Thatch roofs are a traditional building technology in Ecuador for good reason – they keep a home cool and the reeds can be sourced locally. Unfortunately, thatch has become much harder to acquire as land for food has pushed the grass out. Roofs made from steel and fiberglass panels are woeful replacements, as they let in much more heat – and during the frequent rains they can make a racket inside. Dr. David Saiia, a professor of strategic economics and sustainability at Duquesne University has created a unique solution by taking plastic bottles out of the local waste stream and turning them into a thatch replacement with his hand-powered machine.
The idea of using plastic bottles waste as a building material has a lot of potential for its ubiquitous and durability. Dr. Saiia says he first was struck by the idea while teaching a course challenging students to find ways to make waste materials into useful products. After witnessing the encroachment of un-biodegradable waste piling up in the middle of the South American Rainforest, he developed a device which can cut a 3 liter plastic bottle into strips in seconds. He is now developing and testing multiple ways to produce a thatch covering for housing using the strips.
The system works by collecting 3 liter bottles, which are everywhere, cutting off the bottom and inserting them into a spinning drum which allow a cutting knife to run the length of the bottle. The strips are then fastened to bamboo or potentially melted together at one end to make a length of thatch. Layered on top of a roof frame the artificial thatch can last many years as opposed to one year using regular thatch. While breathing and maintaining the cooling advantage of organic thatch the plastic strip also allow natural light through, a dramatic benefit for family members who spend a lot of time indoors. Add the sound dampening from rains compared to conventional roofing and the plastic thatch looks very promising as a way to improve the livability of homes in the tropics.
Dr. Saiia will continue testing on the viability of the roof to make sure it’s durable and not toxic and hope to build a bio diesel powered device. He hopes to see the production of a system which creates local cottage industries in emerging economies and reduce the plastic pollution. The waste becomes a locally procured raw material which can be processed at the source. The local labor would see a boon from re-roofing homes, which could consume 1200-1600 bottles each.