Can I Build Garage Conversion in Chicago, IL? (2026)
Find out if you can build a garage conversion in Chicago, IL. Rules, permit requirements, costs, and next steps.
Yes, garage conversions to living space are permitted in Chicago, IL. Replacement parking is not required.
Converting an attached or detached garage into living space in Chicago, IL is a popular way to add an ADU or additional living area without new construction. Garage conversions are permitted in Chicago, but must comply with habitable space building codes: insulation, ventilation, electrical, egress windows, and minimum ceiling height. A key consideration: California law eliminates replacement parking requirements for garage-to-ADU conversions, making garage conversions particularly attractive.
Garage Conversion Rules in Chicago
Garage Conversion Rules in Chicago: Allowed: Yes. Replacement parking required: No. Garage conversions to ADU (coach house style) allowed under Chicago ADU Ordinance. No replacement parking required. Chicago's rear garages — commonly accessed from alleys — are the standard location for coach house ADU construction. Chicago DOB building permit required for conversion to habitable space. All garage conversions to habitable space require a building permit. The converted space must meet minimum habitable room standards (typically 7 ft ceiling height, egress window, insulation, and ventilation).
Costs & Fees
Garage conversion permit fees in Chicago are typically based on project valuation. Contact the Chicago Department of Buildings at (312) 744-5000 for current fees. Conversion costs typically range $20,000–$80,000 depending on scope (permits, labor, materials, utility connections).
Timeline
Permit timeline: typically 2-6 weeks for plan check. Construction: 2-4 months for a typical garage conversion.
Next Steps
Next steps for converting your garage in Chicago: 1. Determine if the conversion will be an ADU (separate unit with kitchen/bath) or additional living space. 2. Check replacement parking requirements for your zone. 3. Have a contractor assess structural requirements (ceiling height, foundation, utilities). 4. Submit plans and permit application to the Chicago Department of Buildings. 5. See the full ADU rules page for size limits and requirements if creating an ADU unit.
Chicago Department of Buildings
Phone: (312) 744-5000
Website: https://www.chicago.gov/city/en/depts/bldgs.html
Online Permits: https://www.chicago.gov/city/en/depts/bldgs/provdrs/permits.html
Frequently Asked Questions
Can I build an ADU in Chicago?
Yes. Chicago's ADU Ordinance, expanded citywide in July 2022, allows both attached ADUs (basement or attic conversions) and detached coach houses (rear-yard ADUs typically built over a garage). Owner-occupancy is required — you must live in either the primary unit or the ADU. No replacement parking is required. A building permit from the Chicago Department of Buildings is required.
What is a coach house in Chicago, and is it the same as an ADU?
Yes. In Chicago, a coach house is the traditional term for a detached ADU — typically a 1- or 2-story structure built over a rear garage, accessed from the alley. Chicago's ADU Ordinance specifically authorizes coach houses up to 1,000 sqft and 22 ft tall. They are built in the rear yard, behind the principal building. Chicago has a rich history of coach houses from the late 19th and early 20th centuries.
How do I find the zoning of my Chicago property?
Use the City of Chicago Zoning Map at webapps1.chicago.gov/zoneinfo/ — enter your address to find zone designation, applicable district standards, and special overlay zones. You can also check the Chicago Zoning Ordinance (Title 17) at codelibrary.amlegal.com.
Are short-term rentals allowed in Chicago?
Yes, with a license. The Chicago Shared Housing Ordinance (effective 2016) requires a Vacation Rental License or Shared Housing Host Registration ($125/year). Properties in buildings where the condo or co-op association has voted to ban short-term rentals are prohibited. Chicago collects a 4.5% Shared Housing Surcharge plus state hotel tax.
What are the setbacks for a standard Chicago bungalow lot?
In RS-3 (the most common single-family zone for Chicago bungalows), setbacks are: 15 ft front, 2 ft side (minimum — many have 2 ft on one side and 0 on the other with a shared driveway), and 30 ft rear. Chicago's standard lot is 25 ft wide by 125 ft deep. The rear yard is typically used for detached garages accessed from the alley.
Source: Chicago Department of Buildings — Building Regulations. Last verified April 3, 2026. View source