One 75-degree day last month, the playground of the SAE School outside of Atlanta underwent a dramatic transformation. Students and volunteers equipped with paintbrushes and rollers covered the school’s black asphalt basketball courts and preschool play area with a bright coat of blue and tan paint.
Donated by the company GAF and its subsidiary StreetBond, the paint is actually a solar-reflective coating, and the paint job was about more than just aesthetics.
Before the coating was applied on this modestly warm day, the temperature near the asphalt measured about 120 degrees—a hellish environment common to many asphalt-covered playgrounds of parks and schools across the U.S. Shortly after the coating was applied, the temperature on the SAE School’s playground dropped 12 degrees.
“Is it still hot? Yes. But is it as hot as it was? Absolutely not,” says Shannan Tilson, cofounder and director of operations at the school. “I don’t feel like I’m in an oven.”
Neither will the school’s children, whose young bodies are particularly vulnerable to the increasingly frequent days of extreme heat in places like Atlanta. Back asphalt is like a magnet for heat, and a major contributor to the thermal radiation in cities known as the urban heat island effect.
“Asphalt itself essentially acts as a heat sink,” says Eliot Wall, general manager of StreetBond for GAF. “Even when the ambient temperature is recorded at 75 or 85 degrees, uncovered black asphalt can be 120 or 130 degrees. So that’s a really meaningful difference.”
GAF and StreetBond’s solar-reflective coating has been applied to streets, playgrounds, bus lanes, and bike lanes around the world. Recently the material was used to cover more than 1 million square feet of surfaces in the Los Angeles community of Pacoima.
Wall says the coating is effective at reducing heat and also helps extend the life of the asphalt beneath, which ironically degrades when exposed to the extreme temperatures it itself creates.
The 10-year-old SAE School is the latest to get the solar-reflective treatment. A private, project-based learning school for students in preschool through eighth grade, SAE has spent the past few years integrating environmental issues and sustainability topics into its curriculum. It’s also added energy-efficient and climate-sensitive equipment to the school’s facilities, and operates fully on solar power.
When GAF approached SAE about using the solar-reflective asphalt coating, school officials decided to make the project a learning experience.
GAF came to the school about two months before the installation to do a test run, applying the coating to one spot in the school’s parking lot, with painting help from students. The company also donated some digital thermometers, which the students used before the coating application, and in the days after, to check the ambient temperature in the area.
“They were able to see the temperature difference and graph that,” says Scott Starowicz, SAE’s cofounder and CFO.
SAE students even got involved in designing the paint job; they submitted designs and voted for a winner, using the blue of the school’s colors and dragon’s footprint shapes of the school’s mascot. The new playground surface, which Tilson calls its “bluetop,” is now regularly 12 degrees cooler than stretches of blacktop nearby.
But even that will soon change. School officials say they’re planning to spread StreetBond’s solar-reflective coating on another black-surfaced heat sink: its large parking lot.