Updated by Paul Keskeys, April 20th, 2017
Given environmental decay and the construction industry's significant role in accelerating the process, it is imperative that contemporary builders push for the development of renewable building materials capable of revolutionizing the practice of architecture and shaping our future built environment.
In a profile in Smithsonian Magazine, MIT professor and structural engineer John Ochsendorf described the architecture of tomorrow, one not born of titanium or concrete, nor wrapped in space-age sheen, but one belonging to the technological lineage established by past building cultures. He spoke particularly about those whose innovations were not contingent on the rapid manufacturing processes ushered in by the Industrial Revolution and were, thus, more invested, consciously or not, in building sustainably.
Pioneering building materials derived from renewable hemp plants, companies like Hemp Technologies are working towards enacting some of these goals within current architectural production. The primary construction method involves timber-framed walls filled in with Hempcrete, a concrete-like mixture of wood chips sourced from Cannabis sativa and a lime-based binder that can be sprayed onto surfaces, poured into slabs, or shaped with formwork.
Among its many virtues, the material is very fire resistant, is an extremely efficient insulator, can be grown with very little water, and is virtually impermeable to termites. The lime content in the hemp blocks sucks in large quantities carbon dioxide — up to 12 tons, according to the company's own estimates — which it needs to harden, meaning that the wall continuously becomes more solid and that the structure, over time, becomes carbon negative.
The house that cannabis built: Push House by Push Design; image credit: Push Design
Adoption of Hempcrete in construction has not been without its challenges. Hemp technologies has experienced problems obtaining the building permits and approvals to use hemp materials. However, there have been no such problems across the Atlantic, as the New York Times reported: "Hempcrete has caught on across Europe, where hemp cultivation was never criminalized. Hundreds of buildings now use Hempcrete, including a seven-story office tower in France, a Marks and Spencer department store in the United Kingdom, and even a home built by Prince Charles."
Indeed, the cultural issues surrounding the material have not stopped some US-based designers and builders. Anthony Brenner of Push Design saw his prototype Push House completed in Asheville, North Carolina, the first hempcrete dwelling in the US. Brenner's project also proved that buildings using this material need not be archetypal structures with utilitarian aesthetics — the house possesses a beautiful cantilevered exterior that nods to some of the finer example of American Modernism.
Sure, the jokes will persist — if you suggest specifying hemp in a project, some clients will ask you what you're smoking. However, with the previously forbidden plant now gaining social and legal acceptance across the United States, hempcrete projects are becoming more attractive to clients and architects alike.