TechNote 17 Heat Island Roof  

Reduction of the heat island effect can be achieved by selecting cool roof surfaces or installing a vegetative roof. Heat islands are typically defined as ‘urban’ regions that have higher temperatures than the surrounding landscape. Cool roofs reflect sunlight and emit heat more efficiently, and are seen as a potential strategy to reduce the heat island effect. Vegetative roofs installed on top of conventional flat or low sloping roofs are a layered system constructed of living vegetation. The increase in permeability and moisture with living vegetation is seen as another potential strategy to reduce the heat island effect. Details on vegetative roof strategies are not included in this TechNote.