n:w explains
February 6, 2024

Essential insights for Insurers on mass timber buildings

Mass timber construction for residential and commercial buildings is far from a new technology but it may still be unfamiliar to some in the insurance industry.

And that lack of knowledge can result in roadblocks — challenges getting both occupancy and builder’s risk insurance. For building owners and developers aiming to create structures that make the most of mass timber’s advantages in speed of construction, low carbon impact, comfort and beauty, insurance premiums can be five to seven times higher compared to traditional steel or concrete buildings.


wood innovation and design centre photo paul alberts

Wood Innovation and Design Centre construction | Photo: Paul Alberts

The key issues are risk and data. Insurance of any sort is rooted in assessing risk, and the insurance industry uses data from past experiences. As most past data is based on steel, concrete or light wood frame buildings, it is difficult to assign risk to a policy for a mass timber building. This impacts the insurer’s decision whether to provide coverage and how much to charge. While steel and concrete construction is still dominant, Canada has just over 800 completed mass timber buildings and the U.S. just over 2,000, with approximately 200 and 600 respectively erected in the last five years. For more details about North America’s portfolio of mass timber buildings visit the Interactive Map of Mass Timber in Canada and Mapping Mass Timber in the US. 

Both building owners/developers and insurers have roles to play in building successful long-term relationships as well as properly insuring mass timber buildings. 

Here are some common misconceptions about mass timber that building owners/developers can help debunk for insurers.

Mass timber construction is not the same as building with dimensional lumber  

The Canadian Wood Council notes that while building codes in Canada and the U.S. are evolving to address newer types of construction, builder’s risk insurance rates have not advanced along with construction and codes. 

According to the Insuring Timber Initiative, “Historical risk assessment data has largely focused on light wood frame structures such as homes; but there are significant differences that exist for larger buildings that use mass timber as structural elements.” 

Indeed, Annabelle Hamilton, MSc and technical manager, planning and development with WoodWorks BC, says: “It’s important to decouple what mass timber means because it doesn’t perform exactly as a light-frame building does. There are other factors that need to be considered.” She also notes that while mass timber and light wood frame buildings perform differently, they currently fall into the same insurance classification. 

Mass timber is proving to be fire safe

Fire is, predictably, a key concern with mass timber construction but there is a substantial and growing body of international evidence of its fire-resistant properties. “There is a misconception that [mass] timber is more vulnerable to fire,” according to the Insuring Timber report. “In fact, numerous tests have been done that prove mass timber can achieve 2+ hour fire resistance ratings and meet or exceed the standards of  building codes.” 

In 2022, for example, the National Research Council of Canada conducted a series of five tests on a mass timber structure in Ottawa, Ont. in front of more than 150 experts from across Canada, including fire officials, building regulators and insurance industry representatives. In the first, a room with exposed mass timber ceiling, beams and columns, and a typical office layout, was set ablaze.  

Once the room’s contents were consumed, however, the fire quickly died down and burned out, according to the report, which noted: “The fire on the burning structural elements largely self-extinguished within the first hour” — and that was without any water or fire-suppression efforts. 

Tim Buhler, director, programs and operations, with Canadian Wood Council, notes, “It’s important to differentiate the fact that these are much larger, engineered wood members and they’re self-protecting, in a way, through charring that’s limited to the surface.” 

Mass Timber Demonstration Fire Test Program | Photo courtesy of Canadian Wood Council

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Protecting engineered wood from water

Moisture or water damage is another common concern of those unfamiliar with mass timber construction. This can include both exposure to the elements during construction and problems during occupancy such as burst pipes. 

Buhler says when it comes to floors, where water might collect, “There’s also misunderstanding about what mass timber assembly looks like… Nobody talks about the waterproofing membrane, the acoustical topping, the vibration mitigation, the concrete or other materials that are used and sit on top of it. So, if there’s sprinkler activation, the water’s not directly on wood.” 

Mass timber builders can make mitigations part of their design, including the use of floor drains as well as misting sprinklers that spread a third of the water of conventional sprinkler systems but are just as effective in fire suppression.  

But limiting exposure to moisture starts in the planning stage and is critical during construction. The speed of construction/assembly using prefabricated mass timber panels and other elements aids in reducing exposure during the construction process. The quicker a building goes together, the sooner the roof and walls go up, providing protection from the elements.  

Repairing and replacing when mass timber is damaged

If a mass timber product does experience damage due to fire or water, what’s next? 

Hamilton acknowledges that there are fewer data points available for repairs of mass timber buildings than there are for concrete and steel or even light wood framed structures, while Buhler notes that, in case of fire, the thin charred layer on, for instance, a mass timber panel or beam can be repaired in place. 

In a section of the Insuring Timber report titled “Debunking Timber Myths,” it’s stated that “Options vary depending on the severity of the damage but can be as simple as sanding damaged areas or as complex as replacing large sections.” 

Canadian Wood Council’s publication A Guideline for Insuring Timber in Canada notes that repair and rehabilitation of mass timber buildings is a concern for the insurance industry not because of concerns about susceptibility to damage, but because of the unknowns regarding repair costs. “The insurance industry has thousands of historical claims for light wood frame houses and other small buildings, but little data for larger wood and mass timber buildings.” 

Protecting mass timber under construction

The insurance industry also needs information and assurance about mass timber projects while they’re under construction, when builder’s risk or course of construction insurance is needed. That’s where builders can take simple, inexpensive and effective steps to ensure safety on site, says Buhler, noting the more information you are able to provide your insurance broker on how the site will be protected for water or fire damage while under construction, the lower the perceived risk and likelihood of an incident occurring. 

He says in addition to having basic fire protections and water-control and -management plans in place, those steps include having onsite security, especially overnight, as well as secure hoarding and regular waste disposal to remove potential fire fuel. Those are similar to protections required in steel and concrete construction. But mass timber carries advantages, too: assembly is quicker, meaning less time for materials sitting onsite and fewer crew members required for installation, reducing risk of injury onsite. 

Buhler notes these small investments in site security can pay big dividends in reducing risk of loss and getting insurance companies on board. 

For support in sourcing insurance for your next mass timber project, speak to a technical team member at WoodWorks.