Hemp-Lime as a Promising Building Material

History is full of examples of rational ends reached by irrational means, of expectations dashed only to be in a bigger picture fulfilled. James Savage, an entrepreneur and activist trying to carve out a niche for hemp-based construction, has noticed one recent example. He once thought that growing mainstream acceptance of hemp for its many valuable properties would lead over time to acceptance of its botanical kin: marijuana. But history has found another way. It is marijuana, medically employed, that has found or is now finding mainstream acceptance, and it may yet be that acceptance of a more innocuous-seeming substance, hemp, will come in its wake.

 

Starting with a Hurricane

On its home page Savage’s company, Green Built LLC makes prominent reference to Hurricane Katrina, a 2005 storm that proved the third costliest hurricane landfall in the United States in history. This storm dramatically impressed founder Savage with the need for inexpensive, quality housing materials. In time he would hit upon the hemp-lime composite as the “next wave in sustainable building.”

Savage told Marijuana Investor News that after that August 2005 landfall, Katrina “made me feel that we just aren’t solving people’s problems.” “I went down there” to the affected area on the Gulf of Mexico, “and saw the water damage in people’s homes,” Savage said. The FEMA homes “were also toxic.”

This didn’t lead him to create Green Built immediately, but it did get his thoughts started. Later, he “tried to do some work in developing countries” to advance the cause of sustainable construction, especially in Mali, in western Africa.

Hemp-lime, known as hempcrete or by various trade names, can serve as a solution to the “toxic building” problem of the sort that afflicted Katrina related relief efforts. Both halves of the compound contribute to its value. The hemp provides the insulation, regulating temperature and humidity, while the lime binder resists fire and mold and keeps out pests. Virtue is found, too, in what hemp-lime doesn’t do: it produces no volatile organic compounds, and contains neither petroleum nor chemical additives.

The first permitted use of hempcrete in the U.S., in 2009, took place in Asheville, North Carolina, with material imported from Europe. “You’re allowed to import industrial hemp into the United states,” Savage said. Indeed, roughly $2 billion of the stuff is imported each year.

 

The Big Picture

Pulling back from Asheville, one might look at the planet earth, and what is sustainable here. Green Built contrasts hemp-lime on the one hand with spray foam insulation on the other. Yes, spray foam is itself often considered “green” for a number of reasons. For example, spray foam does a better job than, say, fiberglass and cellulose of holding air in, benefitting energy efficiency. Also, traditional materials can retain water, whereas spray foam either allows the water to pass through or repels it in the first place.

However, Green Built makes the point that spray foam insulation is in fact made with chemicals that contribute to global warming. Hemp on the other hand is grown, not manufactured, and the manufacture of lime is not energy intensive. Moreover, hemp-lime sequesters carbon for more than a hundred years, so every such building is in a small way an antidote to global warming.

By 2011, when Savage founded Green Built, it had become clear to him, as he says, that this material provided “an opportunity to develop something that is sustainable,” and something moreover that could revive agriculture as a major U.S. industry. After all, “it is never going to be cheaper getting quality hemp from China” than from, say, the Hudson River Valley.

All of which brings the story back to the initial irony. Between the two related substances hemp and marijuana, it is marijuana that seems to be leading the way toward general acceptance for both of them in the U.S. The not-at-all psychoactive cousin, hemp, seems to be retaining the once-shared stigma longer.

Green Built doesn’t make money at present. “Everybody involved is so far working for nothing because they believe in it,” but the idea is to build a profitable as well as a sustainable industry, and Savage is confident that day is not far off.

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