Cool roofs are an important energy efficiency matter in Southern California. Since our region receives so much sunlight, roofs without cool-roof technology can absorb a lot of heat, which raises a building’s temperature and decreases its energy efficiency. Cool-roof technologies are roofing technologies that reflect the sun’s rays back into the atmosphere.
This is called solar reflectance. These technologies also use a second property called thermal remittance, which is a way of quantifying how much heat a given material doesn’t absorb. Both of these properties are measured between zero and one. The higher these numbers are for a specific material, the “cooler” that material is. With these two properties, roof-cooling solutions reduce the amount of heat a building absorbs, as well greenhouse gas emissions and air pollution.
When you decide your building needs a cool roof, these are three different ways you can get one:
- Replace the current roof with a new, cool one.
- Re-cover the roof with a reflective surface.
- Retrofit the roof with heat-reflective material.
Depending on your budget, retrofitting or re-covering your roof may be more cost-effective than replacing the roof with a new one.
Of course, within these three roofing options are specific cool-roof techniques you can use to protect your roof. One common technique is applying a reflective spray coating, which is often white in color, on the roof. Spray coatings work as extra-thick paints that protect the roof from UV light and chemical damage. However, spray coatings don’t work with every type of roof. Even so, every type of roof can benefit from cool-roof technologies. Here’s how different commercial roof types can be turned into cool roofs:
Modified bitumen sheet membranes: This type can be pre-coated with cool-roof coating at the factory.
Single-ply membranes: These reformulate or coat black single-ply membranes to make them reflective.
Built-Up Roof: This type of roof is usually made of asphalt, and it can be made cool in three different ways: spray a protective coating on top of the asphalt layer; use reflective marble chips or gray slag in a flood of asphalt; or use a factory-based coating or reflective mineral chips or granules on a mineral-based sheet.
Spray Polyurethane Foam Roofs: These roofs are already reflective and possess cool-roof properties.
Metal Roofs: A metal roof is already reflective, but it should be painted to increase its thermal emittance properties.
Think About Your Climate
When you decide to invest in a cool roof, you will have to consider the climate that surrounds your building. Cool roofs often work best in hotter climates because they sacrifice winter heating benefits in cold ones. Some of Southern California has a Mediterranean climate, with dry summers and cool, rainy winters, but the entire state has a wide variety of climates, so that’s definitely a factor you’ll want to consider.
California Cool Roof Services
If you are interested in investing in a cool roof or if you have any questions about this topic, contact us today. We add a cool reflective layer to every roof we install, so we have the dedication and experience to help you determine what your roof cooling needs are.