Austin TX Adopts Hempcrete in Local Building Codes
Austin-based hempcrete builder Carl Gradek poses on the site of the hempcrete Accessory Dwelling Unit (ADU) he built in Austin this year. Photo courtesy of Carl Gradek
Austin TX Adopts Hempcrete in Local Building Codes
By Jean Lotus
The city of Austin, TX on April 10 officially adopted hempline (hempcrete) in the city’s Building Technical Codes as an innovative building material to be used in local construction.
“Hempcrete offers a low-carbon alternative to traditional concrete and aligns with the city’s broader goals to reduce greenhouse gas emissions in the building sector,” a press release said. The city adopted Appendix BL of the 2024 International Residential Code, “Hemp-Lime (Hempcrete) Construction,” part of the model US residential building code which applies to homes and small multi-unit buildings. The new building codes will go into effect on July 10, 2025 in Austin.
Austin, TX-based Realtor and hempcrete pioneer Henry Valles testifies in favor of adopting hempcrete in the local building codes at the Austin City Council meeting April 10. Screenshot courtesy of the City of Austin.
Austin hempcrete pioneer Henry Valles testified to the city council before the vote that adopting the building codes would protect consumers by providing, “rigorous standard operating procedures for construction assemblies as well as mixing and installing the biomaterial.”
Valles, an Austin Realtor, helped build one of the first hemp-lime structures in the city in 2019 with a tiny hempcrete house at Community First! Village.
“I've seen the benefits of this type of building material which can help resolve a lot of the issues we have: mold issues, fire resistant issues, and just higher quality construction,” Valles said in remarks to the council.
Hempcrete, a mixture of hemp stalk hurds or “shiv” and lime binder, creates a long-lasting fibrous insulation wall assembly that makes an excellent insulation. Because hemp sequesters carbon in the walls of a building, hempcrete is an excellent zero-carbon building material that can offset the construction industry’s carbon footprint, supporters say.
A hempcrete tiny house in Austin’s Community First! Village was spearheaded by Realtor Henry Valles in 2019. Photo courtesy of Jean Lotus
“When it comes to our commitments around sustainability, we have to get creative, and hempcrete is more than just a greener building material—it’s the type of efficient, innovative investment that reflects the kind of city we want to be,” City of Austin Policy strategist John Lawler wrote in a note to city council members. The amendment was supported by the American Institute of Architects’ Austin branch, as well as city staff, Lawler said.
“By embracing hempcrete, we can support local farmers and businesses, fostering economic opportunities within our community. …It’s another example of how we can lead with both our innovation and intention,” he added.
A hempcrete home in Dripping Springs, TX designed by Gayle Borst. Photo courtesy of Gayle Borst
Streamlining projects
In Austin, the adoption of the hemplime appendix will speed up city building permits, supporters said. Builders will no longer need to acquire permits via the “alternative methods” pathway, which can add extra costs and delay for engineering and inspection requirements.
For those in Austin interested in building with hempcrete, the new code change will “provide a sense of legitimacy,” said Austin-based natural building architect Gayle Borst, principal of Stewardship Architecture.
“Sometimes it’s one spouse who is really into natural building while the other is not so sure,” said Borst, who has designed multiple hempcrete homes.
She added that architects and builders who “shy away from technologies that are new to them,” might be willing to look at working with hempcrete with guidelines available in the city technical codes.
Austin is a trendsetter
Austin has become a trendsetter in the United States, drawing residents and well-paying jobs as a new tech hub with large creative population, research university and state capital. The city demographers anticipate an additional 750,000 in population and 350,000 new jobs in the Austin US Census area by 2040.
But with that population growth (from 680,000 to 1 million in 20 years) the city’s housing shortage has reached a crisis level with high home prices and rents. Median home prices in Austin shot up around 235% from $218,205 to 760,537 between 2000 and 2025.
In 1991, the Austin Energy Green Building program developed the first rating system in the U.S. for evaluating the sustainability of buildings, inspiring many cities to follow. Today, the AEGB provides resources to help builders and designers choose the most sustainable building materials and methods.
A climate of innovation, sustainability and desire to be first has made Austin a trendsetter in hempcrete construction too.
“The transition of general influence into focused leadership is how I would describe Austin’s purposeful adoption of hempcrete,” said Ray Kaderli, president of New Braunfels, TX-based HempBuild Network in a message. “A small group of natural builders focused on hemp as a building materials have known its value for quite some time. Austin’s municipal leadership will help bring this economic and ecological value to the mainstream,” he added.
A hempcrete workshop at the New Braunfels, TX headquarters of HempBuild Network, near Austin. Photo courtesy Jean Lotus
Hempcrete is drawing interest in Austin
To allow smaller housing types to be built on existing lots, last year the city of Austin changed regulations to make it easier to build an accessory dwelling unit (ADU) on the same lot as an existing home.
Austin-based builder Carl Gradek designed and built a permitted 2-story hempcrete Accessory Dwelling Unit (ADU) for a client last year. He said he had a bumpy road explaining the material to inspectors and at one point had his permit cancelled, only to be reinstated after his client met with the building department. Gradek showed off the house in Austin earlier in the month at an open house.
“I want to thank Austin City Council for the wise and knowledgeable approach of supporting the hempcrete movement,” Gradek said in a statement.”I am so proud that I live in one of the most progressive cities in the nation.”
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