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Could 3-D Printed Plastic Replace Corrugated Iron Roofs?

November 13, 2014

3-D Printed Plastic Could Replace Not-Very-Good Corrugated Iron Roofs In The

Developing World

3-D printed plastic roofs from waste bottles could replace corrugated iron roofs in developing countries. Another option is modularized roofing materials that piece together akin to Legos. "We're aspiring to have the same aesthetic feel as terracotta tiles but also have good insulation," said Wendy Fok, leader of the project for Harvard spinoff Resilient Modular Systems.

Corrugated iron is the default roof material in much of the developing world, and there are several reasons why it's far from ideal. One, iron has tendency to rust and degrade. Two, it heats up like a griddle in warmer climates. And three, it's not insulated: air and water seep in, because the bumpy covering doesn't lie flat to walls. A Harvard spin-off, Resilient Modular Systems has two solutions to the problem. The first involves using new types of materials for roofing, like 3-D printed plastic from waste bottles. The second is to modularize roofing, so that it's adaptable and easily repaired. The idea is to build a Lego-like system of bricks that can made locally, using whatever is closest to hand. 3D printed plastic roofs are alternative to iron roofs in developing world - Image 1"If you're still using corrugated metal as your roof system, there's a way to transition out, or start patching your roof with the new system. It can be integrated with the [existing structure]," says Wendy Fok, who leads the project. RMS has created two prototype products so far: a "chocolate bar" slab that measures four by four feet, and a smaller "plug-in and play" brick for filling holes and making repairs. Each piece is designed to fit together from different directions, and to be interchangeable. Testing shows the tiles can span a room 12 by 12 feet—the size of a small room in many places—without the need for beams underneath. Some startups might look to do manufacturing somewhere cheap like China. But Fok says local is better because there are less transport and climate costs, and there is an opportunity to spread knowledge and expertise to local people. "The key is to work with communities to introduce new job options, and give them the empowerment of new technology. This is at the core of the mission. It's not just introducing a new product," she says. RMS is talking with 3D Systems, in South Carolina, about possibly building a printing kit to make the smaller bricks. The larger slabs probably would have to be injection-molded, so RMS would need local partners. Fok says toy companies are possibilities, as they're used to working with recycled plastic. The roof is designed to be air-tight and fit on cinder blocks. There are no nails or screws—everything fits together like joinery. It's kept in place by fastening the sides to the house, so no holes need to be drilled in the top. 3D printed plastic roofs are alternative to iron roofs in developing world - Image 2"We're aspiring to have the same aesthetic feel as terracotta tiles but also have good insulation, so [families] aren't constantly making sure their furniture is protected," Fok says. It's still early days for the technology. RMS is looking for $250,000 so it can continue testing and fieldwork (it currently has a pilot in the Dominican Republic), but Fok says many of the pieces are in place: from partners to work on materials and structural design, to a host of advisers from Harvard, MIT, and elsewhere. Fok herself is a doctoral student at Harvard, and has 10 years experience working on modular design concepts. "Modular systems aren't anything new per se. But working with unskilled workers in places where it can be executed is new," she says. "For us, it's also about education, because that's not what a globalized supply chain offers."


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