One of our designers led the renovation of an old home in Queensland a few months ago. In pursuit of reducing heat build-up, he changed the tiled roof to a pure white colorbond. His inspiration was the light roof paint used in homes in Mediterranean countries. When the summer season came, the homeowners noticed how quickly their newly renovated home cools down, reducing their need for air conditioning. In addition, they didn’t feel like they sacrificed their home’s design for a white roof.
A lot of scientific research proves that the use of white roof reduces heat build-up in our homes and the heat island effect in our cities. It’s a practice done for centuries in the Mediterranean and Middle Eastern countries. New Zealand followed this initiative a few years ago too.
Now, some Aussie homeowners want to trade their dark roofs for pure white or a lighter colour.
Would you take this step to cool your home?
Before you do, we’ll explain this science a little further:
How white and other light-coloured roof paint works
It’s more bearable to wear a white shirt that a black shirt when you’re out under the sun, right?
The same goes for our buildings.
Having a white roof, the structure is capable of reflecting sunlight back into the atmosphere and into space. Dark coloured roofs absorb sunlight and are stored as heat. Some of the heat escape, but it can’t flow back to outer space because greenhouse gases are present in the atmosphere.
That being said, a country that experiences scorching hot summers will benefit from building white roof cities. It will cut the cost of your electricity bills by 4-8%. More importantly, it will help us manage our local temperature and avoid the heat island effect.
Heat absorption during winter
This design will work on Australian regions with warm climate but might not do much for homes located in cooler areas. Homeowners living in Tasmania and several parts of New South Wales and Victoria will benefit from the heat absorption through the roof, especially during winter.
At the end of the day, it is important to design structures based on their location. That is the key to building comfortable structures.
Green vs white roof?
Recently, we wrote about green roofs, another sustainable and eco-friendly roof idea for both residential and commercial structures. Both have impressive structural and environmental benefits.
It all boils down to the homeowner’s budget. Green roofs cost more than a white roof. White roof paint is the cheapest in the market and you only need a few tradies to complete the project, whereas the green roof requires a few more building materials, soil, plants, and the help of structural engineers, design professionals, and highly-skilled tradies. It is expensive, but it does more than cooling your home. It insulates, limits stormwater runoff, supports natural ecosystems, and filters the air we breathe.
Read all the benefits here: 10 Reasons to Celebrate a Green Roof
The challenges of having a sustainable, white roof
First, white roof, especially ones made from metal is reflective. It might throw a blinding light on your neighbour’s home. Regardless of how strict your local council is on the use of reflective materials, we encourage everyone to mind their neighbours. If your design shows concern for the adjacent properties, the more likely it is to pass the council.
Second, some regions in Australia are prone to mouldy roofs and it’s more obvious when you have a light-coloured roof paint. The solution is to wash it annually (or as frequently needed) to get rid of the moulds.