KEY POINTS:
A "green roof" on top of the Waitakere City Council has withstood the long dry summer and even picked up a couple of awards for promoting sustainability.
The roof of native grasses and other plants was installed in 2006 on the newly-built civic centre in Henderson.
The council's parks planning manager, Renee Davies, said she believed it was the first extensive green roof using native plants to be established on a purpose-built commercial building in New Zealand.
A waterproof membrane had been laid over the concrete surface and covered with a root barrier and light substrate.
Mrs Davies said at the time of the planting in the 2006 winter, the vegetation cover was 15 per cent. It had spread to 27 per cent by the end of the year and was now 63 per cent.
The plants had performed well over the unusually dry summer with no irrigation. The native iceplant and the native sand convolvulus had bewen the species most resistant to drought.
Mrs Davies said the roof supported a surprisingly diverse fauna.
Ants and spiders had settled there, which raised the prospect of releasing lizards.
The roof had cost about $190 a metre which was comparable to the price of carpet.
Mayor Bob Harvey said he was delighted the roof had won two awards from the Institute of Landscape Architects, for communication and promotion and excellence for sustainability.
"This shows that we are leading the way in this environmental field. Now that this has been recognised, it is our job is to ensure that we consistently incorporate more of this type of environmentally friendly technology into our buildings."
The judges had said the 500sq m green roof brilliantly articulated a 21st century sustainable landscape solution.
