Socioeconomic feasibility of green roofs and walls in public buildings: The case study of primary schools in Portugal

Green infrastructure has been applied in urban areas to mitigate the negative effects of urbanization and promote the efficient use of resources. This study suggests a methodology for assessing the economic value of installing green roofs and green walls in public buildings, particularly in primary schools. The economic evaluation considers costs and benefits from three perspectives-(i) infrastructure, (ii) users, and (iii) environment-using three levels of analysis (i) financial, (ii) economic, and (iii) socio-environmental. The methodology is applied to ten alternative green roofs/walls scenarios in two primary schools in Lisbon, Portugal, for validation purposes. The cost-benefit analysis is carried out for a 40 and 50-year life cycle, using a 6.67% discount rate. The results show that all scenarios are feasible. The final benefit-cost ratios range between 3.01 and 34.99. A sensitivity analysis shows that the installation cost, esthetic improvement, and increased sound insulation have a significant impact on the results.