Concrete is terrible for the environment. Hempcrete is not. Here's why.
Hempcrete is a mix of hemp fibers, water, and lime or clay, which acts as a binder. Despite the simplicity of those natural ingredients, hempcrete has a remarkable array of benefits: it's fire resistant, provides soundproofing, insulates or stores heat (depending on external temperatures), repels mold and pests, and is malleable enough to allow for various aesthetic styles. Hempcrete can be made into building blocks or sprayed into place.
Plus, hemp itself is a sustainable crop that needs few pesticides, is ideal for rotation, and has quick-growing roots that prevent soil erosion.
But most importantly of all, hempcrete has a very low carbon footprint. It requires one third of the heat needed to create concrete, weighs about one-eighth as much as concrete (leading to fewer transport-related emissions), and actively sequesters CO2. According to one Cambridge University researcher, hemp absorbs between eight to 15 metric tons of carbon per hectare, significantly more than the two to six metric tons typically captured by forests.
A single cubic meter of its hempcrete removes 75 kilograms of CO2 from the atmosphere over its lifetime - equivalent to a few years of car use. So, the bigger the building, the more CO2 it absorbs. It also has approximately as much thermal resistance as a double-glazed window, and its honeycombed structure offers about enough soundproofing to block out the noise of a washing machine (44 decibels).
No wonder consumers, businesses and governments around the world are growing to view hempcrete as a sustainable building block of the future. It's already gaining in popularity in Europe and now, after a false association with drugs that banned ‘hempcrete’ from the US residential building code has been lifted, the time has surely come for hempcrete's widespread use.