Hempcrete is an alternative material used as non-toxic insulation. It is made out of hemp hurd, or the woody part of industrial hemp plants, and lime. The benefits of hempcrete as a spray foam insulation alternative cannot be understated—the material is naturally fire-resistant, mold-resistant, non-toxic, water-resistant, and has a high r-value. However, traditional hempcrete is complicated to install, meaning construction workers that have special training and higher labor costs.
In recent years, a new product has hit the market that’s changing the game: flowable hempcrete.
What is Flowable Hempcrete?
Flowable hempcrete has a completely different installation process than traditional hempcrete, leading to fast set times and easy zero-tamp, ultra-fast pours. Instead of the manual tamping that traditional cast-in-place hempcrete offers, flowable hempcrete is a slurry mixture that can be mixed on-site and poured into any form, setting within 45 minutes.
Benefits of Flowable Hempcrete
Flowable hempcrete not only offers the benefits of traditional hempcrete—namely, energy efficiency, no-VOCs, negative carbon footprint, mold resistance, water resistance, fire resistance, and pest resistance—but it also eliminates the main issue with hempcrete as a spray foam insulation alternative. Instead of days to tamp and set, flowable hempcrete takes mere hours, significantly impacting the costs of a build.
Flowable Hempcrete vs Spray Foam Insulation
There are many benefits to using flowable hempcrete for a build versus traditional spray foam insulation. A few of these include:
- Moisture management: Hempcrete is vapor-open and hygroscopic, meaning hempcrete acts a bit like breathable fabric; it absorbs moisture without inhibiting its performance. Closed-cell spray foam acts as a vapor barrier, which can lead to moisture trapped against framing if there’s any defect or leak in construction.
- Fire resistance: Lime-bound hempcrete is fire resistant up to three hours and doesn’t produce toxic smoke. Spray foam, on the other hand, is combustible and needs a thermal barrier such as dry wall.
- Pest and mold resistance: The high alkalinity of lime means it is undesirable to pests and insects, and is impervious to mold. Spray foam can be tunneled into by pests.
- Acoustics: Hemp absorbs sound better than most spray in insulation.
- Durability and End of Life: Flowable hemp is long-lasting, repairable, and compostable or recyclable at end of life. Foam, on the other hand, typically goes into a landfill.
- Indoor Air Quality: Hempcrete is non-toxic once cured and doesn’t off-gas. Spray foam insulation involves isocyanates during the installation process, meaning respiratory protection and re-entry waiting periods, and improperly mixed or cured foam can cause lingering odors and health issues.
- Carbon Footprint: Industrial hemp absorbs CO2 as it grows, and lime binder re-carbonates, or absorbs carbon, over time, so hempcrete is considered carbon-negative. Spray foam insulation is petrochemical-based, and many formulations use blowing agents, which can cause severe environmental damage.
Top Companies Supplying Hempcrete Insulation Materials in the US
Bison Biocomposites is proud to be the top provider of flowable hempcrete insulation products in the US. We started in 2024 and have only grown since then, providing supplies for projects that range from a home renovation to large-scale tilt-up precast concrete projects.
Reach out to a member of our team today to learn more about our flowable hempcrete and how you can use it in your next building project.
FAQs
Where can I find companies that install hempcrete insulation?
Check out our certified installer page to find a Bison-vetted contractor in your area.
Where to buy hempcrete insulation for home construction near me
Hempcrete installation can be purchased through Bison Biocomposites, on their products page.