Hemp has been used as building material since Roman times for its insulating properties, and might be an untapped opportunity for sustainable U.S. builders, according to the New York Times. Fast-growing industrial hemp has little in common with the psychoactive indica strain, and can be combined with lime to form “hempcrete.”
Hundreds of buildings across [Europe] use the substance as insulation to fill walls and roofs, and under floors in wood-framed buildings. Manufacturers say it’s ideal for low-rise construction, a product that’s stucco-like in appearance and toxin-free. Its promoters also boast that it has a lower carbon footprint, requiring three times less heat to create than standard limestone concrete.
According to NYT, a wave of builders and botanists are promoting the use of hempcrete in sustainable building, for its anti-pest, anti-mold, low-humidity, and good acoustical properties. According to the Hemp Industries Association, hempcrete can facilitate roughly 60-degree indoor temperatures in most climates year-round, without use of heating or cooling systems.