Abstract The benefits (B), opportunities (O), costs (C), and risks (R) of green roof (GR) installation have been identified by several studies. However, the inner-dependencies among them, potentially significant in the decision-making process for proper adoption of GRs, have not yet been investigated. In view of this gap, this study investigates the inner-dependencies between the BOCRs of GR installation according to Malaysian experts. BOCRs were collated through a review of the literature and categorized into 11 groups. The enhanced fuzzy Delphi method (EFDM) and fuzzy decision-making trial and evaluation laboratory (FDEMATEL) approaches were utilized to investigate the inner-dependencies. The EFDM results revealed that 28 BOCRs were perceived as significant, while the investigation of inner-dependencies showed that stormwater management, contribution to mitigation of urban heat islands, additional structural support, and irregular maintenance were the most influential B, O, C, and R, respectively. Notably, no significant relationships were found among environmental and economic opportunities. FDEMATEL results showed that, to take full advantage of GR installation, the primary focus should be on the most influential (rather than important) Bs and Os. The findings of this research provide stakeholders with insights into the adoption of GR installation, bringing not only environmental benefits but financial upsides.