Boulder County Building Code Amendments

Boulder County Building Code Update – Effective March 31, 2025

The Board of County Commissioners has approved the adoption of updated building codes and amendments. Effective March 31, 2025, all new projects will be reviewed under the 2021 version of the International Codes (I-Codes), with local amendments.

Boulder County Building Code Approved Amendments, March 31, 2025

Our local amendments include additional requirements for energy efficiency, sustainability, and ignition resistant construction requirements in an effort to best protect and prepare our community for a changing climate. These changes also put Boulder County in alignment with anticipated statewide mandates for both energy efficiency and wildfire preparedness. We have also incorporated the new statewide Electric Ready and Solar Ready requirements.

Moving to the 2021 version of the I-Codes will also improve our Building Code Effectiveness Grading Schedule (BCEGS) rankings. This helps the entire community by providing the insurance industry with data showing Boulder County has current building codes and effective code enforcement.

The updated code will be in effect for all Building Permit Applications for properties in the unincorporated portion of Boulder County received beginning March 31, 2025. The cities and towns located in Boulder County adopt and enforce their own building codes.

The current Boulder County Building Code is based on the 2015 Model Codes as published by the International Code Council (ICC). This code has a number of local amendments that allow for alignment with various state and local regulations and let our community pursue specific local goals and initiatives. The current version of our local building code includes regulations regarding energy efficiency and ignition-resistant construction that go well beyond the national model code as published by the ICC.

Current Boulder County Building Code Amendments

The Boulder County Building Code Amendments are adopted by the Board of County Commissioners. The Building Code Amendments apply to construction on properties located in the unincorporated portions of Boulder County (outside of the cities and towns).

In 2022, the Boulder County Commissioners approved an update to the ignition-resistant requirements for construction in Wildfire Zone 2, which comprises the eastern area of unincorporated Boulder County (view the Wildfire Zones map). The update was prompted by recent wildfires including the Marshall Fire. The approved changes guide the use of approved exterior materials and construction details for inclusion into the Boulder County Building Code Amendments to the currently adopted 2015 International Codes. The current Building Code Amendments are in effect for unincorporated Boulder County building permits applied for on or after June 6, 2022. View the May 12, 2024 news release for more information.

Boulder County Building Code

The following publications shall hereby be adopted as the Boulder County Building Code by reference, with deletions and amendments as indicated:

1. 2015 INTERNATIONAL BUILDING CODE (the “IBC”), including specifically Appendix Chapters C, I, J and K;
2. 2015 INTERNATIONAL RESIDENTIAL CODE (the “IRC”), including specifically Appendix Chapters E, F, H, R and S;
3. 2015 INTERNATIONAL EXISTING BUILDING CODE (the “IEBC”);
4. 2015 INTERNATIONAL MECHANICAL CODE (the “IMC”);
5. 2015 INTERNATIONAL PLUMBING CODE (the “IPC”);
6. 2015 INTERNATIONAL FUEL GAS CODE (the “IFGC”);
7. CURRENT VERSION ADOPTED BY THE COLORADO STATE ELECTRICAL BOARD OF THE NATIONAL ELECTRICAL CODE (the “NEC”);
8. 2015 INTERNATIONAL ENERGY CONSERVATION CODE (the “IECC”);
9. 2015 INTERNATIONAL GREEN CONSTRUCTION CODE (the “IGCC”);
10. 2015 INTERNATIONAL CODE COUNCIL PERFORMANCE CODE (the “ICCPC”); and the
11. 2015 INTERNATIONAL SWIMMING POOL AND SPA CODE (the “ISPSC”);

all, except the NEC, as published by the International Code Council (ICC), 4051 West Flossmoor Road, Country Club Hills, IL 60478-5795; and the NEC, as published by the National Fire Protection Association, One Batterymarch Park, Quincy, MA 02169-7471; with additions, deletions and amendments as per the Boulder County Building Code Amendments.

Past Building Codes

• For building permits applied for from 2017 – June 5, 2022, see the Building Code Amendments in effect Jan. 1 2017 through June 5, 2022
• For building permits applied for in 2016, see the past 2015 Building Code Amendments
• For building permits applied for from Jan. 1, 2013 – Dec. 31, 2015, see the 2012 Boulder County Building Code Amendments
• For building permits applied for from Jan. 1, 2011 – Dec. 31, 2013, see the 2009 Boulder County Building Code Amendments

Previous versions of the Boulder County Building Code Amendments are available as reference for all building permits issued prior to the current amendments. Please contact Building Safety and Inspection Services for a copy of older Amendments.