When mixed with lime, hemp makes a durable building material. Hemp-lime composite provides strength while also absorbing carbon, making it a great building block for zero-carbon homes. Now, researchers with the BRE Centre for Innovative Construction Materials at the University of Bath are testing the hemp-lime material’s energy-efficiency. Although several hemp-lime composite buildings have been constructed, the researchers hope to pull scientific data that will persuade the mainstream building industry to use the material more widely.
For the next 18 months, researchers at the University of Bath will monitor the HemPod to see how well its hemp-lime walls insulate. Photo Courtesy University of Bath.
The researchers constructed a one-story hemp-lime building, the HemPod, with walls made from hemp’s woody core, held together with a lime-based binder. For the next 18 months the researchers will closely monitor the HemPod’s indoor temperature and humidity to see how well hemp-lime walls insulate and allow moisture to pass through.
Hemp-lime should provide good thermal mass, making the building energy efficient. The wall’s breathability should act as a passive air conditioning system, keeping humidity inside the hemp structure constant at all times.
Hemp provides a healthy alternative to other building materials as it requires no pesticides or fertilizers and little water to grow. Hemp and lime both absorb carbon, and the lime binder also increases fire resistance. Using hemp as a building material could also open up a new agricultural market and provide economic benefits to farmers—although not yet. Hemp cultivation is illegal in the United States.