An overview of life cycle assessment of green roofs

Green roofs (GRs) have drawn huge global attention due to their multiple social as well as environmental benefits in the past decade. Recently, in-depth and comprehensive research on the environmental impact assessment of the green roofs is being conducted globally. In this study, the life cycle assessment of green roofs has been reviewed and analyzed. The environmental impact evaluation of GRs was assessed through five stages of life cycle assessment (LCA): material extraction, transportation, construction, operation/maintenance, and disposal phases. The content analysis method was adopted to classify the existing studies based on the research area and scope. The results of this study show that the green roof is a sustainable option over the conventional roof. Besides, GRs provides a number of benefits in the operational phase. However, there are several challenges needed to overcome including comprehensively evaluation of the disposal and transportation phase during LCA analysis. The use of recycled materials for GRs layers could be an optimal choice to reduce environmental impacts. Moreover, a comprehensive environmental and economic assessment needs to be carried out for future research work. In the end, a future research agenda is proposed to enhance the GRs design for its broader application in the building industry. Through this literature study, data can provide useful information for decision-makers to adopt green roof projects. (C) 2019 Elsevier Ltd. All rights reserved.