Never would I have imagined city centers and business districts covered by roofs of greenery. Had you asked me a few years ago, I would have said it sounds like something you will only find in Chernobyl.

 

I was recently introduced to the concept of green-blue roofs. Being taken on a tour of a university faculty building in central Amsterdam I was able to see the huge amount of opportunity which lies in simply having a flat roof which would otherwise never be used for more than shelter. Doing some reading, I have found out that I have been in the dark as it is no new concept and I wanted to share what I have found out.

 

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Green roofs are no new invention as they appeared four thousand years ago in the Hanging Gardens of Babylon which is one of the seven wonders of the ancient world. I always find myself pleasantly surprised as history provides us with so many answers if we open ourselves up to reading what is often considered “outdated”. I have been confronted with this thought often when looking up the origins of recycling, circularity and even Aquaponics which can be traced back to the Aztec Indians who raised plants on the surface of a lake around 1000 AD. Moral of the story, in the history of man, resources were scarce and humans needed to get creative if they were to survive. History can inspire the breakthrough innovations which we need in the face of climate change and it does not always need to be in the implementing of new technologies or any new studies which give us yet another overflow of information for finding answers. Maybe we should simply learn from our ancestors.

 

Back to modern green-blue roofs however, rooftop gardens used to be novelty enjoyed by the wealthy as early as the 1890s. It was in the 1970s, during the oil crisis that Germany, as one of the green roof pioneers, began investigating the uses of green roofs for energy conservation. Since then, green roofs have become increasingly common despite the costs involved in implementation and maintenance, which could be due to the multiple benefits and gains which green-blue roofs bring.

 

To discern the differences between green roofs, blue roofs and green-blue roof technologies:

A green roof: A layer of vegetation planted over a waterproofing system that is installed on top of a flat or slightly sloped roof. Green roofs are also known as vegetative or eco–roofs. They use a drainage layer to provide lateral drainage and irrigation. 

A blue roof is designed to hold water. These roofs will collect rainwater and other precipitation so that it can be drained slowly or redirected for re-use. This technique is most commonly used in dense urban areas where other methods of stormwater detention are impractical.

 And you probably guessed it, a green-blue roof combines the two technologies together.

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 Besides the excitement of a rooftop terrace, green-blue roofs come with multiple benefits in terms of health, biodiversity, energy, water and financial, making it a feasible option for any home or organization to start the shift.

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