INSPIRATIONAL
Decarbonizing with Professionals
AMANDINE CADRO
BUILDING CARBON NEUTRALITY ANALYST (NEW AND EXISTING BUILDINGS), STUDIO CARBONE
Design, layout, transformation, reuse, and flexibility of use: Every decision impacts a project’s carbon footprint and its ability to sustainably integrate into its environment. To understand these developments, we spoke with architects who shared their real-world experiences and innovative solutions. Their stories tell us that decarbonization is not limited to piecemeal solutions, but that it can transform the way we design, build, and live. From low-tech innovations, deliberate reuse and new methods in land use, these projects demonstrate that architecture can be creative, responsible and resilient.
From the Ground Up: A Holistic Approach to Decarbonization
Emmanuel Combarel, an architect known for his innovative projects and environmental awareness, has spent several years exploring new ways to reduce the carbon footprint of buildings through his firm, Emmanuel Combarel Dominique Marrec Architectes, while anticipating French regulatory measures.
His work began with the optimization of embodied carbon by focusing primarily on the structure and envelope, which are the main sources of emissions. To achieve this, he made extensive use of biobased materials and wood deemed “favourable” when reducing the carbon footprint of the structure, insulation, and exterior cladding. In his view, however, these do not represent “universal strategies” that can be applied indiscriminately to every context, since the materials involved “present a number of complexities.” According to him, environmental performance is based on a logic of “adaptation” and “singularity.”
Backed by his experience on the structure and envelope, he noted that, as components become more efficient, the relative carbon weight of the building’s mechanical and electrical systems tends to increase significantly. Thus, the electromechanical system in the firm’s most recent projects accounts for up to “40% of the embodied carbon.” He therefore argues for the necessity “to think collectively” about these issues. “Low-tech” strategies intended to bypass systems provide a “starting point” for discussions, but the approach “quickly reveals its limitations,” despite its ability to “precisely identify the relevant factors” when seeking user comfort. He is currently exploring an innovative approach for one project in particular: Replacing “centralized heat generation with distributed generation” by installing micro heat pumps on the building’s facade. This solution helps prevent the use of “high-carbon networks and ducts” while “limiting ceiling height,” thereby reducing the amount of materials needed for staircases and facades.
When considering the unique characteristics of each site, Emmanuel views the relationship with the soil as a key factor when reducing embodied carbon. Limiting the carbon footprint also means “keeping earthwork and infrastructure to an absolute minimum.” The idea is to “work cleverly with the site’s topography” and make use of what it provides to avoid digging. For the Wood project in Grenoble, the decision to “forgo underground parking” in favour of ground-level parking spaces using the site’s natural slope significantly reduced the need for concrete and allows the building to blend more harmoniously with its surroundings.
Beyond design choices and the use of new materials, Emmanuel states that decarbonization also depends on the circular economy. In his view, “the first step toward reuse is to avoid demolition.” This conviction now forms a significant part of his work. He is currently leading a renovation project aimed at converting office space into housing, with “minimal intervention and maximum preservation of the existing structure.”
The goal is clear: “We’re reusing everything: The elevators, the stairwells, the structure.” With this in mind, the project team even explored the possibility of “retaining the office facade,” but the analysis ultimately revealed that it would be “difficult to reuse for reasons involving thermal performance, privacy, and cleaning.”
The architect also prefers to reuse and incorporate materials that have already served a previous purpose: “Repurposing sports flooring, vintage faucets and partition rails to create drop ceilings or mosaics made from broken mirrors” for a more understated design while making the most of the existing resources. His stance is clear: “To call attention to things that have been repurposed” and to embrace the diversity of sources associated with reuse. Rather than trying to hide the differences, he prefers to make them his signature, using architecture to tell a story of the materials and the journey they have taken.
Finally, Emmanuel places the building’s use at the heart of decarbonization: A building is only low carbon if its occupants adopt energy-efficient practices. Thus, performance is not limited to materials or systems, but to the way in which the building promotes energy-efficient behaviour. He therefore focuses on projects that promote active circulation, featuring “open and inviting staircases with natural lighting [that] strongly encourage their use” over the elevators.
In his view, decarbonization relies on a combination of design choices, reuse, site-specific adaptation, and building usage. It is a comprehensive, integrated and context-specific approach that transforms the way we design, build, and live.
Emmanuel Combarel EMMANUEL COMBAREL DOMINIQUE MARREC ARCHITECTES
From the Material to the City: Decarbonization as a Cultural Shift
While decarbonization often begins with materials, Hugo Gagnon, Partner Architect and founder of the sustainable strategies department at NEUF Architect(e)s, states that, above all, it demands a cultural shift rooted in experimentation. Beyond the physical aspects, other factors become critical, including the transformation of existing buildings and strategic development choices. To guide these transformations, two elements become crucial: Accurate measurements and a solid argument that can mobilize those involved.
Hugo believes that, above all, decarbonizing the building sector requires the “right material in the right place.” In a Quebec market still dominated by concrete, he seeks to reintroduce solid wood as an “environmentally friendly” alternative. “Building with what nature provides (earth, stone, clay, wood, bamboo, straw) continues to inspire his approach to sustainable design. With this in mind, he calls upon developers to use an “action research” approach, with support from “federal government grants,” in his efforts to test and validate constructive and innovative solutions.
The ANDAS project, a six-storey multi-unit residential building made of solid wood, exemplifies an approach that “brings together all the necessary expertise” to address the technical challenges associated with this construction system. Comprehensive studies and effective coordination among the various stakeholders have led to the development of innovative and repeatable structural solutions, like the “anchoring of prefabricated CLT balconies with thermal breaks,” or “acoustic floors that include a dry topping, allowing for an exposed structural ceiling.” Wood also offers benefits that involve decarbonization: Prefabrication led to a “faster, quieter, and more precise construction process” during which the teams experienced a “sense of joy”; “the biophilic qualities of wood,” evident even during the construction phase, go on to create a tangible sense of well-being and comfort for users. With a “43% reduction in embodied carbon compared to a concrete structure,” the ANDAS project demonstrates that a solid wood building can be technically robust and economically sustainable, with a “high repeatability index”, a key factor when seeking lasting change within the sector.
For Hugo, however, decarbonization is not limited to materials: The “transformation of existing buildings” is becoming a “key focus,” one he intends to develop further. He states that, while the multi-unit housing market offers enormous potential, it requires “real expertise” from every stakeholder involved due to the “significant level of complexity.”.The technical challenges that must be addressed, including “seismic requirements, acoustics, humidity and phasing [...] can lead to such high transformation costs that developers become discouraged.” At the same time, he wants to encourage the reuse of materials. While he considers it a “highly complex” approach, the roll-out of “material recovery platforms like Réco” should facilitate the integration and growth of reuse in the sector.
Hugo turns to his own work on master plans when discussing transformations in the built environment, noting that “urban sprawl is a major source of indirect carbon emissions,” a topic that continues to receive little attention. He mourns the ongoing inability to accurately calculate the carbon footprint generated by urban sprawl (new infrastructures, longer transportation networks, increased circulation, etc.) despite the fact that such factors make up a significant portion of the overall environmental impact. In his view, we must reassess smart density in light of urban development trends to better identify decarbonization strategies that are truly effective.
Ultimately, Hugo draws on a radical, regenerative design approach when guiding his thoughts on the master plans. The topic is of key interest within the Committee on Regenerative Environments (CORE) at the Royal Architectural Institute of Canada (RAIC). The committee’s mission is to promote regenerative design while supporting the profession in its effort to create built environments that can regenerate ecosystems and improve quality of life while addressing social and climate-related challenges. Inspired by principles found in nature, the approach aims to guide projects like master plans toward long-term, positive outcomes by promoting biodiversity and ecosystem regeneration. Hugo explains that, in his view, no sectoral transformation will be possible without “reliable tools and convincing figures.” When dealing with cities and developers, he notes that progress can only be made with a “well-supported case” that can demonstrate the impact of urban sprawl and objectively assess development choices while quantifying the benefits of a given strategy. Without data, discussions remain deadlocked between “different schools of thought.”
For Hugo, decarbonization therefore represents a comprehensive approach: It combines materials, reuse, building transformation, and urban planning. It calls for a cultural shift and an action-research approach, showing that sustainable construction requires new ideas for both projects and industry practices alike.
A reduction of
less embodied carbon compared to a concrete structure for the ANDAS project.
