France mandates green roofs – time for Oz to look at the pacesetters

The French parliament recently passed a new law requiring all new commercial buildings to have plants or solar panels on their roofs. 

This news will resonate with Australian property owners where green roofs are still their infancy. Issues around this topic will be covered in a strong line up at The Fifth Estate’s Urban Greening 2022 summit on 28 July, in collaboration with the Australian Institute of Landscape Architects, UTS and Living Future Institute. 

While the proposal initiated by French environmental activists was for roofs to be completely covered by greenery, the government decided that to ease costs to businesses, roofs must be partially covered (to at least 30 per cent) with greenery instead of fully covered.

However, this is still a huge step toward more sustainable cities and infrastructure, the main benefits being to improve air and water quality as well as to increase greenhouse gas sequestration and combat pollution. Green roofs are also longer-lasting: the lifespan of green roofs is two to three times longer than traditional roofing materials.

Plants on roofs are known to reduce urban heat effect by providing shade, reducing the temperature of roof surfaces, and removing heat from the air. 

The Green Building Council of Australia’s (GBCA) Living Wall and Green Roof Plants for Australia report by the Australian Government Rural Industries Research and Development Corporation in 2012 found that green roofs and living walls in the built environment “offer significant environmental, economic and social benefits” – so why are there so few green roof buildings in Australia? 

There is some progress in Australia, with some green roofs in Sydney and Melbourne having the Green Our Rooftop project as a key part of the Green Our City Strategic Action Plan towards more green infrastructure. There are no mandates on green roofs.

In the City of Melbourne there are currently about 40 green roofs covering five hectares, which compared to other cities is not much. Toronto has around 500 green roofs and Munich has 300 hectares of green roofs. 

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