The Hemp Building Institute, in partnership with the US Hemp Building Association, completed the final steps to include hemp-lime in the US residential building codes this summer.
At the end of May, the HBI submitted a “commentary” to the International Code Council as a final step in submitting hemp-lime (hempcrete) in an appendix for the International Residential Code. The commentary provides guidance and gives compliance examples, making building with hempcrete safe and repeatable by contractors all over the country.
The IRC adoption will cut red tape for builders of one- or two-story houses in the United States. Hemp-lime has been used for 30 years in Europe, including commercial multi-unit structures.
Appendix BA of the International Residential Code, which will go into effect in 2024, will allow use of hemp-lime in regions of low seismic risk prescriptively without engineering. Regions of high risk still require an engineered design. Forty-nine out of 50 states use the IRC for building codes.
USHBA and HBI thank the following consultants, hemp building experts and donors who assisted with this final step of the IRC process:
The members of the small group on the IRC commentary were Cameron McIntosh, Co-Owner of Americhanvre, Matt Marino from Homeland Hempcrete, Tim Callahan from Callahan Designs, and two representatives from the USHBA Board of Directors Alex Sexsmith, Principal at Sexsmith Architects, and Tai Olson, Director of Operations at US Heritage. There were also over a dozen other professionals that reviewed the documents.
Mary Dempsey from Mpactful Ventures, Kiko Thébaud, and Jacob Waddell from the HBI led the charge on the IRC code development. Mary and Jacob continued to lead the process through the commentary development.
None of the progress would have been possible without the assistance of the code consulting team of Martin Hammer and David Eisenberg. Anthony Dente from Verdant Structural Engineers performed the necessary structural engineering work on all levels of the document.
USHBA will take over further work with the ICC codes, after HBI announced this summer that the institute would pivot away from developing building codes and focus on affordable housing.
“The HBI was proud to lead the completion of the Hemp-lime appendix. However, due to our shift in mission and our new focus on charitable work, we will be stepping down from leading this project,” Jacob Waddell, HBI executive director, said in a statement.
“The USHBA is proud to have partnered with Hemp Building Institute to get these important documents over the finish line,” said USHBA President Ray Kaderli. “We provide value to our members by removing obstacles for those who want to take advantage of the sustainable, natural properties of industrial hemp in building tomorrow’s homes,” he added.
“We want to make it easy for architects, building departments and code officials to say ‘yes’ to hemp-lime and deliver the excellent properties hempcrete provides,” Kaderli said.