How Can Green Roofs Make Our Cities Better?

An excellent article in ArchDaily recently explored some of the ways that green roofs can make cities better. Read on to find out more.

Researchers credit the Hanging Gardens of Babylon as the first examples of green roofs. Although there is no proof of its exact location and very little literature on the structure, the most accepted theory is that King Nebuchadnezzar II built a series of elevated, ascending terraces with varied species as a gift to his wife, who missed the forests and mountains of Persia, their local land. According to Wolf Schneider [1] the gardens were supported by brick vaults, and under them, there were shaded halls cooled by artificial irrigation of the gardens, with a much milder temperature than the outside, in the plains of Mesopotamia (present-day Iraq). Since then, examples of green roofs have appeared all over the world, from Rome to Scandinavia, in the most diverse climates and types.

Nevertheless, inserting plants on roofs is still viewed with suspicion by many, as they are thought to be costly and difficult to maintain. Others, however, argue that the high implementation costs are quickly offset with savings in air conditioning and especially that occupying the building’s fifth façade with vegetation is, above all, a rational solution. In any case, the question remains as to how green roofs can really help with climate change.

A green roof consists of a roof slab that, on top of it, has a layer of soil and vegetation on a waterproofed surface, which can be flat or slightly sloping. The thickness of the soil layer will influence the type of vegetation that can be planted, ranging from 15 centimeters to more than 1 meter. Constructively, below ground, several layers of materials are usually inserted, with variations and sophistication in the details according to the responsible designer. Under the substrate, a geotextile blanket is usually included, which will let the water through but keep the earth contained. Below is a drainage layer, where the water will remain stored and overflow drains are installed. Including an anti-root layer is important to prevent them from infiltrating the structure and triggering more infiltrations. Underneath this, the slab structure, waterproofed in some way, completes the system.

For the full article, please visit – https://www.archdaily.com/967909/can-green-roofs-make-our-cities-better