SHOUT IT FROM THE ROOFTOPS! At the risk of stirring the pot, while light-coloured roofs make all the sense in the world, how about requiring developers to provide real backyards with room for a tree or two, which might make life for the future residents so much better.
AMONG THE MANY THINGS WE CAN BE GRATEFUL FOR, ONE IS THAT WE HAVE A ROOF OVER OUR HEAD.
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ow much consideration do you give to that roof? Without going outside to look, what can you say about the roofing material, its colour or its style? If you were party to your home’s construction, how much input did you have on what went up top? Last year, the New South Wales government outlined plans for builders to cease constructing homes with dark-coloured roofs. Under guidelines being developed by the Department of Planning, Industry and Environment, all new housing would be required to have light-coloured roofing to reduce the urban ‘heat island’ effect, which was particularly determined to be a problem in western Sydney. It’s true. There are many houses in Australian suburbs with dark roofs. Most of us learnt at primary school that black or dark-coloured surfaces absorb a great deal more heat energy than do white or light-coloured surfaces, but it is actually a bit more complex than that. The problem really lies in the fact that the under surface of the roof re-radiates this heat into the roof cavity of the home and rapidly migrates into the living spaces through the ceiling.
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Using high levels of insulation can help combat this, and new technology has allowed darker paints to absorb less heat. A dark roof may blend into the surrounds better, hence the popularity. Ironically, there are local councils with restrictions on how light a colour you can use on a roof. This might be because most existing houses already have dark-coloured roofs, so they expect newbuilds to ‘blend in’. All in all, information on the matter of roof colour seems rather lacking. Can you find anything on your own council web site? A James Cook University study found that, for north Australia, a light-coloured roof has about 30 per cent lower total heat gain than a dark-coloured one. Light roof colours are often criticised for creating glare, but the experts tell us that it is texture rather than colour that is the culprit by means of low angle reflectivity; and a neighbour’s new black tiled roof may create massive glare while an older white metal roof creates none. Since 2010, Queensland covenants and by-laws cannot restrict the use of light roof colours. Moving on from colour, the most common roofing materials in Australia are tiles or tin (corrugated iron or steel) and there are pros and cons for each. Lightweight steels are great for architectural designs, especially where curves are desired. Tiles are winners for lifespan, heritage appeal and sound insulation. A terracotta roof might weigh in at up to 60 kilograms per square metre opposed to steel at five kilograms per square metre.
