Hempcrete: Building Houses With Hemp
Jan 19, 2016
Categories : Other subjects
As the human population continues to grow, housing and the environmental impact it creates raises more and more issues. The construction of a conventional house is not a particularly green process, and as we grow massively as a population, and demand for housing increases. If you are looking for a sustainable way to put a roof over your head, hemp might be the solution.
What is hemp?
The hemp plant is a member of the Cannabis sativa plant that contains only trace amounts of THC. This means that unlike marijuana, hemp is not psychoactive and hence cannot be used medically or recreationally. However, the plant offers more than just a good smoke; its fibres are amongst the strongest naturally found. The high cellulose that the plant contains, and the nourishing seeds that it produces are some of the highest quality resources available to mankind. It is a resource that we are once again beginning to harness as the shadows of prohibition are slowly withdrawing. Whilst more conservative nay-sayers may scoff at the notion, this is no hippie pipe dream: hemp has real practical use that is already being researched and harnessed by global corporations and industries.
What is Hempcrete?
„Hempcrete“ is a word combination of „hemp“ and „concrete“, alluding to the strength of the material. It is created by mixing the cellulose rich hurd fibres from the hemp plant with lime and water. The resulting paste can be cast into walls, bricks and foundations, exhibiting excellent insulation properties at just a fraction of the weight of concrete.
There are many advantages of using hempcrete over traditional concrete. It is up to seven times stronger, less than half the weight and three times more pliable than standard concrete. As hempcrete ages and is exposed to the elements it continues to petrify, becoming harder and harder. But as it grows harder, it retains its flexibility. Unlike the brittle nature of concrete, hempcrete does not crack under small earth movements, and thus does not need expansion joints. It is these two features combined that give hempcrete building the potential to last thousands of years, whereas brick built constructions will only last hundreds. Hempcrete walls also act as a natural moisture regulator, allowing excess moisture to pass out of the wall, helping to prevent damp and mould from growing within the building.
Hemp also scores pretty high on the sustainability side. Firstly, hemp is a renewable and fast growing crop that can be cultivated without depleting the soil. Secondly, the cellulose within the hemp continues to absorb and lock away carbon dioxide, this means the average house build could lock away anywhere up to 20,000 lb of carbon from the atmosphere.
If hemp is so great, why has it not already been used construction?
Hemp is indeed being successfully used to build houses. But it hasn‘t yet received the recognition and widespread adoption that such the material deserves. This is still largely due to prohibition, which in some countries prohibits the cultivation of industrial hemp, or restricts access to it. Often, material has to be imported, which adds costs that makes the use of hemp prohibitive, preventing its use as a mainstream material. However, as prohibition is beginning to end in America, and other countries re-assess their cannabis and hemp laws, the hemp industry is once again beginning to grow; and as supply increases, costs go down – potentially making it a viable option once gain.
Is hempcrete the future?
We certainly hope so. Hemp has incredible potential to become the green and sustainable building material we so desperately need. More and more construction workers and architects are now beginning to look into its practicality as costs reduce. It offers both practical and green benefits that appear to outweigh those offered by standard concrete. It is also worth noting that the oils and fibres from hemp can be used in many other aspects in construction. It is possible to make plastic for pipes, paint, carpet, insulation and even plaster. There is still a long way to go, but the future is very promising.