The US Hemp Building Association, trade association for the hemp building industry, announced upcoming developments for 2024, including hemp-lime (“hempcrete”) listed in US building codes, removing barriers for commercial architects and designers and helping hemp processors attain a “building grade” hemp spec.

At the organization’s online corporate meeting Nov. 15, President Ray Kaderli outlined the association’s past year of participating in outreach and policy activities to bring hemp-lime (hempcrete) into the world of US construction. 

Some highlights included members of the association speaking at the SXSW 2023 Climate Change conference in Austin, TX; EarthX in Dallas; and at the National Association of Home Builders yearly convention and Green Build Expo, both in Washington DC. 

Also in DC, Kaderli mentioned policy activities such as participating in the US Hemp Roundtable Fly-in to lobby for the fiber-grain exemption in the new Farm Bill, and a personal conversation with HUD Secretary Marcia Fudge (who’s a fan of hemp building materials). 

USHBA members speak at SXSW 2023’s Climate change Conference on March 11, 2023. L-R Jean Lotus, USHBA secretary; Kim Croes, Fiber Fort; Sergiy Kovalenkov, USHBA founding member; Ray Kaderli, USHBA president.

What’s ahead for 2024? 

Residential Building Code rolls out

After two long years and lots of hard work by USHBA, hemp-lime will finally take its place in US residential building codes starting in January, 2024, when the International Code Council releases the 2024 International Residential Code. 

The ICC rolls out new codes every couple of years in a staggered schedule. 

Next step is to get hemp-lime listed as a standard infill insulation in the International Building Code, said board member Tai Olson, of Chicago-based US Heritage Group. 

“We’re really just looking for a way to get two elements, thermal rating and fire rating into the commercial building codes,” Olson told the group. Projects will still have to undergo the permitting process, Olson said. 

The IECC deadline for thermal rating is January of 2024, too soon for USHBA to submit any data for that code system until the next code cycle, the association said. 

However, Olson said projects/builders can contract with labs to independently determine R-value rating independently before the IBC is published.

Unlike other insulation such as mineral wool, HempWool or polyurethane foam, hemp-lime is a “system” where multiple ingredients are combined on site. For this reason, builders who are using hemp-lime in blocks or panels or who have a specific recipe can just perform ASTM R-value testing at a laboratory as USHBA corporate member Americhanvre’s Ereasy system has already done, for example.

Hemp-lime (‘hempcrete’) slabs are measured for ASTM thermal resistance testing at  R & D Services in Watertown, TN. Photo courtesy of Americhanvre Cast Hemp

IBC: The IBC fire-rating code cycle deadline isn’t until January of 2025, so USHBA has a little over a year to raise donations and write and submit the code documents to the International Building Code. While US Hemp Building Foundation spent more than $50,000 and hundreds of volunteer hours to submit hemp-lime in the 2024 IRC, the association believes it will take far less work and expense to submit documents for the IBC. 

Meanwhile, for projects that are in the works before the IBC deadline, several private US companies and USHBA corporate members have already acquired ASTM fire testing for hempcrete, such as Hempitecture (ASTM E-84 – fire rating zero) and Perennial Building (ASTM E-119 – fire rating 1 hour). Additionally, fire testing in the EU has a long history.

Guide Spec removes barriers for commercial architects and designers

A new USHBA-funded commercial guide spec will remove barriers for commercial architects and designers to specify hemp-lime in large-scale commercial projects, such as the “Urban Sequoia” hemp high rise designed by SOM. Photo courtesy of SOM

The USHBA has contracted with Connecticut-based Arcat to publish a “commercial guide spec” for hemp-lime to be released in early 2024. Corporate members of USHBA voted at the members meeting in May to produce a commercial guide spec.

“US architects who want to design the big multi-story hemp-lime projects that are popping up in Europe have been frustrated because there’s no easy way to spec these materials in US projects,” said Kaderli, USHBA president, in a statement announcing the spec last summer. “We want to make it easier for architects to include hemp-lime in their materials selection.”

The new guide spec will allow an architect to cut and paste the specifications and put them into bid documents, Olson said. The spec allows designers to bid out large-scale projects “without having to write a guide spec from scratch.” 

As a trade organization it’s our responsibility to make sure that this document is available to the architects and designers that want to build with hempcrete,” Olson said.  

USHBA will runt a draft past a small group of academics, commercial architects and builders before the release, Olson said. 

The spec will be available for free download off the Arcat and USHBA websites.

Announcement made at Architecture League of NY by Parsons Healthy Materials Lab.