Scaling Green Roof Retrofitting: Barriers, Enablers, and the Role of Circular Economy

Abstract

Cities face increasing climate risks, requiring scalable solutions for urban sustainability. Green roof retrofitting offers environmental, economic, and wellbeing benefits, including stormwater management, urban cooling, and biodiversity enhancement. However, adoption remains limited due to financial constraints, regulatory fragmentation, technical feasibility concerns, and a lack of standardized lifecycle performance data. This study investigates the interdependencies among barriers and enablers influencing green roof retrofitting and explores whether circular economy principles can facilitate large-scale adoption. Using Interpretive Structural Modelling (ISM) and MICMAC analysis, the research structures these factors based on their driving power and dependence relationships, identifying critical leverage points for intervention. Preliminary findings from UK-based workshops and interviews with building owner-operators, contractors, and a sustainability consultant are presented. The analysis highlights key driving factors such as lack of performance and ROI data, supply chain maturity, conflicting regulatory requirements, availability of alternative financing, and sustainability incentives, while financial viability, tenant acceptance, property management, and innovation appetite emerge as dependent factors. Although circular economy strategies - such as modular systems, recycled materials, and service-based business models - offer potential to address key challenges, gaps in standards, regulatory clarity, and industry confidence may create additional barriers if not carefully managed.