Challenges of Tall Iconic Building Retrofit

Change happens, for better or for worse, to all living and physical matter. In order to thrive and achieve longevity, we constantly need to adapt to our ever changing environment. For individuals, this means taking actions to reduce and manage physical and mental health risks while achieving positive impacts for our family and community. However regardless of corrective measures throughout one’s life, mortality is a given. For tall iconic buildings, demolition is not an acceptable or practical option given their scale and significance. Facade or component renewal to maintain durable enclosure is necessary to extend the useful life of iconic tall towers.

Further, climate change has been at the center of public and policy discussions, and building energy consumption has been identified as a key contributor to the problem. The key to solving this problem lies in how the building envelope and mechanical / electrical systems perform, preferably not in isolation, but as part of an overall renewal plan. Energy conservation measures through retro-commissioning can make a substantial impact in large buildings. Facade and retro-commissioning work can be carried out as independent project. Tower Renewal Guide (Kesik, and Saleff 2009) and Roadmap for Retrofits (Chisholm 2016) of large buildings have been developed to guide property owners and stakeholders to plan and take the necessary corrective actions.

This paper highlights retrofit of three tall iconic towers in downtown Toronto (Fig. 1) with various degrees of renewal, ranging from spandrel/vision re-glazing to coating finish renewal, coupled with internal system retro-commissioning to complete to over-cladding of the exterior envelope. The business drivers for change ranged from risk management of an aged facade to image renewal to compete with newly built towers in a competitive market. Primary challenges with the retrofits were the required upfront due diligence and the unforeseen conditions, design limitations regarding the character defining facade elements, managing the existing de-construction and re-construction of an occupied building, project scale, and finally public safety as it relates to execution of work in tight/confined downtown area.