Will mass timber cut into the market share of concrete that is used in Industrial Commercial and Institutional (ICI) construction? Two B.C. projects that made use of mass timber, which are wood products made from laminating together smaller pieces of spruce, pine or fir, won Governor General’s Medals in Architecture for 2016.
The two winners are the Wood Innovation and Design Centre in Prince George and the BC Passive House Factory in Pemberton.
"Architects like designing with mass timber," said Russell Acton, principal of Acton Ostry Architects Inc. in Vancouver. "It is clean, quiet, it looks nice and everything fits together easily."
Mass timber products are being used in an 18-storey, 53-metre-high student residence that is being built on the north-west corner of the Vancouver campus of the University of British Columbia.
Designed by Acton Ostry, when the Brock Commons residence is completed in summer 2017, it will house 400 students in one of the world’s tallest mass timber structures.
"Acton Ostry has worked with wood for a long time," said Acton. "In addition, I have a personal interest in wood as a building material. I took part in the 2013 Tall Wood Building Demonstration Initiative and I’m a supporter of wood being used in large-scale projects, such as tall buildings like Brock Commons."
The foundation and first storey of Brock Commons are made of concrete, with 17 storeys of mass wood rising above.
"We’re building with glulam (glue-laminated timber) columns and CLT (cross-laminated timber) floor slabs," Acton said. "Everything goes up quickly, like a wooden Meccano set."
Because mass timber, especially on tall buildings, is still in its relative infancy in Canada, it is a little more expensive to use than concrete.
"There’s an approximate eight per cent innovation gap — the cost of using wood over concrete — on the project," Acton said. "But the cost of using wood is expected to come down over time as demand increases."
He believes the sweet spot for mass timber in the future could be medium-rise six- to 12- storey buildings.
"I would like wood to become a standard structural material, but when and how it is used will depend on the context of each individual project," Acton said. "Concrete is certainly not on its way out. Concrete, and steel, will always be used."
Jana Foit, senior associate in the Vancouver office of Perkins + Will Architects, said structural wood is complementary to concrete and steel.
"It’s another option," she said. "There’s more interest in engineered wood and it’s increasing in use, but slowly."
Foit said there is still a lot of uncertainty in the construction industry about structural wood.
"It’s not the default structural system, like concrete or steel," she said. "The public still thinks mainly in terms of durability and combustibility and there’s a fear of risk. With concrete you know the case for it."
The Canadian concrete industry, for its part, is confident it can maintain its lead role in construction.
"We haven’t seen any evidence of an increased use of wood in ICI construction," said Michael McSweeney, president of the Cement Association of Canada.
"Concrete has over 80 per cent market share of all building materials in the world. None of us is ever more than four feet from a piece of concrete."
McSweeney said concrete has many strengths as a structural material that need to be recognized by the construction industry.
"It’s the strongest building material on earth," he said. "It’s durable, low-maintenance, non-combustible and very versatile. Concrete is inert — it gives off no gases — and it acts as a sound barrier."
In addition, he said, concrete is inexpensive.
"It doesn’t need any public funding support in order to make it economical," he said.
McSweeney said concrete has been on a 100-kilometre construction diet for several years.
"Concrete’s carbon footprint is very small," he said. "The industry can obtain everything that is needed to make concrete, cement, sand, aggregate and water, within 100 kilometres of any major Canadian city."
McSweeney said the move to urban densification in Canada, another initiative to reduce the emission of greenhouse gases, will be accomplished with concrete, not some other structural material.