Green Roofs are a method of construction which consists of a vegetated medium placed upon the rooftop of any building. Green Roofs have unlimited variations and applications but all exist within two categories, an extensive roof; consisting of a shallow soil system with small plants, or an intensive roof; consisting of a deeper and heavier soil system with larger plants and trees.
As modern cities are increasingly affected by rapid urban expansion and unpredictable climate change, effective water conservation and management is ever increasing in importance both economically and environmentally. Vegetated or “Green” roof covers are an unconventional yet highly effective method of decreasing rainfall runoff in the residential, commercial and industrial landscape. Through their installation the severity of stormwater overflow is decreased both through structural and ecological damage.
This report aims to explore existing foreign Green Roof methodology whilst incorporating climatic, ecological and structural considerations specific to the Eastern Australian region. Through water mass balance of a chosen extensive Green Roof system, and selection of several suitable plant and soil types; an optimal design with respect to water retention and aesthetic value was found. Hardy ground covers such a grasses, turfs and sedums were found to be the most suitable for Australian Green Roofs as they require minimal depth of soil strata to be sustained throughout the year and can survive without irrigation. A shallow substrate of loam soil was found to be the most suitable for water retention, survival of plants and lightweight for the extensive system which suits Australian Construction methods.
Green Roofs as a method of improving the quality of amenity, stormwater and pollution management and construction in inner city and suburban environments have been proven to be transferable from foreign roots to application in the Eastern Australian environment. For efficient utilisation of the overwhelmingly positive aspects of Green Roofs, proper and stringent planning is needed in terms of vegetation, soil and structural considerations, as well as planning the overall purpose of the roof and tailoring the design to achieve this.