Industrial hemp is an excellent natural material that can be used in construction. It is not load bearing meaning it has to be used in conjunction with other materials, but the bast fibres from hemp are very sturdy. It was developed in the 1980s in France as they sought for an alternative material to be used for repairs because the previous materials used like Portland cement did not allow the fabric of the building to breath. This led to the buildings retaining vapor and moisture and consequently weakening and damaging of the timber fibers. Its use in construction is slowly gaining popularity, particularly in the UK. The University of Bath in Great Britain in 2010 built a home made entirely of renewable construction material especially hemp.
Hempcrete is the name of the concrete created using hemp. It is made by wet-mixing hemp shivs (chopped woody stem of hemp plant) with a lime-based binder then pouring the product into moulds. The materials are used to make lightweight roofing materials, fiberboards, wallboards and other wood-like materials. This material has several advantages. It is lightweight and is very breathable (Vapor permeable). The vapor permeability allows homes to regulate moisture in the house, therefore, reducing humidity and consequently the growth of molds. The material also makes excellent thermal and acoustic insulating sheets. It also has a low thermal mass which can help in reducing utility bills during extreme weather conditions by regulating diurnal (day-night) temperatures.
Hemp houses are also advancing the green movement by incorporating eco-friendly construction materials. Most construction materials are energy intensive in their production while producing a lot of waste byproducts in the process. Hemp, on the other hand, utilizes most of its parts for different purposes leading to low waste and they also use little energy in there processing. Furthermore, hemp can help in reducing the carbon footprint of their owners and the environment because they absorb CO2 from the house owners and the atmosphere. In the process of reducing the greenhouse effect, the houses also get stronger as they absorb more C02, and therefore they become more durable as time goes by. Moreover, hemp plants take 102 -108 days to fully mature meaning they may reduce the rate of deforestation because they can be an excellent alternative source to timber, therefore, saving the trees. This is beside the fact that trees have 30% cellulose and the rest of it needs to be removed using toxic products while hemp contains 70% cellulose which is easy to get from the plant.
There is still a lot of research that is ongoing in regards to hemp’s use in construction. The discoveries that have been made so far, however, show that we may have a product on our hands that will not only create environmentally sustainable homes but that requires few repairs as the structures made from hemp stronger as time goes by. The only other downside at the moment is the fact that hemp production is still highly regulated making such homes very expensive to construct, but this too will change as more and more countries legalise it.