In a perfect world every building would have a green, living roof. We are talking lush green spaces to replace the ugly, concrete surfaces and airconditioning units that continue to dominate our cityscapes.
That is the dream of organisations like Green Roofs Australia, a group of landscape architects, designers and horticulturists who have joined together to influence government policy and inspire developers to “green up” the hard spaces in our cities.
According to Sidonie Carpenter, president of Green Roofs Australia and principal of her own landscape company in Brisbane, increasing the number of garden roofs could be a crucial step in the fight against global warning and maintaining healthy communities.
“In order to catch up with our counterparts in other countries, we need to set an industry standard in line with Australian conditions and work with all levels of government to set a green roof policy,” says Carpenter.
A green roof is partially or completely covered with vegetation and soil, planted over a waterproofing membrane. They come in all shapes and sizes, for environmental and recreational use, from expansive grass areas to edible gardens or a cornucopia of parklands. These roofs are often simply designed for their environmental benefits, but these sky gardens are increasingly becoming green sanctuaries against the harshness of urban development encroaching on our green spaces. As more people flock to cities and land becomes premium, rooftop gardens will become even more important.
Germany is leading the way and has been incorporating green roofs into residential and civic design since the 60s. In fact, it is estimated that around 10 per cent of roofs in Germany are green, and in some parts of the country new buildings must have garden roofs by law. The city of Chicago in the US has a green roof policy and London is working with developers to encourage more green roofs.
WHY GREEN ROOFS?
Matthew Dillon from landscape design company Material is passionate about the ability of vegetation-clad buildings to reduce energy consumption and as great vehicles for delivering fresh air and sunlight to those who live and work in them.
Matthew believes the future is in living buildings, places where we can minimise our environmental impact, and create healthy communities and cities. Australia needs to move ahead with policy development and implementation guidelines to make it an attractive option for developers. At the moment, the expense often inhibits the decision to include a green roof on new building developments in Australia. Although Australia is lagging behind other countries (Germany, the US, Canada) and cities (London, Tokyo and Chicago), there are some interesting projects in development.
COMMUNITY BUILDING RECREATIONAL SPACE
Architects are starting to include roof gardens in some high- and medium-density developments throughout the country. In Sydney’s M Central in Ultimo, for instance, the garden has helped build a community in what could have been just another medium-density residential development. Daniel Baffsky, the landscape architect responsible for the rooftop garden, believes the garden has contributed to the strong community network in the building.
“Neighbours meet in the garden, they socialise and relax. Many people in the building own dogs, so rather than walk through the streets of Ultimo after work they can walk them in the safety of the garden. It is their own little slice of paradise,” said Baffsky, who is also responsible for the rooftop garden at the redevelopment of the old Weston’s Biscuit Factory in Camperdown, which has also incorporated a lap-pool for residents.
Other notable rooftop developments include the new Barcelona building in Kings Cross, Sydney, which is home to newly launched restaurant and bar, Blanco, and features a private rooftop garden. The Ivy nightclub development in Sydney’s CBD has been designed around a central garden and Cloudland, a nightclub in Brisbane, goes one step better with a living green wall.
And let’s not forget the green roof on Parliament House in Canberra, as well as the rooftop garden in the NSW Parliament House that was originally built in the 70s and is now maintained by the Sydney Royal Botanic Gardens.
GROW YOUR OWN
Edible roof gardens are also a great way to reduce food miles. Matthew talks about some of the great gardens around the world like the Fairmont Royal York hotel in Toronto, Canada, where the chef has set up a produce roof garden to supply the hotel’s restaurant. The green roof supplies a variety of fresh produce, including tomatoes, zucchini, squash, cucumbers and herbs, such as lemon balm, basil, oregano, lavender, mint and chives, for flavouring dishes.
In the UK, the Reading International Solidarity Centre has transformed the once ugly Victorian rooftop into an amazing edible garden with lush plantings of more than 180 species of edible and medicinal plants. “Growing our futures”, the project behind this wonderful garden is all about reducing the environmental impact of cities by promoting biodiversity, producing food, reducing heat islands, storing and managing water, encouraging organic waste management (composting) and recycling, increasing thermal and noise insulation, and creating enjoyable garden spaces.
Edible roof gardens are popping up in some incredible places. Surprisingly, the newly refurbished Changi Hospital in Singapore now sports a hydroponic roof garden that yields some 200kg of cherry tomatoes, which supply the hospital’s catering service as well as providing shade to reduce solar heat gain and energy consumption.
Although the edible option hasn’t taken off in Australia yet, there are plans in South Melbourne for an edible roof garden to supply an attached cafe, the first of what will become a growing trend.
Data out of the Green Roofs Australia conference in Melbourne suggests that these passionate experts will see their dreams come to fruition as we move into the future. Politicians and green roof experts are working together to develop policy in Queensland, New South Wales, Victoria and South Australia. This combined, with the creation of a national standard for green roofs, will mean that the future is definitely getting greener and living cities will be a reality.
BENEFITS OF ROOF GARDENS
Reduction of Heat Island Effect
These roofs can reduce the urban heat island effect by lowering ambient air temperature by up to 2C if just 8 per cent of buildings have green roofs. A US report in BioScience estimates that green roofs can reduce the cost of airconditioning by as much as 25 per cent and electricity by up to 50 per cent.
Storm water management
Green roofs reduce storm water volume and flow, thus reducing pressure on storm water infrastructure. They also filter and cool water run-off and help prevent nitrogen and other toxins entering waterways.
Social benefits
Green roofs enhance wellbeing and happiness, thus creating strong residential and workplace communities.
Increased building marketability
High-rise apartments, office space and even hotel rooms with enhanced green views can command higher rents and room rates. Real estate studies in Britain indicate that good tree cover can increase the value of a property by up to 10-15 per cent.
Amenity
Green roofs can provide sustainable interactive community spaces where people can garden, visit, play and relax together away from the stress of city living.
