Fire Reduction

In the 1880s, German roofer H. Koch put a layer of soil and gravel on tar roofs to prevent roof fires. These roofs were germinated by wild seeds, and the modern green roof was inspired 70 years later when these roofs were found to be still intact and waterproof, having survived 2 world wars. (Earth Pledge, 2005)

A green roof has a burning heat load of 3 kWh/m² while a 3-ply bitumen roofing system, a common membrane type, has a burning heat load of 50 kWh/m². (M Koehler, 2003) This means that the heat from a fire on a green roof will be 1/16th the heat from a bitumen system.

Some plants are more fire resistant then others. Succulents such as sedums contain water and are difficult to burn. Grass, however, can dry out during drought conditions and become more flammable.