By Stephen Wallis
As engineered wood evolves as a construction material, the sky is becoming the limit for timber office and institutional buildings.
Michael Green has seen the future of the building industry, and that future is wood. Lots of wood. The Vancouver-based architect is among the most ardent proponents of what is known as mass timber, prefabricated structural wood components that can be used to construct buildings — even large-scale buildings — faster, with less waste and eventually with less money.
Most crucially, Mr. Green and others say, building with mass timber can ameliorate climate change because it produces less in greenhouse gas emissions than construction with concrete and steel. And wood has the benefit of storing the carbon dioxide trees absorb during their growth, keeping it out of the atmosphere indefinitely.
“Roughly 11 percent of the global carbon footprint is related to what buildings are made out of,” said Mr. Green, whose mass-timber projects include the T3 office building in Minneapolis (the name stands for timber, technology and transportation) and a pair of buildings for Oregon State University’s College of Forestry, including a research and development facility for the school’s TallWood Design Institute.
Over the next 40 years, he added, it is estimated that nearly 2.5 trillion square feet of new construction will be needed to support growth in the world’s increasingly dense urban areas, according to the 2017 Global Status Report issued by the United Nations Environment Program. “If we continue to build the way we are,” Mr. Green said, “we are absolutely not going to meet any kind of climate objective, and we’re going to change our children’s future forever in a pretty bad way.”
While cutting down trees to make buildings may not sound environmentally sensitive, mass timber supporters argue that wood could be harvested from sustainably managed forests.
Increasing numbers of architects, developers, governments, educational institutions and corporations are embracing wood. In Biel, Switzerland, Swatch Group just completed three buildings said to be among the largest timber construction projects in the world. Designed by Shigeru Ban, an architect admired for his innovative use of wood, the complex includes a serpentine company headquarters wrapped in a spectacular latticed timber facade.
By Kira Barrett
North America is on the cusp of a mass timber revolution, and the Waterfront Toronto project is leading the way. But the material faces major obstacles.
Abuilding made primarily of wood conjures public fear of fire, but for a growing number of developers, it evokes opportunity. From constructing towering wooden condominiums, to timber college dormitories, to an entire neighborhood built from trees, experts in “mass timber” are creating buildings of the future.
Sidewalk Labs’ master plan for a futuristic smart city on the waterfront in Toronto includes an entire neighborhood made of wood, called Quayside, with 10 mixed-use building up to 35 stories.
The plan is audacious, considering that in the U.S., there are only 221 mass timber buildings in the works or fully built, according to the American Wood Council’s Kenneth Bland.
In most U.S. cities, mass timber buildings, and specifically tall mass timber buildings, are a rarity, if they exist at all.
But architects, city officials and timber advocates across North America are pushing conventional building codes and public perception because of the drastic impact these structures can have on reducing CO2 through carbon sequestration, compared to traditional concrete and steel.
“I think it’s a big opportunity for a lot of cities out there … The impact on reducing carbon emissions on earth could be dramatic,” Karim Khalifa, director of buildings innovation at Sidewalk Labs, told Smart Cities Dive. “And that gets me excited.”
What is mass timber?
One of the biggest obstacles for city officials is understanding the material. They are more than buildings made of wood — they’re defined by their structure. Steel or concrete buildings with wood accents don’t count, according to Andrew Tsay Jacobs from architecture firm Perkins and Will.
Mass timber buildings use solid wood panels to frame a building’s walls, floors and roofs, creating structures that can reach at least 18 stories, as is the case with the tallest mass timber building in the world in Norway. But these buildings aren’t just pure wood. Mass timber construction utilizes engineered wood, or panels glued together, and there are several types: cross-laminated (CLT), glue-laminated and dowel-laminated timber, with CLT being the most common.
While shorter wood buildings have existed for centuries, CLT panel technology is relatively new. It was developed in Europe in the 1990s, the material was only added to the international building code in 2015. Even then, all-wood buildings were capped at six stories, though that will change to allow taller structures in 2021.
AN has mapped the schools, organizations, and manufacturers across the U.S. and Canada that are powering the domestic timber boom.
The timber industry has long thrived on its small-scale, local nature due to the sourcing of its materials as well as the limits on project size set by the building code. With this has come a good deal of fragmentation and disorganization, so we decided to map out the different schools, organizations, and manufacturers that are leading the way in the research and development of mass timber across the United States and Canada.