Timber buildings are popping up around the world. Are they the solution to construction's carbon problem?
Construction materials alone, including carbon and steel, contribute 11% of global carbon emissions (by comparison, air travel contributes about 2.5%). That’s why architects and development companies around the world are opting for a novel but not-sonew solution: wood. A study from the Potsdam Institute for Climate Impact Research, in Germany, found that with proper forest management, a global boom in wood buildings could sequester up to 700 million tons of carbon a year (wood naturally stores carbon, preventing it from being released into the atmosphere). The idea is catching on: Google’s Sidewalk Labs has proposed a 12acre timber neighborhood in Toronto, while in February, France mandated that all public buildings after 2022 be constructed of at least 50% wood or other organic materials. The University of Arkansas completed the largest timber building in the U.S. last fall, a 202,000-square-foot dormitory. Architects (and governments) are embracing the material, and finding innovative ways to use it.
The Forest Green
Rovers is “the greenest football club in the world,” according to FIFA. All food served to players and fans is vegan. Fittingly, Zaha Hadid Architects’ proposed new home for the team is also a carbon-neutral, alltimber stadium—the first of its kind in the world. The 5,000seat park will be made primarily of sustainably sourced wood, and be daylit, thanks to a lightweight, transparent “roof membrane.” The stadium’s unique shape, says project director Jim Heverin, is also thanks to the material, which “enables the use of unique shapes with little increase to cost,” due to the fabrication process and timber’s light weight. While typical stadiums contribute between 790 pounds and 2,800 pounds of carbon per seat, ZHA estimates Eco Park Stadium will contribute about 440 pounds per seat.
being planned on a former junkyard in Copenhagen, is the city’s first new neighborhood made entirely of timber. It was designed in collaboration with biologists and environmental engineers; 40% of the 45-acre project site is being preserved as undeveloped habitat for local flora and fauna. Henning Larsen partner Signe Kongebro cites the statistic that 70% of the planet’s population is expected to live in cities by 2050: “It is more crucial than ever that the relationship between city and nature is ‘both/and,’ not ‘either/or.’ ” The firm plans to use prefabricated timber panels sourced from partners throughout Europe, and to integrate nests for birds and bats (built directly into the facades), among other elements that foster nature.
There are a number
of timber and steel hybrid high-rises proposed around the world—but Mjøstårnet, completed last spring, is the tallest all-timber tower ever built. Debates over timber’s fire safety are ongoing: Architects in the U.K. are fighting to get it removed from a flammablematerials ban instituted after the Grenfell Tower tragedy (though that tower was not made of timber), and Norway had similar laws until 1997. The wood used in Mjøstårnet underwent extensive tests, including one in which large columns were burned for 90 minutes. They proved to be structurally sound, despite charring on the exterior. The material, as well as structural precautions Voll Arkitekter added to the building to prevent fire from spreading, passed Norway’s stringent building standards.