Green Roofs and Walls
From the turf roofs of Viking dwellings in Scandinavia to the ‘hanging’ gardens of ancient Babylon, green roofs have a history reaching back thousands of years. Modern green roofs and walls are building elements designed to support living vegetation in order to improve a building’s performance. Also know as ‘living’ roofs and walls, they are emerging as important additions to the palette of construction techniques for creating healthy, ecologically responsible buildings.
A green roof is a roof surface, flat or pitched, that is planted partially or completely with vegetation and a growing medium over a waterproof membrane. They may be ‘extensive’ and have a thin growing medium (up to 200mm deep) with ‘ground cover’ vegetation, or ‘intensive’ and have a soil 200mm deep or more supporting vegetation up to the size of trees. Green walls are external or internal vertical building elements that support a cover of vegetation which is rooted either in stacked pots or growing mats.
Green roofs are an accepted part of modern building in Europe where some city and even national governments have mandated their use (Linz, in Austria requires green roofs on all new residential and commercial buildings with rooftops larger than 100m2, German green roof building has been encouraged by the Federal Nature Protection Act, the Building Code and state-level nature protection statutes). Australian examples are less common but in 2007 a national organisation was formed to promote green roofs and Brisbane City Council included green roofs in its proposed action plan for dealing with climate change.
