Green Roofs on Favelas in Brazil
Favelas are neighbourhood communities where the working class and poor live. These neighbourhoods exist when homeless people or squatters occupy vacant plots of land and build their homes out of things they find scavenging. In Brazil, many of the favelas exist around the cities of Rio de Janeiro and Sao Paolo. Over 11 million people live in a record number of 6,329 favelas.
The favelas are typically built of brick, concrete and reinforced steel. Many homes have roofs made from corrugated steel sheets, a material frequently used because of its low cost. One of the major problems with this type of material is that it is a conductor of extreme heat. Brazilian summers can get very hot, reaching temperatures up to 43 degrees Celsius (110 Fahrenheit). Another contributor to the heat is that favelas lack areas of greenery which would lower air surface temperatures instead of absorbing it like concrete does. The increase in heat can have a negative effect on human health, causing respiratory disorders, chronic health conditions, and in some cases, death.
In Parque Arará, a favela in northern Rio, a local named Luis Cassiano began building green roofs on favelas in Brazil to address the lack of greenery and extreme heat in favelas. He founded a nonprofit called Teto Verde Favela, where he educates residents on building their own green roofs. Research suggests that green roofs have a range of benefits for communities experiencing extreme heat. Green roofs on favelas in Brazil cool ambient temperatures, reduce storm ward runoff, improve building energy efficiency and more.
The green roofs on favelas in Brazil cool temperatures in two ways. First, the vegetation absorbs less heat than other roofing materials, and second, plant roots absorb water that is then released as vapour through the leaves.
Because favelas are built out of many different materials, there isn’t a one-size-fits-all solution to the heat problem in Brazil. In Luis Cassiano’s case, he covered his roof with rolls of bidim (a lightweight nonwoven geotextile made from polyester from recycled drink bottles). Several plant types were placed on the roof, and an irrigation system that dripped water down was installed. While recording temperatures over several days, he found that his roof was roughly 86 degrees while his neighbour’s fluctuated between 86 and 122 degrees.
Green roofs can also help to improve air quality. Plants on green roofs absorb carbon dioxide and release oxygen, which can help to improve the air quality in urban areas. This is especially beneficial in favelas, which are often located in areas with high levels of air pollution.
In addition to the environmental benefits, green roofs can also provide a number of social benefits. They can help to improve the quality of life for residents by providing a more pleasant living environment. Green roofs can also provide a sense of community and pride, as residents work together to maintain them.
For green roofs on favelas in Brazil to succeed, there needs to be ample funding and sponsorship from companies or the government. Moreover, more research is required to reduce the weight of green roofs in an already fragile environment. Cassiano has been experimenting with hydroponics, meaning no soil to decrease the roof’s weight.
Because of the informality in how favelas are constructed, public policy doesn’t quite reach these working-class communities in Brazil and other parts of the world. The people within these communities tend to turn to each other for help; making the green roofs on favelas in Brazil a wonderful community-led initiative for the people who live there that they can be proud of.
Cassiano’s nonprofit, Teto Verde Favela, is a step in the right direction to help these communities fight against climate change and to help the health of people living in favelas. It does require more work to reduce costs and make green roofs accessible to these communities, but it could have a significant impact should more people begin to adopt them.