Supporting Critical Hemp Building Code Updates

A hempcrete home in LaVeta, CO

The Breakthrough We've Been Waiting For

After years of dedicated work, the hemp building community in the United States achieved something remarkable in 2024: hemp-lime construction (hempcrete) was officially included in the International Residential Code through Appendix BL. This was a monumental victory that took years of effort by a small team of natural building code experts and volunteers.

But we weren't done yet.

Filling the Critical Gap

While getting hempcrete into the national model residential building code was groundbreaking, there was still a crucial missing piece: comprehensive fire resistance testing data. Without this proof, building departments could still demand additional expensive testing, creating delays and costs for builders and homeowners.

An example: In 2023, one US hempcrete builder spent $8,000 just on fire testing to get building officials to approve her commercial project. With this testing in the code, "I would have saved myself $8K," she said.

That's about to change.

The upcoming 2027 International Residential Code updates will include fire-rated hemp-lime walls, based on three ASTM E119 fire-resistance tests for hemp-lime construction—the first time this critical safety data will be part of the IRC, the national model building residential code. This represents an important piece of the puzzle that will help transform hempcrete from an alternative building method into a fully mainstream construction system.

What This Means for You

These code updates will:

✅ Cut red tape - No more uncertainty about fire resistance requirements
✅ Remove barriers - Building officials will have all the data they need to approve projects
✅ Save time - Streamlined permitting process for hempcrete projects
✅ Save money - Eliminates the need for expensive additional testing
✅ Open doors - More insurance companies and lenders will feel confident supporting hempcrete projects

The Community Investment

This breakthrough didn't happen by accident. Cameron McIntosh of PA-based Americhanvre invested more than $1 million in Army SBIR funding to conduct comprehensive fire testing and other tests. Then, a dedicated team of code consultants—Martin Hammer, David Eisenberg, Anthony Dente, Tim Callahan, and others—contributed countless hours of expertise built over decades of work with natural building materials.

As McIntosh puts it: "If these guys weren't paying attention to this, we wouldn't be making any improvements to this code right now. Anthony, Martin and David are very literally the fairy godfathers of the hemp and natural building appendices."

Hempcrete wall panel undergoing testing at Intertek labs for Americhanvre.

Why Your Support Matters

HempBuild Magazine, Americhanvre, The Hemp Building Institute, Hemp Build School and others have joined together to bring about this fundraising campaign.

A small group of professionals has invested their own time and money to benefit the entire hemp building community. So far, costs are predicted to run more than $10,000.

But this effort has created something that will help every future hempcrete project—from individual homeowners pursuing their dream sustainable home to production builders scaling up hempcrete construction.

Your contribution helps:

Compensate the consultants who made these updates possible
Support ongoing code development work
Ensure continued advocacy for natural building materials
Remove barriers for the entire hemp building community

Here’s what it means for all of us:

🏡 Homebuilders: Faster approvals and lower costs mean you can give families safer, healthier homes without the extra red tape.
🏛️ Architects: Freedom to design with a sustainable, high-performance material that supports modern standards like passive house.
⚙️ Engineers: Clear, codified data on fire safety, structure, and performance so hempcrete projects meet the highest safety benchmarks.
🔨 Builders & Contractors: Less pushback from inspectors, smoother jobsites, and happier clients who get the homes they want.

"The majority of hempcrete homeowners and builders are motivated, capable people who would love the support of the code to put their code enforcement at ease," explains McIntosh. "This is ultimately who this is helping."

IRC Committee votes 7-2 to approve Hemp-Lime (Hempcrete) Appendix BL in the International Residential Code in 2022.

The Bigger Picture

In a world facing increasing wildfire risks and growing demand for sustainable construction, hempcrete's proven fire resistance isn't just a nice feature—it's essential. When building officials see comprehensive data showing hemp-lime assemblies achieving one-hour fire resistance ratings, skepticism transforms into confidence.

"Since hempcrete was approved in the 2024 IRC, it has opened doors," said Jacob Waddell, founder of the Hemp Building Institute who spearheaded the adoption of hemp-lime in the 2024 IRC as former president of the US Hemp Building Association.

"We have started to see hempcrete adopted in Austin, TX and now the state of Minnesota," he said. "When we can codify fire resistance, the more we can add to our competitive argument for hempcrete. This is a huge step forward," he added.

Ready for Growth

With proper fire testing data, refined technical specifications, and a growing track record of successful projects across the country, hemp-lime construction is positioned for significant expansion. These code updates remove the last major obstacles standing between hempcrete and widespread adoption.

Every dollar you contribute supports the community effort that makes hempcrete projects easier, faster, and more affordable for everyone.

Join us in supporting the dedicated professionals who are opening doors for sustainable, fire-resistant, and code-compliant hemp building. Together, we're not just funding code updates—we're building the foundation for a more sustainable construction future.

Giving Tiers and Thank You Gifts:

Our hemp-building community is donating gifts and incentives to help bring this campaign to life! Check back for more gifts including hemp t-shirts, books, consulting and more.

Click "DONATE" button for more information:

$1000 - Ticket to Americhanvre spray-cast training in Pennsylvania, Spring 2026 + 1 hemp t-shirt (specify size)
$700 - One-night stay Kosmos Stargazing Resort Hempcrete Villas (date to be determined) Mosca, CO
$300 - Ticket to Americhanvre cast-in-place workshop (PA) Spring 2026
$100 - Copy of "Hempsteads: Architectural Details for Hemp-Lime Construction" by Tim Callahan + hemp t-shirt (specify size)
$50 - 1 hemp t-shirt + 1 copy "Hemp Building Directory 2025"
$25 1 hemp t-shirt (specify size)

A Message from Cameron McIntosh, Americhanvre Cast Hemp

NOTE: The 2027 IRC updates will be submitted for final review in October 2025 and approved in early 2026. Your support ensures this critical work continues and helps the entire hemp building community benefit from these game-changing improvements.

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Add Hemp-Lime Fire Testing Data to US Building Codes

By HempBuild Magazine

Add Hemp-Lime Fire Testing Data to US Building Codes

Help update the International Residential Code for 2027

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