green roofs could be Australia’s market because:
There’s “green gold”
By Geoff Wilson
All Photos Courtesy Dr. Raelene Mibus, unless otherwise noted
photos updated 10.17.06
built-environment industry has the opportunity to develop global rooftop
service businesses based on our hardy coastal and inland plants.
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.
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
The advance guard of the northern hemisphere green roof industry is
already operating in Australia – and is sniffing out opportunities in
our native plants.
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).
Salt-bush, creeping, mat forming habit, growing in pure sand
in an extreme frontline coastal situation. Courtesy Dr.
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
* 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
* Air cleaning effects – Green roofs trap harmful particulates
* 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
* 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
* 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%
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
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.
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.
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
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.
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.
Blue Tussock Grass;
Courtesy Dr. Raelene Mibus.
A study released early this year in Toronto, Canada, has shown that
green roof technology can save “big bucks” for building owners and the
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
* 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,
Other North American municipal governments, especially in Chicago and
New York, are finding similar financial and environmental benefits from
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:
“GREEN ROOFS FOR AUSTRALIAN CITIES”
is a two-day event in Brisbane, Queensland, on February 22
and 23, 2007. It is hosted by Green Roofs for Healthy
Australian Cities, and supported by Greenroofs for
Sustainable Cities (NZ), based in Auckland, and Green Roofs
for Healthy Cities-North America, based in Toronto, Canada.
Concurrent with it will be a Green Roof Pictorial Display of
up to 100 posters on some of the world’s best green roof
See menu item at
www.urbanag.info for registration details.
Read the related article below including extensive
commentary from Geoff Wilson:
Roof garden idea grows on Power
The Gold Coast Bulletin, by Staff
October 19, 2006
Molendinar, Australia. "The Gold Coast skyline may soon
resemble the hanging gardens of Babylon. Plans are afoot to
transform the city's urban desert into an environmentally friendly
oasis in the sky. Deputy Mayor David Power wants the city council to
investigate creating rooftop gardens on buildings across the
Coast...Geoff Wilson, who promotes green roof schemes in Australia,
said the Brisbane City Council was also looking at similar projects.
He said he had been commissioned to find six potential trial sites
in the Brisbane area..."
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