Garage Conversions: Chicago vs Oak Park
How do garage conversions rules compare between Chicago, IL and Oak Park, IL?
Chicago and Oak Park have similar restriction levels.
Chicago, IL
Cook County
Chicago authorizes garage conversions to coach houses (detached ADUs) and conversion units (attic/basement ADUs) under the Additional Dwelling Unit Ordinance. The pilot ordinance (effective May 2021) was made permanent and city-wide by Ordinance SO2024-0008918, which the City Council passed 46-0 on September 25, 2025, with permits accepted starting April 1, 2026. ADUs are now allowed in single-family zones within the original pilot areas plus all multifamily zones citywide (except downtown).
View full Chicago rules →Oak Park, IL
Cook County
Oak Park allows conversion of a detached garage into a coach house — an ADU located on the upper floor of a detached garage — under the Village of Oak Park Zoning Ordinance. Ground-floor parking is preserved, and no additional off-street parking is required beyond the two spaces for the single-family home.
View full Oak Park rules →Key Facts Comparison
| Fact | Chicago | Oak Park |
|---|---|---|
| Ordinance | SO2024-0008918 (passed 9/25/2025) | - |
| Effective Citywide | April 1, 2026 | - |
| Coach House Height | 22 ft max; rear 50% of lot | - |
| Parking | No additional spaces required | - |
| Labor Standard | Reg. Apprenticeship Program (coach houses) | - |
| Code Reference | - | VOP Zoning Ord. (2017, amended 2025) |
| Coach House Definition | - | Upper floor of detached garage |
| Units Allowed | - | 1 coach house per lot |
| Replacement Parking | - | Not required |
| Max Size | - | 1,000 sq ft |
Highlighted rows indicate differences between cities.
Chicago FAQ
Can I legally convert my Chicago garage to a coach house?
Yes, in eligible zones. As of April 1, 2026, Chicago's permanent Additional Dwelling Unit Ordinance (SO2024-0008918) allows coach houses citywide in single-family zones within the original pilot areas plus all multifamily zones (except downtown), with a 22-foot height limit in the rear 50% of the lot.
Do I need a permit to remodel or convert my Chicago garage to living space?
Yes. The Chicago Department of Buildings requires a building permit for any change of use from garage to habitable space, with plan review under Title 14X (Chicago Building Code). For ADU/coach house conversions, a pre-certification from the Department of Housing is required first.
Do I need additional parking after converting my Chicago garage?
No. The Additional Dwelling Unit Ordinance does not require additional off-street parking when adding an ADU, even when the conversion eliminates an existing garage.
Oak Park FAQ
Can I turn my Oak Park detached garage into a coach house?
Yes. The Village of Oak Park Zoning Ordinance allows a coach house on the upper floor of a detached garage, with kitchen and bathroom facilities, separate ingress and egress, and a maximum size of 1,000 sq ft.
Do I lose my parking spaces in an Oak Park garage conversion?
No — a coach house is built on the upper floor of the detached garage, preserving the ground-floor parking. No additional off-street parking is required beyond the two spaces for the single-family home.
Can I convert an attached garage into an ADU in Oak Park?
The zoning ordinance specifically defines a 'coach house' as the upper floor of a detached garage. Attic and basement conversions inside the principal dwelling are also permitted as alternative ADU forms under the 2021 amendment.
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