To demolish or not to demolish: Life cycle consideration of repurposing buildings

Reduction in energy and resource consumption, as well as other environmental impacts, can be achieved for end of life building stock by recovering building waste after demolition through material reuse and recycling; or building repurposing through selective deconstruction and building system reuse. This research investigates and compares the potential life cycle environmental impacts of building repurposing through reuse of structure and demolition scenarios followed by new construction involving an existing library tower. New building design variations, with and without a Trombe wall, are detailed for both types of scenarios. The Athena EcoCalculator for Commercial Assemblies was used in analysis of life cycle stages of resource extraction and construction; maintenance, repair, and replacement of building assemblies; and disposal. Impacts from energy consumption for building operations were not included. Repurposing scenarios showed a potential reduction, between 20 and 41%, in six of the seven environmental impact categories assessed. The highest reduction is achieved for the Eutrophication Potential followed by Smog Potential at 37% reduction. Human Health Criteria is the impact category with the least reduction at 20% followed by Acidification Potential at 29%. Global Warming Potential and Fossil Fuel Consumption which are closely correlated show an avoided impact of 33 and 34% respectively as a result of the decision to go for repurposing after selective deconstruction rather than complete demolition and new construction. The benefits of repurposing compared to new construction demolition go beyond avoided environmental impacts. Comprehensive consideration of all relevant factors pertinent to the local context is also discussed.