Balehaus: It’s straw, Jim, but not as we know it
by Tim Willmott : Be the first to leave a comment
Bath University’s pioneering work with straw bale technology has gained Passivhaus accreditation. For a building design to achieve the Passivhaus standard in the UK, a number of aspects must be achieved including: very high levels of insulation; extremely high performance windows with insulated frames; airtight building fabric; ‘thermal bridge free’ construction; and a mechanical ventilation system with highly efficient heat recovery.
According to Craig White, Director of ModCell, “Industry certification means that straw is now a viable, affordable means of tackling the housing crisis in the UK. Straw now offers a simple and effective home-grown solution to the UK’s housing needs.”
In Shirehampton, Bristol, seven new straw townhouses have just gone on sale in the open market.
The innovative straw walls in the new houses provide two times more insulation than required by current UK building regulations. Based on monitoring a residential straw-bale development in Leeds, fuel bill reductions up to 90% can be expected.
Thermal imaging shows the difference in insulation between the straw BaleHaus, left, and a typical home, right. The walls have been built using ModCell technology; prefabricated panels consisting of a wooden structural frame infilled with straw bales or hemp and rendered with either a breathable lime-based system or ventilated timber or brick cladding.
This technology combines the lowest carbon footprint and the best operational CO² performance of any system of construction currently available. In fact, as an agricultural co-product, straw buildings can be carbon negative as straw absorbs CO² when it grows.
Dept of Architecture and Civil Engineering
University of Bath