October/November 2006
guest feature
 

The world’s green roofs could be Australia’s market because:

There’s “green gold” across our harsh landscapes

By Geoff Wilson
All Photos Courtesy Dr. Raelene Mibus, unless otherwise noted
photos updated 10.17.06

Australia’s built-environment industry has the opportunity to develop global rooftop service businesses based on our hardy coastal and inland plants.

Hardy native Karkalla.

It could be a proverbial “goldmine.”  But it will require some quick local footwork.

This is because the Europeans are at least 20 years ahead in the environment-enhancing, cost saving green roof business, and the North Americans at least five years ahead.

Northern hemisphere green roof entrepreneurs will probably see the opportunities of our plethora of hardy plants before we do – especially as more of them sniff out green roof business opportunities in Australia and New Zealand.

Left: Native Grass; Right: Flowering Herb.  Photos Courtesy Dr. Raelene Mibus.

Expect it to happen from next February, when a two-day event, “Green Roofs for Australian Cities” will be held at the Brisbane Technology Park in Eight-Mile Plains, Queensland.  The event will have a pictorial display of around 100 of the world’s best green roofs on commercial buildings and on suburban homes.

Green roofs is the new business expansion opportunity now in prospect for Australian architects, urban planners, developers, builders, horticulturalists and building owners.

The good news is that their colleagues overseas have developed green roof technology to a high level of efficiency and reasonable cost.  Even better news is that many overseas green roof experts will be looking for Australian and New Zealand business connections from now on. They will also be interested in Australian native plants for the world’s green roofs.

The advance guard of the northern hemisphere green roof industry is already operating in Australia – and is sniffing out opportunities in our native plants.

Left: Coastal Ruby Salt-bush; Middle: Creeping Boobialla, a green mat growing in a north facing microclimate without irrigation; Right: Flowering shrub.  Photos Courtesy Dr. Raelene Mibus.

Why the sudden interest?

Overseas green roof technology advances in 14 countries of Europe and North America, mean that green roofs of various designs are now considered to be important community corporate and individual responses to the scary prospect of climate change. They are searching for the hardiest “greenery” for less costly rooftop maintenance, and the most attractive visual landscape. Australian native plants can provide both.

Perhaps just as important is the now well-proven selling pitch that green roofs save money – big lumps of it (see side story).

Ruby Salt-bush, creeping, mat forming habit, growing in pure sand in an extreme frontline coastal situation. Courtesy Dr. Raelene Mibus.

Green roof benefits include:

* Thermal insulation – Reduces fossil fuel energy use in heating and cooling of buildings.

* Noise insulation – This is particularly important against transport noises – especially trains, trams, buses, trucks and aircraft.  Tests have shown that a 12cm green roof pad will reduce noise by 40 decibels.

* Slower runoff of rainfall at peak times – Enables drainage infrastructure to cope without massive and costly upgrades. Climate change may bring many more peak loads.

* Reduction of ambient temperatures in cities  – Caused by the heat island effect of buildings and roads, the reduction sometimes is five to 10 degrees Celsius above rural temperatures close by.  The City of Toronto estimates that a mere 8% of green roofed buildings will reduce its “heat island effect” by up to 2 degrees C (see Side Story).

* Air cleaning effects – Green roofs trap harmful particulates and dusts.

* Water cleaning effects – When micro-organisms in a green roof chew up harmful airborne particles the water then harvested from the green roof is much purer than street or rooftop runoff.  A green roof can also be used to renovate “grey water” from homes and businesses.

* Longer roof life and lower roof maintenance costs – Studies have shows that a green roof can protect the underlying structure so that it will last around 40 years instead of 10 to 20 years.

* Visual beauty – A green roof looks great, and has a calming effect that reduces urban stresses on people and enables hospitals to release patients up to two days earlier in some cases.  Green roofs also provide urban workers with more pleasant, restful surroundings and a more pleasant place to enjoy lunch.

* Habitat creation for small song-birds, butterflies and bees – This has been found to be significant in some suburban green roof developments overseas.

* Food from the roof – This is a business opportunity for many as technologies such as hydroponics, aquaculture and aquaponics are being placed on commercial rooftops close to where produce is consumed .  Publisher's Note:  Read Geoff's November/December 2005 Guest Feature Article entitled, "The next profit frontier for green roof companies is…
FOOD FROM THE ROOF."

* Extra revenues for building owners – Renting for food from the roof, or providing a more valuable office or work environment for tenants is possible.

* More valuable buildings – Real estate valuers are predicting that retrofit green roofed buildings will improve in value by 5% to 10% at least.

White Correa

But key to all these benefits is the actual “greenery.”  It must be drought-hardy, low-maintenance and attractive to the eye.  In Europe and North America many of the plants used for green roofs come from Mediterranean or North American cold-hot desert areas where low winter temperatures are experienced (great for the snow-hardiness needed).

Australian native plants of our harsher coastal and inland areas have an important market niche in green roofs both here and in overseas countries with hot, dry climates similar to ours. Our “greenery” supply businesses can be from the cold country of Tasmania and Victoria, to the dry arid zones of South Australia, Western Australian and Queensland, and to the dry and wet tropics of Queensland and Northern Territory.

Left: White Everlasting Daisy (Xerochrysum bracteatum), Middle: Mixed Colors Everlasting Daisy. Source: Association of Societies for Growing Australian Plants (ASGAP). Right: Rock Daisy (Brachyscome multifida). Source: Desert-Tropicals

Myriad native plants of Australia could support significant horticultural and roofscaping businesses.  This applies particularly to the hardy Australian wildflowers we have learned to cherish, and adapt for greater colour.

Left: Native Wisteria (Hardenbergia comptoniana) Source: SunnyGardens.com; Right: Kangaroo Grass (Themeda triandra) Source:  Australian National Botanic Gardens

And that’s another benefit we will experience -- greater urban colour from green roofs.  It could change forever the drab look of parts of our cities, especially during winter.  In Brisbane, green roofs using native flowering plants could provide a riot of delightful, restful colours across our CBD and our sun-dried suburbia.  Big payoffs will be reduced fossil fuel energy use, and more efficient water use – two points that will resonate politically at municipal, state and federal government political levels..

So let’s take a good look at these exciting new uses and business prospects for our hardy coastal and inland plants before the Europeans and North Americans swipe our best.

Left: Native Fuscia; Middle: Hardy Succulent; Right: Austral Stork’s-bill. Photos Courtesy Dr. Raelene Mibus.

It is in our national interest as an exporting nation, and in the global interest as a country blessed with a native plant gene pool of extraordinary potential.  Green roof plant material from Australia can help further develop the ability of the world’s cities to defeat runaway climate change effects before it is too late.

Native Australian Blue Tussock Grass; Courtesy Dr. Raelene Mibus.

SIDE STORY:

Toronto study shows big bucks savings

A study released early this year in Toronto, Canada, has shown that green roof technology can save “big bucks” for building owners and the community.

A key finding was that an 8% cover of green roofs over the city would reduce the city’s “heat island effect” by up to 2 degrees Celsius.

Rapid urbanization around the world has meant that “heat island effects” of cities are becoming significant contributors to global warming.  Compared with nearby rural areas, a city’s ambient temperature can be from six to 10 degrees C warmer because of heat absorbed and then released from roadways and buildings.

Cr Joe Pantalone, Deputy Mayor of the City of Toronto, said the study of the benefits of green roofs to Toronto also included:

* Direct energy savings of C$12 million a year in buildings from reduced cooling demand in summer.

* Indirect city-savings at peak load demand of C$80 million a year.

* Reduced levels of carbon dioxide, nitrous oxide, ozone and PM10 particulates and sulphur dioxide – from reduction of “heat island effects” and the trapping of gases and particulates by plants grown on green roofs.

* Reduction of stormwater flows by 12 million cubic metres a year, so that existing drainage infrastructure can cope, and sewage overflow events were less frequent.

* Cost savings of C$79 million a year from reduced capital costs for storm-water management, erosion control and sewer overflows.

Cr Pantalone said the City of Toronto was now encouraging the built-environment industry, especially building owners, to design and implement green roofs.  The City of Toronto was now planning green roof retrofits on many of the city-owned buildings – especially because such retrofits could often be done within existing maintenance budgets, he said.

Other North American municipal governments, especially in Chicago and New York, are finding similar financial and environmental benefits from green roofs.

Geoff Wilson

Geoff Wilson has been an agribusiness journalist since 1957.  He is now President of Green Roofs for Healthy Australian Cities, and is Australia’s representative on the recently-formed World Green Roof Infrastructure Network of 15 national organisations. Read more about the Conference here, and further information:  www.urbanag.info.

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