When it comes to building materials, concrete is an obvious choice. However, with environmental concerns growing, the search for more sustainable alternatives has become increasingly important. One such option is hempcrete, a unique blend of hemp hurds, lime, and water that is gaining popularity in the construction industry. In this post, we will discuss the origins, ingredients, uses, and potential of hempcrete as a replacement for traditional concrete.
Hemp vs. Cannabis
Hemp is essentially a low-THC form of Cannabis plant. Hemp is non-psychoactive, and has been used for centuries to make everything from textiles to rope, paper to animal feed, and in present day, even biofuels and biodegradable plastics. It is grown as a cash crop, with the bulk of the material going to the textiles industry.
Origins of Hempcrete
Hempcrete is not a new invention. In fact, it has been around for hundreds of years. Historically, hempcrete was used as an insulator in homes and buildings in the form of a plaster-like material. Recently, there has been a resurgence of interest in hempcrete as green building materials and methods are becoming more important in our efforts to reduce carbon emissions.
Ingredients
The primary ingredient in hempcrete is hemp hurds, also known as shives, the woody core of the hemp plant. These are mixed with lime and water, and the resulting mixture is used to form blocks or poured in place like regular concrete. Hemp hurds are a renewable resource and are sourced from the waste product of the hemp industry. The lime acts as a binder, holding the hemp together, while also providing protection against insects and fungi.
Advantages
Along with Bamboo, hemp is one of the fastest growing plants on Earth, with commercial hemp crops reaching maturity in as little as 2-3 months. Hemp absorbs CO2 when it grows, meaning that hempcrete has the ability to act as a carbon-storage material. Because hempcrete is a made from natural materials, it is non-toxic, and does not emit harmful volatile organic compounds (VOCs) like some traditional building materials. It is also remarkably fireproof, with some hempcrete products receiving up to 2-hour fire ratings, on par with brick or concrete.
Replacing Traditional Concrete?
While hempcrete has many advantages, it may not be suitable for all construction applications. Hempcrete has a lower compressive strength compared to traditional concrete, which means it cannot support as much weight. Because of this is it not used for foundations or floor slabs. It also cannot be used below grade in contact with soil, since the material will break down over time.
However, hempcrete can be used for load-bearing walls, as long as it is reinforced with a structural frame or other support system. Canadian company Just BioFiber has created a structural hempcrete block that stacks together like giant Lego blocks, which can be used to build load-bearing walls.
While it may not replace traditional concrete for all construction needs, it can certainly be used in conjunction with traditional building methods to create more sustainable and environmentally-friendly structures.
Key Points:
Hempcrete is a blend of hemp hurds, lime, and water.
Hempcrete has been used for centuries as an insulating material.
Hempcrete is a renewable resource that is non-toxic and does not emit harmful VOCs.
Hempcrete has lower compressive strength compared to traditional concrete.
With reinforcement, hempcrete can be used in load-bearing walls.
Since it will deteriorate below grade, it cannot be used for a foundation.