Builders Looking for Eco-Friendly Bricks Consider 'Hempcrete'

Hemp is the cannabis plant that can be smoked, spun into clothing, pressed into paper, and ground into milk. And now, it's getting used to make a sustainable building material called “hempcrete.”   

Hemp is the sister of marijuana. But it's grown with far less of the chemical that gets users high. It's been used as a building material dating back hundreds of years. In 2019, for example, a French bridge support was found to contain mortar made with hemp. 

Hemp was once banned under illegal drug laws. Today, bricks made of hemp and lime have formed an industry that could grow. Hempcrete is not as strong as concrete. But making it produces far less pollution than concrete. It's also a better insulator. And perhaps best of all, it's great at storing carbon. Researchers have found that hempcrete can capture twice as much carbon as trees.  

The research firm MarketsandMarkets has valued the global hemp industry at $6.8 billion in 2022. The firm said it could grow to $18 billion by 2027.   

“There’s an enormous growth potential in the US for hemp fiber used for building and insulation,” Kaja Kühl told The Guardian. She's a New York City-based urban designer. “Choosing materials that sequester a lot of carbon before they become construction materials can be very beneficial in this quest to get to carbon-neutral by 2050.”  

Hempcrete has been used to build a sports center in France. It's also been used to build a 12-story hotel in South Africa. It's even being used to build some houses around the world.

The downside of hempcrete? It costs roughly 20% more to build with it. 

Reflect: Imagine you’re hired as an engineer to build an eco-friendly house. What features would you add to the design to make it environmentally friendly?

Photo of hempcrete blocks courtesy Romancito77 on Wikimedia Commons.