Building a Strong House From Poop

The construction industry is exploring the integration of human waste and recycled hygiene products as sustainable, low-cost alternatives to traditional building materials. From the development of concrete reinforced with shredded diapers to the creation of bricks from treated sewage sludge, researchers are targeting the reduction of landfill waste and the lowering of construction costs.

Concrete Innovation Using Recycled Diapers

Civil engineer Siswanti Zuraida at the University of Kitakyushu in Japan has developed a method to reduce the volume of sand required in concrete by replacing it with shredded disposable diapers. These diapers, typically composed of polymers, cotton, and wood, are cleaned before being integrated into the mixture.

Research published in Scientific Reports indicates that between 9 percent and 40 percent of sand in concrete can be replaced with shredded diapers without compromising the structural strength of the material. Zuraida’s findings suggest that the proportion of recycled materials can vary based on the architectural application; non-load-bearing components, such as walls, can incorporate a higher percentage of diapers than structural elements like support beams.

As a proof of concept, Zuraida and her team constructed a prototype home measuring 387 square feet. In this specific build, approximately 8 percent of the sand was replaced with repurposed diapers. The project aims to address the environmental impact of disposable diapers in landfills and reduce greenhouse emissions associated with traditional concrete production.

Biosolids and the Production of Building Bricks

Parallel research conducted by Professor Abbas Mohajerani at RMIT University in Australia focuses on the use of biosolids—the byproduct of the wastewater treatment process—to create building bricks. According to a study published in the journal Buildings, turning treated sewage sludge into bricks allows for the recycling of global stockpiles of biosolids.

The research highlights two primary advantages of using biosolids in brick production:

• Cost Reduction: Utilizing waste products reduces the overall cost of building materials.
• Thermal Insulation: Dried feces are more porous than traditional materials, making them better insulators that help buildings retain more heat.

While traditional bricks are manufactured from clay or concrete, the addition of biosolids is intended to make blocks sturdier and more affordable.

Conceptual and Traditional Waste-Based Construction

Beyond industrial research, other concepts and traditional methods have explored the use of bio-waste in architecture. The Australian firm Andrew Maynard Architects proposed a conceptual Poop house, described as a water structure designed to assemble household bio-waste, including food and human excrement, to slowly construct a roof over time.

The proposed design utilizes a semi-circular frame made of polypropylene bags. An interior layer of water is used for toilet duties and sterilized, while waste is pumped into an outer layer. The firm clarified that this project was a tongue-in-cheek fairy tale intended to highlight wasteful water habits in Australia rather than a commercial product.

the use of waste-based materials in housing is noted in certain regions, such as the Great Rift Valley in Southern Kenya, where people have historically built houses using these materials due to specific regional needs.

Market and Implementation Challenges

Despite the technical viability of these materials, large-scale commercial adoption faces significant infrastructure hurdles. In the case of recycled diapers, the primary obstacle is the lack of existing waste management systems capable of separating diapers from other household waste.

The scalability of biosolid bricks also depends on the efficiency of wastewater treatment plants. For example, in Kenya, the Nairobi Water and Sewerage Company (Newasco) reports receiving 100,000 litres of human sludge daily at its Ruai treatment plant, which is significantly lower than the expected 500,000 cubic litres.