Building recycling: A comparison of material recovery and building repurposing
Over the recent years, the topic of enhancing sustainability in the built environment has drawn much attention. In addition to natural resource depletion, climate change and consequent tight carbon budget, society is also facing problems such as rapid urbanisation and ageing built assets. How to deal with buildings reaching the end of design service life efficiently and sustainably under this circumstance has become a pressing problem that needs to be solved.
So far, two different building recycling approaches were proposed by researchers. One is material recovery, which is to demolish the building, retrieve the materials, and reuse them in the new construction. The other one is building repurposing, which is to keep the building structure, carrying out refurbishment, and repurpose it.
This dissertation research aims to evaluate and prioritise these two building recycling approaches by Building Information Modelling (BIM) and Life Cycle Assessment (LCA) methodology, quantifying their environmental and financial performance. By conducting a case study of an office building in Hong Kong, the impact of these two pathways on global warming potential, energy consumption, and construction material cost were measured. Two modified designs aimed for easier material recovery and easier building repurposing were analysed at the same time.
Results showed that building repurposing is more favourable than material recovery in all categories being evaluated. In addition, the two modified buildings performed better than the original design both environmentally and financially, proving that targeted changes at the design stage for end-of-life recycling activities are feasible and effective. By conducting the study, a quantifiable evaluation framework on building recycling options was established. The analysis results can act as a reference for future office building recycling projects in urban areas. Last but not least, a paradigm shift from design-centric to “life cycle performance-centric” was called for in the construction industry.