Skyscrapers built of wood?
Building a skyscraper? The 30m Wood Innovation Design Centre, Canada, completes summer 2014
Forget about steel and concrete, says architect Michael Green, and build it out of … wood. As he details, it’s not only possible to build safe wooden structures up to 30 stories tall (and, he hopes, higher), it’s necessary.
Michael Green wants to solve architecture’s biggest challenge — meeting worldwide housing demand without increasing carbon emissions — by building with carbon-sequestering wood instead of concrete and steel.
Here is his discussion:
If a tree can grow to 40 stories in height, why can’t we design buildings made of wood to do the same?
We believe tall wood buildings are part of the next generation of high-performance sustainable buildings. Wood structures sequester carbon dioxide and offer lower energy solutions that harness the power of the sun. As more and more people move into dense urban environments, tall buildings are our future. And note, we’re not asking, “how tall is appropriate?” Our question is: “how do we build tall?”
New engineered wood products allow us to use lower grade wood, branches and much younger trees to make very strong structural components for buildings. A sustainably managed forest offers us a renewable resource for these materials, and third party certification of the wood ensures that forest ecologies, diversity and indigenous people are valued and protected.
Steel and concrete are wonderful materials to build with and will remain fundamentals of the built environment but they also have significant energy and greenhouse gas footprints that must be considered. Moving from fossil fuels to renewables is an important part of our energy future. Moving from fossil fuel-based building materials to renewables is a critical part of our building future. Currently 70% to 90% of the greenhouse gas (GHG) and energy footprint of developed world buildings is related to heating, cooling, and electrical operations of those structures.
As our energy codes evolve to address the operational side of the equation, materials will form a larger percentage of the overall GHG and energy footprint of buildings in the future.
But while many of today’s ubiquitous structural materials require enormous energy to produce and have large GHG footprints, wood provides us with a significantly lower energy solution and a solution that sequesters CO2. One cubic metre of wood stores one metric ton of carbon dioxide.
Why is this possible now more than ever before?
The answer is a wave of new, engineered products that use lower grade woods. These “MASS TIMBER PANEL” products use the strength of wood’s fibre to create very strong and very large panels.
Like jumbo plywood, these products change the scale of the way we build in wood. Their thickness also changes their inherent fire, thermal and acoustic properties, helping us to develop new ways of building at all scales.
On the subject of fire, remember that 75% of all North American residential buildings are made from wood. The incidence of fire related hazard across the USA is no higher in wooden structures than in any other type of building material, and proportionally is lower per capita. Let’s face it, if you’re going to burn breakfast every house is at risk.
For North Vancouver’s City Hall we used Mass Timber Panels of laminated strand lumber made from 10-20 year old Aspen trees to build a large public atrium space. The panels were cut to 4m x 9m and prefabricated off site. Speed of construction is one of the hallmarks of working in larger-scale wood panels. Although this is not a tall building it provides a proving-ground for many of the issues we are now building at much greater heights.
The modern era changed buildings for ever as modern concrete and steel allowed us to span huge distances with bridges and towers. Wood is a material of past generations ready to become a material of the next. What might that mean for architecture? Will it change the way buildings look and feel? Will the practicalities of engineering wood in efficient rectilinear panels mean that wood simply interchanges with steel and concrete on some buildings?
Several milestones over the last decade have marked the beginning of the tall wood building movement. Waugh Thistleton designed the nine-story Mass Timber (CLT) Stadhaus building in Murray Grove, London in 2008. The Forte building in Melbourne Australia topped the Stadhaus by a single story in 2012. By summer 2014 the Wood Innovation and Design Center in Canada is expected to be the tallest contemporary wood building ijn North America at 30 meters in height with an all wood construction from the ground up. It has been designed as a system that can extend much higher.
Around the world there is a growing community of architects and engineers that believes that these shifts in the future are necessary and very plausible. The needs to provide shelter and counter climate change reside at the epicentre of an architect’s mandate. With today’s building technology we cannot solve global shelter needs without simultaneously exacerbating our energy and greenhouse footprint. Wood is one strong answer.