By Emily Ledger
While the movement to liberate the cannabis plant has picked up significant speed in recent years, with medical cannabis becoming established in many countries, and even the legalisation of recreational use, regulation around hemp remains fractured and extremely restrictive.
In addition to being the main source of CBD – a cannabinoid that has taken the health and wellness world by storm – hemp can also be used for a number of industrial purposes, such as construction.
Hemp has been utilised for industrial uses – traditionally for textiles and rope – for millennia. It has represented one of the most important crops to humans, originating in Asia and eventually spreading through the rest of the world, since ancient times. However, recent decades have seen the plant become stigmatised due to the psychoactive effects of THC and the consequent prohibition of the plant.
Industrial Uses of Hemp
In ancient societies, people were able to make use of all parts of the hemp plant, from seeds and leaves to the fibre of the stalk.
Cannabis seeds have little to no cannabinoid content, however, they do have huge nutritional value. As such, hemp seeds have been used as a food source throughout history, as well as for the production of herbal medicines. Hemp seeds are still used today for the production of food products such as oil and wellness products.
One of the main industrial uses of hemp was traditionally for the manufacture of textiles. The fibres from the stalk of the plant were used to make clothes, ship sails, and ropes. Archaeological digs in Asia and the Middle East have discovered hemp rope and fabric dating back to around 8,000BC. It is said that the word ‘canvas’ took its name from the cannabis plant due to its association with textile production.
In ancient Egypt, hemp rope and textiles were used in an ingenious way of splitting rock for construction: the fabric was pushed into cracks in the rock and soaked with water. The expanding fabric would then cause the rock to crack, splitting into smaller, more manageable pieces.
While this may be impressive, the hurds (inside of the stalk) of the plant was also used for the production of mortar as early as the 7th century. Mortar made with hemp has been found in pillars of bridges built in the 7th century in what is now France. Furthermore, there is evidence that hemp fibre was used to reinforce the mortar in construction.
Hemp in Modern Day Construction
Using similar techniques to those used in the ancient world and middle ages, hemp is still used today for construction. The most well-known hemp construction product, Hempcrete, can be used as a more environmentally-friendly alternative to concrete.
Hempcrete is made of a combination of concrete mixers, hemp, powdered limestone, and water. The mixture can be shaped – often in blocks – for building walls. It may also be poured in linear shapes, much like the more familiar concrete.
In addition to the construction of walls, concrete is also an effective thermoacoustic insulator. Once the hempcrete has fully cured, it retains a relatively large amount of air and is less dense than traditional concrete. This property means that it is extremely effective at insulating homes.
A Greener option for the construction industry?
As many of us continue with our efforts to reduce our carbon footprint and embrace new, greener innovations, we increasingly expect industrial sectors to keep up. Hempcrete could potentially offer a more environmentally-friendly alternative for the construction of homes and commercial buildings in the future, without compromising on the efficiency of traditional materials.