The race is on and even though we are lagging in the contest to reach the tallest heights in the timber ‘plyscraper’ stakes, we are exploring the limits of timber and improving our industry, while meeting global challenges along the way.
The world’s current tallest timber building is a 14-storey apartment block in Norway. If Oakwood Tower in London is realised it will supersede this record by a long shot. But is being ‘tallest’ the most important thing when it comes to timber skyscrappers? Eleven countries, including Italy, Britain, the Netherlands, Norway, New Zealand and Sweden, have no height restrictions when using timber, while France has a 15 storeys limit, Finland eight, and Canada and the United States both six.
Timber is a sympathetic material in the home offering warmth, is excellent for acoustics and helps regulate temperature and needn’t be covered with other costly materials like plaster. Wood is one of nature’s most innovative building materials: the production has no waste products and it binds CO2. Wood has low weight, but is a very strong load-bearing structure compared to its lightness. Surprisingly wood is also more fire resistant than both steel and concrete. This is due to 15% of wood mass being water, which will evaporate before the wood actually burns. Charring also protects other surfaces in the event of fire.
It’s a long time since C.F. Moller architects revealed plans on 2013 to build the tallest wooden skyscraper in Stockholm. Largely a residential project the building plan included a wooden construction with a concrete core.
Australia has been a little challenged to say the least by the concept of high rise timber building. The National Construction Code up until recently has been restricted to only three storeys, beyond that height the code specified only concrete, masonry and other non-combustible materials.
Earlier this month Jean-Paul Viguier and Associates won the competition for a 57m tall timber tower in Bordeaux, France. The project name “Hyperion” is a reference to the world’s tallest living tree (a Sequoia sempervirens in Northern California) and emphasises the use of timber materials. The project will make use if Laminated Veneer Lumber (LVL) and Glulam for post and beam structures and will use Cross Laminated Timber (CLT) for flooring. Timber is also the main feature of the facade and framework. The use of natural materials will be accentuated by the cantilevered balconies, gardens and green roofing.
Bates Smart has also just unveiled its design for a 52-metre-tall office tower in Brisbane that will be made from engineered timber. When completed, 5 King as it is known, will be the tallest engineered timber office tower in Brisbane – only one metre shorter than the tallest tower Brock Commons in Vancouver, designed by Acton Ostry Architects, 2016. The 10-storey office tower will have the largest gross floor area for an engineered timber building in the world. The building will also have integrated water harvesting, energy efficient lighting, and optimized air-conditioning.
Under changes to the use of timber in the National Construction Code the material is now acceptable with the use if extensive sprinkler systems, fire-grade plasterboard and fire resistant insulation material.
The drive to change the height controls on timber has been the development of two large timber buildings in Melbourne: Lend Lease’s 10-storey Forte apartment block in Docklands and Australand’s five-storey timber frame project in Parkville.
In the past a 25 metre hieght restriction had been chosen as the code’s maximum height because it was the height that fire brigades could fight fires with ladder extensions and allowed people to escape from buildings.Timber buildings will have the ability to use traditional stick frame construction and new “massive” timber products such as the cross-laminated timber used in Forte. CLT consists of timber planks glued at right angles under high pressure, creating panels of great strength. Cavity barriers made of non-combustible mineral wool would be mandated under the changes.
The technology is evolving very quickly and with projects on the drawing boards up to 133 metres tall in Stockholm, it’s going to be very hard to stay at the top of this innovation if you want to play the height game, but is it all really about size?
Changes to timber regulations in Australia now means we are able to build higher in wood, and that we will see more timber building projects, both residential and commercial – last year alone there were at least 6 projects in the planning. This is exciting news and it will make considerable contribution to architecture, engineering advances in wood technology, and to a sustainable future.