Author: contributor

The Clay Rotunda is a cylindrical, free-standing structure that encloses the SE MusicLab, a high-fidelity music space inside the renovated Gurten Brewery in Bern. This innovative design uses unreinforced clay, a zero-waste, eco-friendly material, as its primary component. Standing 5 meters tall with a diameter of almost 11 meters, the structure was built entirely on-site over a period of 50 days using advanced robotic technology, assembling over 30,000 soft clay bricks.

The project was initiated by SE MusicLab, a high-fidelity music studio, with the design executed by a collaborative team involving experts from Lehmag (a specialist in earthen construction), Seforb (an engineering firm), and Brauchli Ziegeleien (a brick manufacturer). These partners share a commitment to integrating traditional materials with modern technology, striving to create sustainable, emission-free construction methods. Their collective goal was to push the limits of earthen architecture by blending computational design with ancient building techniques.

Design Concept
The slender form of the rotunda is stabilized by its undulating surface, which increases the footprint and prevents structural buckling. The geometry was carefully calculated using a computational model that integrated engineering requirements, material properties, and the construction process itself. Given the limited reach of the robotic arm and the natural shrinkage of clay as it dries, the structure was divided into trapezoidal sections. This segmentation was key to ensuring that each clay cylinder was positioned correctly and supported the structural integrity of the whole.

Material Innovation and Construction Process
To achieve the desired strength and malleability, a specific clay mix was developed, blending clay with sand, small stones, and water. This mixture was molded into cylindrical “soft bricks,” each 9 cm in diameter and 15 cm in height. A robotic arm then precisely placed and compressed each brick, reducing it by 40% of its height to create strong bonds between the units. The entire structure was built segment by segment, with the robot relocating to different positions as the project progressed. Throughout the process, 3D scanning was used to continuously monitor the structure’s geometry and adjust for any material shrinkage. Cracks that formed during drying were filled to maintain a consistent finish.

Sustainability Features
One of the key aspects of the Clay Rotunda is its commitment to sustainable building practices. By using clay, a natural material that can be recycled and returned to the earth, the project minimizes waste and avoids harmful emissions. The clay’s inherent qualities also contribute to the building’s interior climate, naturally regulating temperature and humidity, reducing the need for mechanical systems. This project pushes the boundaries of how traditional materials like clay can be reimagined through digital design and robotic construction.

Citations

• SE MusicLab Clay Rotunda. SE MusicLab, 2021, www.semusiclab.ch/project-clay-rotunda.
• Lehmag, Seforb, and Brauchli Ziegeleien. Clay Rotunda Process Report. SE MusicLab, 2021, www.semusiclab.ch/research-clay-rotunda.
• Lehmag. Earthen Construction Techniques in Contemporary Architecture. Journal of Sustainable Building, 2021, vol. 32, no. 4, pp. 50-65.

Location: Gagosian Gallery, New York City

Completion: 2021

Architect:  David Adjaye

‘Asaase’ takes the form of a labyrinthine,  walls made from stacked blocks increasing in height toward a “conical vertex” in the center. The British architect’s first large sculpture was one piece to Social Works, a group exhibition of a dozen Black artists, curated by Antwaun Sargent, to engage with social space “as a community-building tool.”

“It’s this idea of construction that works across many modes of sensory perceptions….it’s designed to create moments where the audience is just in – between earth. This is something people have forgotten how to do.”

Constructing the rammed earth blocks began with a combination of crushed limestone and schist from New York, with the tops of the shorter walls at the perimeter revealing some of the loose aggregate from the process.

The ‘Asaase’ project incorporates a sense of collective memory and aims to evoke a deeper connection with the land, specifically traditional black architecture and historical identities. References to historic works of West African architecture such as the Tiébélé royal complex in Burkina Faso and the walled city of Agadez in Niger, can be seen in the sculpture’s maze form.

The project reflects on the unique essence of a place, drawing connections between the present and the past by examining Black communal spaces across the African continent. It delves into how these spaces served as central hubs for families and communities to gather.

The curved walls invite visitors to explore the spaces between the gallery walls and the piece before entering the spaces inside. These overlapping walls mean there are numerous ways to encounter  and move through the installation.

‘Asaase’ contemplates the idea of fragments—both in terms of physical spaces and the buildings constructed from the earth—that provided the backdrop to everyday life for Black individuals, symbolizing a connection to heritage and history. What Adjaye describes as “fragments of chambers,” can be demonstrated the most by the niche at the center of the maze.

References

• David Adjaye Tries Rammed Earth
• Adjaye Associates
• World Architects
• Photography: John Hill

Arup Associates embraced these natural materials to create a structure that echoes traditional Ladakhi building methods while incorporating modern techniques to ensure long-term resilience.

The layout of the school reflects a deep connection to nature and spirituality. Buildings are arranged in clusters, symbolizing Buddhist mandalas, creating a harmonious flow between the interior learning spaces and the surrounding natural environment. The design respects Ladakh’s spiritual heritage while ensuring that students learn in an environment that fosters a connection with their cultural roots.

as well, such as the wooden eaves in the roof, earth-clad for better thermal performance. Wood is also used in the interior, both for floors and the frames of the large windows that bring light into the classrooms. Among the strategies applied to capitalize on passive solar gain are the building’s radiation-maximizing orientation, the functioning of the south facades as Trombe walls, and the use of solar thermal panels for heating and hot water. Water is saved through dry latrines with forced ventilation (by solar chimneys). Because the place is at such a high altitude and the skies are so bright, photovoltaic panels generate all the electricity the school needs.

Engineering and architectural aspects focused very much on sustainability, which was particularly important given the challenges of the location, with limited water supply and sometimes adverse climate conditions.

The supply road to the area could be cut off by snow for up to six months of the year yet, on the positive side, sunlight hours are high. The school is located in an area of considerable seismic activity and the methods used to ensure improved safety in the event of an earthquake needed to be easy to emulate for future structures.

Most traditional local buildings don’t benefit from seismic engineering so the Druk White Lotus will spark a new generation of safety-enhanced structures, better able to withstand the ravages of a natural disaster.

With relatively non-complex structural approaches, using timber frames to resist seismic loads, the school enjoys improved protection from earth movements.
Blocks used for the external walls were quarried on site, making effective use of available resources.

During cold evenings resident pupils feel the benefit of ventilated cavity walls, made of mud brick and glass.
Solar energy is stored through the day and used to heat the interior at night. Solar panels generate electrical energy, minimizing local emissions and making maximum use of the high sunlight hours. The panels feed battery packs in an energy center, powering lighting, water supply, and even computers.
Ventilation is natural and the building is positioned to receive natural light.
Limited water supply led to the creation of a dual recycling and distribution system for irrigation. Ground water is pumped using solar power to a tank at the top of the site. Rainfall is directed to planted trees and gravity fed to gardens and water points.
A solar pump powers the unique recycling system, which supplies drinking water to the school’s occupants. The circuit is completed with the disposal of wastewater: waste is filtered down pipes, eventually feeding and sustaining the shady trees surrounding the school.The introduction of Ventilated Improved Pit (VIP) latrines is a cost effective, low-tech method of maintaining a high standard of renewable sanitation – they do not use water but instead a solar driven flue to counteract smells and insects.
The building is a truly self-sufficient operation on all counts: an effective reusable energy engine and a valid health and sanitation system.

References

1- Architectural Case Study on Druk White Lotus School | PPT (slideshare.net)

2- Druk white lotus school study for material.pptx (slideshare.net)

3- Druk White Lotus School – Arup Associates | Arquitectura Viva

Martin Rauch, founder and managing director of Lehm Ton Erde (LTE) in Schlins, Austria, is internationally known as a leading expert in the field of rammed earth mining. He founded the company in 1984 as the sole manufacturer of ceramics and clay construction, and then founded Lehm Ton Erde Baukunst in 1999. The current studio and operations centre were built in 1990, where he presented his accumulated knowledge of clay construction at the time. Over the course of more than 35 years of working with clay, Rauch and LTE have completed over 100 projects around the world, published 3 books and led the industry in rammed earth innovations.

After the development of a unique precast plant, Lehm Ton Erde is now entering a new phase in which it is a matter of establishing rammed earth as a sustainable building material in order to counter the ecological burdens of the construction industry. ERDEN means clay. It is a grounding of building in natural materials and processes. Clay earth continues to be the roof for everything that has to do with rammed earth. ERDEN is a leader in clay construction prefabrication and is revolutionizing the construction industry. With the ERDEN factory hall, a new plant and headquarters for the production of precast clay elements. The team is made up of people from diverse backgrounds, including design, craft, teaching, research, and management expertise.

The ecological résumé of rammed earth is second to none. No other material has a smaller footprint on our planet. The raw material and the finished product are one and the same. Soil from the ground is dug up and processed. We add a little gravel or clay to optimize them, mix them with water and voilà!

This diagram emphasizes the cyclical nature of rammed earth construction, which starts and ends with the natural earth, with minimal environmental impact. This aligns with Martin Rauch’s philosophy of sustainable building, where the material’s life cycle, from construction to deconstruction, supports ecological balance​.

1- Earth Site: Earth is extracted directly from the building site or a nearby location, using local resources to minimize environmental impact. This is where the raw material for the rammed earth process begins.

2- 100% Earth: The material used for construction is pure earth, without additives. The earth is gathered and sometimes modified by adding gravel or sand, depending on its natural composition.

3-Filling the Formwork: The extracted earth is placed into formwork, which is essentially a mold that shapes the walls. The formwork holds the earth in layers before it is compacted.

4-Compacting Earth: Once the earth is inside the formwork, it is compacted. This can be done manually or with the help of mechanical tools such as pneumatic hammers. The compaction process is crucial for the stability and durability of the walls.

5-Construction: The walls are constructed by repeating the process of filling and compacting. The compacted earth forms solid, load-bearing walls without the need for additional finishing materials like stucco or plaster.

6-Seamless Finishing: After the compaction and construction of the walls, seamless finishing techniques are applied. This helps to smooth out the surface and enhances the natural aesthetics of the rammed earth, maintaining the integrity and beauty of the material.

7-Transport: If needed, components of the rammed earth can be prefabricated and transported to the site. Prefabricated elements simplify the construction process, especially for large or complex structures.

8-Building in Use: The rammed earth structure is then ready for use. These buildings have high thermal mass, providing excellent insulation properties, which make them energy efficient and comfortable to live in, regulating temperature naturally.

9-Deconstruction: At the end of the building’s life cycle, it can be deconstructed. The natural earth material can be reused or returned to the site, making it a completely recyclable and sustainable material.

10-Earth Back to Site: Once the building is deconstructed, the earth is returned to the site, completing the cycle. This step emphasizes the eco-friendly nature of the process, where no waste is generated, and the material is fully reused.

Despite its ecological, functional and aesthetic qualities, rammed earth has hardly been used in recent times. Especially because the experience with the material has been lost. For us, every rammed earth building was, if you will, a prototype. The costs were correspondingly high. Thanks to Martin Rauch’s 35 years of work, rammed earth is now losing this exclusivity. With the introduction of the ERDEN prefabrication process, we have simplified clay construction and made it more affordable. This means that the desire to build their own mud house is becoming a reality for more and more people. But there is still a long way to go. Regulatory hurdles and a broader knowledge of working with rammed earth still pose challenges. But the upswing has begun. The environment urgently needs natural building solutions. Why doesn’t everyone build with clay? Well, it’s only a matter of time.

An urban-rural furniture
There’s nothing new about Earth’s resources becoming scarce, just as public space, especially in urban areas, is becoming increasingly scarce. Only what is the solution? The construction industry is one of the major polluters of our time. The Erdenbürgerin project is something of a prototype for a counter-reaction. A seating place made of 100% earth, the most sustainable building material in the World. The earth used to build this urban-rural furniture comes from our local surroundings.

Of course, this is not the silver bullet either. Rather, it is an impetus and an opportunity to ask questions. Where am I sitting here? And on what? The Erdenbürgerin asks you to take a seat and to widen your gaze. Or just to sit and commune, to chat, to relax. In a freespace, public place, as a healthy society needs. And a healthy environment. This project was developed as a cooperation between the Walgau region and earth specialists, Lehm Ton Erde.

Schlins, the Mecca of rammed earth architecture, one could say, is the home of the founder of ERDEN, Martin Rauch. Since he opened his office in Schlins, several works have been created in the small town in the Vorarlberg province that have become important international precedents of contemporary rammed earth architecture. These include the Rauch Workshop, Haus Rauch, our ERDEN workshop and the Erdenhaus, which is still under construction.

Rauch family home

Schlins: Austria

The materiality and form of the residential house are direct reactions to the steep south-sloping scarp situation of the slender plot in its landscape context – as if a monolithic block, similar to a piece of abstract and artificial nature, had been pressed out of the earth. Two clefts articulate the building of rammed earth, wedging it backwards with the scarp and establishing a frontal prelude or welcoming gesture towards the valley. The inside of the house is developed in the form of sequences of individualizable spaces that respond storey-wise to the variable conditions. As opposed to more organic, archaic clay architecture, the morphology of the building aims towards a certain clarity and sharp-edgedness. The strips of clay bricks that are inserted between the typical clay layers optically stabilise the building structure by emphasising the horizontality and heightening the light and shadow effects.

References 

1- https://www.architectsnotarchitecture.com/archive/martin-rauch/

2- https://www.erden.at/

3- Rammed earth house, Rauch family home by Boltshauser Architekten | Detached houses (architonic.com)

Location:  ETH Zurich
Year:  2021-2024
​Research: Gramazio Kohler Research

Source: https://gramaziokohler.arch.ethz.ch/web/e/forschung/451.html

Impact printing is an innovative robotic construction method that creates full-scale, freeform structures using a custom earth-based material. Unlike traditional layer-based 3D printing, it employs high-velocity deposition, allowing for interlayer bonding at speeds of up to 10 meters per second. The environmentally friendly material consists mainly of locally sourced secondary materials with minimal mineral admixtures.

Currently, prototypes are being developed at ETH Zurich’s Robotic Fabrication Laboratory, with plans to integrate this technology into the HEAP autonomous excavator. The research also focuses on developing a digital design and construction strategy, utilizing advanced computational design and sensing methods. This work aims to enhance sustainable, mobile robotic construction, leading to groundbreaking techniques in the design and manufacturing of earthen structures.

Video

Source: https://www.research-collection.ethz.ch/handle/20.500.11850/668921

The diagram displays different concepts of earth material fabrication methods.

Left: ‘throwing’ technique used during Remote Material Deposition in 2014, Middle:‘pressing’ technique used during Clay Rotunda in 2021,  Right: ‘shooting’ technique currently investigated during Impact Printed Structures.

Source: https://www.research-collection.ethz.ch/handle/20.500.11850/668921

The diagram above illustrates the ideal overlap between each deposited component.

Source: https://www.research-collection.ethz.ch/handle/20.500.11850/668921

The photo above shows the process of printing a wall with a window embedded.