by DJ Reetz
Up a winding mountain road, hidden among the charred pines left behind by the High Park fire, an otherwise innocuous construction site surrounds a cabin being built. Here, in the foothills outside of Ft. Collins, this particular cabin carries a distinction from the others in the area that share its sweeping views over the small town of Laporte and out to the plains, this one is being made using hemp.
“It’s practically impervious to everything,” says Melissa Rabe, CEO of the Loveland Hemp Company that’s providing the materials and one of the small group of people on site, as she pounds on the rough, grey material that makes up the cabin walls.
The modest cabin is constructed from a wooden frame, using the fire-cured standing timber from the surrounding area that gives even the interior space an exterior feel, but the truly noteworthy aspect of the cabin is the otherwise unremarkable grey material that is packed into the frame forming the building’s walls. It’s hemp, mixed with lime to form a sturdy, insulative, stucco-like wall.
“This whole thing will become like one piece of stone,” says Rabe. As the hemp and lime cures, it will absorb the CO2 from the atmosphere, creating a strong, and fire-resistant insulating wall. All it will need is a coat of stucco.
The project began after the landowner made the hard decision to rebuild the cabin he had lost in 2012 during the High Park fire. At the time, the fire was the second largest the state had seen, and homes in this densely forested area stood little chance to withstand the quickly spreading fire driven by high winds. The cabin’s owner, a longtime friend of Rabe’s, had owned the land since 1975, and the loss of his mountain retreat was heart breaking.
“We were able to do stuff up here and enjoy the land before it burned,” says Rabe. “He was very disheartened when it burned.”
Fortunately, Rabe, a hemp advocate and entrepreneur, was in a position to help. While not a strictly charitable endeavor, building the house out of hemp would be an opportunity not just to help a friend, but also to demonstrate the power and applications of hemp.
“On the one hand we’re helping a buddy out,” says Rabe. “On the other hand, it’s to show people what hemp can do. This is really our proof of concept.”
In March of last year construction began and a foundation was set. After some of the nearby dried timbers were lugged over by hand and set in place creating the natural frame, the process of creating the walls began. For this, roughly 8,000 pounds of processed hemp hurd is needed. The hurd is made up of processed hemp stalk and fiber, and looks a bit like wood chips, though it is much softer to the touch and less likely to give you splinters when handled. The hurd is mixed with lime and water in a ratio that is dependant on environmental factors of the area, and up here in the Colorado foothills, extreme cold can give way to blaring sun in a matter of days or even hours. It makes the process tricky, but Rabe says experimentation is key.
The hurd lime mixture is then poured into molds secured between the supports of the house and packed down to ensure it is dense enough. This is also made more difficult by the natural shape of the adjacently sourced wood, which requires the molds to be carefully trimmed to ensure the finished walls will be a uniform nine inches thick. After it has been allowed to cure the hemp is coated in a plaster stucco mix that the team incorporates hemp hurd into as well.
The end result is a sturdy wall that naturally dampens sound, is easily repaired, provides exceptional climate control due to its breathability, and is even resistant to fire.
“It’s a lot like sculpting a house,” says Rabe. “It’s fun, it’s creative.”
“It’s one of those things that’s just really hard to screw up, like an oatmeal cookie,” says Josh Rabe, husband, business partner and construction assistant to Melissa. “It’s a natural building process, you really just have to try it.”
Because of the variable and climate dependent nature of the hemp walls, a lot of builders will be intimidated by the process as there really is no definitive formula to follow, says Josh. But with a bit of experimentation and a willingness to let the process play out organically it really isn’t too hard to figure out, though he says he does recommend retaining an engineer as they have.
For now, the hemp being used comes from foreign sources, which for the time being is about half the cost of the limited amounts of domestic hemp. But Rabe says she foresees a time when the hemp used in these projects is sourced from Kentucky or Colorado.
The process is also more costly than some traditional construction methods due to the increased labor necessary to prepare the hemp walls, and the cost of the lime needed also plays a factor.
But so far, the project is shaping up to be quite a success, and if all goes as planned the cabin should be ready for occupancy this summer.
If you’re interested in learning about hemp construction be sure to check out the upcoming workshop Loveland Hemp Company is putting on June 13. Check out their Facebook page for details.
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