Burnley’s Green Roof

11 July 2013 — The University of Melbourne’s Burnley Campus has been given a green lift with a network of lush rooftop gardens.

The gardens were designed and built by HASSELL and the three green roofs couple green technology with actual greenery.

John Rayner

Melbourne University Urban Horticulture senior lecturer John Rayner said the idea for the roofs, which include a demonstration roof, a research roof and a biodiversity roof, had started with a research group formed in 2007.

The three areas of focus were plant suitability, substrates and water, he said.

Mr Rayner said most research on green roofs was carried out in countries with cooler climates than Australia using different plants and without the issues of water availability.

The demonstration roof

A small roof of just 20 square metres was created in 2008 and the university teamed with the CSIRO to do a study on temperature under the roof, he said.

“In our summer of 2008 to 2009 most of the plants actually died but there was still a significant difference in energy savings in the little room under that roof.”

Mr Rayner said the next step was to apply for funding through various grants for a larger proposal to build more sophisticated research.

After they were knocked back by organisations the university decided to fund the research itself. And the three roofs were created.

The demonstration roof

The demonstration roof welcomes visitors, showcasing planted zones in an exhibition style, from irrigated to non-irrigated areas that are planted over a wedge structure.

The different zones of the demonstration roof are threaded together with a continuing red edging that leads visitors from one garden to the next. Expanded sitting areas also double as outdoor classrooms for studying the experimental landscaped zones.

The biodiversity roof

The biodiversity green roof takes up 52 square metres and has been designed to attract and provide habitat for lizards, insects and birds. Features on the roof that encourage and sustain biodiversity include:

  • Water – a small ephemeral pond and shallow creek bed is fed with water supplied from run-off.
  • A range of substrate types – the main substrate is 10cm deep scoria-based mix, but smaller pockets of sand, gravel, ash and waste rubble materials were added to provide different micro-habitats.
  • Indigenous plants – predominately native grassland species, including known food and nectar sources for beetles, bugs, butterflies and native bees.
  • Habitat features – includes logs and rocks for invertebrates, hollow twigs for native bees, and slate tiles and ceramic pots for basking lizards.

The research roof

A purpose built 80 square metre green roof for research consisting of four quadrants – three with planting beds of varying substrate depths from 15-25 centimetres, and a control bare roof. The research roof is fitted with instrumentation to monitor climate and hydrology data.

Keys areas of green roof research:

  • Quantification of the effects of substrate depth and plant types on stormwater and energy benefits
  • Evaluation of long-term plant performance

Overall benefits

Green roof benefits include:

  • Reduced storm water runoff
  • Lower building energy needs
  • Increased urban biodiversity
  • Potential for local food production
  • Improved health and liveability of cities
  • Visual amenity

Mr Rayner said the main function of the roofs was to support research and teaching at the university and with outreach programs.

“Green roofs are getting bigger in Australia, there are many in Melbourne and across Australia, and we also help people make better designs,” he said.

One of the biggest challenges was the range of disciplines needed to create a viable green roofs from architects and developers, to social scientists and horticulturalists, he said.

“There is also a lot of green wash out there but the only systems we are interested in are long-term installations with multiple benefits like significant energy benefits or biodiversity values.

“Many cities around the world are now creating green roof mandates and we are helping create guidelines for the City of Melbourne now.

“It’s still a relatively new industry but it’s very exciting.”

Open day

Burnley Gardens Open Day will be held Sunday, 14 July.

The day, delivered in partnership by the University of Melbourne’s School of Land and Environment and Friends of Burnley Gardens, will see horticultural experts offering free lectures and paid workshops, kids’ activities, forums and seminars on leading sustainable gardening practice.

The green roofs will be open and Mr Rayner will hold talks and tours. No bookings are required.

Burnley Campus is 500 Yarra Boulevard, Richmond.

Details here.

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