A house partially built from recycled diapers.

Turning used diapers into building materials can reduce landfill waste and lower housing costs. This one-story house in Indonesia was built partly from shredded recycled diapers. Turning diapers into building materials could help the country solve two problems. Scientists say it could make housing more affordable and reduce waste.

Muhammad Arif Irfan

There are diapers in this house - but not where you might think. Used diapers partially make up its floors, columns and walls. A team of researchers tested used diapers as one component of a building material. To build the new house, the team mixed recycled disposable diapers with concrete and mortar. The mortar is used to hold the bricks together. The team designed a one-story house that is about 36 square meters (388 square feet). The recycled diapers could replace nearly 2 cubic meters (71 cubic feet) of building materials. These findings were published May 18 in the journal Scientific Reports.

Recycling diapers into building materials will reduce the amount of trash that is sent to landfills. In addition, the team notes, it could make housing more affordable. There's a big need for this in developing countries like Indonesia. There, the demand for affordable housing exceeds its availability. The number of people in Indonesia's cities has grown by about 4 percent a year over the past 30 years. And more people are moving to the country's urban centers. By 2025, Siswanti Zuraida says, about two-thirds of Indonesia's residents are expected to live in urban areas. She is an ecologist and works at Kitakyushu University in Japan. Zuraida is originally from Indonesia.

All household waste is becoming a problem, she says. And population growth in Indonesia is exacerbating demand for housing. Building materials, especially those that provide sturdy structures, are often expensive. They are often a major barrier to housing affordability. Therefore, researchers have previously studied unusual materials that can save costs. Such materials include, for example, the shelling of rice grains or ash from burning coal. Perhaps using old diapers in a new capacity can help solve both problems.

Used disposable diapers are mostly piled up in landfills or incinerated. But disposable diapers contain cellulose, cotton, and plastic. These are all potentially useful building materials. Zuraida and her colleagues tried to replace some of these materials with diapers.

However, there are major barriers to using diapers or other unusual building materials," says Siswanti Zuraida. The plant-based fibers of diapers can be used for construction. But the plastic parts have to be extracted. This requires a complex process that is so far only available in developed countries. In addition, Indonesian laws restrict the use of materials for construction. Currently, these are only concrete, bricks, wood and ceramics. (The production of these materials emits large amounts of greenhouse gases). The idea of building from waste is quite feasible, says Christoph Schrefl. He works as a chemist at the Technical University of Dresden in Germany. Schrefl was not part of the new work. But using diapers in construction may not be as environmentally friendly, especially on a large scale, he says. Separating dirty diapers from waste and sanitizing them are challenging tasks. Therefore, recycling diapers requires a large amount of energy.