Appendix BJ and Appendix BL 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 BI. Jurisdictions that do adopt Appendix BI may also amend it. Consult your local building department to understand which edition of the IRC is the basis for its current building code and whether Appendix BI is 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 BI and California: Appendix BI from the 202 I4RC 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.