Modular Recycled Roofs to Keep Homes Cool

In Ahmedabad, India, where the temperature soared to 108 degrees and where high temperatures will stay well over 100 for at least the next 10 days—it’s even hotter inside small shacks in slums, where thin metal roofs trap heat. A local start up ReMaterials founded by Hasit Ganatra has designed an alternative: modular roofing ‘Modroof’ from paper and wood waste that can help keep homes cooler. The Modroof design uses cardboard waste and natural binders to make a lightweight panel that’s insulated and has a coating that renders it waterproof. A metal structure makes it strong. The insulation, along with an air gap inside the panel, helps keep heat out. In tests, the company has shown that the new roof can make a home as much as 18 degrees Fahrenheit cooler than it was previously. The roof is also designed to keep homes dry in monsoons; metal roofs often corrode and develop holes that leak, and concrete roofs develop cracks. The roofs are more expensive than cheap metal sheeting, but cost less than concrete slabs because they’re easier to install.  The start-up partnered with microfinance companies to offer loans. (Some families are separately painting their metal roofs white, a cheaper option that can also help lower the temperature.) Over the last few years, the company has installed 500 roofs. While the pandemic has slowed its growth, Gantra hopes his company can expand to countries in Africa and South America. “It’s very easy to ship, it’s very easy to install, it’s very easy to repair or maintain,” he says. “And we can do everything over a WhatsApp video call—we can get these installed anywhere in the world. We have not gone outside India, but it’s only a matter of time before we do.”