After watching thousands of pounds of hemp stalk and leaves go to waste over years in the smokable hemp industry, our Chief Operating Officer (COO) Vanessa Ramirez decided it was time for a change. She sought out local businesses and organizations that might find a useful application for the byproducts of her cannabis flower operation, Soul Hill Farms, eventually coming into contact with a California workforce development company called Pass It Forward. This scrappy, forward-thinking non-profit provided her the perfect opportunity to not only pass on our hemp flower “waste,” but also contribute to creating green jobs and the production of a fire-resistant building material, critical for structures vulnerable to California's wildfire crisis, called hempcrete.
How it works: What is hempcrete?
When growing hemp flower, the only part of the plant that is harvested and sold is the actual hemp buds, or flower, itself. This leaves behind a number of byproducts, namely hemp stalks, leaves, and stems. Without an outlet for these, they usually end up being disposed of in the same way a restaurant disposes of expired, or leftover, vegetables, by throwing them in an organic waste garbage can. While this isn’t the worst thing in the world because it eventually decomposes, it is wasteful insofar as it’s not being utilized to its full potential, the same way throwing away unused vegetables is wasteful.
Enter hempcrete: a substitute for concrete that’s made from hemp shulls, or the interior part of hemp stalk, limestone, sand, and a tiny amount of traditional concrete. These materials are ground up and mixed together to form a concrete-like paste that can be used as insulation, or to build walls, roofs, and floors. Compared to concrete, which accounts for a hefty 8% of global emissions, hempcrete has a low to zero carbon footprint and has actually shown to sequester, or effectively “capture and store,” C02. Its consistency helps to self-regulate temperature and moisture which can cut down AC/heating costs, it has excellent acoustics, and as mentioned before, is fire-resistant. In fact, a standardized fire test done by ASTM, which determines the fire safety of a construction material on a scale from 0 to 450, gave hempcrete the best possible score of 0 for flammability and smoke spread according to hempcrete manufacturer Hempitecture. Still not convinced? Check out this video of a block of hempcrete being blasted with a giant torch.
Imagine the peace of mind homeowners in fire plagued areas like arid Southern California would have knowing that their homes are built with such a protective medium. We donate our hempstalk to Pass It Forward for the production of hempcrete. They provide free education and training for those interested in entering the rapidly growing sustainable construction industry by teaching through hands-on hempcrete based projects. Participants in their 5-week program learn how to make hempcrete, prep sites, install, and finish projects safely.
So what’s the catch? The limitations of hempcrete
Okay, so we’ve established that hempcrete is pretty badass, and we totally support it, but if it’s so amazing then why isn’t it more widely adopted? The most obvious hindrance of hempcrete’s mainstream acceptance is the fact that hemp has only been legal since 2018. Before the passage of the Farm Bill, it was illegal to research, develop, or use hempcrete in any capacity. Four years is not enough time to change the tides of a longstanding, trillion dollar industry that heavily favors traditional construction materials, so here we are.
Consider the adoption of electric vehicles. When Tesla first began production of electric cars in 2003, the technology was lacking, there was no charging infrastructure, and the market did not yet know it wanted an electric car. That’s where hempcrete is right now. There is a lack of research and development, equipment infrastructure, and consumers are generally unaware that there is a more sustainable version of concrete that may work just as well, if not better, in meeting their needs as a homeowner. For these things to change, more time is needed, and bigger players are going to have to invest in more well-funded, larger scale hempcrete projects. Beyond time limiting the growth and adoption of this exciting new building technology, there are a few other slight disadvantages to consider.
1. Price
Way of Leaf, a reputable cannabis blog, estimates that hempcrete costs approximately $12.54 per square foot. In contrast, regular concrete goes for around $6 per sq ft. While the cost estimates for hempcrete are more speculative than fact because of a lack of sufficient data, the discrepancy isn’t favorable. This said, as natural building materials become more widely adopted, the cost will likely decrease as it benefits from economies of scale. With more readily available hemp stalks from farms like ours, more legislation that favors green building, and increased demand for sustainable building materials, this pricing inferiority could be a whole different story in the coming years.
2. Lack of Trained Professionals
Scalability requires predictability. Without consistently proven methods and standards for using hempcrete, it’s difficult for home builders to invest large sums of money into any given project. Being as avant garde as hempcrete is, there is a limited number of experts and construction professionals that have been trained to implement it in any largescale way. That’s why organizations like Pass It Forward, that are working to educate construction workers on hempcrete techniques, are so important. Without a workforce trained to use sustainable construction practices, it’s difficult for hempcrete, or any other novel natural building material, to be adopted in any seriously noticeable way.
3. Load Bearing Capacity
The compressive strength of hempcrete is about 1/20th of traditional concrete, which makes it difficult to build any structures that require a large load bearing capacity with hempcrete. What requires a large load bearing capacity? You may be thinking . . . Well, pretty much everything beyond a two-story building.
As of right now, there are no known three story, or above, structures made primarily from hempcrete. This means that aside from small, single story family homes, the best applications of hempcrete may be as a sidekick to traditional concrete, or other materials. For instance, hempcrete could be used for insulation, wall panels, etc, in a similar way to drywall, while concrete could continue to do the heavy lifting for the structural integrity.
Hempcrete in Action: Real life examples of hempcrete being implemented
Despite there being some disadvantages of hempcrete, there are a number of architects and designers that have been able to find creative solutions to the limitations imposed. To give you an idea of the potential hempcrete has for functionality and beauty, here are 3 inspiring real life examples of buildings that utilized hempcrete.
1. A UK Supermarket
Marks & Spencer is a clothing and food retailer that represents around 5% of the UK's grocery market share. Their Cheshire Oaks location was designed to address multiple areas of sustainability at once and is around 40% more carbon efficient than average grocers. They opted for hempcrete external panels, which help to regulate the store’s temperature, saving a significant amount of electricity. This building is a great example of hempcrete being used in tandem with other sustainable construction techniques. Hempcrete certainly isn’t the star of the show for this building, as it also features a biomass boiler, an 80,000 liter rain collection system, and a sleek wavy roof made primarily from recycled materials and timber. Still, hempcrete found its place and proved to be a viable, functional alternative to concrete that helped to save the store a significant amount of money and emissions from heating and cooling.
2. The Mobius House
When you think of houses built with natural building materials, this modern masterpiece may be the last thing you’d envision. It stands as a symbol of the intersection between nature, mathematics, and beauty. Made almost entirely from hempcrete reinforced with concrete, this house was designed by renowned architect Anthony Gibbins based upon the mathematical idea of a mobius strip. A mobius strip is a surface that can be formed by attaching the ends of a strip of paper together with a half twist. The house only contacts the floor for a few meters, while the roof makes up the entire frame of the building. It’s tricked out with floor to ceiling windows, making virtually the entire house feel like a sunroom. Not bad for a house made mostly of plants!
3. French Sports Center
Anyone who's ever been in an enclosed basketball court, racquetball court, or dance studio, knows that it can get annoyingly loud. As mentioned before, one of the benefits of hempcrete is its excellent acoustics. Hempcrete can absorb sound more efficiently than most other building materials, including concrete, making it ideal for sound intensive spaces. In fact, Pass It Forward recently built a small music studio using hempcrete for this exact reason.
This publicly funded recreational building in Paris, Pierre Chevet Sports Center, is a shining example of how hempcrete can be utilized to solve practical problems. Made with a wooden frame and hempcrete walls, it takes advantage of the columnless design characteristic of almost all hemp based buildings, and critical for large open areas like gyms.
While our main focus is providing the highest quality hemp flower products and working toward drug policy reform, sustainability has always been a value pillar for us. Moving forward, it can be argued that innovations like hempcrete will eventually begin replacing traditional practices in various industries. As we’ve witnessed with electric cars, the rising popularity in sustainable fashion, and biodegradable packaging, people are starting to expect a certain standard when it comes to the businesses they choose to support being environmentally conscious. According to the FDA, hemp has over 25,000 uses. Clothing, rope, paper, and CBD are of the most common. For this reason, hemp is a sustainable and renewable resource that we should all be taking advantage of; hemp is the future!
