BC government to allow mass timber buildings up to 18 storeys

BC government increases maximum height of mass timber buildings to 18 storeys

2016 construction process for UBC's Tall Woodhouse student residence. (UBC)

The provincial government is set to amend the BC Building Code to enable the expanded use of mass timber construction in a very tall way.

Currently, the maximum height of a mass timber building under provincial regulations is 12 storeys, but the forthcoming changes would increase this to 18 storeys — an increase of 50%.

This would apply to not just buildings with residential uses but also office uses.

“These proposed mass timber building code changes align with our recent work to deliver more homes near transit hubs by allowing taller buildings and more sustainable housing options near transit,” said Ravi Kahlon, BC Minister of Housing, in a statement.

“These changes will also help reduce carbon pollution, support the forestry sector, create jobs, build more homes and lead to more vibrant, healthier communities.”

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Also, the changes will allow more exposed mass timber or fewer layers of encapsulation in buildings, depending on the building’s height, and more building types using mass timber construction, such as schools, shopping centres, and industrial facilities.

After it is given final approval, the code changes are expected to be formalized in Spring 2024.

2016 construction process for UBC’s Tall Woodhouse student residence. (UBC)

2016 construction process for UBC’s Tall Woodhouse student residence. (UBC)

The maximum height regulations for wood buildings were last changed in 2019, when the provincial government increased the maximum height from six storeys to 12 storeys. This came two years after the completion of the prototype at the University of British Columbia’s (UBC) Point Grey campus — the 174 ft tall, 18-storey Tallwood House student residence at UBC Brock Commons, which was briefly the world’s tallest mass timber building.

In 2020, the City of Vancouver also amended its separate building code to enable wood buildings up to 12 storeys.

Such taller wood buildings are not typically completely made out of wood, however. Usually, the structural foundations and base level are made of concrete, and a concrete core encloses the elevator shaft and fire exit stairwell. Such hybrid designs using concrete for key structural components are also a seismic consideration.

Researchers and proponents of tall wood buildings say such structures do not possess a greater fire hazard to the extent that wood can be deemed a safer material than steel. Charred wooden surfaces protect the structural wood underneath, whereas steel structures are weakest at the points where they support a post. These mass timber materials are pre-fabricated in a factory and then transported to the construction site for assembly.

Tall wood construction not only reduces emissions compared to conventional construction methods using more concrete and steel materials, including fewer construction truck trips, but it also provides shortened construction timelines.

Some of the tallest mass timber projects currently under construction in BC include a 10-storey office building at 2105 Keith Road in Vancouver, a 12-storey student residence at the BCIT Burnaby campus, and a 17-storey social housing and LGBTQ community centre at 1190 Burrard Street in Vancouver.

The tallest mass timber proposal — now in the rezoning application stage — is a 25-storey secured rental housing tower for a future phase of the Main Alley tech campus at 2105 Main Street in Vancouver.

In 2019, Delta Land Development informally floated the idea of a mixed-use tower reaching up to 40 storeys with mass timber construction at 1745 West 8th Avenue in Vancouver.

2016 construction process for UBC’s Tall Woodhouse student residence. (UBC)

Artistic rendering of the future office building at 2105 Keith Drive, Vancouver. (Dialog Architecture)

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