Ontario Construction News staff writer
Sidewalk Lab’s plan for a “smart city” on Toronto’s lakeshore includes 30-storey buildings made of timber – almost three times the height restriction that came into effect on Jan. 1.
Regulations were changed to allow timber construction with buildings up to 12-stories across Canada – double the previous limit of six.
Waterfront Toronto is reviewing the smart city proposal which identifies sustainability as a “key factor.” The committee decision on approval is expected March 31.
The 521-page report, Toronto Tomorrow: A new approach for inclusive growth, makes the case for all buildings to be built with mass timber – an emerging material that is as strong and fire-resistant as steel, easier to manufacture, and dramatically more sustainable.
Johathan King, architect at 77 Wade and mass timber/tallwood advisor to municipalities across Ontario says he supports construction with nail-laminated timber – a century-old construction method.
“Wood structures need to be commercially scalable to be viable,” King said. “While desirable to pursue an all-wood solution, it comes with challenges, and in the short term is unscalable beyond residential and some institutional typologies.”
King advises municipalities, developers and investors including the City of Toronto, Waterfront Toronto, Starlight Investments, The Rose Corporation and First Gulf.
The search for viability with 77 Wade Avenue in the Junction revealed that success is not seeing 100 per cent wood in a single building, but 30 per cent wood in 10 buildings, he added.
“Pursuing hybrid solutions in which we combine wood, steel, and concrete and play to each material’s best attributes allows us to achieve a tallwood mass timber structure that delivers on all needs and interests.”
While most mid- and high-rise buildings in cities are currently built out of steel or concrete, these materials come with downsides, the Sidewalk Labs report to the Toronto Waterfront Committee states.
Also, traditional construction is increasingly expensive — in Toronto, steel prices rose 16 percent in 2017 alone – and are difficult to produce, assemble, and transport, leading to lengthier, costlier, more disruptive construction projects.
“Cities like Toronto have started to explore a promising alternative: an emerging type of engineered wood called mass timber,” the report says. “Mass timber has been successfully tested in Toronto and is particularly well suited for factory-based construction, an approach in which building parts are created in an off-site facility and shipped to a site for faster assembly. For Quayside, Sidewalk Labs proposes to advance these efforts by supporting the launch of a factory in Ontario that would process mass timber building parts, reducing construction timelines by as much as 35 per cent and catalyzing a new industry around this sustainable material.”
Spruce trees from the boreal forests of Quebec and Ontario and Douglas fir trees from British Columbia would supply the wood for mass timber construction. The factory would process two mass timber products: cross-laminated timber structural panels (CLT) and glulam beams, each created by combining three to seven layers of wood, milled about 25 millimetres thick.
Operating in collaboration with Canadian foresters, sawmills, and other industry partners, a new Ontario-based factory would process building parts out of mass timber, catalyzing a new Canadian industry and the report says factory-based mass timber buildings “can be completed 35 percent faster than traditional concrete construction.”
The proposed $1.3 billion master plan to turn a portion of Toronto’s industrial waterfront into a smart, digitally connected city prototype that would use engineered wood as the primary building material.
If approved, the Google-backed subsidiary plans to invest up to $80 million in a mass-timber factory in Ontario.