Hemp mixed with a lime binder makes green builders drool, according to Modern Farmer. Called hempcrete, this insulation material resists mould, fire and pests. It lasts forever (or close enough). It absorbs carbon. It’s commonly used in construction in Europe and Canada. With sustainable building materials worth billions of dollars, it has the potential to take off here, too.
But few farmers in the US grow hemp for that purpose. They grow hemp for CBD, for bioplastics, for food and for mulch. They’ll grow hemp for cat litter. But not for hempcrete, which uses a different crop, known as fibre, from the more popular CBD cannabinoid variety that yields CBD. There’s no market to speak of for hempcrete, and therein lies a dilemma, says Modern Farmer.
Most building professionals have never worked with it. Some mistakenly think it is a direct substitute for concrete. They have never cast it in place, the most common application method that is messy and prone to human error. They have never sprayed it, an alternative technique, or estimated the load-bearing potential of prefabricated blocks.
“Most people don’t even know what it is,” says Jacob Waddell, president of the US Hemp Building Association. “Architects, general contractors, regulators. Farmers think it’s something to get high. It’s a very complicated puzzle to educate people.”
According to Modern Farmer, hemp farmers have been stung by trying to cash in on CBD which did not happen. Others, if given the choice between growing hemp or THC cannabis, go for the bigger earner.
Until more farmers grow it, there won’t be a demand. But, farmers won’t grow it, unless there already is a demand.
Neither the International Code Council (ICC), which provides standards for building systems, nor the American Society for Testing and Materials (ASTM), which provides standards for products, has published guidelines for the use of hemp building materials. The result is complicated permitting requirements often decided on a case-by-case basis, says Hemp Industry Daily.
Photo credit: Hemp Industry Daily
