Innovation - Spring 2024

FEATURE

Making materials safer Though Wiesner says that these supplementary measures are definitely “credible fire strategies,” his work puts a focus on making the material inherently safer. Toward that goal, Wiesner and colleagues conducted a 2021 study analyzing factors that improved fire resistance in mass timber. “Increasing thickness can help make sure that you maintain structural capacity,” he said. As their paper explains, more layers of laminated timber can compensate for individual weaknesses and defects in a sheet of wood. Adhesives that have a higher softening temperature and are less affected by moisture can also improve the durability of mass timber. But though these factors can help, non-combustible cladding is the first line of defense for most mass timber structures today. “The key there is to limit the amount of timber we have exposed,” he said. Unfortunately, Wiesner’s personal experience with his testing has shown first-hand that real-life construction doesn’t always match up with the design intent. ‘I’ve done fire tests in the past where we got certified professionals. We told them all, ‘we want this to be as close to reality as possible for the encapsulation,’ and got them to put in the encapsulation like you put on a real building,” he said. “Fifteen minutes into the test, the whole encapsulation system collapsed, exposing the timber; and then that kept burning.” Even though quality assurance in Canada is comparatively rigorous, mistakes during implementation can

Mass Timber, By the Numbers

BC leads the country in mass timber construction

100 150 200 250 300 350 400

352

221

148

66

0 50

22

BC Quebec Ontario Alberta

Other Provinces

BC has the highest density of mass timber across all Canadian provinces. But every province – and territory – in Canada has at least one mass timber building. Data: National Wood Buildings Council The US and Canada are champions of mass timber construction. Construction in the US, in particular, has skyrocketed in the past decade. Data: National Wood Buildings Council, Woodworks Innovation Network

Mass timber still makes up less than 1% of new buildings in North America

Mass timber 1%

Masonry 6%

Other 3%

Lightwood frame 9%

Steel 34%

Concrete 47%

Data: RBC

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Spring 2024

Innovation