California requires a cool roof installation if a homeowner replaces in excess of half the existing roofing materials. Also known as a white roof, this type of reflective roofing is supposed to reduce energy consumption. How does it work?
What Do Cool Roofing Materials Do?
A cool roof reflects the sun’s heat. The Cool Roof Rating Council explains performance is tracked via measurements tracking overall reflectance and verifiable thermal emission from the roofing materials. Differences are highly nuanced, since the scale only runs from zero to one.
The Consumer Energy Center points out that the installation of a white roof leads to roof shingles that are between 50 to 60 degrees cooler than customary black roofing materials. It stands to reason that the homeowner will have to deal with less heat buildup and subsequently has a decreased need for cooling technology. As a result, energy consumption goes down.
Will I Have Bright White Reflective Roofing?
Not necessarily. To achieve 0.70 reflectance, California Cool Roofing maintains that roofing materials must feature “white, elastomeric, acrylic coating.” This coating needs maintaining for superior reflectance and thermal emission; in addition, it is very noticeably white. On the upside, it is not necessary to replace the entire roof, which can save quite a bit of money.
For the homeowner who wants a cool roof but simply cannot get cozy with the notion of having a blazing white roof on top of the home, there are other options. Local roofers – Eagle Roofing is just one example – have developed a number of lightly colored roof shingles that qualify as cool roof materials even though they are not white.
There are gold-flecked terracotta (reflectance 35/emittance 76), dark tan (34/77), cream (48/79) and also gray (34/76). Homeowners in California should be aware that compliance with new rules requires 20/75 values.
Unless the building owner opts for coating an existing dark roof with reflective roofing white, basic maintenance is similar to other roofing materials. If the roof is indeed coated, the owner should ensure that the roof is free and clear of debris and also that the seams of dark-colored shingles are not bleeding through the coating.
In the latter instance a professional may need to be called to reapply the cool roofing. Check the warranty of the initial coating application to see if this eventuality is covered for a predetermined period of time.
A cool roof makes sense. Even if you do not buy into the global warming idea, there is sufficient scientific evidence that reflective roofing keeps an attic and living area cooler than conventional roof shingles.
Cool Roof Rating Council: “What is a Cool Roof?”
Consumer Energy Center: “Frequently Asked Questions About Cool Roofs”
California Cool Roofing: “Code Requirements”
Eagle Roofing: “Cool Roofing”