New milestone for mass timber construction in Québec

On July 10, the Régie du bâtiment du Québec (RBQ) released a new guide to support professionals and builders in designing encapsulated mass timber buildings. This guide marks a significant step forward: the maximum height for buildings designed in accordance with its conditions increases from 12 to 18 storeys—a substantial change.

But that’s not all. Beyond the number of storeys, the guide introduces another major shift regarding permitted building uses. While encapsulated mass timber construction was previously limited to residential and office buildings (with some exceptions for the first three storeys), it is now authorized for a much broader range of uses, including educational facilities.

Convinced of the environmental and economic benefits of wood construction in Québec, we systematically consider this option in nearly all our projects. We often propose alternative measures to meet the objectives of the Building Code in different ways.

For example, in the Jacques-Leber high school project, the design team opted for a hybrid structure. In another case, a mass timber structure was proposed as part of a real estate analysis for an eight-storey university pavilion.

Some facts about wood and circularity

Tree growth helps sequester CO₂—up to 1 tonne of CO₂ per cubic metre of dry wood [source]. Compared to steel or concrete, wood requires minimal processing, making it the structural material with the lowest carbon footprint (embodied carbon).

In embodied carbon analysis (life cycle assessment), the sequestered CO₂ is referred to as biogenic carbon. While many include it to reduce the carbon footprint of their buildings, its actual impact depends on how the wood is treated during demolition.

At the end of a building’s life, recovered wood elements can be reused, recycled, or used as biomass [source]. If landfilled or incinerated, they release methane or CO₂, respectively.

Wood structures have excellent longevity. Think of heritage buildings nearly 400 years old whose timber frames are still intact. Although life cycle assessments (LCAs) are typically calculated over a 60-year period, many buildings last much longer, keeping the sequestered CO₂ out of the atmosphere.

The expansion of possibilities for encapsulated mass timber construction marks a major milestone for Québec’s building sector. By allowing taller structures and a wider range of uses, this new guide paves the way for more sustainable, innovative projects that respond to the evolving needs of communities. Committed to climate action, we will continue to explore and promote wood-based solutions, convinced that they are a powerful lever for building a future that is responsible toward generations to come.