Architect Hugo Gilardi is adamant that installing green roofs across schools and government buildings would be a significant proportion of the 1,400 hectares of green roof he believes sufficient to generate a positive environmental impact across the city of some 20,000 hectares. He explained that schools are the perfect starting point for the project due to the effect on the neighborhood. “The green roof becomes an outdoor classroom for learning about ecology and agriculture, by extending the context of teaching and learning media”, he said.

Construction spanned about 45 days and includes an automatic drip irrigation system to overcome the few occasions where local rainfall is not sufficient to maintain the garden. At first, a membrane was installed that protects the roof from continuous contact with water. A layer of around 50mm of substrate was then applied which not only provides a media in which the plants can be grown, but also enhances insulation and retains up to 90% of rainfall to mediate against potential flooding from runoff. The roof was covered with more than 4,000 seedlings, including native species that are best adapted to local conditions. To compare the impact of the green roof, around half of the 240 square meters total area remained as conventional roofing. Analysis includes measuring thermal insulation, rainwater retention capacities, sound insulation, and the ability for the roof to clean the atmosphere by comparing suspended particulate matter.