They say that all trends are cyclical, so perhaps it shouldn’t come as a surprise that designs in architecture are starting to shift from “modern, technologically advanced” building materials—such as concrete and steel—to more “primitive” materials. In particular, wood is seeing a comeback, but there is nothing primitive about how it is being used now. Plans to build the world’s tallest wooden skyscraper have been drawn up by Japan’s Sumitomo Forestry, set for 2041 to mark the company’s 350th anniversary.
Sumitomo’s W350 tower would stand 70 storeys high, containing around 8000 homes with a design honouring the company’s legacy, incorporating trees and greenery on balconies on each floor. Of course, the building will not be entirely made of wood; approximately 10% would be steel, including vibration control braces in a central column for stability during earthquakes, a very important consideration in Tokyo.
Benefits of wooden skyscrapers over steel and concrete
According to architects, there are many advantages to building with wood over more conventional materials. Perhaps the most obvious is the reduced environmental impact: unlike concrete and steel, which lead to an estimated 8% and 5% of global CO2 emissions, wood actually sequesters CO2 and keeps it from being released into the atmosphere.
Wood is also much faster to build with because there is no need to wait several weeks for each concrete floor to dry, and it is more lightweight (although there are also drawbacks to lightweight materials when it comes to skyscraper construction).
Challenges of wood as a construction material
Most people’s instinct tells them that wood is not a safe material for building skyscrapers. What about fire hazards, or rotting, or a Big Bad Wolf (or strong gust of wind) blowing the whole thing over? It is true that all of these are challenges that must be faced by architects, but it seems most of us do not have a good understanding of what wood can do.
After all, there is a reason that the wooden Sakyamuni Pagoda is still standing 900 years after it was built, thanks to careful design and craftsmanship. Considering it is 67 m tall, this is quite a testament to the durability of wood, as long as it is handled correctly.
“If you can keep it dry, it will last forever,” says one structural engineer. Others point out that, in a fire, large, dense pieces of wood usually char on the outside but do not burn down.
Wood is very expensive to build with, though. Today’s wood of choice is cross-laminated timber, sometimes referred to as “plywood on steroids”, and the W350 is estimated to cost around £4 billion. But who knows? Maybe costs will come down by the time we reach 2041.