Hempcrete is a bio-composite material created from the woody core of the hemp plant combined with a lime-based binder. Also known as the “shiv,” this woody hemp core is high in silica that binds with the lime to produce a stable compound. This is a capacity no other plant fibers contain.
The final product is a lightweight concrete form that provides insulation and only weighs about a seventh or eighth of its equal mass in conventional concrete. A fully cured hempcrete brick will float in a bucket of water. This is not used as structural support but rather an insulating infill. While internal frameworks must support all hempcrete, it does reduce the need for racking.
The most common framing used with hempcrete is wooden and best suited to low rise constructions. In Europe, some hempcrete edifices have been constructed ten stories high.
How is Hempcrete Made?
Hempcrete is created by combining its various ingredients in a mortar mixer for a couple of minutes and then placed by hand into the cavities of the wall in construction. The fall is constructed with two temporary plastic shuttering which form the inner and outer wall into which the mixture will be placed. The lightweight material can be mixed and passed about by buckets easily after the construction project is completed, the debris can simply be mixed back into the soil.
The material will then be treated on the exterior side with a study coating about 2cm thick, and then an outer coat will be laid on top of that. The final result looks much like a stucco building on the outside. For the interior, the walls can be left natural or masked over with lime plastic for a more conventional look.
When was Hempcrete Discovered?
This may sound like a thoroughly modern innovation, but hempcrete was discovered in a bridge abutment that was constructed around 500-600 BCE. Since it was found to be so strong and durable, it has been increasingly popular in Europe. Today, industrial hemp is grown by many commercial agriculture projects and is very low in THC, which is the psychoactive compound. Hemp does not contain enough of this substance to be a psychoactive product, and the biomass typically contains low amounts of cannabinoids. Because the use of hemp as a building material has endured more than 14 centuries, it is considered a powerful compound and the cannabinoid rich hemp is often produced into hemp energy drinks.
How Is Hempcrete Used?
Hemp as an agricultural commodity has extensive commercial, industrial and even medical benefits. The roots of a hemp field grow so closely together they choke out weeds, it also contains natural compounds that act as pesticides and fungicides thus significantly improving the quality and conditions of the soil. Farmers can rotate a hemp crop in between crops of barley and rye to fight off weed and pest plagues as well as return vital nutrients to the soil.
The seeds of the hemp plant are sold as superfoods due to their impressive nutrient profile, purified hemp seed oil is rich in amino acids and Omega-3 fatty acids. The out fibers of the hemp stalk can be woven into beautiful textiles for stylish clothing. The inner more robust fibers have been typically chopped into rods of equal length and used as animal beds, this is especially important to the equestrian community.
History Of Hempcrete
For a little over half a century, hemp clone cultivation in the USA has been contraband due to its close relationship with another cannabis plant, marijuana. In Europe, Canada, and the UK hemp it can be cultivated under certain restrictions. The seeds used must create plants with less than .05% THC content. The cloth we use in our facilities is imported from these UK growers. A new plant that will be used to process hemp core is underway in Canada, and there will undoubtedly be more North American suppliers shortly.
The added shipping required for the production of hempcrete nullifies its carbon-negative advantages and increase the costs of production. Furthermore, it adds essential logistical costs considering we had to purchase a large shipping container to store raw materials safely on site. You will need to have a crew on standby to unload the stuff from the truck when it arrives. This is time sensitive as the truck will be charging by the hour and the weather must be suitably dry. It is critical that the raw materials are kept dry so having some tarps on hand is a good idea.