Illinois Building and Residential Codes

The State of Illinois Capital Development Board Act (Public Act 103-0510) requires certain building code standards be adopted or followed statewide effective 1/1/2025. 

The following information and more can be found on this Fact Sheet. The Act does not require municipalities or counties that do not currently have building codes to adopt building codes, but it does require minimum construction standards in those communities. For municipalities and counties that have adopted building codes, the Act requires that those codes meet certain requirements.

Beginning January 1, 2025, any municipal building code or county building code must:

(1) Regulate the structural design of new buildings, other than residential buildings, in a manner that is at least as stringent as the baseline statewide building code standard;

(2) Regulate the structural design of rehabilitation work in existing buildings, other than residential buildings, in a manner that is at least as stringent as the baseline statewide existing building code standard; and,

(3) Regulate the structural design of residential buildings in a manner that is at least as stringent as the baseline statewide residential code standard.

The baseline codes are the International Building Code including Appendix G, International Existing Building Code and International Residential Code, published in the current year or preceding nine calendar years. Plan Analyst for the IBC and IRC are available for code years 2009, 2012, 2015, 2015, 2018, 2021 and 2024.

Further detailed information on the changes coming into effect from 1/1/25 can be found on the CDB website.

The CDB provides two helpful directories; one of local building codes and the other listing state regulations and statutes.

Answers to questions related to building codes can be answered by an Authority Having Jurisdiction (AHJ), or by a design professional.

The 2019 Chicago Building Code (Title 14B) is based on the 2018 International Building Code (IBC).

Building Code Compliance Software for Illinois

Plan Analyst code compliance software programs make it easy for building officials, architects and other designers to quickly perform commercial and residential building code plan reviews / code studies.  Plan Analyst for the IBC and Plan Analyst for the IRC simplifies the plan review / code study process enabling compliance to specific code years.  This proven software allows modifications to accommodate local amendments, where applicable.  Users have the ability to add code requirements and to add to the checklist.  Changes can be made permanent by changing the data file using the setup section of Plan Analyst, or specific reports can be edited for special conditions.

Plan Analyst Calculators: Deck – Sign – Beam & Column

Plan Analyst Deck, Sign and Beam & Column Calculators are additional simple and effective design and code review software tools that will quickly become your go-to resources when working on associated tasks.

Users of Plan Analyst in Illinois have included:

City of AledoArete 3 Ltd.
City of ChampaignArzoumanian & Company
City of MolineBarrie Scott Associates
City of RockfordBLDD Architects, Inc.
City of WilmingtonGleason Architects, PC
Lake CountyNew Era Signs, Inc.
Will CountyOSF HealthCare
Village of BerkeleySarchris Technologies
Village of GurneeShive-Hattery, Inc.

Building and Residential Code Resources in Illinois

Energy Code Compliance Software for Illinois

Visit the U.S. Department of Energy website to see the latest on energy code adoption in Illinois, including the use of COMcheck and REScheck Energy Code compliance software. COMcheck enables architects, builders, designers, and contractors to determine whether new commercial or high-rise residential buildings, additions, and alterations meet the requirements of the IECC and ASHRAE Standard 90.1.  REScheck product enables builders, designers, and contractors to determine whether new homes, additions, and alterations meet the requirements of the IECC or a number of state energy codes.

DOE’s EnergyPlus™ is a whole building energy simulation (BEM) program that engineers, architects, and researchers use to model both energy consumption (for heating, cooling, ventilation, lighting and plug and process loads) and water use in buildings. It supports a number of public and private-sector tools and services including EP3EP3 is a user interface for EnergyPlus™ designed to streamline workflows for building energy modelers. EP3 is well-suited for tasks like modeling ASHRAE 90.1 Appendix G baselines and evaluating energy efficiency measures in new and existing buildings.

The “Building Codes Assistance Project” also provides information on Illinois’s building energy codes.

FEMA Building Code Adoption Tracking

The FEMA Building Code Adoption Tracking program reports on the status of hazard-resistant building code adoption in each state. Illinois is in FEMA Region 5. Read the 2024 Region 5 fact sheet showing the annual metric of the percent of communities adopting hazard-resistant building codes in Illinois.

AIA and ICC

American Institute of Architects – AIA Illinois represents architects in the state. There are just over 9,000 registered and reciprocal architects in Illinois .

Illinois has several ICC Chapters throughout the state.

Illinois code adoption status on the ICC website