Building with Hempcrete
Written by Sarah Stukalin, AMAST Content
Hempcrete is a unique building material that is made up of a mineral binder and a bio fiber. These ingredients are blended with water, resulting in the particles binding together. Hempcrete has been gaining traction over the years for its sturdiness and insulation. Here are the benefits of building with hempcrete.
The cost of hempcrete is widely competitive with other insulation options. With buildings requiring more insulation to lower energy requirements, the volume of insulation needed for a project is going to rise dramatically. Hempcrete stores heat in the thermal mass of its wall and then releases the heat slowly as a structure cools down. Because hempcrete is renewable and eco-friendly, it is a solid insulation solution.
Hempcrete is unique among plant-fiber insulation materials because of its ability to resist moisture in humid conditions. Hemp hurds store moisture because of their porous structure, allowing for the material to take on more moisture when needed, and then release it when conditions allow. A French study showed that 1,314 pounds of water vapor would be stored in 35.3 cubic feet of hempcrete, allowing for the absorption of 93% humidity without overwhelming the capacity of the hempcrete.
Hempcrete cannot support roof loads but can support wall framing. Testing shows a 2x6 wood stud with 19.5 pounds per cubic foot of hempcrete infill supports three to four times the compressive loading of a standard stud wall, as the hempcrete provides support to the stud in weak axis bending. Because hempcrete is rigid, it is an excellent substance for plaster finishes without bonding agents.
Because hempcrete is a benign material, the farming process uses few pesticides and herbicides, creating less environmental damage. Once hempcrete is installed into a wall and fully cured and dried, it does not release gas or toxic emissions into the environment. Because hempcrete is also moisture resistant, the material can reduce the chances of a poor or difficult indoor environment due to excess moisture.
Hempcrete is light and not load-bearing, making it easy to transport to a construction site. Projects that utilize lightweight foundations can take advantage of hempcrete instead of concrete, as it would be lighter, and more environmentally friendly. This also increases safety measures among workers, as there are hardly any concerns with moving such a light material to and from a construction site.