As more states legalize marijuana for recreational and medical purposes, the housing industry is increasingly looking to embrace it as a building material too,
The New York Times reports.
North Carolina boasts the first modern U.S. hemp house, which was constructed in 2010. About 50 homes in the country have since popped up with hemp built in.
Hemp structures date back to Roman times. But now, some builders want to bring it back to their markets, since it’s known for being a fast-growing, sustainable product.
“Mixing hemp’s woody fibers with lime produces a natural, light concrete that retains thermal mass and is highly insulating,”
The New York Times reports. “No pests, no mold, good acoustics, low humidity, no pesticide. It grows from seed to harvest in about four months.”
As for the smell? “It smells a little like lime,” says Sergiy Kovalenkov, a Ukrainian civil engineer who has built hemp structures in the Ukraine. “We’re using the stock. You cannot smell cannabis—it has nothing to do with smoking weed or cannabis plants. It’s an industrial agriculture crop.”
To clarify, industrial hemp is not the same as the product that can give you a buzz. It contains only 0.3 percent of the substance THC, or tetrahydrocannabinol.
But builders are finding hemp houses can be difficult to build. Even in areas that have made marijuana legal, developers still often must have special permits to build with hemp. International standards also still do not exist yet for building with hemp or codes that regulate how it should be used structurally or safely.
Hemp is more widely used across the globe as insulation to fill walls and roofs and under floors in wood-framed buildings. It can become stucco-like in appearance, but it’s more like drywall than concrete so it can’t be used for, say, a foundation.
“In many climates, a 12-foot hempcrete wall will facilitate approximately 60 degrees indoor temperatures year-around without heating or cooling systems,” Joy Beckerman, vice president of the Hemp Industries Associations, told
The New York Times. “The overall environmental footprint is dramatically lower than traditional construction.”
The hempcrete movement is starting to spread. A Washington State company is reportedly using it to retrofit homes; Left Hand Hemp in Denver completed the first permitted structure in Colorado last year.
“When I started Hempitecture in 2013 and presented the concept, venture capitalists laughed at the idea,” Matthew Mead, the founder of
Hempitecture, a construction firm in Washington, told
The New York Times. “Now there are over 25 states with pro-hemp amendments and legislation, and the federal farm bill has its own provision supporting the development of research toward industrial hemp.”
Source: “High Times Beckon for Using Hemp to Build Houses,” The New York Times (Jan. 29, 2018)
