US Edition One of London’s landmark towers, the Cheesegrater, is notable for reasons other than its curious name.
When developers British Land and Oxford Properties decided to build the 736ft tall structure (in the shadow of the recession), the Richard Rogers office block became one of the first in the City to be built almost entirely off-site.
Some 80pc of the Leadenhall Building, which officially opened in October, was digitally planned and prefabricated in factories in the north of England, in Scotland and Northern Ireland.
The parts, and its giant steel frame, were then trucked along the City’s narrow roads and assembled on-site, like a giant Meccano set.
Mike Rayner, head of development at Oxford Properties, says off-site construction enthusiasts Laing O’Rourke won the construction contract because “they had a vision of how they would do it, they wanted to do it off-site and they said they could beat our timetable by four months.
For a building of that size, hitting the market four months sooner is a huge benefit.” As the cost of prime urban real estate continues to rise, the ability for constructors to pass on efficiencies to customers will become increasingly important.
So will their ability to fit innovative structures more efficiently into denser spaces. The 600-bed Mint Hotel on Pepys Street near the Tower of London is another example of the city warming towards unusual approaches that cater to our ancient and crowded capital, as all of the bathroom pods, the major services and the travertineclad external walls were prebuilt and craned into a very narrow space in the heart of the City. And there are many different approaches on the market.
“Cross-laminated timber (CLT) has made real inroads in the last six or seven years,” says Franz Jenowein, director of sustainable solutions at JLL.
They said that by making it off-site they could beat our timetable by four months
“It’s up to four times lighter than reinforced concrete, requires up to 70pc less in foundations and can cut construction times by a third, meaning developers get their money back faster.”
Windows too are due for an upgrade, with vacuumbased glazing becoming a cost-effective alternative to traditional, sealed double glazing. As it doesn’t need expensive gases, and (being nearly as thin as single glazing) can easily be retro-fitted, this is an attractive innovation in new and old developments, he adds. When heating and lighting are required, cheaper sources are providing alternatives to fossil fuels.
“Ground-source and air-source heat pumps have advanced remarkably over the last decade,” says Mr Jenowein. “With clever software you can now get several kilowatts out for every kilowatt you put in.” And despite the rare treat of a sunny day in the UK, solar power is making inroads into mainstream commercial properties. “A high-rise office block with a relatively cluttered roof space probably couldn’t generate more than 2-3pc of its energy needs from PV,” says Mr Jenowein.
Helen Gough, head of JLL’s buildings and construction team, says: “The pressures we see now on the supply chain require us to look more closely at how we build, and the materials with which we build, including the likes of engineered timber frames, vacuum-based glazing, 3D printed materials such as glass and ceramic bricks, or smog-eating concrete.
“Bricks are a large part of the vernacular British urban landscape, but is there scope for us to now show how building materials have evolved and begin using them regularly?”
Planning for the future
In order to have the offices, infrastructure, and living spaces of the future, tackling shortages of materials and skilled workers needs to be a priority.
Key material shortages have caused costs to skyrocket and the impact of “trades shortages”, including demolition contractors, bricklayers and electricians, has meant that new-build projects, particularly in London, have been shelved.
Helen Gough, lead director of JLL’s building and construction team, believes that to tackle the crisis a skilled economy is essential.
Construction needs to be seen by young people as an attractive and worthwhile profession
“There needs to be greater investment in professional and technical apprenticeships and vocational education for secondary-school students, particularly in critically important sectors such as construction,” she says.
“Construction needs to be seen by young people as an attractive and worthwhile profession. Focusing on short-term training and filling quotas will never be sustainable methods for tackling the issue. The scale of key material and skilled worker shortages in the UK has significant implications – a key concern being the further exacerbation of the country’s housing crisis.”
• To find out more, visit JLL