Secret Gardens – growth in green roofs and walls

Rooftop gardens and green walls are sprouting up everywhere around Sydney in efforts to make the built environment more attractive to workers, residents and visitors. Office and residential building landlords are increasingly embracing the idea as part of their sustainability platform, and have been encouraged by local council development policies.

There are already 49 approved green roofs in the City of Sydney area, ranging from simple planter boxes to the a 2600-square-metre roof garden at the MCentral apartment building in Harris Street, Pyrmont.

Green walls are located at 14 sites across Sydney city, including Australia’s largest – the nine-metre- high and 40-metre-long installation at the six-green-star-rated 1 Bligh Building.

Dusty Gedge is an international ambassador for green roofs and walls, creating countless ‘living roofs’ in London as well as an online guide

When asked why Sydney should embrace them, Dusty replied “they can provide essential habitat for city wildlife, help reduce a building’s energy consumption, capture stormwater and even improve the human psyche. It’s been proven visible greenery makes people happier – it’s a great antidote to the hard surfaces of the city.”

According to Sidonie Carpenter of Green Roofs Australasia, there are significant climate change benefits too. “Modern cities have been compared to a giant, baking hot rock, radiating and multiplying heat like a colossal concrete furnace. This phenomenon is well documented: the US Environmental Protection Agency says most American cities are up to 5.6 degrees hotter than the surrounding land cover.”

Sidonie cites a 2005 study by Ryerson University for the city of Toronto that suggested that covering just 8 per cent of CBD buildings with green roofs would reduce ambient air temperatures by two degrees.

Key issues for owners to overcome have been security and safety.  Most roofs are the end point for air conditioning ducts as well as technology antennas. Green walls may then be the simplest way forward, with a clever landscape gardener employed to help out!

Content sourced from SMH stories by Carolyn Cummings and Tim Elliott