A holistic framework for the implementation of green roofs on existing buildings: a case in the Mediterranean climate of Naples

In densely populated cities, the lack of green spaces has a negative impact on urban health. Green roofs are an innovative solution to introduce natural elements into compact urban contexts. This study proposes a holistic framework for the implementation of green roofs that takes into account the parameters that influence the choice of the most appropriate solutions, especially for existing buildings in historic urban areas. The framework, applied to the Santissima Annunziata historic hospital complex in Naples, has demonstrated the effectiveness of green roofs in improving thermal comfort and creating green spaces for social and recreational purposes even in a monumental context. The analysis carried out with the ENVI-met software showed that the greening measure on roofs led to a reduction of 0.2°C in the potential air temperature. Even more significant was the reduction in the mean radiant temperature of the surfaces with a maximum decrease of 4.1°C. If other greening measures such as planting new trees and changing sealed paving with permeable ones are considered, the reductions reach up to 0.70°C and 6.1°C respectively. The proposed model can be replicable in similar urban contexts and contributes to the understanding of the socio-ecological potential of urban greening strategies in high-density areas.