'Green Skins': reconsidering green roofs as sustainable infrastructure

Green roofs are increasingly seen as a key design strategy to increase the liveability, efficiency and productivity of Australian cities. They are also often seen as an antidote to the impacts of the compact dense city: a spatial layout that is well established in sustainable city discourse (Jenks and Jones 2010, United Nations Human Settlements Programme 2009). The list of benefits attributed to green roofs is broad and widely shared. They include reduction in the heat island effect, noise reduction, energy conservation, amenity, replacement of lost green space, increased property values, and storm-water management (Getter and Rowe 2006, Tourbier 2011). Green roofs it is further claimed transform cities from urban grey to green, (Weiler and Scholz-Barth 2011 p.26) while at the same time mitigating the effects of climate change. There is, however, little evidence to support all of these claims particularly within the Australian context where the development and construction of green roofs is a fairly recent phenomenon. This paper presents preliminary findings from a larger on-going study that attempts to monitor, test and evaluate the performance of a Melbourne based experimental system focussing, in the first instance, on soils and plant material. Evaluation of the experimental systems employs performancebased criteria in an effort to shift attention away from considering green roofs as simply sustainable building infrastructure, towards a research agenda that considers what they do and how they do it.