Surrounded by verdant fields, Flat House, which sits on a farm in Cambridgeshire, the UK, looks like a typical barn conversion. But inside, the look and feel of the building immediately make you realize this is something quite different. "The walls remind me of hay bale dens we used to make as kids," says Flat House's owner Gemma Barron. "It has the most lovely acoustic quality. And last year, we had the heating off for 24 hours in mid-winter, and it stayed warm."
What makes this bright, airy, and comfortable home unusual is the material used to build it: hemp. While we may be more familiar with the cannabis plant's association with the psychoactive substance cannabis and its use in health supplements and textiles, hemp is rapidly becoming a sought-after sustainable construction material.
The fast-growing plant is a renewable resource with carbon-capturing properties. When used in building, it typically takes the form of "hempcrete" (also known as lime hemp concrete), a sturdy material made by mixing hemp hurd – the woody core of the plant – with a binder made from water and lime. Hempcrete has a high thermal mass, making it an ideal insulation material that improves the energy efficiency of buildings and reduces greenhouse gas emissions over time. It also continues to absorb carbon over its lifespan.
Sustainable materials are in high demand as the construction industry seeks to decarbonize. Buildings and construction are responsible for approximately 37% of energy and process-related global carbon dioxide (CO2) emissions. This is due to the industry's heavy reliance on fossil fuels, including carbon-intensive materials such as concrete, steel, and glass, as well as the greenhouse gases emitted in heating and cooling our buildings. (Read more: The concrete that helps the climate).
With its carbon-capturing qualities, hemp could help countries reach their net zero goals by making construction more sustainable. "Optimising the way we design, construct, and renovate our buildings has a critical role to play in driving down emissions and enabling the UK to meet its climate targets," says Yetunde Abdul, head of climate action at the UK Green Building Council. "An important part of the solution involves exploring the use of natural, low-carbon alternatives to vital construction materials such as hempcrete or timber."
Read more at bbc.com