Two North American companies — one in Canada and another in the U.S. — have started producing insulation for residential construction from locally sourced hemp fiber, giving builders an alternative to fiberglass, plastic foams, and other more conventional materials.
European builders already have access to hemp insulation, but in the U.S. availability has been limited. Some builders here have tinkered with a mix of hemp fibers and lime called “hempcrete,” but the wide-scale use of industrial hemp has been stymied by U.S. law.
Montreal-based is apparently the first company in North American capable of producing fibrous hemp insulation on a commercial scale. A biomaterials supplier in Louisville, Kentucky, called is not far behind with production of a hemp fiber insulation batt.
A new factory in a town with a darker history
MEM opened its new factory in Asbestos, Québec, a community of about 7,000 people that until 2011 was home to the largest asbestos mine in Canada and a major producer of the fireproof mineral used in everything from shingles to insulation. The terrible long-term health effects of asbestos exposure helped close the Jeffrey Mine, and even prompted one to change the town’s name.
The new factory makes non-structural hemp blocks that can be used to build walls, rolled hemp felt, and semi-rigid sheets of hemp fiber with R-values roughly equivalent to fiberglass and cellulose. MEM’s public relations director for the U.S., Pierre Cloarec, says the natural fiber offers a variety of environmental and performance benefits, and the fact that MEM’s new factory is in a town carrying so much environmental baggage only sweetens the deal.
“We went there to help establish a new economy,” he said in a telephone call.
Hemp in several forms
Among the hemp products described at MEM’s website (MEM stands for “Manufacturer of Ecological Materials for the Home”), is NaturHemp, which Cloarec describes as a semi-rigid panel looking something like mineral wool. It’s designed for use in wood-framed construction and comes in sheets 15 1/4 inches and 23 1/4 inches wide by 48 inches long.
There are three thicknesses: 3 1/2 inches for 2×4 frame construction (R-13), 5 1/2 inches for 2×6 framing (R-20), and 8 inches. The density is 35 kilograms per cubic meter, or about 2.2 pounds per cubic foot.
The insulation isn’t available in rolled form, like fiberglass.
The cost is about twice that of fiberglass insulation, Cloarec said: $1.80 per square foot for 3 1/2-inch panels, $2.40 for 5 1/2-inch panels, and $3 for the 8-inch material (all prices are in Canadian dollars and do not include shipping).
Hemp insulation has many advantages, Cloarec said. If it gets wet, it can be removed from a wall, dried out and re-installed with no loss of performance. It’s biodegradable. It has a very long service life — walls opened up in France 50 years after construction showed hemp insulation looking essentially brand new. It’s composed mostly of a natural fiber (88% hemp fiber and 12% polyester fiber) with no chemical binders and no VOC off-gassing. It’s vapor-permeable. And it’s naturally repellant to rodents and insects.
“It’s the best product to take care of our planet,” he said.
Cloarec said that MEM will focus its attention on the northeastern U.S. The company would like to open a factory on the American side of the border to reduce shipping costs, although he didn’t say exactly where that might be. Ideally, the second factory would be near an area where hemp could be grown. Even if that proves impossible it would be cheaper to import hemp from Canada, where it’s been legal to grow since the 1990s, than it would be to ship finished products here.
MEM’s venture into hemp insulation is not entirely new. In 2012, GBA editor Martin Holladay reported that the company was manufacturing hemp batts from fiber imported from Europe. At the time, NaturHemp batts were available in 3 1/2-inch and 5 1/2-inch thicknesses, rated at R-13 and R-20 respectively.
In Kentucky, rolled batts
Sunstrand supplies natural fibers to a range of industries and for a variety of purposes. But now the company is launching a finished consumer product of its own in the form of a hemp insulation batt.
Theresa Guerra, a product sales specialist for building materials, says that the batt is a blend of hemp and kenaf fibers. Hemp is grown locally from seed that Sunstrand supplies. To date, the company has produced enough batts to let local builders try them, but it’s still doing final testing and trying to set up a retail distribution chain.
For the time being, batts are being produced in one size and thickness: 15 1/2 inches by 97 inches and 3 1/2 inches thick. They cost about $1 per square foot, Guerra said.
Sunstrand says that the insulation functions like traditional insulation “without agitating the skin like glass fiber.” The unspecific binder in the proprietary blend is fire, mold, and fungus resistant.
Adam Block, the company’s vice president for sales and marketing, says that Sunstrand developed the insulation because people were “sick and tired” of fiberglass and saw only a limited number of alternatives.
Asked whether the company was considering expanding its line, Block said that would depend on consumer demand. Sunstrand chose an R-13 batt because it’s the most commonly used type. Whether it would be worthwhile investing more money in research and development, engineering, and manufacturing to make other forms of the insulation it isn’t clear quite yet.
So far, however, interest has been high, and the company has field queries from a number of states.
A growing interest in hemp
Hemp has a long history in the U.S. But its cultivation was outlawed in 1937, the same year that marijuana was banned. The industry has been struggling ever since to draw a distinction between industrial hemp, which has no psychotropic qualities, and THC-rich strains of marijuana popular with recreational and medical users.
Erica McBride, the executive director of the , a trade group, said that federal law is “extraordinarily vague,” helping to explain why hemp production is not more widespread. Currently, federal law allows states to set their own rules for the cultivation of hemp for research purposes, and at least 34 states have adopted some kind of regulatory structure permitting farmers to grow it.
But only some 25,000 acres of industrial hemp are now in cultivation, she said, and without any clear federal guidance, hemp production is subject to a hodgepodge of different regulations and rules.
“It makes it kind of a nightmare,” she said. “The industry is hobbling along as best it can.”
A bill that would allow hemp to be grown as a commodity crop (HR3530) is now in committee, with hearings scheduled this month. It has bipartisan support, McBride said, and with any luck it will be passed by the end of the year. With wide-scale production possible for the first time in more than 80 years, prices for hemp insulation, as well as other hemp products, would fall.
“The fact that it’s hemp is in itself interest to a lot of people,” she said.