In the United States alone, 47 billion plastic bottles are discarded annually, and worldwide, enough plastic is thrown out in a single year to circle the globe four times. But a form of construction being used throughout Africa and Latin America is making a difference, not only by reducing plastic waste but also by taking advantage of the durability of plastic bottles to provide shelter for the homeless.

Outside view of plastic bottle house. (Photo: Aminu Abubakar/Getty Images)

The “bottle wall technique,” developed by German firm Ecotec Environmental Solutions, has been training people in Nigeria, where 16 million people are homeless, to build homes out of plastic bottle

The process is simple. Bottles are collected and filled with sand, then stacked on their sides and bound together with mud or a cement mix, creating solid walls. The structures are well insulated, incredibly strong (20 times stronger than brick), fire resistant, and even bulletproof. A typical two-bedroom home with a toilet, a kitchen, and a living room requires 14,000 plastic bottles and costs a quarter of what a conventional house would.

An increasing number of communities around the world are experimenting with the technology. An Ecotec house in Ecoparque El Zamorano, Honduras, was built with 8,000 bottles without using cement, and it supports a green roof that weighs up to 30 tons when wet. Ecotec plastic-bottle greenhouses, office partitions, sheds, benches, walls, and community centers are also popping up in Tokyo, the U.S., Europe, and South America.

Design-wise, colored bottle caps protrude from the walls for a colorful effect, and exposed rows and sections allow light to filter through the structures. Ecotec even created the world’s first vaulted ceiling made out of plastic bottles in Honduras.

(Photo: Aminu Abubakar/Getty Images)

This type of environmentally friendly construction requires a community effort. The bottles must be recovered through massive cleanup efforts and recycling drives, and filling each one with sand often involves many hands.

While this construction technique is now being used in developing countries across the world, some think it makes sense to use it in all countries with high homeless numbers.