This adaptation measure refers on the installing of cool roofs to reduce the urban heat island effect. Cool roofs reflect more light and absorb less heat than traditional roofs. Or in more technical terms, cool roofs have both a high solar reflectance (or albedo) and a high thermal emittance, so that much of the heat that is absorbed is quickly radiated back to the atmosphere. As a result, cool roofs can be 10 to 15 °C cooler than traditional roofs.
Cool roof materials come in a variety of colors from light to dark and are available for both lowsloped and steep-sloped roofs. They work for a variety of building types and aesthetic requirements. Creating a cool roof can be as simple as spraying on a light-colored, paint-like coating. There are two basic types of coating that reflect more light and energy than a traditional roof: cementitious and elastomeric. Cementitious coatings contain cement particles. Elastomeric coatings include polymers to reduce brittleness and improve adhesion. Both types have a solar reflectance of 65 percent or higher when new and have a thermal emittance of 80 to 90 percent or more. Slightly more complex approaches include membranes that can be applied to the roof, roof tiles that reflect the sun much better than traditional tiles, coolcolored metal roofing, and asphalt shingles.
Impacts:
In addition cool roof can benefit a building and its occupants by:
Costs
Although costs will vary greatly depending on location and local circumstances, cool roof coatings on a low-slope roof might cost €7,5-€15 per square meter, while single-ply cool roof membrane costs vary from €15-€30 per square meter