Life cycle assessment (LCA) is playing an increasingly important role in building design. By quantifying the greenhouse gas emissions associated with construction materials, it enables design teams to compare different approaches and make informed decisions based on measurable data rather than assumptions.

At STGM, we are progressively integrating this methodology into our practice. Following an initial assessment conducted for the Waterloo project, we applied the same approach to the Pointe-aux-Outardes Nature Park Pavilion, a 527 m² visitor and interpretation centre designed to blend harmoniously with its natural surroundings.

An analysis based on data tailored to the Québec context

The study was carried out using Gestimat, a tool developed by Cecobois to estimate the greenhouse gas emissions associated with construction materials. The assessment covers modules A1 to A3, which account for emissions related to material production, using a database specifically adapted to the Québec market.

The analysis focused on the structural systems and the main building envelope components, while interior finishes, mechanical systems and site work were excluded from the study scope.

This work was completed in collaboration with CIMA+ as part of our participation in the CBCB – Low Carbon Buildings initiative. It also contributes to Cecobois' ongoing efforts to expand the Gestimat database and document the average carbon footprint of various building types.

A building already designed for a low carbon footprint

The project incorporated several design strategies recognized for reducing embodied carbon in construction materials:

Steel pile foundations, significantly reducing the use of concrete;

A lightweight wood-frame structure;

Cedar exterior cladding;

A simple building form that optimizes material efficiency.

The results confirm the effectiveness of these design choices. The total embodied carbon of the materials included in the assessment amounts to 103,221 kg CO₂e, or 196 kg CO₂e/m², a particularly low result for this type of building.

The analysis also identified 342,029 kg CO₂e of biogenic carbon stored in the wood products used in the project. This value should, however, be interpreted with caution, as it depends on assumptions regarding the materials' end-of-life scenario.

Using LCA to compare design scenarios

The value of a life cycle assessment extends beyond measuring the environmental impact of the completed design. It also provides a powerful decision-making tool by allowing different design options to be evaluated.

For this project, an alternative scenario was tested by replacing conventional insulation materials—fiberglass and mineral wool—with bio-based insulation such as cellulose and hemp.

A commitment to continuous improvement

At STGM, life cycle assessment is not simply a verification exercise carried out after design is complete. It is a decision-support tool that informs the design process, helps compare alternatives and contributes to the continuous improvement of our projects.

Each assessment also contributes to advancing collective knowledge across the industry. Through our participation in the work of Cecobois and the CBCB – Low Carbon Buildings initiative, we aim to help develop reliable benchmarks that will support the design of increasingly low-carbon buildings throughout Québec and beyond.