A team of engineers working across Japan and Indonesia has built a small prototype house in which shredded, cleaned disposable diapers replace a portion of the sand in the concrete and mortar. The single-story structure, built to test whether diaper waste can be safely engineered into standard building materials, diverted roughly 1.73 cubic meters of processed diaper fiber into its columns, beams, and partition walls — a demonstration project the researchers frame as an early proof of concept, not a ready-made housing solution.
The work, led by The University of Kitakyushu researcher Siswanti Zuraida along with colleagues Bart Dewancker and Romi Bramantyo Margono, was published in May 2023 in Scientific Reports, a journal in the Nature portfolio. The paper, titled “Application of non-degradable waste as building material for low-cost housing,” documents both laboratory testing of diaper-derived concrete and mortar and the construction of a 36-square-meter demonstration house in Indonesia sized for a family of four.
Turning a waste problem into a building material
Indonesia disposes of an enormous volume of single-use diapers each year, and like most disposable diapers worldwide, they are made from a mix of materials — wood pulp, cotton, superabsorbent polymers, and various plastics including polyester, polyethylene, and polypropylene — that do not readily biodegrade and are difficult to recycle by conventional means. Most end up in landfills or, in areas without organized waste collection, in rivers and open dumps. The research team set out to test whether the fibrous, granular material left after processing used diapers could substitute for part of the fine aggregate — typically sand — in concrete and mortar.
To do that, the researchers washed, dried, and shredded used diapers to produce a processed fiber-and-plastic material, then mixed it into concrete and mortar samples at varying proportions in place of sand. After a standard 28-day curing period, they tested the samples’ compressive strength and compared the results against Indonesia’s national building standard, known as SNI.
What the testing actually showed
The results varied significantly depending on how much diaper material was used and where in a structure it was applied, which is central to understanding both the promise and the limits of the approach. Compressive strength declined in a roughly linear relationship as the proportion of diaper waste increased — the paper reports a baseline plain-concrete strength close to 25 megapascals, with strength falling predictably as more sand was replaced. That decline meant diaper content had to be capped much lower in load-bearing elements than in non-structural ones.
For a single-story structure like the demonstration house, the researchers found columns and beams could tolerate diaper substitution up to roughly 27 percent of the sand fraction in laboratory testing before strength dropped below acceptable thresholds, while a three-story building’s load-bearing elements — under far greater structural demand — were limited to about 10 percent. Non-structural partition-wall mortar tolerated substitution as high as 40 percent, and mortar used in floors and outdoor paving, which bears the least load, was capped near 9 percent.
For the actual 36-square-meter demonstration house, the team applied the maximum substitution rate the testing supported for a single-story structure: roughly 27 percent diaper-fiber substitution in the structural concrete for columns and beams, and 40 percent in the non-structural partition mortar. Averaged across the whole house, diaper material made up about 8 percent of the total concrete and mortar volume — equivalent to the 1.73 cubic meters of processed diaper waste, out of roughly 22.8 cubic meters of total building material, that the house diverted from landfill.
Honest limits on the safety claims
The paper’s own testing covered compressive strength only, and reports that, within the tested proportions, diaper-blended concrete and mortar met Indonesian building code strength thresholds for the applications tested. A separate body of prior research the paper cites — not this study’s own experiments — has found the mechanical properties and microbial content of diaper-based concrete comparable to conventional concrete at specific compositions. That distinction matters: this paper did not itself test microbial content, and its own claim is meaningfully narrower than saying diaper-based concrete is broadly proven safe for residential construction. The researchers flagged what remains unresolved.
The published study did not include a full structural analysis covering soil-bearing capacity and complete load calculations for the house as built, and the authors called for further comprehensive structural assessment before any wider rollout. Outside researchers have raised additional concerns. Technische Universität Dresden materials scientist Christof Schröfl, who was not involved in the study, told Nature’s news team that using waste materials this way is worth exploring but that separating and sanitizing diapers at scale — and transporting the resulting material to construction sites — could introduce its own logistical and environmental costs. The research team acknowledged separately that reliably separating plastic components from organic fiber in used diapers currently requires recycling infrastructure available mainly in wealthier countries, not the kind of decentralized collection system that would be needed to scale the idea in Indonesia.
Indonesia’s current building code also does not recognize diaper-derived material as an approved construction input; it restricts standard residential construction to concrete, brick, wood, and ceramic. The researchers describe regulatory approval, along with the development of large-scale diaper collection and sanitization systems, as prerequisites for any broader use of the material — an open problem the paper leaves for future work, including from the government agencies and waste-management companies whose cooperation the approach would require.
Taken together, the study demonstrates that diaper-derived aggregate can be engineered into concrete and mortar that meets code-level compressive strength at specific, tested substitution ratios in a single demonstration structure — not that diaper-based building materials are validated for widespread residential use, long-term durability, or occupied housing beyond this one prototype.
A small house with a larger ambition
The house itself is modest: a single story, two bedrooms, one bathroom, sized for a family of four on a 60-square-meter plot, reflecting the kind of low-cost housing that is in high demand in much of urban Indonesia. The researchers’ broader argument is less about this specific building than about the volume of waste such an approach could divert if adopted more widely — a single-story home of this scale can absorb noticeably more diaper waste than most other proposed reuse methods, according to the study’s authors, at a time when Indonesia lacks large-scale infrastructure for diaper recycling.
Whether that translates into real housing stock will depend on the questions the study leaves open: whether collection and sanitization can be organized affordably and safely, whether regulators update building codes to permit the material, and whether follow-up structural and durability testing — including long-term performance, moisture resistance, and full-scale load testing beyond the demonstration house — supports use beyond a single prototype. For now, the Kitakyushu-led team has shown the concept can be built once, under controlled conditions, at a specific set of substitution ratios. Scaling it into a viable construction material is a separate, unfinished task.