Although the global trend in green roof systems might seem to be a development of recent decades, green roofs have been around since ancient times.
The first known historical reference to man-made gardens on rooftops is of ancient Mesopotamia. These were built from the fourth millennium until approximately 600 B.C. In the 13th century, the French planted gardens on top of a Benedictine abbey and in Norway, sod roofs have been used for centuries as a means to thermally insulate buildings. These sod roofs are still being used in Norway and also in the United States today, to guard against extremely cold winters. The famed Rockefeller Center in New York City had five roof gardens installed between 1933 and 1936.
So, while green roofs cannot be seen as a new development, they are certainly becoming increasingly more innovative and multifunctional. Modern green roofing technology began in Germany in the early seventies with the first rooftop gardens that offered sophisticated technology for irrigation and for the prevention of root ingress.
The subsequent development was extensive green roofs. These came about in the later 1980s with the development of lighter and cheaper green roof systems that could be quickly applied to large flat roofs. These green roofs protected roofing membranes from temperature fluctuations and other weather elements while also restoring nature in urban areas.
Finally, we come to today’s green roofs. Because this area has been the subject of considerable scientific research, the multiple additional advantages of green roofs have begun to be recognized. Benefits include: reduced energy consumption for heating and cooling; heat island mitigation; habitat restoration; water filtration and storm-water retention and many more… Progressively, the benefits of green roof – from noise reduction to the therapeutic effects of bringing nature to urban populations – are now widely accepted.
GreenRoof Asia recognizes the importance of scientific research and innovation and always looks at ways to push the boundaries of what green roofs can offer. Our current projects include roof-top wetland projects and, uniquely in Hong Kong, we are now collaborating with academic researchers to investigate the added benefits such a project can have on the local environment and on green building efficiency.
Wark and Wark (2003) – Green Roof Specifications and Standards