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As Canadas demand for housing and infrastructure continues to grow, contemporary approaches to construction and demolition pose major social, cultural, and environmental challenges. The prevailing approach to redeveloping a site is one of re-establishing a tabula rasaindiscriminately tearing down old structures to make way for new ones. This practice has led to a general disregard for the cultural and material value of existing buildings and colossal wastefulness in terms of resource consumption and associated carbon emissions and ecological impacts. Proposed redevelopments at key sites like the Ontario Science Centre and Ontario Place have sparked debate over public space, heritage, and privatisation, where political expediency and real estate economics seem to outweigh all other notions of value.The demolition of landmarks and culturally significant buildings represents only the most visible and widely spoken examples of a demolition practice that seems endemic in a city like Toronto. A study of the Citys demolition permit data reveals that over 60% of permits issued are for single-family homes in unassuming post-war neighbourhoods, like York, North York, Don Mills, and Etobicoke. The Yellowbelt is quietly undergoing a rapid transformationwhere modest post-war homes are typically replaced by ever-larger single family residences, with only a few multi-unit developments adding density.Active demolition sites in April 2022 in Lansing, North York. Source: Woodloop, Rashmi Sirkar M.Arch Thesis, 2022.This pattern of redevelopment not only turns once-affordable neighbourhoods into more expensive enclaves, but also fuels Canadas mounting construction, renovation, and demolition (CRD) waste problem. Each year, CRD projects across Canada produce around 3.4 million tonnes of construction materials that are sent to landfill. According to Statistics Canada, CRD waste typically represents 20-30% and sometimes more than 50% of total municipal solid waste, equivalent to an estimated 1.8 million tonnes of embodied carbon from landfill off-gassing. This volume of dumped material also represents an estimated $4-6 billion dollars of valuable material resources that have potential for recovery and reuse. Sending potentially reusable material to landfill drives an increased demand for virgin materials, and propels further associated upfront carbon emissions.What if we were to imagine an alternative scenarioone that embraces circular methods of development, replacing destructive demolition with deconstruction and material recovery?Wood elements from the deconstruction of a typical wartime house.Source: Woodloop, Rashmi Sirkar M.Arch Thesis, 2022.Take the typical 1,000-square-foot post-war house of North York: a single home would yield approximately 70-80 cubic metres of salvageable material, including around 8,000 linear board feet of clean sawn lumber, that could be reused, recycled, or repurposed instead of being trucked to a Michigan landfill. The salvage of the wood elements alone would be equal to $5,000 of material, and almost 25 tonnes of CO2 equivalent of sequestered carbon, analogous to offsetting 25 years of driving a Canadian car. By scaling these circular practices across the city, province, and nation, we could reintegrate valuable materials into the building supply chain, addressing the housing crisis and the pressing need for more sustainable construction methods. In doing so, we would also preserve material heritage, reduce carbon emissions, and unlock significant monetary resource value that is currently being squandered.The Shift of ValueTo understand how we might incorporate circular development practices today, its essential to recognize that the redevelopment of sites did not always involve the demolition and landfilling of older structures as the norm. Up until the 1910s, deconstruction was the primary method for dismantling buildings at the end of their life. Across North America, house wreckers meticulously took apart structures, salvaging valuable materials like wood, bricks, and stone, which were resoldoften directly on-siteor stored in warehouses for future use. This process supported a robust, local secondary market for building components, exemplified by companies like the Chicago Wrecking Company, which maintained extensive stocks of salvaged materials in a series of large warehouses.Demolition of the Astor House in 1913, showing piles of lumber and rubble, possible brick sorting, derricks and a sign for the Hudson Wrecking & Lumber Co. Source: The New York Public Library, Manhattan: Broadway Vesey Street New York Public Library.This began to shift in the 1910s and 1920s, when the concept of building obsolescence began to take holdthe idea that a building had declining functional worth. This concept was closely tied to increasing investment in a growing real estate industry. Publications like Reginald Boltons Building for Profit (1911) and experts from organisations like the Chicago-based National Association of Building Owners and Managers (NABOM) promoted rapid cycles of demolition and redevelopment as a modernist virtue. As this idea rooted itself deeper into North American practices, it led to the prevailing mindset that constant urban renewal signalled progress, and contributed to more and more buildings ending up in landfill.In Canada, the revision to the Income Tax Act of 1942 reflects how pervasive and powerful this shift was. The Act instituted tax deductions based on the assumption that commercial, industrial, and rental buildings would lose two-thirds of their value within ten years. If the cumulative deductions exceeded the buildings actual loss in market valuation, the owner was not required to repay the government if the building was demolishedthereby rendering the existing building entirely valueless.New York Times headline: To Study Decline in Building Value, July 8, 1928. Source: The New York Times Digital Archives.The contemporary resistance to deconstruction and reuse remains entrenched in the financial systems that govern development. Current tax codes make demolition and rebuilding more profitable than preserving or repurposing existing structures and materials. To truly enable a circular economy in the building industry, it is crucial not only to mandate deconstruction over demolition, but also to revise the financial tools that govern and incentivize our industry. To catalyse a renaissance of salvage and reuse, we need to explore raising taxes on demolition and landfilling, along with issuing credits and tax breaks for deconstruction and reuse.Closing the Deconstruction GapIn the last decade, cities across North America have adopted deconstruction ordinances and bylaws aimed at diverting CRD waste from landfills, and reintegrating it into the building materials market to catalyse regional circular economies. In the United States, cities like Portland, Boulder, Pittsburgh, and San Antonio have led the way in legislating deconstruction. In Canada, Vancouver introduced the Green Demolition Bylaw in 2014 as part of its broader climate goals, mandating that 75% of materials from pre-1950 homes be salvaged, reused, or recycled instead of sent to landfills. Following Vancouvers lead, Port Moody and Victoria have recently enacted deconstruction bylaws. Toronto, Guelph, and Edmonton are also developing their own circular economy roadmaps, and actively consulting to introduce viable deconstruction and reuse practices.A result of these policies is the re-emergence of independent deconstruction operators like Vema Deconstruction in Vancouver and Ouroboros Deconstruction in Toronto, which have begun offering alternatives to mainstream demolition. However, these businesses face several barriers to reaching the scale of the home wreckers of a century agonotably, a disorganized secondary marketplace, and the absence of spatial infrastructure for storing, processing, and sorting salvaged materials. For wrecking and reuse to once again be part of the mainstream of construction supply, cities will need to pair new regulation with spatial provisions. As an extension of existing waste-handling logistics, cities are uniquely poised to provide the space for the re-establishment of warehouses to gather, sort, grade and store materials.While existing policies have primarily focused on harvesting materials from buildings, future regulations and programs need to create a framework that facilitates the reintegration of these materials into the mainstream construction market.Reclaiming Value Through DeconstructionDeconstruction Timeline. Source: Ha/f Climate Design.To better understand the barriers and opportunities in deconstruction, Ha/f undertook a pilot project with Ouroboros Deconstruction and Haley Anderson Consulting in Southern Ontario. Working with Guelphs Circular Opportunity Innovation Launchpad (COIL), the team dismantled a 9,850-square-foot wood-frame house, salvaging 40,000 linear board feet of lumber and 44 large Douglas fir beams in the process. The materials were quantified, sorted, and processed for reuse or resale, helping to understand their potential reusability and to inform a lifecycle assessment.De-nailing workshop at the project site hosted by project partner Ouroboros Deconstruction for University of Waterloo students, November 2023. Source: Juliette Cook.The project highlighted both the value and logistical challenges of storing, processing, and marketing reclaimed materials. Wood held the highest reuse value in this project, and lumber sales were primarily managed through platforms like Kijiji and Facebook Marketplace. Other materials required additional outreach efforts. For months, materials were stored on-site in rural Ontario, where space was abundant and local sales were feasible. However, as the site needed to be vacated, finding affordable warehousing for salvaged materials in Toronto became an obstacle. Sustainability-oriented real estate developer TAS eventually provided temporary storage at a nominal rent, as part of their own circular economy initiatives. The reclaimed lumber is now being sold as graded lumber packages for new construction, but although sales are steady, demand has been slower than anticipated.For deconstruction efforts to succeed, sites and applications for reusing salvaged materials are essential: materials must flow out of warehouses and into active projects for the industry to remain viable. The project team connected with local makers who turned salvaged wood into furniture. The houses deconstruction process was showcased alongside the resulting products at the 2024 DesignTO Festival, generating immense public interest in building material reuse and its potential environmental benefits.These experiences also highlighted the importance of quantifying the environmental benefits of deconstruction and material reuse through tools like Life Cycle Assessment (LCA). By capturing the substantial carbon savings these practices offer, LCA can help make a compelling case for policies and incentives, such as carbon taxes or credits, that reward low-carbon building strategies. Once frameworks are in place to account for and reward the emissions reductions achieved through material reuse, deconstruction could become a more competitive and appealing alternative to traditional demolition.The project saved roughly 31 metric tonnes of CO2 emissions and stored an additional 54 metric tonnes of biogenic carbontogether, equivalent to 20 homes energy use for one year. Scaled to Toronto, which has approximately 2,700 active demolition permits for single-family homes, deconstruction and reuse could avoid nearly 64,000 tonnes of CO2 emissionsanalogous to the energy used by 14,988 homes for one year.Mapping the carbon reduction potential of deconstruction and material reuse across Toronto. Source: Ha/f Climate Design.A Way ForwardRealizing the environmental and economic potential of building material reuse requires strengthening deconstruction legislation and fostering synergies among policymakers, market drivers, and reuse businesses. Traditional demolition, with its speed and cost-efficiency, remains the preferred option for most developers. To counter this trend, financial incentivessuch as tax breaks, grants, or subsidiesare critical in making deconstruction a competitive and attractive alternative. By highlighting the significant carbon savings achievable through deconstruction and material reuse, these incentives can further motivate developers to embrace these more responsible practices. Moreover, it is vital to account for the true costs of construction and demolition (CRD) waste by considering both the financial expenses associated with disposal, and the environmental and ecological impacts resulting from landfill use and resource depletion.Investment in reuse infrastructure is another critical area requiring attention. Facilities for storing, processing, and certifying salvaged materials are essential to support a circular economy in the construction industry. Without these facilities, even the most well-intentioned deconstruction efforts may fail to prevent materials from ending in landfills.Finally, public perception remains a significant hurdle to advancing deconstruction and material reuse. Many builders and consumers still view new materials as superior to reused ones, creating a barrier that must be addressed. Shifting this mindset will require targeted education and awareness campaigns that emphasize the environmental, economic, and social benefits of material reuse. To move forward, we must engage in a process of unlearning entrenched notions like building obsolescenceand instead recognize and appreciate the inherent value of our built fabric and building materials.Juliette Cook is a partner at Ha/f Climate Design and an enthusiast of reuse at the scale of the building and of the material. She believes that a return to a deeper understanding of materials, the way they are made, and the ways in which they go together, will enable a more regenerative design.Rashmi Sirkar is a partner at Ha/f Climate Design where her work encompasses life cycle analysis of buildings and landscape, material strategies for decarbonization, and advocacy for reuse in the built environment. Her research explores the potential for circular design practice through building reuse, material reuse and bio-based construction practices.The post Full Circle appeared first on Canadian Architect.
