Roof Coatings - Creating a Cool Roof

Roof coatings are used generally on flat roofs to add additional protection and enhance the life of the particular roofing product. There are a number of roof coatings that act as so-called "cool roofs", a very desirable quality building owners.

Which Roof Coatings Create Cool Roofs?

• Light or white coatings. Any of a variety of coatings or membranes that are white or light-colored will act, at least to some degree, as cool roofs. That's because lighter colors have naturally-occurring properties that help to reflect direct sunlight. One example is a thermoplastic white roof, which is rated to reflect up to 80 percent of direct sunlight, including at least 70 percent of the solar radiation the building would otherwise absorb without the coating. A built-up roof, for example, with its dark asphalt base, reflects as little as 10 percent of solar radiation.
• Green roofs. Roofs that have plants, grass or flowers growing in layer above the waterproofing roof coating base are also cool roofs. These types of roofs usually include a number of different layers, including a drainage layer, the waterproof coating, filter and the growing medium. The living green portion of the roof uses the sunlight in the growing process and sends carbon dioxide back out in the atmosphere. The temperatures on a green roof are considerably cooler than other flat roofs.
• Coated roofs. This is a general category for any of a variety of white roof coatings available specifically for the purpose of creating a cooler roof. The coating will generally be white, of course, and will be Energy Star rate with percentages listed for the amount of direct sunlight and solar radiation reflected.

Benefits of Cool Roofs through Roof Coatings

• Save money. Your summer cooling bill can be reduced up to 25 percent, according to roofing experts, with cool roofs. A reflective roof can reduce the temperature on a roof by 50 to 70 degrees. That makes it easier for the cooling system in the home to maintain a comfortable temperature.
• Keep your roof longer. The roof will last longer with a significant percentage of harmful UV rays from the sun being reflected away. It is the combination of very hot temperatures and the ultraviolet rays from the sun that can break down many roofing products over time. The roof, as well as the roof coating and insulation, also will last longer because of the lower temperatures on the roof.