The use of mass timber in construction is accelerating, with major projects that use this building material appearing across Canada. As mass timber has become more common in residential, commercial and institutional developments, it has prompted questions from insurers about its resilience over time and in the face of water and fire.
What is mass timber?
Mass timber refers to a group of engineered wood products made by layering, bonding and compressing pieces of wood to create strong structural components such as large panels, beams and columns. These products can replace traditional building materials, such as concrete and steel, in many types of construction.
There are several reasons why mass timber use is growing. Specifically, the products:
Are flexible and lightweight. Because mass timber weighs less and is more flexible than concrete or steel, it has the potential to perform well under strong winds or seismic activity.
Are fire-resilient by design. When exposed to fire, mass timber forms a protective “char layer” on the surface. This helps the core retain its structural integrity, allowing it to meet fire-resistance standards.
Have a lower carbon footprint than traditional construction materials like concrete and steel. Wood stores carbon throughout its life cycle. Using mass timber can help reduce the greenhouse gas emissions associated with construction – especially when mass timber replaces carbon-intensive materials.
Support modular and prefabricated buildings. Many mass timber components - such as panels, columns, and beams - are manufactured at a factory and assembled on-site. This approach can shorten construction times and reduce costs.
How mass timber is being used in Canada
The adoption of mass timber is expanding across the country. Natural Resources Canada maintains a public dashboard identifying more than 850 mass timber projects nationwide, along with nearly 20 manufacturing facilities.
British Columbia leads in both the number of mass timber buildings being constructed and production capacity, followed by Ontario, Quebec and Alberta. Most of these buildings are low- to mid-rise, although taller projects are becoming more common.
Building codes are evolving to support this growth. In 2020, the National Building Code of Canada approved encapsulated mass timber construction for up to 12 storeys. More recently, British Columbia, Ontario and Quebec have introduced amendments that allow encapsulated mass timber projects up to 18 storeys.
Understanding the challenge for insurers
Compared with traditional steel-and-concrete buildings, there is limited long-term performance data for mass timber buildings. More information is required on:
• How these structures perform over several decades;
• The potential impacts from moisture or water-related incidents; and
• The typical repair and replacement costs following fire or other damage.
Because the performance data set is still maturing, some insurers may approach mass timber cautiously until more long-term information becomes available. Reinsurance capacity for mass timber, particularly mid to high rise projects, have also been constrained. This directly affects the terms and availability of primary coverage. Insurance brokers, such as AON, have noted that the limited long-term loss history makes it more difficult for insurers to model risk with the same confidence they apply to more established materials.
However, as more mass timber projects are completed, occupied and observed over time, the insurance industry’s understanding of their long‑term performance will grow. This expanding body of data will help support informed assessments across the insurance sector and contribute to greater confidence in how these buildings perform throughout their life cycle.
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