Cool roofs and building materials – the answer to extreme heat?

New research into “white roofs” shows that choosing building materials with certain properties could help Australians stay cool in the summer months.
Australia is known for its hot weather, but this summer set new records – leaving people reluctant to step outside and desperate for a cool reprieve.
Temperatures reached a stifling 47 degrees celsius in NSW – one of the hottest days Australia has experienced in decades. Queensland wasn’t far behind, with mercury rising to 10 degrees above average.
Sweltering days are no longer a rarity, so people are looking for ways to stay cool.
It’s become more important than ever to factor extreme heat conditions into the construction of buildings, whether they’re apartments, offices, houses or shopping centres.
Roof material selection is an area that’s gaining more importance. Dark-coloured roofs may be more popular, because they’re pleasing to the eye, but is this the most practical option, when it comes to lowering temperatures?
Studies show that white roofs are the best choice for hot climates, since they can reflect 75 percent of sunlight away from buildings – drastically reducing the need for air conditioning by cooling the building.  
Dark coloured roofs, on the other hand, absorb more solar energy. A standard black roof can become more than 40 degrees hotter than surrounding air temperatures, compared to a cool white roof, which doesn’t rise above 10 degrees warmer than ambient levels.
Further research is being done in this area, which could influence the way engineers, architects and builders design and construct commercial properties and homes. The Cooperative Research Centre for Low Carbon Living is also investigating the surface temperature of different paving materials and colours in Brisbane, using satellite images.
They confirmed that white roofs create lower surface temperatures, but they also recorded higher surface temperatures on new paved areas and development zones, compared to unsealed areas before construction began.
This highlights the importance of selecting materials and colours that reduce heat levels in development zones, going into the future.
When it comes to choosing “cooling” materials and colours, construction companies can take inspiration from the Lawrence Berkley National Laboratory, which predicts that painting the majority of roofs white in 100 major cities could translate to similar climate benefits as removing all cars from roads across the world for 10 years.
No small feat!
The selection of “cooling” building materials is an area worth exploring, because of benefits to the environment, as well as energy savings for businesses and homes.