Revival: A study of regeneration for unitised curtain walls in healthcare sector

Abstract

This study examines the circular potential and limitations of current aluminium unitised curtain wall facades, primarily through strategies such as reuse, refurbishment, and remanufacture. Despite being widely used in commercial buildings, including healthcare facilities, curtain walls present significant challenges in performance, adaptability, and sustainability. The research aims the critical issue of embodied carbon and resource depletion associated with these facades, particularly in the context of Toronto's healthcare infrastructure, which is undergoing extensive renovations. Buildings contribute immensely to environmental disruption, accounting for a significant portion of energy consumption, waste generation, and carbon emissions. The construction industry is working to reduce operational carbon emissions and enhance occupant safety. However, there is little focus on embodied carbon and the act of valuable materials in the early design phase, particularly in complex facade systems where high-carbon-intensity materials are found in curtain walls, such as aluminium and glass. To address global issues, the development of Toronto's healthcare infrastructure from the 1970s onwards, with ongoing renovations focusing on its building envelope systems, has become a potential model for studying, analysing, and applying sustainable practices. Hospitals like SickKids, Mount Sinai Hospital, and Toronto General Hospital are in the process of sustainably upgrading their building exteriors. This process includes updating their curtain wall and window-wall systems with material substitution and modular designs. It's crucial to incorporate end-of-life plans for new products and strategies for older ones to combat the "take-make dispose" culture", especially in Toronto's healthcare sector. A forensic analysis, including a Life Cycle Analysis (LCA), is being carried out to measure the quantity and quality of curtain walls and window wall systems and to assess the potential carbon emissions produced by facilities like the Patient Support Centre (Research site) at SickKids. Also, a mixed-method approach, combining interviews with international facade and material experts and case studies, is being used to investigate the possibility of implementing circular practices. The Design for Disassembly practice is customised and adapted to the research site (Patient Support Centre building), reflecting the opportunity and limitations of the curtain walls and offering guidance for handling such complex facade systems. The study found that while downcycling unitised curtain wall components is possible, achieving true circularity through reuse and remanufacturing is hindered by factors such as poor thermal performance, complex disassembly, and limited compatibility with new building designs. While the research demonstrates the potential for upcycling certain components, it highlights the need for a paradigm shift toward building better envelope systems that prioritise disassembly, adaptability, and material recovery. The findings emphasize the importance of developing alternative facade systems that better align with circular economy principles and exploring policy incentives to encourage their adoption. By uncovering the current unitised curtain wall systems, this research contributes to a broader understanding of the challenges and opportunities for achieving circularity in the building industry. The findings provide valuable insights for policymakers, designers, and building owners seeking to reduce the environmental impact of the built environment.