Steel and glass may not shape our skyscrapers in years to come, as architects rethink the potential of wood.
Forget the Shard: steel and glass may not be the building material of the future. Architects are rethinking the potential of wood, thanks to innovations in structural engineering. An open-source research study, published by Michael Green of MGB Architecture and Design, makes the case for timber as “a safe, economical and environmentally-friendly alternative for tall building structure”.
It’s certainly not the first time beautiful wooden high-rise has been proposed. Japan boasts 19-storey pagodas, built 14 centuries ago and still standing, despite the humid climate and sometimes seismic conditions. But, says Green, new approaches to engineered timber mean that wood should now be considered a viable material for buildings on a much larger scale.
The study gives the full structural design for a 30-storey skyscraper – a concept called ‘Tall Wood’, intended for Vancouver City. It’s based on three new mass timber products: there’s cross-laminated timber, which is made of layers of solid wood set at 90 degree angles; there’s laminated strand lumber, made from a matrix of thin chips; and finally there’s laminated veneer lumber, made from thin laminations – a bit like plywood but on a much larger scale. The benefits of these products over light wood frame techniques, the report claims, range from stability and structural performance to fire protection (thanks to a well-tested laminate mix) and soundproofing.
These techniques have been tried and tested on a smaller, though impressive, scale by architect Andrew Waugh, in London’s nine-story Stadthaus apartment block. This is currently the tallest modern timber structure in the world, and testimony to the commercial competitiveness of the material: its 29 properties sold in just 90 minutes.
But what of the environmental benefits? Waugh estimates that the building’s wooden structure will store over 186 tonnes of carbon for its lifetime, and that a further 125 tonnes of CO2 equivalent were saved during construction by avoiding traditional concrete-based techniques. There are cost benefits too, he claims. Although wood is a little more expensive than concrete as a raw material, it’s quicker to work with and requires less foundation to be built.
Nigel Sagar, Senior Sustainability Manager at Skanska, is positive about the potential. “Wood ticks all the boxes from a sustainable point of view… It is a renewable resource, can have recycled or reused content as a product, and can be reused or recycled at the end of a building’s life. It also has good product transparency, via chain of custody schemes like FSC, PEFC.”
“Our ability to harness the ingenuity of a tree, and to do so with responsible forest practices that encourage healthy forest ecology, is the beginning of righting the ship of modern building”, he said. – Laura Dixon