Urban greening has long been promoted as an easy and effective strategy for creating natural beauty in the built environment and increasing investment opportunities. Our experience designing over seven football fields of green roofs demonstrates this growing trend.
Whilst green roofs are known for their aesthetic features, one of their many benefits is to provide added insulative properties to the building beneath.
In the short term, savings can be achieved in heating and cooling costs because the layer of vegetation provides excellent insulation to the building. The green roof acts as thermal mass keeping the internal temperature of the building relatively constant. Should the plants be allowed to spread, this enhances the biomass and access for the root system for the plants and living in an ecosystem not unlike being on natural ground. Established green roofs regulate rooftop temperature with a flow on effect to the interior temperature therefore reducing the dependence on HVAC systems. Established green roof structures also assist to increase the efficiency of rooftop infrastructure including Photovoltaic cells and the efficiency of other service equipment by reducing glare and air temperature on the exposed surfaces.
Key to achieving insulation benefits is the varying depths of soil and vegetation, with current research indicating that a minimum soil depth of 300mm and shrub planting required to achieve a 15% annual reduction in energy consumption.
For further information regarding Green Roofs we recommend that the following sources may be of benefit.
Wong, N.H et al. 2002. The effects of rooftop garden on energy consumption of a commercial building in Singapore. Department of building, school and design and environment, National University of Singapore.