Gramitherm is made from grass clippings, sourced from public parks and grass verges, mixed with recycled jute fibres and a binder made from recycled polyester.
The new product is said to be naturally hygroscopic, meaning it absorbs moisture from the air and helps to regulate humidity within the building envelope. This enhances breathability, says the manufacturer.
Gramitherm has secured an environmental product declaration (EPD) which demonstrates that 1kg of the material sequesters 1.5kg of CO2, equivalent post production making it a highly efficient and sustainable insulation choice.
As well as the EPD, Gramitherm holds European Technical Approval confirming compliance with relevant standards as well as its sustainability credentials and low environmental impact. Ecological Building Systems claims that Gramitherm is ‘carbon negative’ and has achieved A+ ratings in VOC (volatile organic compounds) emission tests.
One hectare of grass can produce enough material for 200m3 of insulation, says the company, and nearly all of the material is sourced locally. The manufacturing process is also highly sustainable, using heat from biogas, a by-product of grass fermentation, for drying.
Gramitherm can be installed in rafters, joists, walls, ceilings and floors. The fibrous structure of the grass gives the insulation a high density of 40kg/m3. The resulting product is both flexible and rigid, ensuring a snug fit, without settlement, says the manufacturer.
With a thermal conductivity of 0.041W/m2K and high heat storage capacity, Gramitherm keeps buildings warm in winter and cool in summer, due to its high specific heat capacity. Gramitherm is also said to have good acoustic properties, absorbing 99 per cent of sounds at 1,000Hz to reduce noise transmission.
Gramitherm comes in 390mm and 580mm widths and in various thicknesses. It can be easily cut to size, is easy to install and safe to handle.
Ecological Building Systems’ technical director Niall Crosson said: “Natural insulation materials are becoming increasingly popular and there’s nothing quite like Gramitherm on the market. It has impressive environmental credentials, plus strong thermal and acoustic performance to match.
“Gramitherm represents the perfect combination of technically high-performing insulation with minimal environmental impact. Materials such as Gramitherm have a key role in the future of insulating more sustainable buildings.”
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