Namibia bets on mushroom waste to tackle housing crisis and reduce emissions

With a population of approximately 3.02 million, more than 40% of Namibians live in informal settlements, with over 70 per cent of the urban population living in these areas where inadequate housing, overcrowding, and lack of basic services are widespread. Urbanisation and rapid population growth have exacerbated the problem, particularly in the capital, Windhoek, where demand for affordable homes far outstrips supply. 

According to statistics, over 300,000 new houses are needed to meet the growing demand, yet the construction industry struggles with high costs and limited resources.

The situation is further complicated by the environmental impact of conventional construction methods, which rely heavily on materials like cement, steel, and timber, resources that are not only expensive but also contribute to environmental degradation. This makes affordable housing even more elusive for the average Namibian.

Encroacher bushes have invaded 45 million hectares of the country’s land enveloping grass and other vegetation. This encroachment has taken a toll on agriculture land and groundwater at a time when the country has been struggling with dwindling water supplies due to limited rainfall. 

To tame the menace, the government has introduced an initiative to burn an estimated 300 million tonnes of the invasive bush every 15 years. The idea is to counter the adverse environmental effects of the bushes while earning from charcoal, even as the country continues to record high levels of carbon emissions - land use and forestry tops the chart for greenhouse emissions in Namibia. 

Affordable, sustainable ‘mushroom houses’

Amid these challenges, a group of local researchers, entrepreneurs and organisations came together in 2019 to explore alternative building materials using organic waste products, specifically, mushroom waste and invasive weed species. 

The project, which has gained traction in recent years, has turned agricultural by-products and weeds into durable, cost-effective building blocks that can be used to construct homes. The project is chaperoned by MycoHab, a collaboration between the MIT, Standard Bank and architecture firm Redhouse Studio.

The process involves combining standard mushroom cultivation techniques with light scale manufacturing. The bush is harvested and chipped into sawdust directly at the extraction point. It is then brought to a facility where it is mixed with water and some nutrients. The mix is put into cultivation bags and pasteurised in large custom-made steamers. 

Once the material cools, it is inoculated with fungal mycelium, the root-like structure of mushrooms, in a small lab. The bags are then moved to a growing room and in less than 30 days, mushrooms growing out of the bags are harvested. The material that is left over – mycelium and bush grown together – is put into a large custom-made press that compacts the material into metal forms that are baked in ovens at relatively low temperatures. The blocks can then be  ready for use.

The use of mushroom waste and invasive weeds for construction has seen notable success in several pilot projects across Namibia. The blocks have been tested for structural integrity, insulation properties, and resistance to the harsh climate conditions in Namibia, including extreme heat and occasional rainfall. 

Early tests have shown that these blocks not only meet the required building standards but also offer better thermal insulation compared to traditional materials, potentially lowering energy costs for homeowners.

“The project in Brakwater,a settlement in the north of Namibia’s capital Windhoek, culminated in the world’s first self-supporting mycelium structure, the root-like structure of mushrooms. We converted over 12 tons of bush into over three tons of mushrooms that went to market to feed Namibians and roughly 1,000 mycoblocks to build the structure. The building of this first house also sequestered over 12 tons of carbon dioxide,” Christopher Maurer, principal architect at Redhouse Studio, told FairPlanet

Restoring local ecosystems

The project has also contributed to a potential reduction of invasive weed species, which are a persistent problem in Namibian agriculture. By removing these plants and repurposing them, the project is helping to restore local ecosystems while simultaneously providing a sustainable building material. The mushroom waste component from local farmers, which would otherwise contribute to landfill accumulation, is also being put to productive use, reducing waste and promoting a circular economy.

“We found through lifecycle analysis that MycoHab’s processes stored a net ton of carbon dioxide for every ton of material we produced. One can compare that to the concrete industry that emits a ton of carbon dioxide for every ton produced - roughly four billion tons per year. Concrete, steel, and aluminum alone are responsible for 23% of the world’s greenhouse gas emissions,” Maurer added. 

The project’s shortfalls

Despite its successes, the project faces several challenges. One of the main obstacles is the scalability of production. While the blocks have been successful in pilot areas, scaling up production to meet the high demand for housing across Namibia requires significant investment in infrastructure, technology, and training. 

The process of producing these eco-friendly blocks is still relatively new, and there is a need for greater awareness and education on their benefits among local builders and communities, according to the project lead. 

The biggest challenge for mushroom housing is market and building code adoptions. To mitigate these challenges, we are prioritizing the building of structures rather than selling materials for others to build with. That way we are demonstrating the possibilities in the hopes we can later team with industrial partners with means of production and political and economic prowess to effect change globally,” Maurer said. 

Another challenge has been the initial cost of setting up production facilities, which can be prohibitively expensive for small-scale operations. While the raw materials such as mushroom waste and weeds are in plenty, the machinery required to process these materials into building blocks is costly, and the technology is still evolving. 

To address this, partnerships with government agencies, private sector investors, and international organizations are being explored to ensure that the project can expand and reach a broader population.

Research institutions such as the United Nations University and the University of Namibia are exploring various uses of mushroom among them housing. This work has led to training of locals on mushroom cultivation and construction of alternative mushroom houses especially for rural communities. 

Future focus

Fungi has gained attention in the global construction industry as a sustainable alternative to conventional building materials. The use of mycelium as a base for bricks and panels is being explored worldwide for its low environmental impact, rapid growth cycle, and ability to be cultivated on agricultural waste.

“We believe the processes are boundless. There is over 1 billion tons of agricultural biomass that is wasted each year, and may be as much, or more, in invasive species of plants that could all be put toward regenerative architecture and agriculture through these processes,” said Maurer.

In Namibia, researchers are already looking into further developing the use of fungi-based materials, with an emphasis on large-scale production. The hope is that, as the technology matures, fungi-based building materials will become a mainstream solution for affordable housing. This could reduce dependency on non-renewable resources, lower construction costs, and mitigate the effects of climate change by reducing the carbon footprint of the building industry.

“The environmental impact of traditional building materials like cement and steel is well-documented, and we must move away from that. By using local organic materials, such as invasive weeds and mushroom waste, we can reduce our carbon footprint while simultaneously tackling the issue of limited resources. This housing model doesn’t just hold promise for Namibia, it represents a potential game-changer for Africa and the world. If we can scale this process, we could reduce housing costs and environmental harm while supporting sustainable development,” said Jackton Wairegi, an environmentalist. 

Fungi is not a new material in construction. In 2014, the Hy-Fy building in Queens, New York, was constructed using crop waste and mycelium, marking a significant experimental use of the material. Since then, architects and researchers have continued to explore its potential in building design.

“Mycotecture and other biofabrication technologies will help regenerate land, mitigate climate change, and provide food and housing security through the use of circular and waste resources. 9.6 billion tons of carbon dioxide are emitted from just the raw material extraction of steel, aluminum, and concrete components. These mined constituents are becoming more and more recognisably finite as time goes on. Researchers are alerting us that we are even running out of sand for concrete,” said Maurer. 

Beyond the use of mushrooms in construction, RedHouse Studio is also exploring recycling and remediating construction and demolition waste into new healthy materials with the goal of fully recycling buildings through a process called biocycler. 

“This could have profound implications for environmental justice, and disaster recovery. Imagine the possibility of building directly from the ruins of hurricanes, wildfires, wars, and other disasters with the assurance that fungal metabolism has effectively neutralized any pollutants,” noted Maurer. 

Picture by Jennifer-Coffing Grey