Indigenous entrepreneur makes building bricks with hemp waste – The Globe and Mail

Mary Mason, president, and Joel Marriott, chair of the board for TOP Carbon Capture, in Richmond, B.C., on Feb. 1.Jimmy Jeong/The Globe and Mail

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An Indigenous-founded construction startup based in Nelson, B.C., will launch a pilot project this month to use hemp biowaste to build more sustainable houses – and potentially more affordable homes and community centres for Indigenous and rural communities.

Joel Marriott, chair of the board for TOP Carbon Capture, started the company alongside his wife, Mary Mason, its president. The company will start manufacturing its first hempcrete bricks this month in anticipation of building pilot homes this spring.

Chipped-up stalks of hemp plants, discarded from the production of hemp fibre, are known as hemp shiv. Hempcrete is formed from combining hemp shiv with water, a lime binder and sometimes sand.

It will take TOP Carbon Capture 12 hours to finish 1,800 hempcrete blocks at its Arizona production facility. Each batch, Mr. Marriott says, will be enough to build two or three houses.

After three days, Mr. Marriott should have enough blocks for nine pilot project houses to show off to potential buyers in Canada and the United States. The company will build the first homes in Arizona, and then six will be transported to B.C. for testing in a colder climate – three to a property the company owns in Nelson, and the rest to a second location Mr. Marriott is in the process of securing.

“We want to make sure that our houses fit the right demographic and needs for Canadians,” he said.

Mr. Marriott is hoping to keep the construction cost between $200,000 to $500,000 for each house, depending on the size and customizations. The lower end of his estimate, which represents a two-bedroom house, compares with an average building cost of $217,500 to $390,000 for a 1,500-square-foot home, according to the financial website In the long run, he expects it to be more affordable than a traditional home, as using hempcrete cuts out the need to install concrete or insulation. As well, TOP Carbon Capture intends to use a biodiesel fuel made from hemp to power these homes.

The start-up won first place in the Synergy Foundation’s 2022 Project Zero incubator, which Georgia Lavender, director of program operations at the foundation, attributes to TOP Carbon Capture’s potential for environmental and social impact. The building sector accounts for 13 per cent of Canada’s greenhouse gas emissions.

“I think they could be a real player within the construction industry and really be able to support our transition towards more net zero building and focusing on sustainable building practices,” Ms. Lavender said.

Umberto Berardi, Canada Research Chair in Building Science, said natural materials have been growing in popularity in Canada’s construction industry because of elevated concerns about sustainability. According to the Hemp Building Association of New Zealand, a cubic metre of concrete creates around 150 kilograms of carbon dioxide, while a cubic metre of hempcrete sequesters approximately 300 kilograms of carbon dioxide.

Hempcrete has started to gain traction domestically and abroad in countries such as New Zealand, Australia, France and Czechia. Although it is still largely an emerging building material, Dr. Berardi feels it will gain popularity with time.

The benefits of building with hempcrete are numerous, according to Hana Karafiatova, a sustainable building researcher at the Brno University of Technology in Czechia who has studied hempcrete since 2014. Hempcrete is more sustainable than many traditional building materials, particularly given that it can be broken down and repurposed as part of a new hempcrete mixture. She also lists the material’s breathability, fire resistance, sound insulation, thermal regulation and ease of assembly among its perks.

“Given the current energy and materials crisis, the use of hempcrete is very promising,” she said in an e-mail interview with The Globe.

However, Ms. Karafiatova notes that the overall quality of hempcrete depends on the quality of the hemp shiv and binder that is used. Some hempcrete recipes can pose a risk for mould, she said, and hemp that is not locally sourced can detract from the building material’s low environmental impact. But overall, the potential drawbacks are the same as those of standard building materials.

For Mr. Marriott, some of the reasons for working with hempcrete are more personal. As a child, he was taken away from his home on the White Bear First Nation reserve in Saskatchewan as part of the Sixties Scoop, he says; reconnecting with his family there as a young adult opened his eyes to the need for affordable, durable housing in Indigenous communities.

For the past 17 years, Mr. Marriott’s 73-year-old uncle has been struggling to get his home repaired owing to a lack of materials or funds. He needs to fix holes in the walls and floor, bring the house up to code and prevent pipes from freezing each winter.

“He’s been under his house with a hair dryer, heating up his pipes for them to run without insulation,” Mr. Marriott said.

He hopes TOP Carbon Capture will be able to help by building resilient homes that people such as his uncle will not have to worry about replacing.

[We’re] making sure that our homes are more affordable so that people don’t have to choose between heat, food and the future.”

To this end, his team has set their sights on a more ambitious undertaking for when the pilot project is completed, which Mr. Marriott expects will take place this year. They’ve secured nine acres of private land in Nelson on which they plan to build a large community centre and living spaces, although the final design is still in the works. The company is in conversation with the regional district, the City of Nelson and the B.C. Chamber of Commerce to shape the outcome of the project as well as potential future ones in the area.

Mr. Marriott’s dream is to partner with a local Indigenous nation or an organization that supports Sixties Scoop survivors to make this an Indigenous community space, potentially for those who were displaced to stay when reconnecting with long-lost family members.

B.C. Chamber of Commerce director Tanya Finley has been helping guide the project in Nelson. She’s excited for the innovation and job opportunities hempcrete construction could bring to B.C. if the company can overcome zoning red tape, secure enough funding and address other hurdles that may arise.

There’s still a way to go before TOP Carbon Capture’s first homes are built in Canada. The company is in the process of being International Code Council certified and is hiring a construction crew to assemble the hempcrete structures in Arizona.

With a small team overseeing all of the manufacturing, architectural design and construction, Mr. Marriott says they’re “working furiously” as they near the start of production.