• Guest Blog
  • Dec 1, 2023

Circular strategies can help reduce carbon emissions from office buildings

Carbon emissions are typically associated with cars and heavy industry. But the buildings we live and work in also contribute a significant portion of greenhouse gases (GHG)  to the atmosphere. In fact, a staggering 30% of Canada’s total GHG emissions result from the operation of buildings, as well as the manufacturing, transportation, installation, maintenance, and disposal of building materials.

There are more than 482,000 commercial and public buildings in Canada1. Office buildings generate around 12% of Canada’s total GHG emissions from buildings2. As the federal government sets targets for GHG emission reduction by 2030 on a path to the net-zero future, the commercial real estate sector has been exploring ways to decarbonize office buildings. Adopting circular economy strategies and practices, such as extending the life of existing buildings, offers one way the sector can lower its overall carbon footprint.

New construction versus extending the life of existing buildings

As CSA Group’s research report Opportunities to Apply Circular Strategies to Existing Office Buildings notes, “office buildings are most likely to be threatened with demolition when they are no longer viable.” However, reducing GHG emission cannot be solved by simply demolishing existing buildings and replacing them with new ones. Even the most energy-efficient new buildings come with substantial upfront GHG emissions because of the resource-intensive nature of construction and the materials supply chain.

While new construction may still be necessary in some instances, extending the life of existing buildings through retrofit, repair, maintenance, and flexible, adaptive reuse can offer an alternative to demolition. Adopting these circular strategies will require rethinking the design, construction, usage patterns, operational processes, and end of life of a building from the beginning. Most current buildings were not designed to be easily adapted or reconfigured, but advances in technology such as digital design, scanning, and prefabrication help introduce innovative solutions for extending the useful life of underperforming commercial buildings.

While circular strategies are not new in Canada, there are many opportunities for the development of standards addressing the application of the circular economy in existing buildings. For example, terms such as restoration, retrofit, renovation, alteration, refurbishment, and renewal are all used interchangeably when, in fact, they mean different things.

Helping make informed decisions about retrofits and carbon emissions

To further demonstrate the benefits of extending the life of buildings, CSA Group conducted research on whole-life carbon emissions of retrofits and how they compare with a demolish and build new approach. This assessment considered both operational and embodied GHG emissions.

The research report Exploring Circular Strategies to Extend the Life of Existing Buildings presents case studies for mid-rise and high-rise office buildings in Toronto, Vancouver, and Edmonton. The results show that deep carbon retrofits can reduce whole-life carbon emissions by 35-70% by 2030, compared to a demolish and rebuild scenario. These reductions were mainly achieved through the avoidance of upfront embodied carbon emissions, as retrofits maintain the existing structure.

The study can help the commercial real estate industry make carbon-informed decisions about retrofit versus demolition and new construction.

Toward the circular economy ecosystem in Canada

Extending the life of existing buildings is just one of the circular strategies Canada’s construction sector has been exploring in recent years. Other practices include the use of durable materials and products, design for disassembly, design for flexibility of buildings, the use of modular construction methods, and salvaging, reusing, and upcycling building products and materials at the end of buildings’ useful life. Applying them can bring many benefits, from preserving natural ecosystems, lowering resources and raw material use, reducing waste and GHG emissions, and improving supply chain resilience, investment, and employment opportunities.

To complement ongoing industry efforts, CSA Group is continuing to collaborate with Circular Economy Leadership Canada (CELC) on new research that will help contribute to the development of a strategic framework for the circular economy in the built environment in Canada.

To learn more about CSA Group research and standards for circularity in the built environment, visit our website.


This work was funded in part by Circular Economy Leadership Canada (CELC) as part of a broader CELC-led initiative in collaboration with partners from industry and government, which resulted in the publication of a Guide for Canada’s Commercial Real Estate Sector

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