The Sustainable Urbanist: Looking Above for Sustainable Solutions
From New York, Mexico City to Milan, cities around the world are looking up for green inspiration. A ‘green roof’ is a fully vegetated garden embedded on a roof with layers including a waterproof membrane, drainage and soil. Cities experience increased daytime temperatures caused by bare rooftops. Rooftops absorb heat and light and radiate it back into the area. This raises the temperature of the city, and is known as the ‘heat island effect.’
Green roofs reduce the temperatures of cities by absorbing this
heat. They also act as an insulator for buildings and aid in reducing the use of heating and cooling mechanisms. The concept also increases the possibility of cultivating food in urban spaces and can be fitted to catch and store rainwater. Green roofs increase air quality, reduce the strain on storm water drains and lessen the heat island effect.
The ‘Do It On The Roof” campaign is striving to bring the craze down under so that Melbourne too can bask under the joys of rooftop agriculture. Dr Shelly Meagher says the ‘Do It On The Roof’ campaign is out to educate the public, business and politicians that fully vegetated rooftop gardens are possible and have many benefits.
“The City of Melbourne is very keen to create green roofs because of all the excellent civic benefits. But whilst government can get money for capital expenditure – covering the cost of implementing a green roof – it is difficult for it to get a budget for expenditure on maintenance for a project without evidence of public demand for it,” says Meagher.
In Mexico City green roofs are seen as a real tool in reducing air pollution and improving quality of life. The municipal government has constructed green roofs on public buildings over the city. It also encourages residents to get involved with a tax incentive of ten per cent of the value of the building if one third of the roof is covered by garden. New York is also committed with the world’s biggest green roof currently under construction.
Meagher says the posibilities are limitless, with people around the world “growing oak trees and pine trees, grazing sheep and goats, and growing vegetables all on their roofs.”
The City of Melbourne is currently compiling a guide to constructing and maintaining green roofs, walls and facades. Its aim is to inform people about the full process involved and to recommend policy, which will create incentives for building owners, facility managers and developers to construct and maintain green roofs.
Meagher says at present there are no strong incentives for developers or building owners to invest in the creation of green roofs, but believes the city council’s guide is a promising start in fleshing out a plan for the future.