Believe It Or Not, This 'park' Is On The Roof Of A High-rise

Sun Herald

Sunday August 26, 2007

By Hannah Edwards Environemnt Reporter

RICE paddies and orchards on city rooftops could become reality with a plan to green Sydney's roofs.

A group of architects and environmentalists will explore ways to green the CBD's rooftops following approval of a $48,000 grant from the City of Sydney council.

A committee member, architect Tone Wheeler, hopes to demonstrate that 25per cent of city rooftops and half of those in fringe suburbs, such as Pyrmont, could be transformed.

"It'd mean an enormous increase in parkland in the city," he said.

The rooftop gardens could also have commercial potential.

"There could be organically grown food grown on the roof and sold in the cafe below," Mr Wheeler said.

The group's first step is to draw up plans to overhaul a Pyrmont high-rise's 2000-square-metre roof that could be used as a template.

"We can plant trees and do carbon offsets, provide shade and make a substantial change to its look," he said.

Mr Wheeler, who runs environmental architect firm Environa Studio, said the old-fashioned idea of English-style allotments could also be introduced to the building as well as water tanks. More households are incorporating roof gardens, designers say, and developers spruik them as a selling point to environmentally conscious city dwellers or office workers.

Lend Lease's new Millers Point development, 30 The Bond, has a roof garden with rows of low-growing, drought-resistant species such as agave, agapanthus, and lomandra.

Garden designer Jamie Durie's company, Patio, has worked on several Sydney rooftop gardens and is working on projects in Chicago and New York, where the concept is more advanced.

"Wherever the sun falls there's an opportunity to grow a garden," he said.

Garden designers at landscape architects 360? have created a green oasis on the roof, complete with timber boardwalks, cascading water features and plenty of spiky succulents, at heritage development M-Central, in inner city Pyrmont.

Resident Margaret Holmes, who has lived in the building for two years and visits the garden daily with her dog Zulu, is enjoying the green space. "It's pretty rare for an inner city apartment building," she said.

JAMIE'S TIPS FOR A TOP ROOF GARDEN

* Good drainage is essential. Water from plant pots should be filtered through fibrous membrane so it isn't laden with silt. There should also be a good layer of gravel under the plants and soil.

* Rooftop gardens need to slope. They also need to sit on impervious membrane so water doesn't flow to floors below.

* When choosing what to grow, "you really want bulletproof plants", Durie said. Ornamental grasses, New Zealand Christmas bush, Westringia fruticosa and grevilleas work well.

* Weight is important. When building, most engineers don't allow for a rooftop garden, Durie said. Rooftops can be strengthened with beams and the weight needs to be spread out over a large area.

* Council approval is needed for a rooftop garden.