Wooden skyscrapers

Featured Image: If built, the W350 tower in Japan will become the tallest wooden skyscraper in the world.

Saturday, 1 June 2019, New York, NY – A Japanese company named Sumitomo Forestry has ambitious plans for a 70-story, 350 m (~1150 ft) tall skyscraper made almost entirely of timber. Its planned date of completion is in 2041 and its cost estimate is around $5.6 billion. In addition to becoming the tallest wooden skyscraper in the world, the building will also feature a steel skeletal frame to protect it from earthquakes, as well as numerous green balconies to connect the building’s residents to nature. According to Sumitomo Forestry, “The aim [of the building] is to create environmentally-friendly and timber-utilizing cities where [cities] become forests through increased use of wooden architecture for high-rise buildings”.

The Japanese government is encouraging architects, developers, and construction firms to create more wooden skyscrapers. The Japanese Government even passed the “Promotion of Use of Wood in Public Buildings Act” in 2010, mandating all government buildings three stories or less to be constructed with wood. And it’s not just Japan, either. All over the world, places such as London, Chicago, Stockholm, and even Bali are constructing wooden buildings. But wait, that sounds ridiculous. Doesn’t wood rot, or catch on fire? Is wood, as a building material, strong or stable enough for skyscraper construction? These are legitimate concerns, but there are actually some pretty creative solutions to these problems. And of course, there is one major reason why wood has seen a massive growth in popularity over the past decade: climate change.

The reality of climate change, and its detrimental effects, has spurred an increased sense of urgency to keep carbon emissions below that 1.5% growth rate. One of the solutions to this is to build more wooden skyscrapers. Concrete and steel, the materials traditionally used in the construction of skyscrapers, are thought to be responsible for 8% and 5% of total carbon emissions respectively. What’s more, a mid-rise building made out of timber will emit up to 5,000 tons less carbon over its lifetime than a concrete or steel building of the same size. After all, trees are well known for sucking up carbon dioxide and outputting clean, oxygenated air in its place. With hundreds of thousands of cubic metres of wood in just a single wooden skyscraper alone, that would mean phenomenal carbon savings. And finally, switching every concrete and/or steel building to timber could reduce worldwide carbon emissions by up to 31%.

Environmental benefits aside, the massive growth of urban areas also plays a factor. By 2050, we could see an additional 2 billion people living in urban areas around the world. Wooden skyscrapers are faster and cheaper to build than concrete or steel buildings, with a greater potential for compact, livable, and environmentally friendly housing. This means that wooden skyscrapers are more likely to keep up with the growing demand for urban housing than concrete or steel skyscrapers, all the while offering better quality housing at a more affordable price.

Of course, there’s one big problem. Wood is famous for being an extremely flammable material. It also has the potential to rot over time. How do wooden skyscraper developers plan to combat this? The solution is simple: cross-laminated timber. It’s kind of like Jenga – it has alternating perpendicular grain directions, just like the image below:

Cross laminated timber

This design is an incredible breakthrough in wooden skyscraper construction. The structure of cross-laminated timber derives its strength from its ability to reduce the weakness of any one individual piece. Cross laminated timber has been tested multiple times in fire and earthquake simulations, and surprisingly, it has performed at-par, if not better than, concrete or steel materials. This makes sense, because, during a forest fire, living trees get damaged, but they aren’t usually completely destroyed, and recover from the fire shortly afterwards. Anyway, cross-laminated timber structures are especially strong during earthquakes, because they not only survive the earthquake, but are lighter than concrete or steel as a whole, and put less stress on the foundation.

Meanwhile, the architectural designs of wooden skyscrapers emphasise the natural materials in the structure. Research has shown that more natural materials in our environment increases self-esteem and well-being.

There are numerous proposals for wooden skyscrapers around the world, each one wackier than the next (you can Google them yourself). But, one must concede that there is as much excitement and potential for wooden skyscrapers as there is uncertainty, skepticism, and doubt. After all, no wooden building anywhere is greater than 120 m (~400 ft) in height, so a 350 m tall structure like the one mentioned at the beginning of this post just seems like an architect’s fantasy. But despite the limitations, wooden skyscrapers have enormous potential to create affordable, environmentally friendly housing and commercial office space, and building more of them is a step in the right direction. But what do you think? Would you like to live in one of these wooden skyscrapers? Or are you skeptical about them? Let us know in the comments. We’ll see you again in two weeks.

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