Disadvantages of Mycelium Bricks

While mycelium bricks are a revolutionary step toward "growing" our future cities, they are not yet a perfect replacement for traditional clay bricks or concrete blocks. As of 2026, several technical and practical hurdles limit their use to niche architectural projects and interior design.

 Key Disadvantages

1. Low Compressive Strength

The most significant drawback is that mycelium bricks cannot yet match the load-bearing capacity of concrete or fired clay.

• The Gap: A standard concrete block can withstand roughly 20–30 MPa (megapascals), whereas a typical mycelium brick sits between 0.2 and 2 MPa.

• The Impact: You cannot currently build high-rise structures or heavy load-bearing walls using only mycelium. They are mostly used as "in-fill" or for temporary, lightweight pavilions.

2. High Water Absorption (Hydrophilic Nature)

Mycelium is essentially a dried organic network. Like a sponge, it naturally wants to absorb moisture from the environment.

• Structural Decay: If the bricks become saturated, they can lose their structural integrity and become soft.

• Mold Growth: Even though the mycelium is "dead" (heat-treated), the organic substrate (hemp or corn husks) can become a breeding ground for unwanted molds or fungi if kept in damp, dark conditions.

• Requirement: They must be treated with specialized bio-coatings or kept in dry, indoor environments to last.

3. Limited Lifespan

Traditional bricks can last centuries. Mycelium bricks are designed to be biodegradable, which is a double-edged sword.

• Degradation: Over time, especially when exposed to the elements, biological bonds can weaken. Most current mycelium structures are rated for a lifespan of 10 to 20 years unless heavily protected, whereas concrete lasts 50 to 100+ years.

4. Long Production Time (Growth Cycle)

You don't "manufacture" mycelium bricks; you "grow" them.

• The Timeline: While a concrete block can be cast and cured quickly, a mycelium brick requires 5 to 10 days to grow in a mold, followed by several hours of heat-deactivation.

• Scaling: This biological timeline makes it difficult to scale production to meet the demands of massive, fast-paced infrastructure projects.

5. Regulatory and Coding Hurdles

Building codes (like the IBC or Eurocodes) are built around the predictable behavior of steel and stone.

• Lack of Standardization: Because every "batch" of mycelium can vary slightly based on the agricultural waste used (hemp vs. sawdust) and the growth temperature, it is difficult for engineers to get them certified for safety in residential housing.

 Comparison Table: Mycelium vs. Traditional Brick

 The Verdict: Where should they be used?

Mycelium bricks are not currently better for foundations or structural walls. However, they are vastly superior to traditional materials for:

• Temporary structures (exhibition pavilions).

• Interior partitions where weight and insulation are more important than strength.

• Acoustic insulation where their porous nature is an advantage.