Top innovations from Insite09

published: June 24th, 2009
author: Tracy Edwards
source: Construction News
website: http://www.cnplus.co.uk

Low-carbon buildings and sustainability fuelled fresh thinking at the BRE Insite exhibition

BRE's Insite exhibition has built up a reputation as the showcase for modern-day sustainability and this year's line-up certainly proved no exception.

The four-day event at BRE's Innovation Park in Watford offered an insight into the future of low-carbon buildings through specialist stalls, seminars and - the bit that everyone always talks about - 10 full-scale buildings incorporating a range of groundbreaking products and technologies, including three new builds for Insite09.

1. Hemcrete by Limetechnology

What is it?

Hemcrete by Limetechnology is an established hemp-based walling material for carbon negative, thermally efficient walls.

Originally developed as a spray, it is newly available in block form and provides the main building material for BRE's sustainable house.

How does it work?

Hemcrete is made from renewable UK grown hemp based materials. Hemp, in common with all similar plants, captures CO2 and releases oxygen during its rapid growth. The immediate and positive effect of this process is the sequestration of the principal greenhouse gas.

This captured carbon is then locked into the fabric of constructed buildings. When the air-lime based binder sets,

further carbon dioxide absorption occurs. Limetechnology says the material becomes better than carbon neutral.

The product is highly insulating, resulting in thin walls with a very low U value.

However, it is vapour permeable and when used with Baumit lime based renders and plasters creates a breathable walling system.

Where are the savings?

Independent studies have shown that for a 300mm wall, Hemcrete locks up around 40 kg of carbon dioxide for every sq m of wall. A typical brick-and-block cavity wall creates in its manufacture around 100 kg of CO2 per sq m of wall.

The net benefit of using Hemcrete over traditional wall construction is 140kg per sq m of wall, or 20 tonnes of CO2 for a typical house. This can reduce the embodied carbon dioxide emitted in the construction of the house by as much as 40 per cent.