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Sustainable Architecture Materials: Why Rammed Earth, Mycelium and Lime Plaster Are Replacing Concrete and Glass
- Style Essentials Edit Team
- May 5
- 6 min read
Updated: May 6
The materials shaping architecture today are no longer being chosen only for how they look or how easily they replicate at scale. They are being reconsidered for what they cost the planet, and that reconsideration is producing some of the most serious building being done anywhere in the world right now.
For most of the twentieth century, the dominant materials of construction were chosen for their predictability. Concrete, steel, and sealed glass performed consistently regardless of where they were used. They could be specified from a catalogue and delivered to a site without reference to local climate, geology, or craft tradition, and they produced buildings that looked and felt broadly similar whether they were built in Mumbai, Manchester, or Minneapolis. This was understood as progress. The detachment of architecture from place was, for several decades, one of modernism's proudest achievements. What is becoming clear, across a growing body of practice and a deepening crisis of environmental consequence, is that this detachment carried a cost the industry is only now beginning to fully account for.
Rammed earth is part of the response, though calling it a revival misrepresents what is actually happening. The material never disappeared from building practice in the regions where it was always the logical choice: the earthen architecture of the Sahel, the pisé traditions of southern France and northern Africa, the compressed earth construction of rural India. Its reappearance in serious contemporary architectural practice is less a nostalgic gesture than a recognition of performance qualities that no synthetic material has yet matched at equivalent environmental cost. The thermal mass of a rammed earth wall is exceptional. It absorbs heat during the day and releases it slowly through the night, reducing the energy demand of a building's mechanical systems over its entire operational life. Martin Rauch, the Austrian specialist whose firm Lehm Ton Erde has done more than any other single practice to advance the technical possibilities of contemporary rammed earth construction, collaborated with Herzog and de Meuron on the Ricola Herb Centre in Laufen, Switzerland, completed in 2014, producing walls of compressed local earth whose surface quality and structural performance together made the argument that rammed earth was not a material of limitation but of genuine architectural ambition. The Chapel of Reconciliation in Berlin, completed in 2000 by architects Reitermann and Sassenroth on the former death strip of the Berlin Wall, makes a different but equally serious case: a rammed earth cylinder whose material carries the specific weight of the ground from which it was made, in a place where the ground itself is the whole subject.
Ricola Herb Centre, Herzog and de Meuron with rammed earth specialist Martin Rauch, Laufen, Switzerland, 2014. Walls compressed from local earth, their surface bearing the striations of successive layers — each a record of the construction process and a thermal instrument within the building's environmental strategy.
The limitations of rammed earth are real and should not be softened for the sake of the argument. It is slower to construct than conventional masonry, dependent on skilled labor that is increasingly difficult to source outside specialist practices, and its performance in high-rainfall climates requires careful detailing that raises both cost and complexity. These are not trivial objections in an industry whose economics are calibrated around speed and repeatability. But they are objections about the system surrounding the material rather than about the material itself, and the distinction matters because it locates the problem where it actually sits: not in rammed earth's performance, but in construction culture's reluctance to reorganize itself around materials whose demands differ from those it has normalized.
"The detachment of architecture from place was, for several decades, one of modernism's proudest achievements. What is becoming clear is that this detachment carried a cost the industry is only now beginning to account for."
Lime plaster operates within a similar tension between material logic and construction habit. The widespread adoption of cement-based renders across the twentieth century solved one problem, namely speed and uniformity of application, while creating another that went largely unexamined for decades. Cement seals walls. It prevents the movement of moisture vapor through the building fabric, trapping humidity within the structure and creating the conditions for condensation, mold, and the progressive deterioration of the materials behind the finish. Lime allows walls to breathe, regulating moisture through the wall's cross-section and producing an interior environment whose air quality is measurably better than that of a sealed cement-rendered space. The surface itself behaves differently over time: where cement cracks and stains in ways that are difficult to repair without complete removal, lime develops a patina, carbonating slowly as it cures and producing a surface that deepens and enriches rather than simply deteriorating. John Pawson, whose use of lime plaster across projects including the Novy Dvur Monastery in the Czech Republic, completed in 2004, established it as a surface capable of spiritual as well as sensory refinement, understood long before the sustainability conversation caught up that lime is not a substitute for cement but a categorically different proposition about what a wall should do and how it should age.
The more speculative end of the new material palette is occupied by mycelium, the root structure of fungi, which has attracted serious architectural attention since Ecovative Design, the American biomaterials company founded by Eben Bayer and Gavin McIntyre in 2007, demonstrated that mycelium grown on agricultural waste could be formed into structural blocks with compressive strength comparable to conventional insulation materials, produced with a fraction of the embodied energy. The most architecturally visible demonstration of mycelium's potential was the Hy-Fi tower, erected at MoMA PS1 in New York in 2014 by the architectural practice The Living, led by David Benjamin, who grew approximately ten thousand mycelium and corn stalk bricks on site and assembled them into a structure that stood for the duration of the summer programme before being composted entirely at its close. The project was honest about being an experiment, testing at architectural scale a material whose durability, structural range, and performance under sustained environmental stress remained unresolved. Those questions remain substantially unresolved today, which is not a reason to dismiss the material but a reason to describe its current status accurately: a serious research direction whose translation into standard construction practice is a question of years rather than months, and possibly of decades.
Hy-Fi Tower, The Living (David Benjamin), MoMA PS1 courtyard, New York, 2014. Approximately 10,000 mycelium and corn stalk bricks grown on site and composted in their entirety at the close of the summer programme. The most architecturally serious public demonstration of mycelium's spatial potential to date.
Recycled composites sit in a different position within this conversation: less speculative than mycelium, more immediately deployable than rammed earth, and carrying a particular honesty about what they are doing and what they are not. Interface, the American flooring company that committed in 1994 to eliminating its negative environmental impact by 2020 under the Mission Zero programme initiated by founder Ray Anderson, has over three decades developed flooring systems incorporating recycled fishing nets, reclaimed carpet tiles, and post-consumer waste into products whose performance matches or exceeds conventionally manufactured equivalents. The argument for recycled composites is straightforward and should not be overstated. They manage the waste that the construction industry produces rather than reducing the rate at which that waste is generated. They operate within the existing system of material consumption rather than proposing an alternative to it. This is a meaningful contribution but not a transformation, and the distinction between the two is one that the broader sustainability discourse in architecture has not always been careful to maintain.
What connects rammed earth, lime plaster, mycelium, and recycled composites is not a shared aesthetic or a unified theoretical position but a shared shift in the criteria by which materials are being evaluated. Carbon is no longer an abstraction managed in annual reports. It is a number that clients, regulators, and a growing number of architects are insisting on knowing before a material specification is finalized. The question of where a material comes from, what was consumed to produce it, and what happens to it at the end of a building's life is moving from the margins of the design brief toward its center. This shift is uneven across the industry, far more advanced in practices working at the scale of the individual house or small institution than in those working at the scale of urban development, where the economics of speed and replication continue to exert a pressure that no amount of environmental conviction has yet fully overcome. But the direction of the shift is clear, and the buildings being produced at its leading edge are, by any serious measure, among the most architecturally interesting work being done in the world right now. Not because they are made from unusual materials, but because the discipline those materials demand has produced an architecture more specific, more considered, and more honestly connected to the conditions of the place and time it was built in than the glass and concrete default it is beginning, slowly and unevenly, to replace.
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