Grown, Not Made: What the Mycelium Tower at MoMA PS1 Tells Us About Building With Fungi

In the summer of 2014, a cluster of pale, honeycombed towers rose in the courtyard of MoMA PS1 in Queens, New York. From a distance it read as sculpture — three interlocking cylinders, wider at the top than at the base, glowing faintly white against the brick warehouse behind them. Up close, the material was the story: every one of its roughly 10,000 bricks had been grown, not manufactured, from mushroom mycelium feeding on chopped corn stalks. By September, the tower was gone — not demolished, but composted, its bricks returned to soil in New York City community gardens within about sixty days. The project, called Hy-Fi, was designed by David Benjamin and his studio The Living, winner of that year's MoMA PS1 Young Architects Program.

Mycelium is the root-like vegetative network of a fungus — fine branching threads (hyphae) that spread through a growth medium, digesting it and binding it together. In building applications, mycelium is grown through a mass of agricultural waste — corn stalks, straw, sawdust, hemp hurd — inside a mold. Over one to several weeks, the fungus digests part of the substrate and knits the remaining fibers into a lightweight, semi-rigid composite. Heat is then applied to stop growth and dry the block, which prevents the fungus from fruiting into mushrooms and halts further decomposition.

Hy-Fi's bricks were developed and manufactured by Ecovative Design, a company that had already been growing mycelium-based packaging as an alternative to polystyrene foam. For the tower, Ecovative's brick-shaped mycelium blocks were combined with a second brick type — a reflective, mirror-coated brick developed with 3M — used at the top of the towers to bounce daylight down into the structure. Arup provided structural engineering throughout: testing the bricks, calculating safe stacking heights, and verifying the towers could resist wind gusts above 65 mph. The result was a self-supporting, temporary outdoor structure over 12 meters tall built almost entirely from a living organism's growth process.

A separate line of laboratory research — a 2018 study led by Yangang Xing at Cardiff University and Aberystwyth University — asks a narrower, more technical question: not "can mycelium hold up a tower," but "can mycelium bricks insulate a building as well as the synthetic materials — mineral wool, expanded polystyrene — that dominate the market today." Their study grew mycelium bricks from three basidiomycete fungi species on wheat straw and measured their thermal performance directly.

Ecovative's process, as described by the company and by outlets covering Hy-Fi, is close to the general mycelium-composite method: agricultural waste is inoculated with fungal spawn, packed into a mold, and left at room temperature for the mycelium to colonize the substrate. No kiln firing, no cement, and no significant energy input is required to form the brick itself — a sharp contrast with a fired clay brick or a block of expanded polystyrene, both energy- and emissions-intensive to produce.

The Cardiff study followed a similar principle with tighter laboratory controls. The team inoculated rye grain with three fungal isolates — Oxyporus latermarginatus, Megasporoporia minor and Ganoderma resinaceum, all originally isolated from trees in Egypt's Nile Delta — then used the colonized grain to inoculate wheat straw packed into plant-tissue-culture vials. After eight weeks of incubation at 28°C, the straw blocks were dried at 70°C to arrest growth, yielding solid mycelium-bound blocks with densities between roughly 51 and 62 kg/m³ — for comparison, about a fortieth the density of a fired clay brick.

The researchers then measured thermal conductivity and specific heat capacity using a dual-needle transient probe, standard equipment for soil and porous-material thermal testing. The three species produced blocks with thermal conductivities between 0.078 and 0.081 W/mK — Oxyporus latermarginatus performed best, Ganoderma resinaceum worst. Notably, Ganoderma resinaceum was also the fungus that broke down the most straw over the incubation period, which the authors read as a trade-off: fungi that colonize and bind a substrate quickly without over-digesting it make a stronger, more thermally consistent block than fungi that consume the substrate more aggressively.

Two separate claims are being tested here, and it's worth keeping them apart. Hy-Fi tested whether a mycelium composite could be load-bearing at architectural scale, even temporarily and with a wide safety margin. The Cardiff research tested whether it could be thermally competitive as insulation — a much larger potential market, since insulation doesn't need to carry structural loads, only to sit inside a wall assembly and slow heat transfer.

Both point at the same underlying appeal: a building material whose manufacturing energy is close to zero, whose feedstock is agricultural waste that would otherwise be burned or landfilled, and whose end of life is composting rather than demolition and disposal. For a discipline responsible for a large share of global material flows and construction waste, a material that is grown at ambient temperature from waste and returns to soil is a genuinely different proposition from making a "greener" version of an existing product.

It also matters as a demonstration, in the most literal sense. Hy-Fi wasn't hidden in a lab; it was a public, occupiable structure that tens of thousands of visitors walked through over one summer, engineered by one of the most credible structural firms in the industry. That combination — a real institution (MoMA), a real structural engineer (Arup), and a real fungal-composite manufacturer (Ecovative) — is part of why the project is still cited as a reference point more than a decade later.

Grow. This is the capability Hy-Fi and the Cardiff research most directly embody. Both are examples of architecture approaching biological growth and fabrication rather than industrial manufacturing: the material is not cast, extruded, or fired, it is cultivated. The fungus performs the binding work that would otherwise require cement, resin, or heat. This is closer to what the framework means by biofabrication than most "organic-looking" architecture — the mycelium is not decorating the form, it is producing the material's structural cohesion through its own metabolic process.

Regenerate. Hy-Fi's closing act — disassembly, composting, and the return of the resulting soil to community gardens — is a small but real demonstration of a regenerative material cycle: a building material that participates in, rather than escapes, a biological nutrient loop. It's worth being precise about scale here: one temporary pavilion's worth of compost is not a claim about regenerative design at the scale of a district or a city. But the principle — a construction material designed from the outset to biodegrade productively rather than end up in landfill — is exactly the kind of resource-cycle thinking the Regenerate capability is meant to track.

Where the connection is weaker: Hy-Fi and this insulation research don't Sense, Think, Respond, Adapt, or Connect in any meaningful sense. The bricks don't monitor conditions, make decisions, change behavior, reconfigure, or participate in a larger urban system once installed — they are a static (if biologically produced) material once grown and dried. That's a fair limitation to name rather than paper over: this is a story about how a material is made and how it ends, not about a building that behaves like a living organism once built.

Technology maturity: EXPERIMENTAL. Neither the Hy-Fi tower nor the Cardiff insulation research represents a commercially deployed building product. Hy-Fi was an explicitly temporary installation, disassembled after roughly ten weeks by design, not engineered or certified for permanent occupancy. The Cardiff study describes itself as preliminary — the authors note calibration limitations in their transient thermal method given the material's high porosity, and list steady-state testing as necessary future work.

Structural limitations. Mycelium composites of this kind have low compressive strength — reported figures for mushroom-based bricks are on the order of 0.2 MPa, against 28 MPa or more for a conventional fired brick, a roughly 140-fold difference. Hy-Fi's engineering worked around this by keeping the structure lightweight, wide at the base, and modest in height, with Arup's calculations built around generous safety margins for a temporary public installation — not by demonstrating that mycelium brick can bear meaningful structural load in a permanent building.

Thermal performance is competitive with other biomaterials, not yet with synthetic insulation. The Cardiff bricks' measured conductivity (0.078–0.081 W/mK) beats some other bio-based composites cited in the same paper but is still roughly twice as conductive as expanded polystyrene (0.029–0.039 W/mK). In practical terms, a mycelium-insulated wall would currently need to be substantially thicker than an EPS-insulated wall to achieve the same performance.

Durability and moisture remain open questions. Water absorption and long-term durability in exposed or humid conditions are unresolved issues for mycelium composites generally, and neither Hy-Fi nor the Cardiff study addresses long-term weathering. There is also no building-code pathway yet for mycelium composites as a certified insulation or structural product.

What would need to be true for this to scale. The Cardiff authors point to increasing the density of the grown material, addressing fire performance, and validating results with standardized steady-state thermal testing. On the structural side, nothing in the public record since Hy-Fi suggests mycelium composites have moved from temporary-installation-scale demonstrations toward permanent, code-compliant, load-bearing use.