Technical Offsite and M&E

offering a more diverse housing delivery option for the industry that embraces both new design principles and methods of delivery.

“Hammersmith & Fulham is to all

intents and purposes the lead developer, they’re taking the risk, and at the moment we provide the supply chain, but come back in six months and we have a different [funding] model that reduces the funding and construction risk for the client,” he hints. Ultimately, the ambition is to deliver

more than 1,000 units a year by 2020, a level similar to Kier’s private housebuilding division Kier Homes. Probably this will involve tapping into Aecom’s expertise on masterplanning and delivering major sites, and possibly — as de Waal has hinted — it could also encompass taking on development risk. Rational House is an urban housing

“product” named in tribute to the underlying research that informed it: a study into successful urban housing in nine world cities by co-founder Bob Dalziel of 3D Reid. Factors identified include high daylight levels with large windows, open plan living spaces and high ceilings — a Rational House home has a 2.85m floor to ceiling height compared to the recommended 2.4m in the London Design guide.

But, equally important, the homes have a solidity and permanence that the

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London streetscape needs, and can sometimes be missing in lightweight steel or timber-framed construction. “It suits the ambience of Hammersmith & Fulham, the product we’ve got sits comfortably in that environment,“ says Rational House chairman and co-founder Tim Battle, formerly of services consultant Rybka Battle. The product also answers a call for the

“new London vernacular”: homes that draw on the proportion and street presence of much-loved Georgian and Victorian terraces but apply 21st century design and technology.

Multiple unit sizes The system can be configured for flats in blocks up to 10 storeys, maisonettes, three-storey town houses, terraced or detached houses, and can accommodate

A mock-up showing Fusion’s steel frame and Sterling’s panels (top); a CGI of the Spring Vale scheme (above)

multiple unit sizes to suit the site’s constraints. At Spring Vale (left), there will be eight flats and two three-bedroomed houses. Primarily seen as an urban product, the team also envisages it could be suitable for edge of city sites. With Aecom already acting as masterplanner for the vast North West Cambridge development, de Waal says Rational House is likely to submit a proposal. However, in construction terms,

Rational House isn’t particularly ground- breaking. It’s an MMC modular system, based around a library of pre-selected, mutually-compatible components that are available in a range of dimensions. But rather than establishing a new manufacturing capability, Rational House has pulled existing companies into its supply chain: Fusion Building Systems is responsible for building and installing the structural frame, and Sterling Services manufactures and erects the concrete cladding panels. Windows and doors are supplied by

Nordan, and AST supplies the metal window shutters that gives Rational House a decidedly Continental feel. “In summer, you can close the shutters but keep the airflow, and they help with security — Secured by Design loves them,” notes Battle. There are also plans to extend the predetermined supply chain to encompass fit-out trades in future iterations — de Waal says they didn’t want

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