There was a time when roofs were green—literally covered with grasses for grazing animals. The term, “green roof” however; has taken on a meaning that those hearty individuals of 100+ years ago would never have been able to imagine.
The term “cool roof” is a go-green term that refers to a roof having been designed to maintain a lower surface temperature in bright sunshine than that of a traditional roof. The Department of Energy Building Technology Program states that “cool roof” qualifications are determined by the roofing materials’ abilities to reflect the sun and release absorbed energy. The higher the rating of these two factors determines the “coolness” of the roof.
Let’s take a look at some roofing options that put “green” into the roofing equation.
Clay tiles are not only beautiful and quaint in terms of aesthetics, they are a popular choice in hot climates due to their curved shape which lends itself, perfectly, to excellent ventilation. Not only will tile outlive most home-owners (clay tile will last up to 100 years), their heaviness keeps more cool air inside on sweltering days.
Single-Ply Thermoset roofs incorporate a roof membrane created from oil and natural gas. This membrane is cured and bonded to roofing materials. These roofs boast of exceptional sealant and insulation properties keeping the homes and buildings they cover cooler and more temperature- consistent.
Unlike roofs that are constructed and sealed at the construction site, single-ply thermoset roofs are factory-constructed and sealed; and when the membranes are manufactured as white, a cooler roof results due to heat being reflected instead of absorbed.
Shingles or Shakes:
In and of themselves, shingles and shakes do not offer cooling properties and they remain the least cool of cool-roofing options; but there is a happy ending. Contractors like Waters Custom Roofing can treat shingles and shakes with reflective pigments to help make them a greener option. This doesn’t solve all the issues since the mere surface of this type of eye-catching covering has a rough, bumpy surface which is prone to reflecting less light, not more.
Roof pavers are the same as paving tiles, yet designed for a roof. Depending on the variety, their more-than-two-inch thickness can reflect a minimum of 78% of ultraviolet light. One drawback would be the weightiness of this material, coming in at 23 pounds per square foot. However, for buildings designed to carry that load, the insulating benefits can be impressive.
“Metal?” you might ask. This isn’t just your “cat on a hot tin roof” kind of metal. This metal is coated and painted a lighter color with added light-reflecting pigments that provide for a “cool” roof that can even be installed over an existing roof.
Have a sturdy roof that just isn’t “cool”? There is a coating that can be applied to just about any existing roof; and it’s versatile in that it can be applied on-site. The material contains special pigments that reflect 72% of incoming infrared light which makes up half of the solar energy that hits planet Earth.
The first real line of defense against the heat is a building’s roof and a competent roofing company. Releasing the sun’s rays is the goal, not storing and absorbing it. Theoretically speaking, according to the Unites States Department of Energy, if all roofs and roads were light-colored, the costs of running air conditioners in the U.S. would be reduced by 15%. In reality, since that will never happen, by knowing what’s “cool” in roofing products, we can control the heat instead of the heat controlling us.