On a sweltering, sunny day, the temperature on the surface of a traditional black roof can be more than 50 degrees warmer than the surrounding air temperature. When you imagine that hot rooftop next to another, and another, and another, like the row homes in Washington DC, it's no surprise that the air in a large city with block after block of dark, heat absorbing rooftops can often be 6 to 8 degrees hotter than surrounding areas.
Even in rural and suburban neighborhoods, the heat absorbed by a traditional roof on a sunny day raises temperatures inside the house, contributing to higher air conditioning requirements, higher energy costs, and more discomfort on hot days for anyone without air conditioning. Fortunately, the remedy for all this extra heat is relatively low-tech, low-cost, and increasingly easy to find: it's called a cool roof.
A cool roof is a roof designed to maintain a lower surface temperature in bright sunshine than a traditional roof . The surface of a cool roof will reflect more sunlight and release more heat than an asphalt or black top roof. While the term "cool roof" is sometimes used to describe any roofing surface that is cooler than a standard rooftop, green certification programs such as LEED, Energy Star, the U.S. Green Building Council, and the Department of Energy Building Technology Program base their respective cool-roof credentials on a roofing material's ability to reflect the sun and release absorbed heat. The higher the solar reflection and emissivity the cooler the roof.
Cool roof coatings are best applied to low-sloped roofs in good condition. Aluminum coatings improve the solar reflectance of the roof surface. Aluminum coatings act as a watertight membrane, while cementitious coatings must be applied over roofing materials that have already been thoroughly waterproofed.
Cool roof coatings are sprayed, rolled, or brushed onto an existing flat or low-sloping rooftop to create a bright white, paint-like reflective surface These coatings are more commonly used in re-roofing projects than in new construction, and their cost ranges from about 75 cents to $1.50 per square foot.
Ready to save money, conserve energy, and cool the planet by turning your old, hot roof into a cool roof? Contact your local Washington DC, roofing professionals at Boyd Construction Co Inc today, online or call 212-223-ROOF today to set up a free estimate.
Boyd Construction Co
Family owned and operated in the greater Washington DC area since 1932.