Hempcrete (hemp concrete) is one of the most environmentally friendly solutions worth considering when choosing a future material for construction. Globally the construction industry is estimated to be responsible for about 39% of carbon emissions. Of this, just over a quarter of emissions are from raw material procurement, treatment and production, transport, construction, demolition, waste treatment and recycling. Almost 3/4 of the emissions are due to operations; such as electricity consumption, ventilation and maintenance during the building’s operating period.
Although the construction industry’s share of total emissions is lower in Iceland than in many other places, such as due to the high proportion of renewable energy used for space heating and electricity production, it is clear that the Icelandic construction industry needs to reduce emissions significantly. Numerous studies have been undertaken in Iceland and abroad related to the climate and environmental effects of the construction sector, with the aim of mapping and reducing emissions.
More steps need to be taken to promote carbon-neutral buildings in Iceland. Among the most carbon-intensive building materials on the market today is concrete, largely due to the production of cement. The benefits of reducing the amount of concrete or reducing the carbon footprint of concrete can therefore be considerable.
But what is Hempcrete?
Hemp concrete is a building material that can be made partly from Icelandic raw materials and is composed of crushed hemp, limestone powder and water and has extremely desirable properties. Hemp concrete does not mold or burn and is especially insulating both when it comes to heat and sound.
Recycling hemp concrete is also very simple. When its function is complete, the hemp concrete can be crushed and used directly as organic fertilizer on arable land. This allows you to close the cycle of the process.
Role in house construction
Hemp concrete can not be used as a load-bearing material in structures and will therefore not be able to completely replace concrete. It can, however, be used in conjunction with concrete, steel or timber structures, for example. Hemp concrete is very suitable as an insulating layer in exterior walls, in interior walls in house buildings or even in sounds during traffic jams, for example.
During the growing season of hemp, it absorbs carbon dioxide from the atmosphere and acts as a carbon store during its lifetime, like wood and other organic building materials. The advantage of hemp over timber, is how fast it grows, and it acts as a uniquely carbon-absorbing plant for both long and short periods of time. Carbon uptake of hemp grown under good conditions can be around 0.32 kilograms per kilogram of hemp. During hemp processing and production of hemp concrete, there will be some emissions, but the carbon footprint of hemp concrete is negative when looking at the entire lifespan, ie. the product causes net sequestration of carbon dioxide instead of emissions. The building material thus works directly against pollution in the atmosphere. Hemp concrete, like other concrete, also attracts carbon dioxide from the environment during its lifetime due to carbon dioxide, if it is not covered with paint or other materials.
Experimental breeding of hemp in Iceland
Although hemp has been cultivated and used abroad for millennia, it has only been cultivated in Iceland for experimental purposes for the past two summers. Initial tests give good results, because hemp grows very fast. Studies also show that under Icelandic conditions, hemp can grow up to a height of about two meters during the growing season. Hemp can be used to make paper, textiles for clothes, plastic, cosmetics and of course as well as concrete. The stem of the plant is rich in fiber, but the fibers make hemp a suitable raw material for concrete processing. It should also be noted that the hemp plant can also be used to make the substance CBD, which has been used against various diseases.
Icelandic companies, like EFLA, are now studying the production and use possibilities of Icelandic hempcrete. It is clear that in the Icelandic construction market today there is no product that has a comparable possitive effect as hempcrete in regards to environmental factors. For that reason, hempcrete is a very special product.