By WAYNE THOMPSON
Waitakere City Council is living up to its self-styled "eco city" tag by plumping for a roof of living plants for its new civic centre in Henderson.
The council has approved spending $450,000 on a "green roof" for the building, which council promotion material says will incorporate the "very
latest in environmental design to maximise energy and water efficiency".
Mayor Bob Harvey said the green roof was a fantastic idea. He had seen them on buildings in Germany and London saving power and money.
He said adopting the green roof was typical of his city's leadership among councils in the region in exploring different ways.
Councillors were enthusiastic about the roof serving as a demonstration project of sustainable stormwater management.
A green roof is a waterproof and root repellent membrane, drainage system, filter cloth, growing medium and plants. Manufacturers claim the extra insulation of plants cuts building heating and cooling costs and gives a longer roof life.
Reductions in pollution and flooding from stormwater runoff are also claimed due to the roof garden holding rain and filtering it.
The $25 million Waitakere Central building, which features a delta-shaped council chambers, is due for completion in two years.
The council's 2020 vision is that the city will be an energy cell rather than an energy sink.
But in its decision this week it had to abandon one potential sustainable building feature - a roof-mounted wind turbine to generate electricity.
Henderson Valley Rd was a "low wind site" and the turbine would not produce enough power to warrant the $192,000 outlay, said city development manager Lois Easton.
Makers of rubber membranes for green, or sod, roofs report a small demand in New Zealand and only for houses.
