Advancing the Hemp Building Industry: Q&A With the U.S. Hemp Building Association

In early January, the U.S. Hemp Building Association (USHBA) took a step toward helping advance the industry by submitting hemp-lime (hempcrete) insulation for certification in U.S. building codes.

© Courtesy of USHBA

Jacob Waddell, USHBA interim executive director, says the hempcrete insulation is a “mixture of hemp herd with a lime-based binder [that] creates basically a monolithic wall system.” If the certification is approved, hempcrete would be permitted as a standard material for residential construction.

Here, Waddell describes the application process, what the certification would mean for the industry, the challenges it will help solve, opportunities it would present, and more.

Andriana Ruscitto: For those who may not know, can you talk a bit about what the USHBA does?

Jacob Waddell: The U.S. Hemp Building Association [was] formed to help support and drive the hemp building industry forward. Currently, we’re accomplishing that through trying to get codes and standards set up for the industry, as well as educating people and starting a workforce development process.

AR: What are the organization’s main areas of focus? Does the organization focus solely on the use of hemp as a building material?

JW: Yes, it’s completely, solely focused on hemp as a building material. It can be basically any building-related product, but [currently includes] hemp wood, hemp batt insulation, and hempcrete in its various forms, or hemp-lime in its various forms.

AR: Can you briefly describe what the U.S. building codes are?

JW: The codes in the United States are heavily splintered. Decisions on whether a building can be built can vary from county to county, or even from permitting officer to permitting officer. Now, those are because of judgment calls. So, with that kind of divided sense, there’s a group of people [who make up] the International Code Council (ICC), which basically sets out recommended building codes for the United States. The International Code Council [is] divided into 15 [modern building safety codes]. Two of those that [are] our biggest focus is the IRC, the International Residential Code, and the IBC, which is the International Building Code. We just submitted [hempcrete to] the residential code. The building code is basically commercial codes. So, we submitted it to the IRC, which is a subsection of the ICC.

AR: What will this certification do for the hemp building industry? What challenges or problems will this help amend for construction projects seeking to use hempcrete?

JW: The residential codes describe what is allowable on residential buildings. Now, buildings have been built with hempcrete without being in the residential code because there’s an allowance for a variance; it’s an alternative material variance. This takes time, and you [have to prove] out your material in order for people to accept it. Even at that point, it’s basically up to the permitting officer whether [they] will let that go or not. So, by establishing ourselves in the building codes, the hope is to avoid the need for variances and any delays in projects caused by using hempcrete as a material or hemp-lime as a material. That’s the goal of the submission.

As an industry, really, to exceed and grow, we need to get to a point where large developers and larger businesses feel comfortable doing business in our environment. Having an extra three-month delay in your scheduling because you’re using this material is not going to work for most businesses that are looking at a grand scale. It can work project to project, but if people are building large amounts of buildings, they’re not going to want to focus on this detail [for] every project. So, the hope is to lower the risk of entry for people building with this material and make it more viable. And that’s so much of what we’re doing right now, is just trying to clean up the things that can mitigate risk for businesses entering into our industry.

It both opens up the ability for easy access to the smaller builder to be able to build with this material, [and] it also opens up access to the larger builder to eliminate a hurdle. So, ... it helps everybody, but for different reasons.

AR: Can you briefly walk me through the application process of what it took to submit hempcrete for certification in the U.S. building codes?

JW: Basically, we had to write an appendix for the IRC. We brought in two consultants: Martin Hammer and David Eisenberg, who developed the IRC appendices for strawbale, straw-clay, tiny homes, and cob [monolithic adobe]. … We had meetings with them and [worked with] a group of what started as three and then ended up being a six-member team. ... Many of us were in over a hundred hours of meetings over three months, basically going over this line by line, writing things, rewriting them, correcting them, trying to get them to be code language accessible, trying to ask for the things we needed to ask for, leaving out the things we couldn’t prove with enough data. That [took] about three months from basically starting in October. 

AR: Now that the certification has been filed, what happens next?

JW: So, there’s the committee hearing at the end of March [or] beginning of April, and then there will be a public comment period. [After that], there’s going to be another hearing in September. And then, in October, the government officials make a final decision.

AR: So, if this certification passes, are we looking at 2024 for hempcrete to be used as a building material without any additional approval?

JW: Yes and no. Yes, they will be in the code. Then, at that point, we get back into the fact that we have a very splintered system in the United States. So, even after getting into the codes, we will have to appeal to different states and maybe even down to counties for them to allow this, but it’ll be an [much] easier argument if it’s in the building code. 

I know most or some counties just accept the building code outright. ... So, step one is to get this approved, and then … the next step will be lobbying in different states to get them to outright approve it based on the submission.

AR: What processes or tests does hempcrete have to pass to be certified under the U.S. building codes?

JW: Basically, this has been put in as an insulation; that’s the way the code’s written. For insulating materials, you need to prove your insulative ability, as well as your fire-spread. Now, we’ve had test results with fire-spread that gives you basically a score of zero. So, the fire spread was something that you do need to prove, and we were able to prove and feel extremely comfortable with it.

Editor’s Note: A “fire-spread” test, also referred to as the American Society for Testing and Materials [ASTM] E84, is used to assess the burning behavior of building material used for interior walls and ceiling finishes. Results of these tests are measured by Flame Spread Index (SFI) and Smoke Developed Index (SDI), and each building material is given a standard class based on the results, according to Applied Lab.

A flame spread score of 0-25, also known as Class 1 or A, means the building material will adequately restrict fire spread. In this case, the score of zero for hempcrete insulation is preferred, compared to maple wood, which scored 104 (Class C or 3) based on this chart.

The insulative value, as the other point, was taken from data we [compiled] from around the world and [put] in a table, and then [it] gives an alternate option of running your own ASTM tests that are approved by the Federal Trade Commission.

AR: What opportunities will this certification present for the hemp industry as a whole?

JW: For the hemp industry as a whole, hopefully, we will be lowering some hurdles for applications of use so that we can continue to grow and become larger entities in this area. In reality, if we don’t have a consumer side purchasing the end products made of hemp, there’s no reason for a farmer to grow it or a processor to process it. So, we’re focused on end products, making them viable, [and] growing those markets so that we can then pull the demand from lower down the chain.

AR: Is there anything I missed, or you think would be beneficial to add or include?

JW: This is just another step in a very long process to make this industry grow in a safe and robust manner.

Editor’s Note: This story has been edited for style, length, and clarity.