Temps soar in Brazil's summer (from December to March). Low-income favelas would benefit from green roofs but there are two problems: Cost.
Luis Cassiano is the founder of Teto Verde Favela, a nonprofit that teaches favela residents how to build their own green roofs as a way to beat the heat without overloading electrical grids or spending money on fans and air conditioners. He came across the concept over a decade ago while researching how to make his own home bearable during a particularly scorching summer in Rio.
Over the next 10 years, his nonprofit was born and green roofs started popping up around the Parque Arará community, on everything from homes and day care centers, to bus stops and food trucks.
Summer heat has been known to melt water tanks during the summer in Rio, which runs from December to March. Pictured is the water tank at Luis Cassiano's house. He covered the tank with bidim, a lightweight material conducive for plantings that will keep things cool.
Luis Cassiano outside his green-roofed home in Rio de Janeiro.
"When the elite build, they plan," says Cassiano. "They already consider putting green roofs on new buildings, and old buildings are built to code. But not in the favela. Everything here is old and goes up any way it can."
Without the oversight of engineers or architects, and made with everything from wood scraps and daub, to bricks and cinder blocks, construction in favelas can't necessarily bear the weight of all the layers of a conventional green roof.
That's where the bidim comes in. Lightweight and conducive to plant growth — the roofs are hydroponic, so no soil is needed — it was the perfect material to make green roofs possible in Parque Arará. (Cassiano reiterates that safety comes first with any green roof he helps build. An engineer or architect is always consulted before Teto Verde Favela starts a project.)
And it was cheap. Because of the bidim and the vinyl sheets used as waterproof screening (as opposed to the traditional asphalt blanket), Cassiano's green roofs cost just 5 Brazilian reais, or $1, per square foot. A conventional green roof can cost as much as 53 Brazilian reais, or $11, for the same amount of space.
"It's about making something that has such important health and social benefits possible for everyone," says Ananda Stroke, an environmental engineering student at the Federal University of Rio de Janeiro who volunteers with Teto Verde Favela. "Everyone deserves to have access to green roofs, especially people who live in heat islands. They're the ones who need them the most."




















