The green roof movement is slowly taking root in Hong Kong. A green roof, as opposed to the collection of potted plants typically found on Hong Kong rooftops, refers to a continuous layer of soil and vegetation that covers the surface of a roof. Think of it as a lawn on the roof that you can play, relax, lie on and walk on.
Green roofs are environmentally friendly. They combat the urban heat island effect of higher temperatures in metropolitan areas created by too many buildings packed too closely together.
They keep rooftops cooler, which reduces the need for air conditioning, especially on top floors which absorb more heat than lower floors during Hong Kong's sweltering summers.
Less air conditioning means lower electric bills, thus less energy usage. 'It would not be difficult to get energy savings in the order of 20-50 per cent in the summer,' said Professor Jim Chi-yung, chair professor of geography at the University of Hong Kong, who is conducting research on green roofs.
They also absorb rainwater, are a source of oxygen, provide insulation and help protect the roof from the damaging effects of sunlight, which breaks down a roof's waterproofing layer.
He added that well-designed and maintained green roofs do not attract mosquitoes or other insects.
