Get Better Building Codes with the NAHB 2024 I-Codes Adoption Kit

NAHB has published its 2024 I-Codes Adoption Kit, a set of resources designed to help home builders and HBAs understand what’s new in the codes and to guide state and local code officials considering adoption of the latest set of building codes.

The adoption kit for 2024 covers most of the International Codes published by the International Code Council: The International Residential Code (IRC), International Fire Code (IFC), International Building Code (IBC), and more. This kit does not cover the 2024 International Energy Conservation Code (IECC) or Chapter 11 of the IRC. NAHB staff are working on a separate adoption kit for the 2024 IECC and Chapter 11 of the IRC.

Significant Changes to the 2024 International Residential Code

The kit provides a list of significant changes in the 2024 building codes compared to the 2021 versions. For the all-important 2024 IRC, these changes include:

• IRC Section R401.4.1 Geotechnical evaluation: The existing table of soil classifications is moved to a more logical location and expanded to allow the use of USDA data and textural descriptions to allow builders to select a proper soil classification without having to obtain a geotechnical investigation.
• IRC Section R502.11 Floor framing supporting guards: Prescriptive options are added for framing at the open edge of a floor supporting a required guard assembly. Details are included for both conventional and heavy timber edge framing.
• IRC Section R506.3.3 Vapor retarder: A 6-mil construction-grade polyethylene vapor retarder is allowed to be placed under a concrete floor slab instead of a 10-mil vapor retarder complying with ASTM E1745 Class A requirements. This reverses the change from last cycle requiring the 10-mil proprietary vapor retarder under floor slabs.

The kit also covers significant changes to relevant codes for multifamily home builders.

Cost Impact of 2024 Building Codes

Cost is often the most significant change in building codes. But the 2024 codes rolled back some previous high-cost changes and introduced additional options for code compliance. As a result, Home Innovation Research Labs’ cost impact analysis study of the 2024 changes shows no cost impact or even a cost savings for new homes compared to the 2021 codes.

Read the full report, Estimated Costs of the 2024 IRC Code Changes, from Home Innovation Research Labs for more details on the cost impact of code changes.

Helping Building Officials Adopt Favorable Codes

Many states and municipalities adopt the ICC’s model codes as-is. But they are not required to do so, and many states and communities make amendments to the model codes for various reasons.

NAHB always provides a list of suggested amendments to the model codes, and 2024 is no exception. Members and HBAs can use the 2024 I-Codes Suggested Amendments to inform their conversations with local building officials, or simply provide the entire document. The suggested amendments document is also available in Word to allow for editing or for copying the amendment text and reason statements into a state or local jurisdiction’s form for submitting amendments.