As urbanisation increases around the globe and the available space for construction in cities is squeezed further, buildings are reaching for the skies.
To date, most of these buildings have been glittering towers of steel and glass. But with new construction systems and technologies coming on stream, a key shift in how buildings and cities are conceived, plus growing concern about their environmental impact, engineered timber has an exciting role to play.
That was the view of speakers and delegates at Solid Timber House/Vertical Timber City, a Wood for Good conference that explored timber’s role in tall building. Andrew Waugh, of Waugh Thistleton Architects, recalled the stir created by the nine-storey Murray Grove development, built for Telford Homes using cross-laminated timber (CLT) back in 2008.
“It started a bigger conversation than we envisaged,” said Mr Waugh. “The attention and media coverage gave us the confidence to continue.”
Other “exciting” timber buildings, sometimes clad in stone or brick, started springing up in central London and in other cities around the world, leading to “a closer understanding of what could be built in timber and a new way of approaching an urban architecture.”
The aim now is to keep it exciting so that architects and engineers continue to engage. “We’re now looking for our Tesla moment,” said Mr Waugh.
Different structural approaches are often called for and the Bergen and Omegn Building Society (BOB) looked to a timber bridge for inspiration when designing Treet, a 14-storey (plus basement) residential block on the seafront at Bergen.
The building comprises four-storey stacks of engineered timber apartment modules enclosed in a structural glulam frame, which, in effect, is a series of bridge trusses stood on their ends. CLT, which was accurate to within 3mm, was used in the staircases, elevator shaft and some inner walls and balconies.
Construction was not without its challenges, but these were logistics and climate-based rather than issues with materials and the success of the final building has led BOB’s chief project manager Ole Kleppe to believe that timber buildings of up to 30 storeys would be possible using this method.
“We must believe the impossible is possible, otherwise we will continue building high-rises in concrete,” he said.
The areas between buildings, tall or otherwise, are equally important in city spaces as both Matt Hoad of HTA Design and Julian Weyer of CF Møller Architects were keen to point out.
HTA has been involved in many regeneration projects and, said Mr Hoad, designs “places” rather than just individual buildings.
“When you’re building in timber you have to think about how it will look in 20 years time and how it sits in the landscape,” said Mr Hoad. “The landscape is incredibly important to us.”
Julian Weyer said his practice “deliberately blurs the boundaries between architecture and landscape”. He went on to describe the Örnsro Timber Town in Örebro, Sweden, where freestanding “super-villas” are integrated with nature.
“They have their front door to the city and their back door to nature,” he said. “It’s a new type of urbanisation.”
Delegates also heard about ongoing research and development by London and Chicago-based SOM Inc. Associate director Dmitri Jajich and associate Phil Obayda described their work on composite _ oors, combining timber and concrete.
“We want to focus on getting timber in through the back door,” said Mr Jajich. “It’s not as sexy [as CLT tall timber buildings] but we’ll sneak more and more timber in to buildings in the _ oors and then we can sneak it in the beams.”
There’s nothing undercover about the Barbican timber tower, a conceptual project by Smith and Wallwork structural engineers with Michael Ramage, architectural engineer and senior lecturer at Cambridge University. Mr Smith said the project to explore the possibility of building an 80-storey 300m-high timber tower was “intentionally provocative.” Challenges are many and multiplying – for example, new methods of constructing extremely large sections of timber and then ways of lifting them into place would have to be devised; and the estimated 55,000m3 of timber required means it is not _ nancially viable at the moment. Foundations, wind loading and logistics are just a few of the other outstanding issues to be tackled. “This project is being used provocatively to look 10-20 years in advance,” said Mr Smith. “That’s why we’re doing the research now – it’s very ambitious.”
Architect Alex de Rijke, director at dRMM, also looked to the future in the final presentation of the conference, suggesting that timber construction could provide both high-rise and low-rise solutions. What was important, he said, was that expertise and knowledge should be imported and exported as well as timber
