For a city of its size and place as a global leader, Melbourne is only just beginning to foster the idea of green roofing as a sustainable form of landscaping design. While growth is slow, the incentives to retrofit city buildings with green roofs are insurmountable.
Award winning retrofitted building 131 Queen St in Melbourne’s CBD is the first of its kind in the city. The 2010 design was won by architecture group Bent architecture at the “Growing Up” Green Roof competition last May. The award gifted to the company that best fitted the brief was the contract sponsored by the government in association with Melbourne Water, Sustainability Victoria, VicUrban, City of Melbourne, and Australia Post.
The major design focus for the project was a “looking inwards” principle which emphasised the idea of a private space in a very public domain. In order to complete this task the following design aspects were initiated.
After waterproofing the sectioned off roof that would be used for the retrofit, a central landscaped hill was created. This was added to have a 3D quality, and to create a level of relative privacy. Perimeter seating was then added with elevated garden beds surrounding in order to use the limited space to its greatest capacity, as well as create an intimate space of inward focus.
It is important to note that not only would this area become a sustainable landscaping aspect, it would be a haven for the 13 floors of occupants of the building. This includes a law firm, Fo Guang Yuan Buddhist art gallery, the Lyceum Language Centre and Open Universities Australia. Due to this factor user friendly aspects had to be included, taking a simple sustainable retrofit into the realm of sophisticated landscape gardening.
The actual materials for the project were all craned onto the roof in a day. The major issue the design team found was the weight the hill. Traditional designs for the fixture would be too great for the 70 person max rooftop. Instead a recycled polystyrene faux hill was created, covered in hessian and filled with soil and topped with plants. In place of a tree that was to be the focal piece of the hill, a sculpture was added due to its light weight nature. Over 1300 donated plants were used on the rooftop, both indigenous and hardy, most without the need of irrigation.
Other sustainable aspects of the green roof include recycled glass for roof paving, seating covered with salvaged tiles and recycled timber. Any waste throughout the building is used as mulch and the area is being used increasingly by building occupants, leading to a sense of social responsibility and sustainability.
The green roof as an insulator has been predicted to lower summer cooling by more than 50%.
Bent architect and the designer of the buildings green roof emphasise design as a major focus to the modern sustainable green roof. Green building does not mean that style has to be forgotten.
“A rooftop is an architectural element” the designer said.
This idea that sustainability is simply an added fixture in landscape design is incredibly important when moving forward with modern urban landscaping. The design of the green roof at 131 Queen St. is a testament to this theory.
Image: as sourced from australian design review