Hemp Concrete: Promising New Green Building Material


Last April I wrote about innovations in hemp as a building material. At the time of that blog post, researchers were developing ways to use hemp as a building block for zero-carbon homes. Because cultivating hemp is illegal in the U.S., all of that research was conducted overseas. 

Hemp Concrete from Nauhaus Building System
Nauhaus Building Systems’ workers mix the Hemcrete. Photo Courtesy Nauhaus. 

Hemp production hasn’t been legalized since then, but hemp has moved into the U.S. building industry. Two homes in Asheville, North Carolina, are being built using a hemp material called Tradical Hemcrete. The product, sold by Asheville-based Hemp Technologies, mixes four parts ground-up hemp stalks with one part water and one part lime to create durable, resilient walls that European researchers have found can last up to 700 or 800 years. 

In addition to durability, hemp concrete walls provide many benefits. They’re resistant to mold, mildew, fire and insects, and the lime absorbs carbon, making the walls carbon-negative. 

Hempcrete wall
Check out a close-up of a Hemcrete wall with an electrical box. Photo Courtesy Nauhaus. 

Because the materials have to be imported, hemp concrete is more expensive than traditional building materials. Despite this, it’s possible to save money in other aspects of building when using hemp. Hemp construction uses less lumber for framing, and because it’s all-purpose, hemp concrete can be your sheetrock, insulation and moisture barrier all in one. Hemp concrete walls are also energy-efficient, saving homeowners on their energy bills each month. 

We think this is a promising material, and we’d like to see more of it. What do you think?