Quantifying and spatializing building material stock and renovation flow for circular economy

Abstract

The linear system of take, make, and waste, has led to deleterious environmental impacts and material use; circular economy strategies may offer benefits. Since the building sector is a major consumer of materials and contributes to many environmental impacts, it is a prime sector to be examined for the implementation of circular economy strategies. Understanding where and what materials are available due to renovation and demolition/deconstruction is lacking in the U.S. Thus, implementation of circular economy strategies like reuse in buildings will be incremental at best. Material stock and flow analysis can be used to understand baselines via accumulated materials and the material flow of buildings. In this study, we developed a bottom-up model using aspects of our previously developed urban building energy model to analyze the accumulated and renovation flow of specific materials in commercial buildings. We focused on renovation as this area was identified as a gap in the literature. The photogrammetry and image processing techniques in this paper provided the opportunity of using actual physical attributes of buildings instead of assumptions, which improved the accuracy of the bottom-up model. The results showed that concrete (37%), brick (30%), and minerals (17%) comprised most of the accumulated materials. Also, there was notable differences in the distribution of materials in different components. Brick had the highest mass in exterior walls; whereas, the largest mass-based quantities in roofs and floors were insulation and minerals, respectively. Brick followed by minerals and concrete had the largest share of renovation flow during 2020 and 2030. These outcomes aid policy makers and businesses in decision-making regarding the availability of secondary resources from buildings.