How good is hemp and lime? Study pins down performance
The environmental potential of hemp as a building material has never really been in doubt - it absorbs carbon as it grows and can be grown almost anywhere, cutting down on the need for energy-intensive transportation.
But is it any good?
A study underway at the BRE Centre for Innovative Construction Materials at the University of Bath is attempting to clear up any doubts.
“The idea of using hemp and lime has been around in the UK for ten or 12 years now and there have been a number of applications but there’s still relatively little scientific information on the performance of the materials,” Prof Pete Walker, director of the centre, told edie.
“We’ve identified this as a significant barrier to market uptake.”
He said that mainstream engineers, architects and buyers were shying away from a potential tool in the fight against climate change due to the absence of reliable independent information on its characteristics.
The research project is providing concrete answers to the questions of the construction industry and also experimenting with different ratios of hemp to lime in an effort to maximise its carbon cutting potential.
“The lime has all the embodied carbon and energy and, if we’re honest, the cost,” said Prof Walker.
“The hemp offsets this. Using renewable crops to make building materials makes real sense – it only takes an area the size of a rugby pitch four months to grow enough hemp to build a typical three bedroom house.
“Growing crops such as hemp can also provide economic and social benefits to rural economies through new agricultural markets for farmers and associated industries.”
Hemp-lime is a lightweight composite building material made of fibres from the fast growing plant, bound together using a lime-based adhesive making it better-than-carbon neutral.