Why is hempcrete so important?
As the building industry hunts for less carbon-intensive materials, hempcrete is emerging as one exciting alternative with multiple benefits for buildings.
For one thing, hemp makes an extraordinary carbon sink when it is growing — research suggests that the crop can capture twice the amount of carbon dioxide that trees can. You can grow hemp 1-2 harvests per year in most climates and in some climates have 3 harvests a year. So hemp, which is a kind of grass, grows much faster than trees!
That carbon dioxide is then locked away in the walls of your hempcrete home for as long as it stays standing.
Hemp’s strength at sequestering carbon could be crucial for a building industry that is currently responsible for 39% of global energy-related carbon emissions.
Making cement, a key ingredient in concrete, produces vast amounts of air pollution. Manufacturers use fossil fuels to heat limestone and clay in a kiln, releasing an estimated 600 kilograms of CO2 into the atmosphere for every ton of cement made.
Concrete is also made out of nonrenewable sources like sand and gravel. These materials are currently being mined faster than they can be replenished by erosion.
Sand mining in river and marine areas increases the frequency of flooding while also contributing to collapsing riverbeds and coastal erosion. Excessive sand extraction is linked to habitat loss and declining biodiversity.
Switching to hemp, which is renewable, could reduce these environmental impacts while benefiting the buildings too. Hempcrete has high vapor-permeability, meaning that moisture can escape its walls easily and prevent any buildup of dampness and mildew.
The material is slow to cure, though, and not always ideal for load-bearing walls, according to Insider Growth, which still rattled off far more advantages than disadvantages.
How hempcrete helps to reduce carbon emissions
On top of being a carbon-negative crop, hemp continues to help reduce carbon dioxide pollution after it is turned into hempcrete.
Hempcrete is a highly effective insulator for two reasons. First, air pockets between the pieces of hemp shiv, as well as microscopic spaces within the material itself, are ideal for storing heat.
Second, once the lime binder has set, heat can be stored in the material itself, unlike other typical insulation materials that store heat only in the trapped air.
This means that heat is released very slowly from a hempcrete wall, which makes it easier to maintain a constant temperature even in the face of atmospheric fluctuations outside.
Over time, this reduces the amount of energy needed to heat and cool the building, which cuts both energy bills and carbon emissions.
Hemp is a very energy efficient insulation material with the potential to bring down energy use in a home by about 15% depending on detailing.
This post was adapted from this article:
ARCHITECTS ARE TURNING TO CANNABIS-BASED ‘HEMPCRETE’ THAT COULD REVOLUTIONIZE THE WAY WE BUILD OUR HOMES
