Although they may at first seem like kindling for a modern-day Towering Inferno, timber skyscrapers—also known by the delightful portmanteau "plyscrapers"—are in vogue right now. Thanks to smart new materials like cross-laminated timber (CLT), which is stronger than steel by weight and resistant to fire for up to three hours, wooden buildings are getting taller in the 21st century.
Now, Canada's University of British Columbia has reached a milestone for the new building type. The school recently finished the structure of the world's tallest wooden building: Brock Commons, an 18-story student housing facility designed by Vancouver-based architecture firm Acton Ostry and made almost entirely from lumber harvested in the forests of British Columbia. The structure, as the school pointed out this week, was completed a full four months early—a huge margin in the construction industry.
Like other plyscrapers, Brock Commons is largely made up of CLT, a material invented in 1990s that plasters together alternating layers of imperfect wood to create thick, strong beams. In the case of Brock Commons, the floors are made from CLT panels supported on glue-laminated timber columns—another material that adds strength to traditional timber—in a grid. This actually results in a structure that forms a two-way slab diaphragm, eliminating the need for load-bearing beams.
Brock Commons uses some traditional construction materials, like steel and concrete, but they're minimal. The building is kept stable thanks to two massive concrete cores, which prevent the structure from swaying. Elevator shafts and staircases are lined with steel, as is the roof, which is made of prefabricated sections of steel beams and metal decking. Then, of course, there's glass: while the cladding of Brock Commons is 70% wood fiber, the remaining 30% is made up of windows, which should bring light into the world's tallest plyscraper. Building Brock Commons out of wood keeps it green friendly, too: compared to similar-sized buildings made out of typical materials, Brock Commons saves the environment 2,432 metric tons of CO2, or the equivalent of taking 500 cars off the road for a year.
All told, the finished Brock Commons structure stands 173 feet tall. That's nothing for a traditional skyscraper, but it's a world record when it comes to wooden structures, the previous record holder—the Wood Innovation and Design Center, also in British Columbia—standing just eight stories tall.
Even so, Brock Commons isn't likely to be the world's tallest wooden building for long, with architects like Sweden's. C.F Moller and others proposing timber skyscrapers that will ultimately stand over 30 stories tall. The plyscraper race has just begun.
[All Images: courtesy Acton Ostry]