By Danny Mueller for THE PRESS DEMOCRAT
Tucked away on a quiet country lane in Sebastopol, a construction crew is building a simple house with sturdy walls and large windows. The only unusual thing about the project is hidden inside the walls.
“I became familiar with hempcrete because I’m always looking to build in the ‘greenest,’ most sustainable way possible,” said Steve Sheldon, an architect, property developer and builder. “We’re always looking for materials that are rapidly renewable, and as carbon-neutral as possible.”
For more than four decades, Sheldon has designed homes and buildings with sustainable building materials and energy-efficient features. When a client expressed interest in building a “unique” accessory dwelling unit, Sheldon said his mind jumped to a newer version of one of the world’s oldest building materials.
Hempcrete is made by mixing the wood-like core of the hemp plant with hydraulic lime and water. The result is a sturdy, breathable building material with a lower carbon footprint than concrete and a host of other benefits.
At the construction site in Sebastopol, a work crew formed three blocks of hempcrete, each configured for a different purpose. The lightest block represents the material poured for the roof of this 1,000-square-foot house. Harder-packed hempcrete forms the walls and floor of the structure. Later, these walls will be coated with more lime to form a smooth surface.
Mike Brandt, a construction supervisor, said he was initially skeptical about the material.
“It took me a while, but now I’m on board with (hempcrete),” he said.
What are the downsides?