To determine which roofing materials are best for your building, first you must determine the slope of your roof, then select the cool roof product that best suits your slope, budget, and architectural style.
One of the most common cool roof options for a flat or low-sloped roof is a modified bitumen roof. Modified bitumen roofing is a membrane made up of sheets of plasticized or rubberized asphalt held together with rolled reinforcing fabric and fastened to the roof deck with hot asphalt or cool adhesive. Traditional modified bitumen roofs are black or gray, with a low solar reflectance, meaning that they absorb, rather than reflect, most of the sun's light. But simply applying a white coating over the surface of the material at the factory can raise the solar reflectance to acceptable cool roof standards.