COOL ROOFS change lives in Limpopo

SANEDI’s cool roofs pilot project in Limpopo, implemented in collaboration with the SANDF, is a game changer on a multitude of levels.

At two of the South African National Defence Force’s four military bases in Limpopo, SANEDI is coating roofs with cool-paint technology in a pilot project that simultaneously explores the technology and raises awareness. The body of knowledge that is being built, will be used by SANEDI to present a strong business case for the widespread adoption of cool-roof paints that will improve overall energy efficiency in South Africa and result in electricity and cost savings.

Local people have been co-opted on the project to help gather data. One such person is 25-year-old Hilda Muthivhi. No stranger to the scorching temperatures of her home province, Muthivhi knows the impact of cool-roof paint technology extends beyond energy savings. “Where I grew up, children in school became sick during summer when it was very hot. This paint will keep our buildings cooler when it gets too hot in Limpopo. Usually, people in Makhado and Musina cannot stay and work indoors in summer; with this paint, they can.”

Muthivhi is responsible for noting and documenting how different roof materials respond to the paint, and how surfaces must be prepared to ensure the lasting integrity of the paint. “We record, document and monitor everything that team members like Hilda report so that we can build a business case,” says Dr Karen Surridge, acting general manager at SANEDI. “When we started there were only two manufacturers of these paints. Now there are seven, which creates opportunities and a need for more skills. Ideally, we would like to see more women coming into this space because it is a robust technology that is easy to apply, and the benefits are enormous.”

For every square metre painted, Surridge and her team can quantify the annual electricity and cost savings. Coolroof paint delivers higher solar reflectance and higher thermal emittance than standard building envelope coats, making cooling accessible to people who do not have access to conventional air conditioning. A cool coating immediately reduces temperatures on the surface by up to 20°C, keeping heat expansion and cooling contraction to a minimum and thus extending the lifetime of the roof. The paint also strengthens the structural integrity of the roof and, importantly, reduces indoor temperatures by up to 10°C by reflecting heat away from the roof, which reduces the absorption and penetration of solar radiation into the building.

Not surprisingly, teachers and staff at the military base school and creche are reporting positive changes in the children’s health and focus since their classrooms are cooler in summer.

“The military base is an ideal pilot to test whether we can create a cool bubble effect, which is essentially what happens when surfaces are cooled in a cluster of closely-knit buildings. This net cooling effect reverses the heat-island effect associated with urban heating,” explains Surridge. In addition, cool-roof paint acts as a fire retardant, giving people inside a burning building time to escape. It also protects roofs from the elements and can seal asbestos effectively where it has not been removed.

Muthivhi is aware of the market potential of cool-roof paint technology and has set her sights on her own business in the near future. “We are approached by a lot of curious people who want to know how they can access the paint for their buildings or houses, so I can see the interest is there,” she says. “One day my own company could provide this service beyond Limpopo. I hope through this field I can build people, encouraging unity and development around me.”