Cannabis waste could fuel the green building movement

hempcrete homes: graphic of cut out house with cannabis leaf in the middle

From construction to sustainability, the benefits of hempcrete homes have been touted for years. Building with hemp could lead to easier climate control in a home, better air quality—and that’s just the beginning.

There’s no denying the benefits, but that’s not what’s stopping hemp houses from lining suburban sidewalks. In fact, it’s easy to convince even anti-cannabis people that hemp building is a wise choice. The trouble has always been with acquiring the materials, the lack of education, and stringent regulations.

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Acquiring hemp building materials is only one hurdle. Working with new materials in building and construction requires training, testing, and trust. In a world where cannabis stigma still stands in many states, that has been lacking for generations. Still, people are working on every end of the fight to make this sustainable building modality more accessible.

Education is key

Contractors aren’t traditionally trained to build hempcrete homes. It is a porous, non-structural, non-load-bearing material. Despite implications from its cheeky name, hempcrete isn’t a concrete replacement; it’s an insulation material for floor to ceiling. Without education on the product and its applications, it’s impossible to use it correctly.

Hempitecture, a longstanding hemp building materials brand based in Idaho, wants to change that. The company produces Hempwool and hempcrete and teaches people how to use it. In 2017, the company announced a successful collaboration on the first public-use building made of hemp materials, and it’s only been up since then. Now, they operate an energy-efficient manufacturing facility, bringing the sustainability mission full circle.

“Several companies are bringing to market sustainable solutions,” Meade told GreenState. “Hempitecture focuses on natural fiber insulation as well as Hempcrete for the most radically sustainable buildings on the planet. We only help reduce carbon through energy-efficient materials, but our products also store yesterday carbon in the fiber itself, as well as in the soil.”

Those seeking hemp building materials can also look to Hempire USA, the American branch of a Ukraine-based sustainable construction company.

There’s multiple U.S. hempcrete manufacturers, but one Pacific Northwest hempcrete advocate shared that bags of hemp lime she once bought for $11 is now upwards of $60.

Putting the work into action

The Highland Hemp House is a sustainable, non-toxic, breathable, carbon-negative construction located in Bellingham, Wash. Pamela Bosch was ahead of the curve on hemp building when she started the project, but luckily she had funds to bypass difficulties. At the time, things like acquiring insurance, licensing, and permits were a huge hurdle.

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When construction began, hempcrete was a mystery to many contractors without standardized methods for building or stabilization.

But as Bosch says, “Building with hemp and lime is not difficult or expensive.”

Additionally, the International Code Council and the American Society for Testing and Materials had not yet verified the material. Now, hemp building has never been easier, with materials made in the U.S. by multiple manufacturers. In March, the ICC updated the Residential Code to include hempcrete construction.

The ASTM created a hemp subcommittee to discuss non-consumable commodities in 2017 and set performance standards. Now inspectors can test hempcrete homes, informing builders and city inspectors on hemp lime in the future.

Despite these strides, Bosch doubts change will come with out commercial incentive for big players.

“In general, what slows the adaptation to building with these healthy and carbon negative methods is inertia to preserve current revenue streams,” Bosch said to GreenState. “Builders and material manufacturers are not incentivized to change while making so much money as they are.”

After years of work, the Highland Hemp House is complete. And though Bosch is wary after seeing behind the curtain, lawmakers in her state are working to make builds like hers more possible than ever.

Legislation freeing the plant

Hemp has more freedom in the legal system than THC-strong cannabis plants–even when it comes to waste. One state passed a bill at the top of the year hoping to offset some of that waste, THC or not.

Washington state Senator Derek Stanford was instrumental in passing SB 5376, which makes highly regulated THC-free organic cannabis waste like stems, stalks, and fan leaves available for composting or production. Not only that, cannabis companies will have the opportunity to sell the waste when applicable, bolstering those struggling with monumental tax rates.

“The cannabis industry has a significant compostable waste stream, which currently must be mixed with fillers and sent to a landfill. SB 5376 will help reduce that waste in a way that is better for the environment and for growers,” said Sen. Derek Stanford (D-Bothell).

Hopes are that the new legislation will cut costs for growers and the environment, keeping waste from landfills and using whatever is possible in new ways. Movement in the state is good news to Pamela Bosch, the creative behind the Highland Hemp House, and anyone else hoping to construct a hemp building.

Hemp building is closer than ever

A lot has changed since American hemp-building pioneers set out to change how the country constructs structures. There are multiple sources for U.S.-made hemp building materials, and legislation is moving to make hemp stalks and hurds more available for production. The ICC and ASTM are even in on the conversation with code approvals and inspection parameters.

Thanks to work from people like Meade, Bosch, Sen. Stanford, and more have made this possible–but it’s up to those who believe in the cause to keep it going.

EDITOR’S NOTE: This article has been updated to include quotes from Pam Bosch and correct information about the building process of the Highland Hemp House.

Cara Wietstock is senior content producer of and has been working in the cannabis space since 2011. She has covered the cannabis business beat for Ganjapreneur and The Spokesman Review. You can find her living in Bellingham, Washington with her husband, son, and a small zoo of pets.