The Linford Group, a Birmingham, United Kingdom-based building company, is looking back at natural products and techniques that have actually been around for hundreds, if not thousands, of years, as its vision for the next generation of 'better-than-zero carbon' sustainable building materials. The company is working with Abingdon-based specialists Lime Technology to explore ways of cutting the industry's carbon footprint by using hemp and lime in place of concrete and cement.
"Over 50 percent of the United Kingdom's CO2 emissions come from the construction and use of buildings, and in the United States that figure is more like 75 percent," said Simon Linford, Chief Executive at an event organized to introduce Birmingham architects, engineers and surveyors to the potential of 'new' building materials. "That is why the Government is looking so closely at the construction industry, and why everyone in that industry has a duty to look very seriously at both the building process and the long-term costs of using its buildings.
Lime, made from naturally-occurring limestone, was first introduced to Britain as a building material by the Romans. Despite a range of exciting properties it has gradually been replaced in mortars and renders by modern cement products. Hemp, meanwhile, is a fast-growing crop product that can be bound with lime to create revolutionary new masonry materials which actually lock away CO2 to create sustainable buildings that require minimal heating or cooling.
"Since we first encountered the potential of using lime and hemp to create a new generation of more sustainable buildings, Linford Group has been working closely with Lime Technology and other partners on a range of projects," added Linford. "We are excited by the potential here, and confident that it won't be long before lime and hemp products will sit alongside other new materials which will transform the nature of buildings and the way they are built."
Speaking at the event, Ian Pritchett from Lime Technology first outlined the chief benefits of lime-based mortars and renders – including the fact that they allow bricks to be reclaimed and re-used, unlike super-hard modern mortars. This represents a substantial sustainability advantage. However, it is when lime is combined with hemp to make Tradical&Reg; Hemcrete® product that the real carbon reduction advantages become clear.
"While a square metre of traditional brick-and-mortar cavity wall might create 100kg of CO2, a square metre Hemcrete® wall can actually capture and lock-in up to 53kg of CO2 from the atmosphere – a reduction of 153kg of CO2 emissions per square metre of walling," explained Mr. Pritchett. "If you scale that up to the size of an average building, and then to the number of buildings we create every year, you can see that there is huge potential to reduce the carbon impact of the building process."
"If you then take into account the other properties of hemp building products, such as thermal insulation, sound insulation, low density, good vapor permeability and fire resistance, you begin to realize that it is a material which is crying out to be used to create healthy, efficient and sustainable buildings for the future."