Historically speaking, construction materials have predominately consisted of concrete, steel, wood, and brick. However, when the Hemp Farming Act of 2018 was passed on December 20, 2018, builders worldwide began to familiarize themselves with a new material deemed the eco-friendly material of the future: Hempcrete.
What is Hempcrete?
Hempcrete is a unique bio-composite material comprised of the hemp hurds, a mineral binder (lime), and water. When blended, “a chemical reaction occurs between the lime binder and the water, resulting in the binder setting and gluing the hurd particles together. Generically speaking, it could be referred to as “bonded cellulose insulation.”
Hempcrete dates back to the Roman Empire when the Gauls used a hempcrete-like material to build a sizable bridge over two-thousand years ago. Since then, hempcrete has grown in popularity in regions such as Asia and Europe; it was illegal in the U.S. until recently.
However, passed in 2018, the Hemp Farming Act opened the doors to hemp use on an industrial level in the U.S. According to analysis, “[the] bill [legalized] industrial hemp that has a tetrahydrocannabinol (THC, the psychoactive component of marijuana) concentration of no more than 0.3% by removing it from Schedule I of the Controlled Substances Act. States and Indian tribes may regulate hemp production by submitting a plan to the Department of Agriculture (USDA). The bill also makes hemp producers eligible for the federal crop insurance program and certain USDA research grants.”
Benefits of Hempcrete
The influx of hempcrete in the construction industry has been attributed to the material’s benefits. Today the material is recognized for its sustainability, efficiency, and safety features. Let’s review.
As we face ongoing global warming challenges, industries worldwide are developing methods to improve sustainability practices. Hempcrete, a plant-based material, has been reported to be much more environmentally friendly compared to its alternatives, recognized as a natural, chemical-free substance, which uses fewer petrochemicals.
Hemp can also be grown relatively quickly, allowing for its use at an industrial scale. From start to finish, hemp takes approximately 60 days to produce. During the process, the plant requires little water and thrives without pesticides. Its chemical makeup allows for it to become one of the largest industrial crops, replacing soybeans and cotton due to its sustainability.
Compared to that of concrete, which is recognized as the third-ranking producer of human-made CO2 globally, accounting for 4 to 5 percent of worldwide emission, hemp is a CO2 negative resource, indicating that the use of the material lowers our CO2 emissions.
Construction of a home must consider the structure’s longevity. A builder’s goal is to create a building that can overcome the test of time. In recent years, hempcrete has become a valuable resource when implementing more efficient construction practices.
- Hempcrete is vapor permeable – In a building where humidity is a factor, condensation, instead of forming as water on surfaces, can be released, significantly reducing the risk of mold.
- The natural composition of hempcrete helps regulate the temperature within a building without the use of heating and air conditioning. Joyce Beckerman, vice president of the Hemp Industries Association, identified that “In many climates, a 12-foot hempcrete wall will facilitate approximately 60-degrees indoor temperatures year-round without heating or cooling systems… The overall environmental footprint is dramatically lower than traditional construction.”
- According to an analysis conducted by Green Building Canada, the material is considerably cheaper than other materials.
- Hempcrete requires much less maintenance when compared to its counterparts.
Proof of hempcrete’s efficiency can be seen throughout history. The Ellora caves of India, a UNESCO World Heritage Site, consisting of 34 caves dating back to the 6th century to the 11th century, have proven the test of time, withstanding the earth’s elements. Unbeknownst to researchers until 2014, the caves were constructed from a mixture of clay, hemp, and lime, preserving the caves along with their sculptures and paintings. Armed with this information, the construction industry has found a market utilizing hempcrete for both sustainability and efficiency.
Most importantly, hempcrete is recognized for its safety features – It is mold, fire, crack, and termite resistant.
Mold Resistant: As mentioned previously, vapor permeability reduces the risk of mold, improving the safety of a structure. Once in the home, mold can lead to varying health problems ranging from itching eyes, sneezing, and coughing to severe allergic reactions, asthma attacks, and even permanent lung damage. Furthermore, once the mold is in the home, it can be challenging and expensive to remove. The best solution to reducing the risk of exposure is to use a material that prevents mold in the first place.
Fire Resistant: Hempcrete is fire-resistant, an especially important feature for California residents. Following tests conducted by the American Society for Testing and Materials (ATSM), the researchers determined that the material had a profound ability to resist fire. According to Hempitecture, a construction company that specializes in the utilization of hemp fiber, “the flame spread index and the smoke index developed are two scales used to measure the amount of flame spread and the amount of smoke that is generated. It’s a scale from 0 to 450. Hempcrete got 0, the highest possible rating.”
Crack Resistant: Due to the material’s low density, it is more resistant to cracking under movement. In areas at risk of earthquakes, hempcrete can reduce the hazard of potential damage. The U.S. Geological Survey predicts that there is a 72 percent chance in the San Francisco Bay area within the next thirty years and a 60 percent chance in Southern California that an earthquake of a magnitude 6.7 or larger will strike. If retrofits and renovations were to utilize hempcrete, could we reduce the number of damaged structures?
Termite Resistant: Termites destroy approximately 600,000 homes in the U.S. each year, costing Americans over $5 billion annually to control and repair the damage. Hempcrete is termite resistant. And, research has even discovered that hempcrete used as a coat to a standard wooded house-frame actually reduces termites’ damage.
Hempcrete in California
After many years of record-breaking fires, with the most recent fires damaging over 4 million acres of pristine California landscape, builders are eager to identify a material that can reduce the risk to structures during these natural disasters. As a new method for building, the research on how hempcrete can play a role in reducing damage is yet to be determined; however, the construction industry appears hopeful that hempcrete’s sustainability, efficiency, and safety will be a game-changer in future developments.