Courtesy Jnzl's Photos via Flickr Commercial Commons Hempcrete

Courtesy Jnzl’s Photos via Flickr Commercial Commons Hempcrete

As more states approve the medicinal and recreational use of marijuana, the building industry is taking note. A strain of the Cannabis sativa plant, hemp is a promising material for buildings that has been similarly regulated, though it differs in several ways from the everyday variety. The presence of buzz-inducing tetrahydrocannabinol in industrial hemp is quite low at around 0.3 percent, as compared to the 20 percent of recreational cannabis. Hemp must also be grown outdoors, can reach up to 15 feet tall, and has a dense, fibrous core suitable for making rope and other fiber-based substances.

In fact, hemp has a history in construction. Roman engineers used its fibers to enhance the mortar for bridge abutments, for example. Because the plant grows rapidly, without the need for pesticides or chemical fertilization, and improves soil health with air-circulating roots, it is an attractive crop for farmers. Although special permits are still required to use hemp-based building products in the U.S., a variety of potential applications suggests a promising future for the plant.