What is the Chicago building code?

Chicago's building code went through a major modernization starting in 2019, integrating the International Building Code (IBC) framework while preserving Chicago-specific amendments. Before 2019, Chicago had one of the most idiosyncratic codes in the country — many provisions predated the IBC and created compliance challenges for out-of-state contractors.

Current Chicago Construction Code structure:

1. Chicago Building Code (CBC) — new construction and substantial rehabilitation of buildings 3 stories and taller. Integrates IBC with Chicago amendments.
2. Chicago Existing Building Code (CEBC) — alterations, repairs, and change-of-use for existing buildings.
3. Chicago Mechanical Code — HVAC.
4. Chicago Electrical Code — based on National Electrical Code with local amendments.
5. Chicago Plumbing Code — based on Uniform Plumbing Code with Chicago amendments.
6. Chicago Fire Prevention Code.

Single-family and small residential:

• Most single-family and 2-flat buildings fall under the Chicago Residential Code.
• Many pre-1945 Chicago buildings are "nonconforming" to current zoning and code.

Chicago-specific amendments to note:

• Tuckpointing — Chicago requires permits for significant masonry repointing work (unusual vs other cities); see dedicated /ask entry for tuckpointing.
• Porches and exterior stairs — Chicago code has specific structural requirements for exterior wood porches due to historic porch collapses.
• Boiler/steam heat — much of Chicago's housing stock uses steam or hot water radiator heat; changing to forced-air triggers significant code compliance.
• Basement dwelling units — 2021 pilot program legalized some basement apartments in specific zones with code upgrades (formerly illegal in many cases).
• Landmarks — Chicago has both city-designated landmarks and National Register properties requiring Commission on Chicago Landmarks review.

Permit types:

• Standard Plan Review — for residential work over a threshold (typically anything with structural or added plumbing/electrical).
• Easy Permit Process (EPP) — for simple projects like interior remodel without structural/electrical/plumbing work.
• Same-day permits — for minor work like reroof, water heater.
• ePlan — Chicago's online plan review submission system.

Typical 2026 Chicago permit timelines:

• Easy Permit Process: 2-4 weeks.
• Standard Plan Review residential: 6-12 weeks first cycle.
• New construction: 3-9 months.
• Landmarks review: add 8-16 weeks.

Chicago-specific hot topics:

• Additional Dwelling Unit (ADU) ordinance — 2021 ordinance legalized ADUs in specific pilot zones; citywide expansion under discussion.
• Retrofit requirements — unreinforced masonry building programs.
• Energy code — Chicago adopted the International Energy Conservation Code with amendments.

How Chicago compares to other Midwest cities:

• More stringent than Milwaukee, Minneapolis, Indianapolis on structural.
• Distinct on masonry and porch requirements.
• Integration with IBC as of 2022 means out-of-state architects find it easier to work in Chicago than historically.

AskBaily's Chicago contractor pool is familiar with CBC / CEBC requirements, ePlan submission, and landmarks overlay. See /chicago and /ask/how-do-chicago-tuckpointing-permits-work for deeper local context.