Climate change may necessitate constructing more buildings above ground

Friday 27 September 2024 - 10:43

As the impacts of climate change become increasingly evident, policymakers and researchers are questioning the traditional design of buildings, particularly the ubiquitous basement. With extreme rainfall and flooding events on the rise, the once-popular basement is facing scrutiny for its vulnerability and environmental implications.

The movement to ban basements has gained traction in certain regions, notably in Montreal, where politicians have proposed regulations to prevent new basement construction in flood-prone areas. This follows devastating floods in Quebec and Ontario, causing billions in insured damages.

Craig Stewart, Vice-President of Climate Change and Federal Issues for the Insurance Bureau of Canada, highlights a precedent set by the province of Ontario, where homeowners affected by flooding along the Ottawa River were offered disaster relief funds on the condition that they elevate their homes to prevent future flooding.

Beyond the immediate risk of flooding, basements also contribute significantly to greenhouse gas emissions. Shoshanna Saxe, Canada Research Chair in Sustainable Infrastructure at the University of Toronto, discovered that basements account for a staggering 56% of the average building's material intensity, which is directly linked to greenhouse gas emissions from construction.

The problem is exacerbated by the trend of larger, more spacious basements in new single-family homes, which not only increase carbon footprints but also elevate flood risks. Bernard Deschamps, a retired insurance industry professional now conducting research for his PhD, proposes regulating and banning basements in certain cases, arguing that it makes little sense to build basements in flood-prone areas.

However, the question arises: Are basements necessary? Saxe suggests alternative foundation options, such as pile foundations, which are commonly used in regions with higher frost lines or wetter soil conditions. She also highlights the City of Toronto's recent bylaw changes to incentivize above-ground construction in multiplex buildings, aiming to reduce their climate impact.

For existing buildings with basements, especially basement apartments, both Deschamps and Saxe advocate for preservation and protection measures to mitigate flood risks. Basements provide valuable housing options without requiring additional materials, making their preservation a sustainable choice.

As climate change continues to shape our environment, the future of building design must adapt. The debate surrounding basements highlights the need for innovative solutions that balance flood resilience and environmental sustainability. With further research and policy interventions, we can create a new generation of climate-resilient buildings, ensuring the safety and well-being of communities while minimizing our environmental impact.