What is Hempcrete?

Hempcrete, or Hemp-Lime, is a strong eco-friendly building material. It is a concoction of four parts industrial hemp hurd, to one part water, then one part lime based binder, in that order. Although research has shown hemp being used to build structures for thousands of years, most of the data on using it in construction has been lost. Modern society just recently in the late 1980’s re-discovered hempcrete in France, and they have been studying it ever since.

Hurd, or Shives, refers to a mound of splintered or shredded plant-fibers, like wood fibers often used to make paper. Industrial Hemp hurd is made from the inner part of the cannabis stalk.

Hempcrete Approved for U.S. Residential Construction

As we mentioned, Hempcrete is a sustainable construction material that has been used in France for a long time now, and more recently Canada jumped on the bandwagon. Despite its outstanding sustainable properties, federal hemp prohibition in the U.S. made it impossible to get it approved for official U.S. building codes. This changed in September 2022, when hempcrete was approved for U.S. residential construction in 49 out of 50 states. Although the changes are not expected to take effect until 2024, businesses in the U.S. who have been using hemp materials for years are starting to come out and reveal the true nature of some of their materials. In this article I will briefly touch on all the great attributes of hempcrete, but I’d really like to focus on the resolution to the challenges we currently face with this amazingly resourceful building material. I’m a strong believer that there is a solution to everything!

Check out the final hempcrete proposal that was approved for U.S. residential construction!

Hempcrete’s Resourcefulness

Hempcrete is strong, fibrous, and flexible enough to be shaped into bricks, panels, sheets, coverings, and can even be sprayed into cavities. It’s lighter, and not as brittle as concrete.

Benefits of Building with Hempcrete.

Research and studies have shown that hempcrete has many sustainable properties that make it beneficial for building homes.

To name a few of these properties:

Hempcrete has proven to be stronger and more elastic than concrete, allowing it to handle a greater degree of movement. This is especially ideal for RV and van dwellers.
The longevity of hempcrete is exceptionally dependable, if made properly, as it’s known to take hundreds of years to erode.
Hempcrete is a natural insulator, making it ideal for construction use in either hot or cold temperatures.
Hempcrete doesn’t need to be made with any toxic chemicals, so it is good for the environment. In contrast, cement emits tons of carbon dioxide.
The breathable material allows for better airflow, which in turn reduces the build-up of toxic gases indoors and helps prevent the development of mold.

Even with all of these benefits we are still facing some challenges, but none that we can’t overcome!

Challenges With Hempcrete

The following are some drawbacks we are facing according to this article, Biggest Disadvantages of Hempcrete as a Building Material, and an interview with Rocky Mountain Hemp Build!

Challenge 1: Knowledge – Wayofleaf.com claims there are not enough companies to model who are using hempcrete in building projects.

Opportunity: As mentioned earlier, businesses who have been using hemp products for years are now starting to reveal the true ingredients of some of their materials. For example, Just BioFiber and their awesome hemp blocks! Many other companies are becoming open to learning about and newly integrating hempcrete in their construction work as well! So although there are still some challenges to learn about and overcome, there are plenty of Hemp companies emerging with information from many years of experience in the U.S. and across the globe.

Challenge 2: Limited Uses – Because of it’s breathable texture, wayofleaf.com states that “companies can’t feasibly use hempcrete for marine or underground works.”

Opportunity: There are sources that claim depending on how the hemp is treated, it can indeed be used for building ships. For example, after being treated with tar, Hemp was used to make ships watertight in a process called caulking.

Challenge 3: Not Suitable For Warm Wet Climates- Wayofleaf.com believes in certain climates hempcrete buildings will increase to an uncomfortable indoor temperature.

Opportunity: There are many plant-fiber insulation materials available like, wood fiber, cotton, and cellulose. However, recent studies have actually found that hempcrete differs in its capability of maintaining itself in humid conditions specifically because of the lime-binder. According to a study performed on “The potential of hemp buildings in different climates” hempcrete buildings performed similar to, if not better than, traditional houses in the warmer southern climates.

Challenge 4: Increased Drying Time- Another downfall Wayofleaf.com found is that hempcrete takes several weeks to cure and can be affected by weather conditions during the building process.

Opportunity: Companies are innovating premade hempcrete building materials, which overcomes the challenge of having to build with fresh hempcrete.

Challenge 5: Hemp herd availability– In an interview with Rocky Mountain Hemp Build, we learned that cultivators are struggling to find good processors to produce quality hemp hurd, and shipping hemp for processing is very costly.

Opportunity: We need to make strides for (1) more Cannabis Education Programs, while making sure they are accessible to everyone, and (2) Accessible Cannabis business licensing. If cultivators were able to integrate a hemp herd processing facility on premises, or at least nearby, they can cut shipping costs out of the process. Education and accessibility will inspire people to start-up more processing facilities across the country.

Challenge 7: Hempcrete is not load-bearing – Wayofleaf.com claims construction firms won’t be able use hempcrete in heavy load bearing projects.

Opportunity: This means the hempcrete must be used with a supporting structure like wooden frames to withstand heavy weight. In addition, a recent study treated hemp with rHDPE, a plastic made from High Density recycled Polythene, to increase the mechanical strength of hempcrete. The overall study indicated that a compound of 40% hemp fiber and 60% rHDPE volume, increased it’s tensile strength to 60.2 MPa, significantly surpassing that of concrete. We definitely want to stay away from implementing toxic plastics, however, this give us hope to find other compounds that could potentially be used to increase hempcrete’s load-bearing capacity.

Read the full study report from South Dakota School of Mines and Technology on the efficiency and drawbacks of hempcrete!

Challenge 7: Less square footage – Since hempcrete walls are made thicker due to its insulating factor, Wayofleaf.com sees this as a major drawback as you will have less living space, and this could potentially lower the value of your home.

Opportunity: If walls were made thinner, could hemp wool be used for insulation to compensate for thickness of the hempcrete walls? This is an idea I’ll have to research more.

Challenge 8: Cost – It’s a known fact hempcrete is more expensive than traditional concrete at this time.

Opportunity: One of the major factors of hempcrete being slightly more costly than traditional concrete is the fact that it’s “new”, to us. Due to decades of hemp prohibition, people don’t know much about it, so there aren’t many companies producing it yet. Scarcity drives cost up. High Cannabis taxes also get in the way of being able to keep cost down. So this challenge comes down to the fact that we need more educational programs on hempcrete, access to cannabis business licensing, and improved cannabis tax reforms. As cannabis continues to push forward more cultivators and processors will be in a position to supply affordable hempcrete.

The Future of Hempcrete

All in all, the opportunities hempcrete has to offer far outweigh the challenges we are currently overcoming. Cannabis reform has everything to do with the success of hempcrete, as we need access to more education as well as businesses to gain access to Cannabis licenses.

Cultivators Needed!

As the industry rapidly grows more cultivators will be needed in the near future, and HeavenlyHerbs is here to help beginner growers get started on their journey. Tap into the next HeavenlyHerbs Learn To Grow Herbs: Beginners Workshop to learn:

The 5 phases of cultivating your home grown bud
The supplies you’ll need to get started from A to Z
How to recycle your plant
Q&A sesh following the workshop where you can ask all the questions you’ve had about growing.

Let’s cultivate and create a more sustainable world! Paradise is just a plant away!