Quickscrews
Quickscrews Cabinet Install Screws
Built for strength and precision, Quickscrews Cabinet Install Screws are the go-to choice for professional cabinet installers. Designed specifically for cabi...
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What is Hemp?
Hemp is a relative of the marijuana plant without high concentrations of THC. It is also one of the fastest-growing biomasses on the planet. The thick, woody pulp of the hemp plant offers many different uses. The textile industry can use industrial hemp for making clothing and footwear and as an alternative building material. Hemp can also be used to make paper, oil, soap, and other beauty products, protein flour, food supplements, biodegradable plastics, and biofuel.
What is Hempcrete?
Hempcrete was first used in construction to build non-weight bearing infill walls in France during the early 1990s. Hempcrete is made from mixing the hemp hurd with lime and water and weighs only about an eighth of regular concrete weight. The lightweight nature of hempcrete can also reduce the embodied energy of a building by reducing the emissions associated with transporting heavy materials. Since industrial hemp can also be grown in a wide range of climates and soils, it is also an excellent alternative as a local building material.
What is Hemp Hurd?
Hemp herd is the soft, woody, highly absorbent core of a hemp stalk. They are available in various grades and are a natural by-product after the hemp stalk has been stripped. Hemp hurd is sometimes referred to as hemp wood or shives and is comparable to shives in flax. A process called scutching helps separate impurities from the raw material.
What is a Lime Binder
Descended from limestone, a lime binder acts as a bonding agent. It has been used in mortar and plaster construction for thousands of years. It's available in various grades and types and mixing ratios, impacting its durability, strength, and setting time.
What is the R-value of Hempcrete?
Hempcrete has an R-value of 2.4 to 4.8 per inch, compared to 0.1 to 0.2 per inch of concrete. Hempcrete can also achieve a higher R-value than fiberglass batt and cotton batt, whose R-values are, at most, 3.8 and 3.7, respectively. The thermal performance of hempcrete can be impacted by several variables, including the type of binder used, moisture contents, and density.
How Strong is Hempcrete?
The compressive strength of hempcrete is 1/20 that of concrete, coming in at 1 MPa, meaning it can't be used as a foundation material or in situations where it may be load-bearing. It's resistant to cracking due to its low density making it an attractive alternative to areas prone to earthquakes.
Hempcrete also breathes, allowing moisture to evaporate (no mold), does not off-gas, and is avoided by termites. The non-toxic and lightweight properties of hempcrete also ensure it is easy to move around a job site.
While hempcrete may be growing in popularity, it's still not widely available on the market. Nonetheless, hempcrete has a comparable cost to other insulation options and will become more affordable as production volumes increase.
How Long Does it Take to Grow Hemp?
Hemp fiber and seeds are usually ready for harvest in two months. The rapid growth rate allows it to outcompete other raw materials because it is rapidly renewable and can be used in a wide variety of diverse industries. For example, hemp can produce about four times as much paper as trees per acre. The difference, of course, is that trees take years to reach maturity.
What are The Disadvantages of Hempcrete?
While this may not qualify as a real disadvantage, hempcrete cannot be used as a foundation structure due to its low compressive strength. In most cases, it is not a load-bearing material. A project that could utilize a lightweight foundation could take advantage of hempcrete instead of concrete, providing it adheres to local building codes and is approved by an engineer. While research and development around the use of hempcrete are still in infancy, preliminary findings are incredibly positive.
Hempitecture
While hempcrete, hemp insulation, and hemp building blocks offer numerous sustainability advantages, specific construction requirements must be followed due to hemp's lightweight nature. Finding a builder with experience in hemp building is essential. Hempitecture is one company that offers its services across the US with a hempcrete installation. Tiny Hemp Houses is another Colorado-based company that specializes in building tiny homes from hempcrete.
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Hemp Tech Global
Hemp Tech Global is another company that can help with designs, builds, logistics, and personnel for hemp-built homes. As hemp continues to gain momentum in the United States as a renewable alternative for the building (and other) industries, local suppliers and manufacturers should emerge. However, suppose you currently have a hard time finding a hempcrete supplier in the United States. In that case, Hemp Tech Global can help you source large amounts of hemp hurd (which can then be made into hempcrete) from international suppliers for around $17.40 for a 15 kg bag.
Bottom Line
The benefits and potential uses of hemp in the building industry make it worth checking out as the trend continues to grow and becomes widely available. At Rise, we like hemp because it represents just one of many innovative, more sustainable products in the building industry—a bright spot for our future!
Rise Writer
Expert. Practical. Sustainable.
Article by
Tobias Roberts
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.
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