Investigation of thermal benefits of an extensive green roof in Istanbul climate

Green roofs have become an ecological solution in cities with the environmental problems that have increased in recent years. Green roofs are used as aesthetic elements as well as their ecological benefits for the city and urban environment. Comparative measurements were performed through field study in Landscape Architecture Department, Faculty of Forestry, Istanbul University, Green Roof Research Station (IUGRRS), to produce quantitative data on this subject and investigate the thermal properties of a typical extensive green roof. This paper analyses the thermal properties of a typical extensive green roof in comparison with a bituminous membrane roof (reference roof). During measurement period, it has been confirmed that a typical extensive green roof with 50 mm-thick growing media provided a thermal protection to the building envelope against extreme temperature effects. Impacts of extreme temperature fluctuations on the surface of the green roof to the building envelope were reduced by the green roof system by 79%. Results obtained from the field measurements show that green roofs are a sustainable choice in Istanbul climate conditions.   Key words: Green roofs, field measurement, thermal benefits, urban environment, Istanbul climate.