When it comes to saving the Earth, not to mention the arm and a leg it costs to buy a home, the industry is being encouraged to make the most of modern methods of construction

The Council of Mortgage Lenders says it is probably true to say that there are more types of non-traditional construction in the UK now than in almost any other country in the world and the number of types is growing.

The housebuilding industry is changing. Market forces are driving the industry to reconsider their approach to serving their customers. Government agendas on rethinking construction, planning policy, issues of supply and demand and building regulations are forcing the industry to reconsider the way houses are built.

In May, code level three of the Code for Sustainable Homes becomes mandatory, and as part of the drive for ‘zero carbon’ housing, code level six is expected to be in force by 2016. This puts a powerful onus on the industry to do what it can to meet this regulatory demand. At this year’s Ecobuild 2008 exhibition, ‘eco-architect’ Zedfactory took the opportunity to display its latest house type - Rural ZED.

Developed in partnership with Donaldson Timber Engineering (DTE) and other MMC manufacturers, the home is claimed to meet the demands of code six to create an affordable, practical and zero carbon home. “Due to the use of a range of prefabricated components, Rural ZED 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,” said Zedfactory’s Matt Hoad.

DTE’s Jim Provan added: “Certified timber is without doubt one of the most sustainable standard building materials - renewable, biodegradeable and a proven carbon sink. When it is used to produce engineered products such as roof trusses and cassette floors, it makes an unbeatable contribution to MMC and the development of low carbon housing.”

In the sustainable communities plan the government has linked the use of MMC with the drive to boost housing supply, thus further raising the salience of the issue for lenders and other stakeholders. The Housing Corporation has stated that 25 per cent of all new grant-aided construction by housing associations should be by MMC. It is bound to play a crucial role in the development of the Government’s new eco-towns proposals.

English Partnerships says a good overview of MMC is provided in the National Audit Office report: Using modern methods of construction to build homes more quickly and efficiently.

Volumetric construction, for example, is where the whole dwelling is prefabricated off site in modules, which are then assembled on site. Modules may be constructed in a variety of forms from a basic structure to fully finished and serviced units. English Partnerships’ Summit House was constructed using this method.

Panelised construction, where flat panels are produced off-site and assembled on site to produce a three-dimensional structure. The most common approach is to use open panels, consisting of a skeletal structure. More complex, or closed panels involve more prefabrication typically including lining materials and insulation. Services, windows, doors, internal finishes and external cladding may also be incorporated.

Hybrid: a method also referred to as semi-volumetric that combines both the panelised and volumetric approaches. Typically, volumetric units for highly serviced areas such as kitchens and bathrooms (sometimes referred to as “pods”) are used with the remainder of the dwelling or building constructed using panels.

Non-off-site MMC, encompassing innovative house building techniques and structural systems typically including technologies such as “TunnelForm” or “Thin Joint Blocks”, which fall outside the off-site categories.

English Partnerships says it no longer requires MMC, but has replaced the MMC target (25 per cent by number of homes started and completed) with a requirement for developers to submit a Statement of Construction Efficiency covering all English Partnerships projects.

The statement outlines how developers have used the lessons of the Design for Manufacture Competition by using new technologies and supply chain processes to improve the quality, performance and deliverability of their schemes. The approach must be of an acceptable standard appropriate to each project. All buildings should be specified to attract lending and insurance and provide adequate consumer warranties.

The recent National Audit Office report ‘Homebuilding: Measuring Construction Performance’ recommends that performance measures should be comprehensive, covering business efficiency; quality of the building; environmental performance and customer satisfaction. This is a theme also emphasised by the Callcutt Review of Housebuilding Delivery.

The urgent need to address the challenge of climate change requires a step change in construction practice through innovation and new technologies. English Partnerships believes that this can best be achieved through a more rigorous approach to the construction process.

Lessons learnt from the DfM Competition show that the costs are managed down not by specifying cheaply but by rationalising the construction process. Incorporating integrated teams requires involvement from the manufacturing supply chain at an early stage to inform the design process.