Hemp, or industrial hemp, is a botanical class of Cannabis sativa cultivars grown specifically for industrial and can be used to make a wide range of medicinal products.
Recently, hemp is being used in making hempcrete, a bio composite material used in the building industry for construction and insulation.
Also known as Canobiote, Canosmose, Isochanvre and IsoHemp, hempcrete has been revolutionizing the construction industry due to its environmental benefits. Hempcrete is made from the dried woody core of hemp stalks and a lime-based binder, and it can be cast like concrete.
However, unlike concrete, which accounts for 8% of human-generated carbon dioxide emissions annually, hempcrete actually sequesters CO2.
According to a recent study, hempcrete can sequester 307 kilograms of CO2 per cubic meter (19 pounds per cubic foot), roughly the equivalent of the annual carbon emissions of three refrigerators.
In addition to its environmental benefits, hempcrete also has impressive functional properties in terms of insulation, durability, structural strength, and acoustic control. While it may not be able to replace concrete in load-bearing applications, it can be used to insulate and cover walls.
Hempcrete has a high thermal capacity compared with concrete, making it good for both the structure of a wall and its insulation. It can also cut down on construction waste, as it can be used to replace non-structural elements of walls that traditionally could use concrete.
It can also be used in place of common construction materials like drywall and plaster, which account for about 8% of building construction debris.
Despite its potential, hempcrete faces several challenges. Availability is a major issue, as there are only about a dozen hemp processing plants that are able to process hemp into a form usable in the creation of hempcrete, and most are in Europe.
Also, the legality of growing hemp is a major issue, as it can be hard to distinguish from marijuana plants.
However, laws are beginning to change. In the U.S., the 2018 Farm Bill allows for the broad cultivation of “industrial hemp,” but with tight restrictions on grower licenses and the crop’s psychoactive content, tetrahydrocannabinol, or THC.
Steve Allin, director of the International Hemp Building Association hopes this will lead to more farmers producing hemp crops and entrepreneurs seeing the opportunity to build the processing plants necessary to turn that hemp into building products.
The use of hempcrete as a building material is not just environmentally beneficial, but it also has cultural significance. Hemp has a long history of use in various cultures around the world, dating back thousands of years. For example, hemp was used in ancient China to make paper, and it was used in ancient India for religious purposes.
In more recent times, hemp has been associated with counterculture movements, particularly in the United States during the 1960s and 1970s. The plant was banned in the U.S. in 1937, largely due to the efforts of the paper and textile industries, which saw hemp as a threat to their profits. The ban was lifted in 2018 with the passing of the Farm Bill.
The other major challenge in the U.S. and other countries is the legality of growing hemp, which may affect the acceptance and adoption of hempcrete as a building material. This is because some people still associate hemp with its illicit cousin, marijuana, and may be hesitant to embrace it as a legitimate building material.
However, as more people become aware of the environmental benefits of hempcrete and the potential it has to transform the construction industry, attitudes may begin to shift.
The use of hempcrete in construction could also have a positive impact on rural communities. Hemp cultivation and processing could provide new economic opportunities for farmers and entrepreneurs in areas where traditional industries have declined. Additionally, the use of hempcrete could reduce the demand for traditional building materials, which often have a negative impact on the environment and contribute to climate change.