Building Codes: Getting Approval for Straw Bale Homes
Imagine standing on the verge of building your dream home with straw bale construction. You're excited, but questions loom: Will it pass inspection? Does the design meet local codes? What's the correct code for your area?
These very questions spark lively discussions at each and every one of our workshops. They come from all levels of experience, and their curiosity is well-founded; here are a few good reasons to get code savvy:
Building a home is a significant investment, and decisions about building to code involve impacts on safety, durability, resale, insurance, financing, and more.
Specific requirements vary by region, jurisdiction, and structure type. Not every jurisdiction has adopted the latest model code or all of the Appendices.
New updates come every three years to the building code; it's essential to remain current on innovations and changes.
These reasons and more were why the room was packed during the session on Natural Building Codes at the 2023 Natural Building Alliance conference. Building codes are a significant point of interest for builders, do-it-yourself enthusiasts, and design professionals. What made this session even more compelling was the presence of Martin Hammer, architect; David Eisenberg, Executive Director at Development Center for Appropriate Technology; and Anthony Dente, Professional Engineer (P.E.), who were the presenters.
These three experts, joined by many many others, have invested an immense amount of time and energy over the years to secure ICC approval for an Appendix in the IRC dedicated to Straw Bale Construction. Their commitment persists as they work to enhance safety standards and promote alternative building methods. Notably, the ICC recognized the expertise of Martin and David by inviting them to contribute to the upcoming Commentary updates for Appendix AS.
(Side note: If you haven’t encountered a copy of the IRC with Commentary yet, you are missing out! While a typical code book simply states the code, the Commentary version provides the ‘why’ behind the code and additional prescriptive information. More details below.)
If you have questions or want to stay up-to-date on straw bale building code, read on for historical highlights, definitions, and FAQs. Want to go straight to the code? View the 2021 IRC Appendix AS for Strawbale Construction here.
History & Highlights of US Straw Bale Building Codes
Virtually all jurisdictions (States, Counties, and Cities) in the United States use the IBC and IRC as the basis for their building codes. They adopt parts or the whole of the IBC or IRC and specific Appendices as relevant to their local vision and needs. It varies as to which year of the model code they have adopted.
Every three years, the code cycle completes, where prospective updates are examined by the ICC in a public code change proposal process and potentially adopted into the new code version. This process makes the straw bale building code a living document, able to evolve to add improvements in technology and best practices over time.
Code versions are identified by year, for example, 2018, 2021, 2024, etc. The first approval for a proposed appendix on straw bale construction was at the International Code Council’s (ICC) Final Action Hearings in Atlantic City on October 4, 2013.
Please note that the IRC's appendices are not integral to the body of the code and must be explicitly adopted by jurisdictions using the IRC. Even if your jurisdiction does not adopt the appendix, you could cite the appendix in the IRC national model code, which would carry enormous weight.
The inclusion of a straw bale construction specific (Appendix AS) since 2015 in the IRC has made getting building approval so much easier anywhere that those codes are enforced. After all, if it is in the code book, it has passed the extreme scrutiny and review process of the ICC. If your project design meets those code requirements, there is nothing to stop you from getting approval. It won’t matter if your local building inspector has never heard of straw bale construction or if they think it’s stupid. The conversation can be elevated to identifying where the design may fail to meet their interpretation of the IRC guidelines and what modifications are needed to meet code compliance to gain their approval.
It is worth noting that there were pre-2018 straw bale-specific codes in some areas, such as those developed in 1995: Tucson-‐Pima County, Arizona, and the State of New Mexico.
Years have passed; testing, research, and designing and constructing hundreds of straw bale buildings have significantly advanced our knowledge and understanding to raise the minimum standards bar. The IRC code appendix AS and ongoing updates reflect this evolvement.
It is impossible to speak to the history of straw bale building codes and not acknowledge with deep appreciation the individuals and organizations that have invested countless hours of volunteer time over decades to achieve Appendix AS!
Martin Hammer, Californian architect and lead author of Appendix AS, has been working on draft straw bale codes since 2001 for the State of California, the International Green Construction Code, and the International Building Code. He co-authored the code approved in the 2015 International Residential Code (IRC) and has continued to work on updates since then. Martin has worked tirelessly for the benefit of all of us. Thank you, Martin!
But, the approved IRC appendix was made possible by invaluable efforts and contributions from many other straw bale builders and experts.
In particular, Kevin Donahue SE, Mark Aschheim PE, Dan Smith, Architect, John Swearingen, David Eisenberg DCAT, and Jane Andersen PE. Members of the Global Straw Building Network also contributed, including Laura Bartels, Andy Mueller, Bill Steen, Derek Roff, Graeme North, and Jacob Racusin. Ongoing support from Maurice and Joy Bennett, former directors of the California Straw Building Association (CASBA), was also vital to the effort. For a further historical glimpse, check out this article in Structure Magazine from 2012 on Strawbale Construction.
Of course, the fruit of any labor can be traced to its roots and branches. Martin Hammer wishes to acknowledge the pioneers of straw bale building, especially Matts Myhrman and Judy Knox, and Bill and Athena Steen. He also acknowledges Matts Myhrrman and David Eisenberg as authors of the first-ever straw bale code in Arizona in 1995, the many people involved in testing and researching straw bale building over the last 20 years, and the entire inspiring straw bale building community worldwide.
Going back to 2008, it is well worth mentioning the contributions made at a Congressional hearing on straw bale construction. Presenters David Eisenberg, Sandy Wiggins, Laura Bartels, and Bob Gough demonstrated their commitment to this wonderful building technology.
As you may know, David has been long committed to the growth and development of straw bale construction and is the Executive Director at the Development Center for Appropriate Technology (DCAT). Sandy, among holding several other credentials, is the past chair of the U.S. Green Building Council (USGBC).
At the time of the hearing, Laura was the President of Green Weaver, Inc., a team member of Builders Without Borders, as well as a builder and teacher. Bob was the Secretary of the Intertribal Council On Utility Policy and spoke on behalf of those interested in affordable and healthy housing.
We hope we can speak for all of us who love straw bale construction by saying you have helped us all move one step forward toward our goals. Thank you!
ICC, IRC, IBC...
Let’s talk definitions…
ICC, or the International Code Council, is a global source of model codes and standards for safe building solutions. The international part is a bit aspirational, as building varies greatly from the US to across the globe, but ICC has influenced code standards in other countries. (Exciting news! The ICC is drawing attention to embodied carbon; see more here.)
IRC, or International Residential Code, is focused upon, you guessed it, residential construction! It applies only to one- and two-family dwellings not more than three stories above grade and is prescriptive, as it is intended as a pre-engineered code for the people. It is also the code in which Straw Bale Construction has an Appendix since 2015. Learn more about the IRC here.
IBC, or International Building Code, is based on strength-designed approval or focused on both prescriptive and engineered solutions. Residential structures can be designed under the IBC; typically, an engineer is involved when the IBC is used. Learn more about the IBC here.
FAQs on Straw Bale Building Code
Why Have Building Codes?
Some consider codes the government’s way of extorting money from homebuilders and owners. For the most part, we disagree.
While there are likely some codes that step beyond necessity, we believe most are in place to protect the people dwelling in the structures.
In short, straw bale building codes help to create safe buildings.
“The purpose of this code is to establish minimum requirements to safeguard the public safety, health and general welfare through affordability, structural strength, means of egress facilities, stability, sanitation, light and ventilation, energy conservation and safety to life and property from fire and other hazards attributed to the built environment, and to provide safety to firefighters and emergency responders during emergency operations.”
2018 International Residential Code (IRC) R101.3 Intent.
We have seen unsafe homes because the builders did not understand the risks involved in the design or the huge weights and forces involved in constructing a home.
Standardized building codes can help provide guidelines, recommendations, and best practices for people who would otherwise not even know what to look for. (Check out Building Permits for Straw Bale Houses for more tips on the permitting process.)
Where Can I View The IRC Straw Bale Building Code?
Check out the International Residential Code (IRC) 2021 Appendix AS Straw Bale Construction as generously provided by CASBA. We HIGHLY recommend taking the time to explore this resource because it includes COMMENTARY.
The code itself is written as prescriptive, while the commentary provides an explanation to inform on the ‘why’ behind the code prescription. This is extremely useful to the owner-builder as well as bale professionals.
How Do I Know What Code My Jurisdiction Is Using?
Not every jurisdiction has adopted the latest version of the IRC, nor all of the Appendixes as part of their local guidelines.
If you are unsure if your local jurisdiction covers straw bale construction in their building code, check out this site to research what code book is required in your area.
My Jurisdiction’s Code Doesn’t Include Natural Building! Now What?
If there is nothing for alternative homes or straw bale construction, call your building department. (Here are some considerations for working with building departments.) Let them know you plan to build a house using natural construction methods and intend to use approved IRC building codes from another state or include engineering services to develop the design. See if they have a preference.
You may need an engineer to review and stamp your plans or simply use a state-recognized code like the one in Oregon.
Please Note: The code in Oregon is different than the details in our How To Straw Bale Construction videos because of the Code update cycles since filming; however, you can use it as a base and then move forward from there.
How Do I Best Prepare for My Project?
Consider buying the code book for your state. You will need the code book no matter what structure you build, so you may as well buy it now.
Once you have the code book (make sure you get any local or state addendum to the code book when you order it), check for an alternative or natural building section.
Here’s the ICC’s store’s IRC Reference section to help you research. Use their filter features to explore International Codes such as the IRC, access by State Codes, and more. And, here are tips on the building permit process.
How Can I Support Future Code Updates?
It’s so much easier to build a straw bale house now because of the straw bale building code. It’s easier to get insurance and financing, all because of the code.
Volunteers contributed endless hours (it took 13 years of effort to get the initial Straw Bale Appendix approved!), and travel costs, engineering, testing, and other hard costs must be covered.
If you’d like to support a key organization behind advancing straw bale construction technologies, donate to the California Straw Bale Builders Association (CASBA) and their ongoing efforts.
Learn more about CASBA and current initiative donation opportunities here.
Conclusion
The straw bale building code is a living document with ongoing changes. Check back here for periodic updates to this article. Last updated: October 28, 2023
Have questions about your bale build? Check out our consulting options here or join us at one of our workshops! Our workshop schedule for the upcoming season is released every November. View our Current Workshop Schedule here.
