CASBA

Appendix BJ – Strawbale Construction with Commentary

Appendix BI - Light Straw-Clay Construction with Commentary

from the 2024 International Residential Code (IRC)

$1.00 Download  (please download only the Appendix or Appendices you need)

Appendix BJ and Appendix BI as downloaded from this page are from the 2024 International Residential Code and Commentary as published by the International Code Council (ICC). These downloads are made available by agreement between CASBA and the ICC.The complete  IRC and Commentary is available for purchase from the ICC here  

The 2024 IRC without  commentary is also available as read-only (not downloadable) for free on ICC’s website at https://codes.iccsafe.org/codes/i-codes

Appendix BJ and Appendix BI sometimes reference sections of the IRC, so access to the complete IRC is important for full understanding and full use. The IRC applies to one and two-family dwellings, their accessory structures and townhouses.

The IRC is a model code with no legal standing of its own, but it is the basis for the residential code in virtually every state and local jurisdiction in the United States. However, many jurisdictions have not yet adopted the 2024 IRC, and some may not adopt Appendix BJ or Appendix BI. Jurisdictions that do adopt Appendix BJ and Appendix BI may also amend them. Consult your local building department to understand which edition of the IRC is the basis for its current building code and whether Appendix BJ and Appendix BI are included.

Project applicants who wish to use Appendix BJ or Appendix BI for a project where the state or local jurisdiction has not adopted the 2024 IRC or the Appendix, can propose their use on a project basis with the local building official.

The Commentary describes intent, and gives compliance examples for the Appendix code requirements. This is especially helpful for design professionals, builders, building owners, and code officials with little or no experience with strawbale or light straw-clay construction.

Appendix BJ and California

Appendix BJ from the 2024 IRC is included in the 2025 California Residential Code (CRC) and was adopted by the Department of Housing and Community Development (HCD) for mandatory statewide use. The 2025 CRC took effect January 1, 2026 for permit applications dated Jan. 1, 206 through Dec 31, 2028. If a local building department or official claims their jurisdiction did not adopt it or otherwise refuse to use Appendix BJ, please contact Martin Hammer (see below).

Appendix BI and California

Appendix BI from the 2024 IRC is included in the 2025 California Residential Code, for voluntary use by local jurisdictions. Unlike Appendix BJ, it was not adopted by a state agency for mandatory statewide use, but it can be proposed for use on a project basis.

Other Editions of Appendix BI or BJ (2015,2018,202) and information re:IRC 2024 can be obtained through Martin Hammer (see below). Past editions could be in force for current or past projects depending on the State or local jurisdiction and the project application date. The 2024 IRC and appendices have been finalized through ICC’s code development process and will be published sometime in 2023. They will go through State and local adoption in subsequent years.

Questions or Comments regarding IRC Appendix BJ and Appendix BI can be directed to their lead author, Martin Hammer, at mfhammer@pacbell.net .

Appendix AU – Cob Construction (Monolithic Adobe)

Appendix AU is available for free download through the Cob Research Institute (CRI) at https://www.cobcode.org/code-download

Please consider a donation to CASBA

CASBA is happy to offer IRC Appendices for  download, but also encourages donations that help fund our ongoing agreement with ICC, and help allow CASBA members to periodically revise the appendices and advocate for other sustainable advances in the building codes. Please donate here https://strawbuilding.org/donate