Concrete is the most widely used building material on the planet, but its production comes with a heavy environmental cost. The cement industry alone accounts for roughly 8 percent of global carbon dioxide emissions, driving researchers to search for viable alternatives. One of the most promising developments comes from an unexpected source: mushrooms. Scientists have discovered how to harness fungal mycelium to create a brick made of concrete alternatives that could reduce the construction industry’s carbon footprint. These bio-based bricks are not biodegradable novelties; they demonstrate remarkable strength, insulation properties, and fire resistance. Before exploring this innovation, it is useful to understand common issues with traditional masonry, such as efflorescence in concrete brick masonry, which occurs when water-soluble salts migrate to the surface of concrete and brick assemblies.
What Are Mycelium Bricks and How Are They Made
Mycelium bricks are a biofabricated building material grown from the root-like network of fungi. The mycelium acts as a natural binder that holds together agricultural waste materials such as sawdust, soybean hulls, or hemp fibers. Unlike traditional clay or concrete bricks that require high-temperature kilns or energy-intensive curing, mycelium bricks are grown at room temperature with minimal energy input. The appearance of these bricks resembles standard construction blocks, but they are lighter and have a distinct organic texture. For comparison, colorful concrete tiles for decorative concrete floor and wall applications show how traditional materials can be adapted aesthetically; mycelium bricks offer a similar design flexibility with a much smaller environmental impact.
The Production Process Step by Step
- Inoculation. A small sample of fungus, typically from a species such as the cracked cap polypore (Phellinus robiniae), is placed in a petri dish with a nutrient medium. The mycelium begins to grow and spread through the medium.
- Expansion. After the mycelium becomes viable, it is transferred to small jars filled with sterilized grains. The fungus colonizes the grains over approximately one week, building biomass and density.
- Substrate Colonization. The grain-mycelium mixture is moved into larger containers filled with sawdust pellets and soybean hulls. This agricultural waste serves as the substrate that will form the bulk of the brick. The mycelium weaves through the substrate over another week.
- Molding. The colonized substrate is packed into brick-shaped molds. The mycelium continues growing and fusing the particles together for one more week, forming a solid, cohesive block.
- Termination. The finished brick is baked at low heat for several hours. This kills the living fungus and stops further growth, stabilizing the material for use in construction.
The entire process takes approximately four weeks from start to finish. While this is slower than manufacturing a traditional concrete block, the energy requirements are dramatically lower because no kiln firing or high-temperature curing is needed.
Comparing Mycelium Bricks with Conventional Concrete Blocks
Understanding the differences between mycelium bricks and conventional concrete blocks helps builders evaluate where each material fits best. Traditional concrete blocks rely on cement as a binder, which releases significant CO2 during production. Mycelium bricks, by contrast, sequester carbon within the biomass of the fungal network and agricultural waste. The relationship between concrete strength and concrete porosity in cement-based materials is well documented; mycelium bricks exhibit a different porosity profile that affects their thermal and acoustic performance.
| Property | Mycelium Brick | Concrete Block |
|---|---|---|
| Compressive Strength | Moderate (2-4 MPa) | High (10-40 MPa) |
| Density | Low (200-400 kg/m3) | High (1800-2400 kg/m3) |
| Thermal Insulation | Excellent (R-value ~2.5 per inch) | Poor (R-value ~0.1 per inch) |
| Carbon Footprint | Negative (carbon sequestering) | High (~1 kg CO2 per kg cement) |
| Fire Resistance | Good (self-extinguishing) | Excellent (non-combustible) |
| Production Energy | Very Low (ambient temperature) | Very High (kiln firing at 1450 C) |
| Biodegradability | Biodegradable (with proper treatment) | Non-biodegradable |
| Water Resistance | Moderate (requires coating) | High (inherently water resistant) |
As the table shows, mycelium bricks are not a direct replacement for structural concrete blocks in load-bearing walls. Their strength is significantly lower. However, for non-structural applications such as interior partitions, insulation panels, and acoustic baffles, they offer compelling advantages that concrete cannot match.
Applications and Limitations of Mycelium-Based Building Materials
Mycelium materials are best suited to applications where their unique properties provide a clear benefit. Proper material handling remains essential, just as consolidating concrete in congested reinforced concrete members affects the integrity of traditional pours. Understanding how to work with each material prevents failures on site.
Primary Applications
- Insulation Panels. The porous structure of mycelium provides excellent thermal insulation, making it ideal for building envelopes in passive house designs.
- Interior Partition Walls. Lightweight mycelium blocks can replace drywall or gypsum board for non-load-bearing internal walls.
- Acoustic Treatment. The fibrous mycelium network absorbs sound effectively, reducing noise transmission between rooms.
- Temporary Structures. For event spaces, exhibition booths, or emergency shelters, biodegradable mycelium panels offer an eco-friendly solution.
- Furniture and Interior Fixtures. Designers are using mycelium composites for tables, chairs, wall cladding, and decorative panels.
Current Limitations
- Low Compressive Strength. Mycelium bricks cannot support the loads required for structural walls or foundations.
- Moisture Sensitivity. Without protective coatings, mycelium absorbs water and can degrade over time.
- Production Time. Four weeks of growing time limits manufacturing throughput compared to concrete block production.
- Building Code Acceptance. Most building codes do not yet have provisions for biofabricated materials, requiring special approvals.
- Scalability. Commercial production is still in early stages, with limited manufacturing facilities worldwide.
Environmental Impact and Sustainability Benefits
The environmental case for mycelium bricks rests on three key factors: carbon sequestration, waste utilization, and low-energy manufacturing. Unlike concrete, which emits carbon during production, mycelium bricks lock carbon into their biomass. The agricultural waste used as substrate, such as sawdust and soybean hulls, would otherwise decompose and release methane. Repurposing this waste into building materials creates a circular economy model. When considering surface treatments for concrete, such as when builders pour new concrete over an old concrete surface, energy and material costs add up quickly; mycelium avoids these additional processing steps entirely.
Production energy is another major advantage. Concrete requires kiln temperatures exceeding 1450 degrees Celsius to produce cement clinker, consuming vast amounts of fossil fuels. Mycelium production happens at ambient temperature with only a short low-heat baking step to terminate growth. Researchers estimate that mycelium brick production uses roughly 90 percent less energy than conventional concrete manufacturing.
At end of life, mycelium bricks can compost back into the soil, returning nutrients rather than creating landfill waste. This stands in sharp contrast to concrete demolition waste, which accounts for a significant portion of global construction debris.
Commercial Viability and Ongoing Research
While mycelium bricks remain in the research and development phase, several companies and academic labs are pushing toward commercial production. Understanding different block types and their applications is key; the differences between concrete blocks types including hollow concrete blocks versus solid concrete blocks provide a useful reference for where mycelium blocks might fit into existing construction categories.
Key milestones in ongoing research include:
- Genetic Optimization. Researchers are selecting and breeding fungal strains that produce denser, stronger mycelium networks for improved structural properties.
- Hybrid Materials. Combining mycelium with natural fibers such as hemp, flax, or bamboo increases tensile strength and durability.
- Surface Treatments. Bio-based waterproofing coatings derived from plant oils or natural waxes are being developed to address moisture sensitivity.
- Accelerated Growth. Optimizing nutrient formulas and environmental conditions may reduce the four-week production cycle significantly.
- Compression Enhancement. Heat pressing and densification techniques are being tested to increase compressive strength toward structural-grade levels.
Testing protocols are also evolving. Similar to how post concrete inspection and testing concrete buildings ensures the integrity of traditional construction, standardized testing frameworks are being developed to certify mycelium materials for building code compliance.
The Future of Biofabricated Building Materials
The emergence of mycelium bricks represents a broader shift toward biofabrication in the construction industry. As climate targets tighten and material costs rise, the demand for low-carbon alternatives will accelerate. Mycelium materials are unlikely to replace concrete entirely, especially in structural applications where high compressive strength is essential. However, they can complement traditional materials by taking over roles where insulation, acoustic performance, or lightweight construction are priorities.
The construction sector has relied on concrete, steel, and timber for centuries, each with well-understood performance characteristics. Understanding the engineering trade-offs, such as those explored in a detailed analysis of prestressed concrete over reinforced concrete and arch systems, helps contextualize where novel materials like mycelium can fit. Mycelium bricks will not replace prestressed beams, but they can reduce the overall carbon footprint of a building by replacing energy-intensive insulation and cladding materials.
The project led by William Padilla-Brown and documented by Verge Science demonstrates that a single cracked cap polypore mushroom can inspire an entirely new category of construction material. As research continues and production scales up, mycelium bricks may become a standard option for environmentally conscious builders. The path from laboratory curiosity to commercial product is long, but the fundamental science is sound. Nature has been perfecting mycelium networks for millions of years; it is time the construction industry learned to put them to work.