Assessment of long term solar reflectance performance of roof coverings measured in laboratory and in field

Heat island refers to the temperature increase in urban areas compared to rural settings, intensifying the cooling energy consumption of buildings. Roofs constitute a major part in urban areas, hence cool roof coverings contribute to mitigate heat island. Heat island is an important issue for cities located in western and southern parts of Turkey, however cool roof coverings are not a common application. This study presents the assessment of long term solar reflectance performance of commonly used roof coverings in Turkey. Assessment is based on the data obtained from laboratory measurements conducted on new and 1-year aged several test specimens and field monitoring of red clay tile and red shingle using pyranometers for duration of one year. Laboratory results revealed that standing-seam profiled metal coverings and red colored mineral coated modified bituminous membrane required surface treatments to serve as cool roof coverings. Field results indicated that both the red clay tile and the red shingle showed a slight decrease in the solar reflectance due to weathering. Comparison of the new and 1-year aged solar reflectance values of red clay tile and red shingle measured both in laboratory and in field showed that there was no significant difference between the values.

► Some metal coverings and red modified bituminous membrane require cool coatings.
► Red clay tile is a cool roof covering while red shingle is not.
► Field-laboratory results of new-aged clay tile and shingle were nearly the same.