Waste Into Walls: Building Casas Out of Sand

Andreas Froese is madly in love with trash, especially plastic soda bottles. To him, they are not only a thing of beauty but a means of solving some of the problems vexing Honduras, his adopted country. Over the past five years, Froese has built nearly a dozen houses with sand-filled soda bottles, creating humbler versions of tiled Mediterranean villas complete with bottle top mosaics.

Froese, a thin, intense man, and a construction worker by trade, had his first brush with garbage while restoring old houses in his native Germany. “I had to go to the dump to get wood that would match,” he said. Upon arriving in Honduras 12 years ago, Froese was struck by the country’s profound poverty and environmental degradation. Drawn to green building and eco-tourism, he had found himself in 2000 working in an eco-park. While cleaning up after a typically huge Latin American Easter celebration, he realized that something had to be done with bottles. “We realized we had more plastic bottles than organic rubbish,” he said. “If you have 25,000 people having fun and drinking, you have 20,000 bottles.”

Froese began a for-profit business, Eco-Tec, to introduce training in clean technologies— specifically building with plastic soda bottles—into poor communities. This technology not only provides constructions with sustainable features like composting toilets, green roofs at half the cost of regular construction, but creates small businesses, promoting long-term self-reliance—vital in a country that receives $557 million in aid each year. But working with trash requires a shift in attitude: “You have to show people that it’s quick, it’s safe and they can make money with it,” Froese said.

Besides houses, Eco-Tec has built cisterns and two whimsical eco-tourism offerings: a camping igloo and a replica of a Roman aqueduct. According to Froese, the bottles that make up 70 percent of these constructions are far stronger than the concrete blocks used in normal construction. They’ll last for 300 years, he says, and can support a 36-ton green roof without difficulty.

This summer, Froese oversaw projects on Honduras’ Bay Islands. On the largest, Roatan, he worked with government environmental educators and the children of the Fausto Miguel Alvarez School to build a 3,500-liter water tank in the schoolyard.

For several weeks, the school became a construction zone, buried under mountains of bottles, trash and gravel. Froese looked on as the children mixed cement in exact proportions in a wheelbarrow—a hands-on math lesson. With coordinated turns of their shovels, two boys worked the powder into paste and wheeled it to a bottle bench rising out of the corner of the yard. They worked like little men, wasting no movements as they laid the bottles, stabilizing them with twine and spreading mortar between them.

Looking over the yard, their teacher, Delmis Sauceda Arquijo, shook her head. “Fea, fea,” she said. “Ugly, ugly.” Earlier though, she had extolled the benefits of suffering a few weeks’ ugliness. “The most important thing is that this work can be done by children,” she said in Spanish. “Apart from learning the math, they’re also learning something practical. It’s a trade.

Froese’s efforts have garnered numerous plaudits, among them a place in a United Nations book about successful Honduran development projects.

But on a hot day in July, Froese contented himself with the building of the water tank. Directing the children in nearly flawless Spanish, he watched as they put the last touches on the bench. Nearby, Arquijo and the remaining students gathered the remaining bottles to throw away—again.