Hemp, the building material revolution?

Brickwork decoration on property

Hemp has been used for thousands of years for such things as its fibre for rope making, food and traditional medicines. It belongs to the same species as marijuana but has much lower levels of its psychoactive component.

Today, it is in use as a popular material for sustainable clothing, holistic medicine, and various health food products alike – but its revival within the construction industry as “Hempcrete” is a refreshing and optimistic solution – touted as an energy efficient alternative to concrete.

Hempcrete in the form of hemp bricks is made when extracts of hemp are mixed with water and natural lime and formed into a fully natural brick that is as hard as stone.

There are several advantages to using these bricks, not just for environmental reasons but also a number of practical benefits. They are stable, fire and mould resistant, and resistant to rodents. Hemp removes dust, fungi, and bacteria from the air because of its ionizing effects. And as a natural material its also non-toxic, creating a harmonious, healthy indoor environment.

It is estimated that hemp can capture up to 15 tonnes of CO2 per hectare, through photosynthesis. Making hemp bricks is not only a sustainable solution to building but an almost carbon neutral process, opposed to building with more standard materials such as concrete or timber. Around 8% of planet-warming carbon dioxide emissions is created by the cement industry alone.

Hemp is known (by suppliers’ calculations) to grow fifty times faster than trees, and cultivation takes up only 25% of the world’s agricultural land used for livestock. Because of this, the use of hemp outweighs the logistic and economic downsides of more standard building materials.

Hemp is also being implemented to help with humanitarian efforts. In partnership with Ukraine’s Hemp Technology, a company that grows and cultivates hemp on a large scale, Tao Climate, announced they would be using Hempcrete to make housing for 170 orphans and people displaced from their homes in Lviv.

The specific formulation of Hempcrete currently being used was first developed in France in the 1980s as a method of insulating medieval timber frame houses. Hemp is an extremely efficient insulator. But Hemp as a building material is far from a recent development – its use stretches back at least 1,500 years. Hemp plaster from the 6th century can still be found in places such as the walls of the Ellora Caves in India and in many wooden-framed buildings in central Europe.

Could this move towards more natural methods of building, indicate that many of the answers to our current climate crisis could indeed be hidden in the methods of the past?