An affordable future for low carbon volume housing
With the government announcement that all new homes will be zero carbon code 6 by 2016, (except for Wales where it’s even earlier- 2012), and with code 3 becoming mandatory for the public sector in May 08, developers in the private and public sectors have already started to look seriously at developments which achieve the escalating codes.
Eco-architects Zedfactory are leaders in the field of zero-carbon design and development, with a unique track record in delivering Zero Energy Developments (ZED) buildings in the UK. Their latest house-type, RuralZED, takes this a stage further, and certainly stole the show at the Ecobuild 2008 exhibition back in February.
There, Zedfactory, partnered by Donaldson Timber Engineering, and other offsite manufacturers, presented the marketplace with what RuralZED’s project architect Matt Hoad is calling “the UK’s first affordable, practical and ready- to- purchase zero-carbon home.”
Certainly, RuralZED has managed to achieve the much sought–after zero carbon standard, and has been designed to meet code 6 (subject to site specific requirements and a BRE assessment) – the highest level in the government’s Code for Sustainable Homes. Built with energy-saving fabric and renewable energy systems, the claim is that the RuralZED house generates its own power per annum using micro renewable technologies on site.
A major factor in the house’s affordability and practicality is the ability to upgrade from code 3 all the way to code 6. The core building fabric is supplied by a dedicated supply chain and consortium with ecologically sound and prefabricated components delivered at a fixed cost.
RuralZED utilises a hybrid laminated timber frame, strong enough to support thermally massive walls, floor finishes and ceilings, with flexible masterplan options allowing all orientations with flexible architectural design.
The glulam frame can be erected in a couple of days, as shown at Ecobuild, and is used to support white eco concrete internal panels that are installed easily with no need for wet trades. The roof utilizes pre-fabricated timber roof trusses, manufactured from high quality, stress graded PEFC certified timber, in this case by established Zedfactory supplier, Donaldson Timber Engineering. Trusses deliver a flexible, practical, simple-to–erect engineered solution to roofing requirements and as they can use up to 40% less timber than a traditionally formed roof, they also deliver on competitive pricing and the environmental agenda. Jim Provan, DTE’s Sales and Marketing Director, explains about supplying RuralZED’s roof:
“Given just a two week time frame, our Oxford factory designed, manufactured and delivered roof trusses, on the day requested, to a site in East Sussex. Here the whole house was pre-constructed and the building was then transported, in sections, to Ecobuild, where the various component parts were successfully craned into position.”
He added:
“Certified timber is without doubt one of the most sustainable standard building materials. - renewable, biodegradable and a proven carbon sink. When it is used to produce engineered products, such as DTE’s roof trusses and cassette floors, it makes an unbeatable contribution to MMC and the development of low carbon housing.”
Zedfactory’s Matt Hoad confirms the importance of utilizing MMC in the project: “Due to the use of a range of prefabricated components, RuralZED can be built by a local semiskilled labourer, removing the need for highly skilled, expensive dry and wet trades, with all the benefits that implies for affordability.
Zedfactory’s cost projections for RuralZED make interesting reading, particularly the comparisons with standard housing and other zero carbon housing. The approximate cost for a three-bedroom version of RuralZED, including erection by Zedfactory, is given as about £150,000; the build price of a standard three-bedroom home built to current building regulations is given as about £100,000; and the build price of the only other Code 6, zero-carbon home so far designed in Britain, the Lighthouse, is given as about £180,000, excluding erection.
This cost differential makes the RuralZED house a practical proposition, and a serious contender, particularly in the affordable housing sector. With the new standards looming for carbon free homes, RuralZED provides more than a great demonstration project: for Zedfactory, and for supplier partners such as DTE, it proves that the zero carbon house is a serious, deliverable proposition, available now and one which can be designed and constructed using mainstream technology.
