The hemp plant, also known as industrial hemp, is an incredibly versatile natural resource. Hemp seeds offer nutrition, and hemp seed oil has both nutritional and healing properties. The oil extract from hemp buds, flowers, leaves, and stalks also has a number of health benefits. In this blog, we will talk about how hemp in the form of Hempcrete can transform the construction industry.
Hemp fuel is one of the most renewable biofuels available. Hemp fibers can produce bioplastic, a natural solution to plastic pollution. It is also possible to generate wearable fabrics from hemp fibers. When mixed with lime, hemp fibers can be used as a building material.
Hemp Fibers as Building Material for Construction
The Ellora caves of India, a UNESCO World Heritage site, consist of 34 caves cut out one after the other on a high basalt cliff. The earliest of these caves date back to the 6th century and the latest ones to the 11th century. Both national and international tourists have been visiting these caves for years for their exquisite paintings and sculptures.
How these caves have withstood the elements for so many years has been a subject of wonder, and of research. Finally, in 2014, two Indian researchers discovered the secret. The use of a mixture of clay, hemp, and lime has helped the preservation of these caves along with their paintings and sculptures.
A detailed report in the online version of Daily Mail, U.K in March 2016 quotes the researchers to explain the connection. The use of the hemp mixture as the plaster has regulated humidity and the attack of destructive insects.
The nearby Ajanta caves, also a UNESCO World Heritage site, date back to the 1st and 2nd centuries. These have faced a lot of damage from humidity and insects. There is no use of hemp plaster in the Ajanta caves.
That is how valuable hemp as a building material can be. We refer to it as hempcrete today.
Why Is Everyone Talking Hemp Only Now?
The answer is too simple to believe: due to human fallibility. Hemp is by no means a new discovery. It is one of the earliest plants to be cultivated and used. Hemp farming and the production and use of items generated from this plant had been in practice till the early decades of the 20th century.
Then we banned hemp as a contraband substance. The Marihuana (Marijuana) Tax Act of 1937 is the first known attack against the cultivation and use of hemp and its products in the US. Finally, the Controlled Substances Act, 1970, banned hemp all over the country.
Most countries across the globe soon followed suit. It is only recently that we have become aware of the costly mistake. Attitudes towards the versatile hemp started changing with the turn of the century. It has now been legalized to different degrees in several countries across the globe now.
That is why hemp has only recently entered into public discourse.
Why the Ban?
The plant species to which hemp belongs is responsible for that. Cannabis Sativa L: also the plant species to which cannabis or marijuana, the plant with psychoactive properties, belongs. The important difference in the chemical composition of the two plants got overlooked for some reason.
The hemp has no psychoactive properties. It cannot give anyone the ‘high’ that cannabis, also known as marijuana, can. This is because of the difference in the concentration levels of the chemical called tetrahydrocannabinol (THC).
Cannabis or marijuana has a high concentration of this psychoactive chemical. Hemp, on the other hand, has only 0.2-0.3% THC and cannot produce psychoactive effects. Therefore. Instead, hemp has a high concentration of cannabidiol (CBD), which has several health benefits and healing properties.
The Evolution of Hempcrete
The earliest known uses of hempcrete used the fibers found in the hemp stalks in combination with water and lime. Lime served as the binder. Modern hempcrete uses the inner core of the hemp stalks that are woody in nature. This internal core goes under the name of hemp hubs or shives.
Hemp hubs are typically the byproduct of hemp fibers used for ropes, coils, and, clothes fabric. Once the fibers from the outer parts of hemp stalks have been taken out, the inner hemp hubs remain for a different use.
In current times, many binders other than lime also gets used in hempcrete. Sand, and minerals or mineral derivatives like gypsum, metakaolin, pozzolan, etc. are some such binders. Some people have also experimented with mixing cement and hemp hubs.
Experts describe hempcrete as a biocomposite insulation made of bonded cellulose.
What is Special about Hempcrete?
Hempcrete has remarkable preservation capacity, as the Ellora caves have proved. In addition, buildings made of hempcrete are suitable for both warm and cold kinds of weather. Hempcrete has high breathability. It can both store and release warm air. That helps a building made of hempcrete to maintain an optimal temperature.
Hempcrete is toxin-free, naturally immune to molds and pests, and is highly fire-resistant. Some insurance companies in the UK charge a lower premium on houses built with hempcrete insulation because of its durability.
Hempcrete also has the natural capacity to absorb and store moisture. A France-based study reports that one cubic meter of it can hold up to 596 kilograms of water. It can hold that much water even in a situation of humidity as high as 93%.
However, the greatest advantage of it is, perhaps, the way hemp can transform the construction industry. Hempcrete adds a new dimension to the notion of green buildings. Prevalent insulation materials are not renewable and have an environmental cost, therefore. They are also known to pose several health hazards.
Hempcrete is a byproduct, which makes it an ecofriendly option. It also has an annually renewable source. Hemp plants are annual plants that take between three and four months to mature.
Hempcrete is also considerably less expensive than the insulation materials currently in use. Hempcrete also enhances structural qualities. For instance, when used in combination with wood, it adds to the strength of wooden columns or pillars.
The energy consumption levels are considerably lower than concrete at every stage: from the production of hempcrete from hemp plant up to the construction of a house built with hempcrete insulation. The polluting effects are also substantially less when insulating a building with hempcrete.
Yet another great environmental feature of the hemp plant is its ability to trap and store carbon dioxide. Hempcrete retains this capacity. Constructing concrete buildings leaves a high carbon footprint. Just the opposite happens when construction uses hemp.
Buildings with hempcrete insulation are carbon-free. They also reduce the amount of carbon dioxide in the atmosphere by holding it.
Other Uses of Hemp in Construction
Ropes with different diameters made from hemp fibers are usable in joints for installing door and window frames, as also doors and windows. Hemp ropes are also a good sealing agent. They are usable for repairing bridges, tunnels, and wooden buildings.
It is possible to use thick sack-like hemp fabric for water constructions also. Hemp bioplastic can replace harmful conventional plastic in the construction of pipes, etc.
On the Flipside
Hemp is a natural product and it cannot be entirely free from some shortcomings or the other. In hempcrete, the deficiency appears in two features: it cannot bear the load of a ceiling. In other words, it cannot be an independent building material. It is good for insulation only.
The other issue is that it takes a long time to dry. Hempcrete insulation needs six to eight weeks to dry completely. That increases the time necessary to build a house. Given the many benefits of it for a greener and healthier planet, that is a small price to pay.