A Second Life for Wasted Soda Bottles: High-Tech Roofing

Engineers have figured out how to turn plastic trash into a material that keeps rain and heat out while letting sunlight in.

Vananh Le, co-founder of the Reuse Everything Institute, displays the plastic thatch material they have developed. (David Saiia)

Perhaps the iconic image of developing-world poverty is a small collection of huts with thatched roofs. Unfortunately for those living in such places, these roofs are terrible. They leak and, when water-logged, often collapse. The grasses used to fabricate them are becoming scarcer. Insects and other undesirable critters live in them. People moving out of poverty quickly ditch thatch, upgrading to materials such as corrugated tin.

Corrugated tin roofs are waterproof but have serious downsides. They trap heat, and though a super hot home may be less miserable than getting rained on, it is nevertheless is unpleasant. When it rains, the noise can be so deafening it drowns out everything.

David Saiia, a professor of strategic management and sustainability at Duquesne University, has come up with a brilliant alternative: plastic thatch, sourced from the vast soda-bottle waste stream.

Saiia specializes in developing business solutions that will help people out of poverty while preserving habitats. On one of his many trips taking university students to the Ecuadoran nature preserve, Maqui Picuna, he challenged them to think of something useful to do with all the plastic bottles littering this scenic Andes cloud forest. Saiia’s sculpture, painting, and drawing skills kicked in; shortly a proverbial back-of-the-envelope drawing launched his business transforming bottles into thatch strips. The tops and bottoms are sliced off; the remaining body of the bottle is flattened and then cut into strips. (Saiia and Carnegie Mellon’s Engineers without Borders are now tweaking a human-powered machine to do this work.) Next, the strips are adhered to a cross-strip using ultrasonic sealing machines provided by Dukane. If you’ve ever sliced yourself wrestling with a device encased in clam-shell plastic, you know how effective ultrasonic sealing is.

Plastic thatch combines the waterproof qualities of tin with thatch’s ventilation. It allows light to filter in and muffles sound. It can come in a variety of colors, depending on the bottle combinations. It is made of local waste materials and will provide livelihood fabricating, selling, and installing roofs, which are expected to last more a decade.

Their pilot in Maqui Pacuna delivered a surprise. Dust and dirt gradually accumulated on the thatch roofs, turning them into NOGR’s—Naturally Occurring Green Roofs. Maqui Pacuna is home to rare orchids and bromeliads, which are now growing right on the roofs. The soil also helps diffuse the direct sunlight and adds several years to the life of the roof.

Saiia, along with his partner Vananh Le, founded the Reuse Everything Institute to develop and promote the plastic-thatch roofing.  Their video gives a great summary of what the product is and why it is so beneficial:

The strips could also have useful applications in the industrialized world, such as fencing and greenhouses. And, fortunately, planet earth has plenty of discarded bottles for everyone.