Green building explained: How green is your roof?
Green roofs vs rooftop garden: While typical rooftop gardens are primarily an aesthetic feature of a buildings ‘roofscape’ the green roof embodies proven sustainable concepts.
|According to a 2005 study by the City of Toronto, if just 8% of urban roofs are covered in plants, city temperatures can be cut by 2 degrees. That’s because buildings are responsible for over 50 per cent of greenhouse gas emissions in most cities and over 70 per cent in mature cities such as New York and London.
Green roofs counteract the urban heat-island effect, caused by hectares of unrelieved asphalt and concrete. Green Roof programs already operate successfully overseas in Berlin, Chicago, Toronto, Portland and Oregon.
City of Sydney guide to green roofsIt’s something the City Of Sydney seems to take seriously. The council gave an Environmental Grants Program to a community group of environmental experts that includes Australian Institute of Architects' Environment Chair Prof Tone Wheeler, Landscape Architect Environmental Chair for NSW Chapter of Australian Institute Landscape Architects Jim Osborne, and water specialist Toby Gray, to develop a model process to retrofit green roofs to existing multi-storey apartment buildings.
The result is a Design Reference Manual that can guide commercial building owners and strata buildings to retrofit green roofs.
Green to the core"Building roofs are an under-utilised resource, particularly in the CBD where there is a limited amount of green space. There's merit in exploring rooftop plantings - particularly as part of our Sustainable Sydney 2030 vision," says Councillor Marcelle Hoff, Deputy Chair of the Cultural and Community Services Committee.
"Where it is practical, green roofs would create more open space and enhance bio-diversity. They will also reduce energy consumption by insulating buildings, reduce storm water runoff, reduce greenhouse gases and could be practical too by growing fruit and vegetables.
Resources for homeownersWhile aimed at commercial buildings, the guide covers a number of areas that homeowners learn about, from types of green roofs, to architectural design considerations to sustainable energy technologies.
You can also watch the City of Sydney video on the green roof concept here.