Government-backed researchers in Mexico are proposing extensive construction of low-cost housing using discarded PET bottles.
A team from the Cideteq public research and development center in the central Mexican city of Querétaro has constructed several residential prototypes in rural areas with the financial backing of the government's National Science and Technology Council (Conacyt).
Cideteq (the Center of Research and Technological Development in Electrochemistry), is a regional arm of Conayt (National Council of Science and Technology).
According to project leader José de Jesús Pérez Bueno, the researchers found that a single 97-square-foot room cost the equivalent of $6,000 to build $1,000 for materials and the rest covering the cost of labor.
The walls were constructed on traditional foundations using PET bottles with a capacity of 20.29 U.S. fluid ounces each, filled with red clay and placed horizontally between commonplace concrete support columns.
Once constructed to the desired height, the walls were lined with chicken wire or soffit panels and covered with concrete, mud, stucco or clay to increase their rigidity.
Three horizontal lines of empty, plain glass bottles were then placed at the top of the walls to allow daylight into the room.
The roof comprised galvanized metal sheeting covered with plastic supermarket bags, more empty PET bottles and, finally, an additional layer of red clay.
The researchers found that each room's constant temperature was a comfortable 69.8° F and was damp-proof and sound-proof.
According to Pérez Bueno, it took two laborers three months to build a single room.
However, he said, that included the time spent collecting discarded PET bottles and other materials.
Querétaro's Autonomous University has also given support to the research project, according to a Conacyt news release.