What is Hempcrete? The short answer: it is a biocomposite building material. However, the short answer doesn’t tell the whole story.
Hemp and mortar mixes have been used as building material for hundreds of years. During the 1990s, it was rediscovered and the use of hempcrete started gaining popularity in France and other parts of the world.
According to the Hemp Industries Association, the inner core of the hemp plant is mixed with a lime-based binder to create the product used in today’s building material. While strong and durable, Hempcrete is not used as a supporting structural element, but is generally utilized in applications such as walls (around supporting structures such as wood framing), and when cured and finished, has a stucco-like appearance.
Some of the benefits of hempcrete over traditional concrete are its light weight (which is less than half of concrete’s weight), its ability to transmit humidity while remaining mold resistant, and its resistance to cracking under movement (which makes it ideal in earthquake zones). Additionally, with an R-value of 2.4 per inch, it is an effective and fire-resistant insulation material.
While hempcrete is an accepted building material throughout much of Europe and in Canada, it is just now gaining traction in the United States, not for lack of interest, but for laws that had restricted the growing and use of hemp until the 2018 Farm Bill allowed for the growing of hemp for industrial purposes. While there are still some sourcing issues in the US, mainly due to industrial farming and need for processing plants, there are plans to move forward to obtain certifications needed for insurance standards, building permits and other code requirements.