Trend Watch: Mass Timber Construction

Brock Commons Mass timber construction
After becoming the first province to allow mass timber towers up to 12 storeys in 2019, BC is now pledging to support the forest industry by encouraging the use of mass timber building products in its capital construction programs. This includes the future development of St. Paul’s Hospital and the Royal BC Museum. Last month, BC Premier John Horgan appointed Ravi Kahlon, Parliamentary Secretary for Forests, Lands, Natural Resource Operations and Rural Development to lead the expansion of mass timber in BC buildings.

"As our economy bounces back from the COVID-19 crisis, we want to do everything we can to support forest workers. By focusing on mass timber, we have an opportunity to transition the forestry sector to high-value over high-volume production. This will mean opportunities for local workers, strong partnerships with First Nations and greater economic opportunity while making a significant contribution to advancing CleanBC."

John Horgan, BC Premier, https://news.gov.bc.ca/releases/2020PREM0033-001076

Benefits Of Mass Timber

Premier Horgan claims that the use of mass timber is cost-effective, sustainable, and generates jobs for BC’s forest communities and workers. The increased demand from both local and global markets will help to revitalize the industry, increasing production in forest communities and creating jobs.

The use of mass timber will also offer a cost-effective solution for the construction industry. Because mass timber products are custom-made off site and assembled on-site, construction time can be reduced by up to 25%. Using this method of building, constructions sites are also cleaner and safer due to fewer hot tools and machinery.

Tall wood buildings are considered sustainable for multiple reasons.

  1. Mass timber has a lower carbon footprint than concrete or steel as it is made of a natural resource. Additionally, as it is only one-fifth the weight, mass timber panels have reduced transportation emissions and decreased congestion to and around construction sites.
  2. Mass timber generates less waste since panels are manufactured custom for each application. Scraps may be re-used by the manufacturer.
  3. Mass timber is sourced from sustainably managed forests, of which Canada is a leader.  One BC company, Structure Craft, is even engineering mass timber products from beetle-kill wood which would otherwise be waste, or worse, kindle for catastrophic wild fires.
One other benefit, specifically important to British Columbians, is that buildings using mass timber are more earthquake resistant. Structurally, mass timber weighs less than concrete and steel, and is more pliable, therefore the impact on the building is reduced.

The provincial government in Ontario is also in support of mass timber and tall wood structures, having prepared a comprehensive technical resource for engineers, architects, designers, fire service, and building officials.  This guide focused on two important topics: architectural design and fire safety.

Building Codes + Safety

In Spring of 2019, BC updated its provincial Building Code to allow the construction of wood buildings up to 12 storeys tall, doubling the previous maximum height of six storeys.  At the same time, 13 BC communities signed up as early adopters of mass timber technologies. These communities represented 35% of the province’s housing starts in 2018. To be eligible, each community was required to have the following:

  • Support from their city council and the planning, building and fire departments;
  • Level 3 certified building officials; and
  • Land use bylaws for buildings higher than six storeys.
The National Building Code 2020 will soon see the same revisions and it’s believed that UBC’s Brock Commons helped pave the way for taller wood buildings across the country and around the world.

Until now, the biggest hindrance to the use of mass timber in construction was building codes, which deemed tall wooden structures a fire hazard. However, thanks to new mass timber building technologies and techniques, tall wood structures are as safe or safer than traditional steel or concrete structures.

Cross Laminated Timber (CLT), for example, holds a high level of fire resistance thanks to its cross-sectional thickness and air-tight construction, reducing a fire’s ability to spread. If a fire does ignite, the burn is slow and predictable, meeting fire resistance ratings. Fire resistance can and should be enhanced with fire-resistant lining to the flooring or walls.

For Brock Commons, Vancouver Fire and Rescue Services (VFRS) was involved in the project early on, overseeing the initial approval process and executing the fire and safety plan. The project required a site-specific regulation that included fire and seismic standards exceeding those for steel and concrete buildings. Check out VFRS video covering the specifics of Brock Commons’ fire safety measures, which included compartmentalized spaced to prevent a total loss, which is common with traditional wood structures.

Cause For Concern

The debate about safety is not a closed case, however. While building codes are changing, insurers and insurance brokers are still uncertain of the risks posed by tall wooden structures using mass timber. Canada’s condominium market is already under scrutiny in the face of a hard insurance market. New constructions using mass timber may see additional premium hikes due to existing concerns about wood structures.

A recent study conducted in the US by Boston College found builder’s risk insurance quotes for concrete buildings to be 22-72% less than quotes for wood frame buildings, and quotes for commercial property coverage was 14-65% less than wooden frame structures. It should be noted that this study was commissioned by the National Ready Mixed Concrete Association (NRMCA) and did not differentiate between dimensioned lumber and engineered lumber which has a higher fire resistance rating.

On the other hand, Vancouver based Globe Advisors conducted a similar study that suggested there were other factors for determining higher insurance costs in wooden structures than fire peril alone. This study indicated that wood buildings are less durable, cost more to maintain, and have shorter life spans, all leading to difficulty in obtaining insurance for wood frame structures.

In addition, wood structures can have major moisture management issues leading to mold. Prevalent in BC and Central Canada, mold not only creates structural issues for the building, but it can also pose significant health risks to occupants, including coughing, nasal congestion, eye, skin, and throat irritation, and can sometimes be fatal.

The study emphasizes the importance of minimizing factors that could lead to mold and water damage in wood structures and claims that much of the annual losses from lumber decay is preventable. There is no one-size-fits-all when it comes to wood structure construction across Canada – what works in Prairie provinces, may not work in the coastal region.

According to the Insurance Bureau in Canada, water damage costs insurers, on average as of 2016, more than $1.7 billion annually. This includes water damage caused by flooding, sewer back ups, and burst pipes which can all lead to expensive repair and clean up bills for insurers. Wood structures are more susceptible to excessive water damage caused by any of these man-made or natural disasters.

Time will tell if insurers will begin to favour the new technologies of mass timber over steel or concrete. Mass timber technologies will need to address all of these additional and important concerns: durability, fire safety, and moisture. For now, BC is committed to growing its mass timber industry and will continue to innovate and find long term, sustainable solutions for the construction industry.

Notable Mass Timber Projects

Check out this interactive map of mass timber projects being developed around the world.

The experts at Normac keep their finger to the pulse of the construction industry and are familiar with all construction types, materials, and techniques that might impact replacement cost. For a complimentary, no-obligation quote, click here.