by an attached or detached garage. Converting a garage to living space, a home office, or any other non-parking use requires that replacement enclosed parking be provided on the property. This effectively means a new garage must be built before the existing one can be converted. A building permit is required for any garage conversion, and the work must comply with residential building code standards for habitable space including insulation, egress windows, ceiling height, HVAC, electrical, and fire separation requirements. Converting a garage without providing replacement parking is a zoning violation. The conversion must also comply with lot coverage maximums for the zoning district. If the converted space would create a separate dwelling unit (with its own kitchen and entrance), ADU restrictions apply and the conversion would not be permitted without special zoning approval. Detached garage conversions are subject to the same requirements. The Village Building Division reviews all conversion plans for code compliance before issuing permits.