Kangan Institute Green Roof

 Location:                     Docklands Campus, Kangan Institute, Harbour Esplanade, Docklands, Victoria

Completion date:         November 2012

Area:                           250 m2 on a new building

Description

This water-efficient green roof is designed as a space to provide amenity for staff. The area is not open to the general public. Decking and seating is provided. The roof is built on a concrete roof deck with 1.5 degree slope, it is above the third storey.

Introduction

The Kangan Institute Automotive Centre of Excellence (ACE) is located in the Batman Hill Precinct of Melbourne’s Docklands. The building holds a 5 Star Green Star rating. The building houses a 2,000 m² area of automotive workshops, and 1,200 m² of specialised training and office areas.

The green roof is located adjacent to the administrative offices, and over the learning suites, which will benefit from reduced heat loads.

The green roof was designed by ASPECT Studios, in collaboration with Gray Puksand Architects. Robert Bird Group provided structural and civil engineering services. 

The green roof was installed on the concrete roof deck of the new concrete-framed building.

Design and Components

The roof weight loading is 200 kg/m2. Roof drainage is achieved through a series of in-floor sumps, with overflow risers installed along the bottom of the roof slope.

The drainage layer is Atlantis® 20 mm Flo-Cell™ drainage cell, with flow across the roof to perimeter drain. The filter sheet is Bidim® geotextile, Grade A14. For waterproofing, Waterproofing Technologies’ Enviro HP1200 was used. This is a two-component, spray-applied, flexible polyurethane membrane. A leak detection system was not installed.

As HP1200 waterproofing treatment is rated as root-resistant (through a testing procedure specified and assessed by CSIRO), a root barrier was not required. Separation sheets of low-density polyethylene (LDPE) were installed to protect the waterproof membrane during construction.

Stormwater run-off was captured to irrigate the green roof, as well as toilet flushing: one point was awarded under Green Star’s WAT-3 criterion for the required measurable reduction (by 90 per cent) in potable water consumption on the site from these initiatives. Fytogreen Australia designed and installed the irrigation system. Irrigation is delivered through a Netafim™sub-surface dripper system. This is water-efficient, programmable and automatic enabling the duration and frequency of irrigation cycles to be adjusted.

ASPECT Studios developed the planting design, which consists of low water use herbaceous and succulent perennials: all have performed strongly.

Plant species used
Anigozanthus ‘Ruby Velvet’Carpobrotus edulis

Crassula capitella ‘Campfire’

Dianella caerulea ‘Cassa Blue’

Dianella caerulea ‘Little Jess’

Lomandra longifolia ‘Tanika’

Poa poiformis ‘Courtney’

Sedum palmeri

Maintenance

Establishment maintenance was provided for eight weeks after planting. The green roof was then managed by the Kangan Institute maintenance team. Plant nutrition is provided as 12 to 14-month low phosphorus controlled-release fertiliser applied at half the recommended rate.

Cost

Total: $56,000.

Results and reflections

The garden has suffered somewhat from a lack of maintenance. A maintenance strategy is now being developed. Bird control has been needed as seagulls have been nesting in the garden after being disrupted from nesting elsewhere on the building.