Taking timber to brand new heights
Wood frames in midrise buildings could prove invaluable for growing GTA
Wood has played a big part in Toronto’s construction past, and now, thanks to advancements in technology and a rethink of how we build, it could be making a comeback.
Walk by any residential construction site in the Greater Toronto Area (GTA) and you’ll see single-family houses with wood frames. But what about new buildings taller than two storeys? Not likely. Most Torontonians have not seen a hometown wood-frame building over four storeys built in their lifetime.
But the construction landscape is changing.
“Toronto has got a lot of wood buildings that exceed four storeys in height from a hundred years ago,” says Steven Street, technical director with Wood WORKS! Ontario, an initiative of the Canadian Wood Council, the national association representing manufacturers of Canadian wood products used in construction.
“Our codes have taken some steps backwards, and now we’re going in a much more forward and positive way.”
Midrise buildings (mixed-use structures above four storeys) can now be made with wood frames, thanks to recent amendments to the Ontario Building Code (OBC).
The goal of these amendments? Allowing designers and builders to create innovative and affordable new buildings, while maintaining Ontario’s rigorous fire-safety standards.
Support for the code amendments, which took effect in January, came from the entire building and planning industry. “It was seen as a critical step forward in unlocking the potential midrise markets within the GTA,” says Street.
Opening corridors
Why the focus on midrise? Within the GTA there are hundreds of main streets that have been designated in regional and municipal plans for intensification. Although each corridor is different in terms of lot sizes, street width and existing uses, planners say there is one common denominator: they are most useful with mixed-use buildings.
“These sites could include obsolete properties, vacant lands, underutilized sites and sites with one-storey buildings that are easy to redevelop,” says former city of Toronto planner Paul Bedford, adjunct professor of urban and regional planning at the University of Toronto and Ryerson University.
“In all cases, the midrise building is the best opportunity to develop a range of housing choices for people of all ages.”
Spread of midrise
Midrise buildings have been made in jurisdictions around the world for years using systems ranging from pre-fabricated and pre-engineered to conventional wood frames, notably in Europe, where the wood-building phenomenon of cross laminated timber (CLT) first developed almost 20 years ago.
CLT is an engineered wood panel with layers of lumber oriented at right angles and glued to form panels that have exceptional strength, dimensional stability and rigidity. It’s now being utilized in taller wood buildings more and more, notably in the 10-storey Forte in Melbourne, Australia, the world’s tallest timber apartment building.
The pioneering province in Canada is British Columbia — which has been making residential-only midrise buildings with wood frames since 2009 — where there are more than 200 projects currently underway. Quebec and Alberta have followed in making changes to their codes, as well.
In Ontario, the code has gone significantly further. Beyond residential, the province allows wood to frame mixed-use buildings, with business and personal services, restaurants, bars, art galleries and mercantile on the first two storeys.
“This is the mixed use occupancy that makes this code amendment so progressive,” says Street.
Currently in Ontario — where in March the first permit was issued in the city of Hamilton for the 200-unit Sandman Hotel — an estimated dozen wood-frame midrise projects have begun the process of planning, zoning and permit acquisition.
What took so long to green-light taller wood-framed buildings in this province? Fire safety was a key consideration. In short: wood burns. Thus, concrete and steel — the more expensive options — have been the go-to materials for midrise development for years.
The OBC’s new safety amendments make growing with wood possible. The code now includes rigorous requirements around the use of fireblocking material and sprinklers. And, for the first time, fire department access routes are based on the height of a building.
Wood-frame midrise buildings check a lot of boxes for planners. All GTHA regional and municipal plans, including the provincial government’s Growth Plan for the Greater Golden Horseshoe, encourage development in built-up areas instead of allowing continuous sprawl outward.
And now that the safety-concern hurdle has been cleared, wood’s affordability is also a bonus.
“Not all sites can be built out economically using concrete and steel,” says David Sunday, group leader in the municipal, land use and development law group at Sorbara, Schumacher, McCann LLP.
“So allowing a wood-frame option for midrise buildings should increase the number of viable development sites and ultimately add to the mix of new housing options.”
Why use wood?
How we construct buildings greatly impacts the environment. In Canada, home to 10 per cent of the world’s forests, wood can (literally) be considered the natural choice as a primary building material. It’s renewable, less expensive to use, and in great supply. And, unlike steel and concrete, wood captures and stores carbon for the lifecycle of the building product.
Still there are concerns about its use in the construction of larger buildings, which typically take longer to construct. No one wants to see vast amounts of timber sitting on sites being compromised by weather or, worse, presenting a fire hazard.
One solution that reduces con- struction time is a technique known as panelization: Walls and floors are built off-site, and just-in-time delivery reduces the volume of wood supply that sits on site, and how long it sits there.
And the efficiencies of assembling pre-made panels mean the building can be erected much faster — at significant savings for the developer.
Robert Kok, director of research and development for H+ME Technology, which has been designing and building two-storey panelized homes for10 years, believes their factory-built process dovetails with the industry’s heightened use of wood.
“With the Building Information Modeling (BIM) that we do, you can really fix a lot of things in the 3-D environment before you actually build them,” says Kok.
“If you’re making these large buildings and you don’t have the things worked out ahead of time you could run into a lot of issues, a lot of delays that would affect the cost of building.”
“In all cases, the midrise building is the best opportunity to develop a range of housing choices for people of all ages.”
PAUL BEDFORD FORMER CITY OF TORONTO PLANNER
Building for the future
For Street, the future of building with wood looks promising if municipalities and the building departments work collaboratively to better understand new wood technologies and code changes. And he says the learning curve is being actively scaled. “The bubble of projects that are now looking at a wood solution is vast — it’s set to burst in 2016.”
The proof of wood-framed buildings’ enduring strength is their very existence, says Street.
“There’s a reason the older midrise buildings in Toronto are still there. And they would still be everywhere, but the land that they sat on became incredibly valuable to put much higher tower blocks.”
Bedford believes growing upward with wood rather than outward with more expensive, less sustainable materials is the best use for the GTA — particularly with 100,000 new residents arriving each year.
“Unleashing the untapped potential of urban corridors is an extraordinary opportunity,” he says, “to build the next generation of buildings and create the great urban streets of the future.”