The Evoke housing project in Kitchener is using prefabricated wood panels in its walls and floors. Evoke/Supplied

Three years ago, the Ontario Building Code required that any developer taking on a mid-rise wood-frame building had to construct stairwells out of non-combustible material.

That was expensive. It made construction challenging, and, according to the Canadian Wood Council, resulted in a lower adoption of wood-frame building.

Since that requirement was removed in 2023, allowing full buildings to be constructed with wood, interest in mid-rise wood-frame building has increased considerably, especially for residential builds, said Hailey Quiquero, senior manager with the WoodWorks Ontario program, an initiative of the Canadian Wood Council.

“Now, in our market, we’re sitting at around 50 per cent of five- and six-storey buildings being built out of wood construction, so a great jump,” Quiquero said during a June 4 online webinar.

“We've still got a long way to go. In British Columbia, I think it's greater than 80 per cent of this market is built out of wood, so lots of room and opportunity to keep educating our market here about this really cost-effective method of building housing, especially.”

Under the code, wood-frame building is permitted for five- and six-storey buildings that fall into Group C major occupancy buildings — apartments, hotels, motels, student residencies and dormitories — and Group D major occupancy buildings, which are classified as business and personal services, such as banks, offices, or medical or dental offices.

But currently in Ontario, mid-rise wood-frame building is largely being used in residential projects, Quiquero said.

“This type of construction is one of the most cost-effective ways of building housing in our market right now,” she said.

“It's very fast and lightweight, especially if you make use of panelization, and due to the fact that you can now do combustible stair shafts and exit shafts, this really just makes it extremely cost-effective and easy to build.”

Panelization, which involves constructing wood panels off site to use for walls or floors, allows developers to do parallel construction, Quiquero noted, so panels can be built in a factory at the same time as work is done on site.

This approach results in higher quality buildings, fewer reworks, less waste, a shorter build time, lower neighbourhood disruption, and safer labour conditions, she said.

Different types of composite structural lumber are used for different purposes and each has its benefits, she added.

Laminated veneer lumber is made up of veneers of wood a few millimetres thick that are shaved off a log and glued and pressed together in the same direction, Quiquero said.

With laminated strand timber, wood shavings are cut into strands a few inches wide, glued and pressed together into a dense mass of wood fibre.

Parallel strand timber, which has the highest strength rating, uses the same process as laminated strand timber, but the strands are oriented parallel to each other.

In using structural composite lumber, “you’re not limited to the length of the tree, so you can get unlimited length in production of these studs or beams, whatever you’re using them for,” Quiquero said.

“It’s a more effective use of the wood fibre in the trees as well, which is nice.”

Structural composite lumber also has a lower moisture content than standard lumber, which makes them more dimensionally stable, and it has increased fire resistance, she added.

Dimensional stability, and the fact that it tends to be more square or rectangle, makes structural composite lumber a popular choice in factories, because it’s easier to handle, especially if the factory uses automation, Quiquero said.

“Of course, they do come with a bit of a cost premium to lumber, so it’s worth exploring whether or not it’s worth investing in those engineered products in certain applications inside these buildings,” she said.
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Source: elliotlaketoday.com