A History of Green Roofs – From Vikings to Urban Dwellers

A History of Green Roofs

From Vikings to Urban Dwellers

Green roofs. We know them, we love them, they’re innovative, they’re sustainable. But did you know they’ve been around a lot longer than we think? As stunningly innovative as most green roofs in the 21st century are, they aren’t a new idea. In fact, they’ve been around for centuries, with ancient civilizations finding innovative ways to integrate nature into their structures. From the mythical Hanging Gardens of Babylon and Scandinavian turf huts to the eco-friendly rooftops of modern cities, green roofs have evolved into a crucial part of the sustainable urban environment. Let’s take a journey through history to see how green roofs have changed over time.

Green Infrastructure Throughout History

One of the earliest and possibly most legendary examples of green infrastructure can be traced back to ancient Mesopotamia. That’s right folks, we are heading all the way back to 600 B.C.. And while the ancient Mesopotamians didn’t have the technological advancements that we do today, they created one of the Seven Wonders of the Ancient World; the Hanging Gardens of Babylon. These were an architectural and horticultural marvel, said to have been created by King Nebuchadnezzar II for his wife, Amytis, who longed for the lush greenery of her homeland. Now, their existence still remains to be a subject of debate among historians, but the very idea of them shows an early human desire to bring nature into constructed spaces.

Traveling far, far away from the deserts of Babylon, we find the rugged landscapes of Scandinavia, where a long-standing tradition of green roofs still holds strong to this day. Norwegian sod roofs, which date back to the Viking Age, were a practical solution for insulation and protection against any harsh weather. These roofs were constructed with layers of bark and turf, and had grass and other plants growing on top. The vegetation helped provide natural insulation, which kept homes warm in the winter and cool in the summer. Sod roofs are first and foremost there for functionality… but we know you can’t argue that they blend so seamlessly into the surrounding environment and create that perfect rustic charm.

Not all examples of historical green infrastructure are on the rooftops. In ancient Rome, wealthy citizens often incorporated gardens and terraces into their homes. Mediterranean summers can be quite warm, and (unfortunate for ancient Romans) air conditioning did not exist back then. To combat the heat, homes of the wealthy were designed with a central open-air courtyard which would promote air circulation and provide the perfect space to cool off. These open-air courtyards would most often be equipped with central fountains as well, which helped cool off the space even more. While not essentially a green roof, this is an example that shows humanity’s long-standing desire to bring nature into architecture, and recognition of the benefits of doing so.

This desire, however, lost its spark in place of industrialization during the Industrial Revolution (1760-1840). Urbanization prioritized factories and infrastructure over green spaces, leading to the decline of green roof practices. Buildings became more about function than form and aesthetics. Very little thought was given to environmental integration during this time period. Green roofs, like many other sustainable practices, were largely forgotten during this era.

We know that this changed, and sustainability started to make a comeback, but why? In the mid-20th century we saw a resurgence of interest in green roofs, driven by growing environmental awareness. As people began to recognize the consequences the unchecked urbanization of industrialization brought, green spaces started to reappear in cities around the world. Germany was a leader in this cause, adopting green roofs on a larger scale starting in the 1960’s. These early pioneers helped pave the way for the modern green roof. This is when we started to realize that while green roofs could still be about keeping the house cool or warm, they would also address other environmental concerns such as air quality, stormwater management and biodiversity.

Urban Green Roofs and Their Future

Thanks to modern advancements, green roofs today have evolved with two main types in use; Extensive Green Roofs and Intensive Green Roofs. Extensive Green Roofs are lightweight, low-maintenance and often seen on commercial buildings. They typically feature drought-resistant plants and require minimal upkeep. Intensive Green Roofs, on the other hand, are more like a rooftop garden. They can support a wider variety of plants, including small trees, but require more maintenance and a stronger structural foundation. These are the rooftops that we typically see as forms of sustainable agriculture, or gardens for residents and other patrons to visit.

The advancements in technology also play a large role in how green roofs have changed. Waterproof membranes, drainage systems, and lightweight growing mediums make it easier than ever to incorporate green spaces into any urban architecture. Green roofs aren’t just spaces for plants either, some integrate solar panels or contribute in some way to make the buildings they sit atop more energy efficient.

With all this advancement comes a multitude of benefits. In urban areas like Vancouver, green roofs help reduce the “heat island” effect (where cities become significantly warmer than surrounding rural areas). They also manage stormwater by absorbing rain, which helps reduce the strain on drainage systems and helps filter pollutants. Green roofs also improve air quality, provide habitats for birds and insects, and even contribute to the mental health of residents by giving them a space to soak up some vitamin D!

As cities continue to grow, the role of green roofs will become more important in creating sustainable urban environments. It’s incredible to see more cities around the world embracing green roof policies. For example, Toronto mandates that new buildings above a certain size must incorporate green roofs, while Paris is planning to cover half of its city’s rooftops in greenery or solar panels by 2030. A global leader in green infrastructure happens to be Singapore, which is often referred to as the “City in a Garden”.

From the ancient Hanging Gardens of Babylon, to the sod roofs of Norway, to the courtyards of ancient Rome, green infrastructure has a long and rich history. What started as practical solutions for insulation and aesthetics transformed into a modern-day necessity for the urban environment to continue to be sustainable. As we look to the future, green roofs will continue to evolve, helping cities manage environmental challenges while bringing nature back into urban spaces!