C. L. Tan, N. H. Wong, S. K. Jusuf and P. Y. Chia
Bibliographic info:
Proceedings of the 34th AIVC - 3rd TightVent - 2nd Cool Roofs' - 1st venticool Conference , 25-26 September, Athens 2013

The treatment of roof space with cool paint or vegetation is a widely employed urban heat mitigation strategy. As the allocation of roof space for social activity becomes more prevalent in the urban environment, there is a need to understand how cool roofs and green roofs can affect the outdoor thermal comfort of its users. 

The study seeks to quantify the cooling effect of cool roofs and green roofs. Six plots, each measuring 3.0 m by 3.0 m, are set up at a rooftop. The setup consists of four plots of vegetation, one plot painted with cool paint and one with exposed concrete. The type of vegetation used for the green roofs are categorized according to regulatory guidelines. Analysis of air, surface and mean radiant temperature is conducted for the six plots. 

Results show the effectiveness of cool roofs and green roofs in reducing surface temperature under direct sunlight. Significant reduction in mean radiant temperature is observed for plots with vegetation. The Leaf Area Index and physical dimension of plants do not show good correlation with the reduction mean radiant temperature. This study confirms the need for cool roofs and green roofs to be strategically sited to achieve optimal cooling effect.