Tor Alva Open: A Milestone in 3D Concrete Printing

On 20 May 2025, Tor Alva was officially opened in the village of Mulengns, Switzerland. Designed as a temporary performance space, the tower is the world's tallest building to date made using digital concrete fabrication. It was developed by the Chair of Digital Building Technologies (DBT) at ETH Zurich, in partnership with the Origen Cultural Foundation. The project marks a significant outcome of ongoing research within the NCCR Digital Fabrication.

The inaugurated Tor Alva is located in the Swiss mountain village of Mulegns. Photo by Benjamin Hofer, Nova Fundaziun Origen

3D Concrete Printing Without Formwork

Tor Alva builds on seven years of research into 3D concrete printing (3DCP), with a focus on eliminating the need for traditional formwork. This approach enables greater design freedom and reduces material use. The foundation for this work was laid in 2018 within the Chair of Digital Building Technologies (Prof. Benjamin Dillenburger) by Dr. Ana Anton, who began developing robotic extrusion methods for large-scale components as part of her doctoral research. Her thesis, Tectonics of Concrete Printed Architecture, explored how 3DCP could move from lab experiments to real buildings. Since then, research at DBT has advanced significantly. Dr. Eleni Skevaki and other reserachers have refined the structural and material aspects of 3DCP. Their shared aim: reduce waste, increase automation, and open up new possibilities in architectural geometry.

From Columns to a Full-Scale Tower

The collaboration with the Origen Cultural Foundation began in 2019 with a smaller project: Concrete Choreography. This installation featured nine 3D-printed concrete columns used as stay-in-place formwork. It served as a first step in testing the material and construction methods under real conditions. With Tor Alva, the scale and ambition of the collaboration increased. The tower serves as a venue for cultural performances and events in the mountain village of Mulengns. At the same time, it acts as a demonstration of how digital fabrication can respond to architectural and regional needs—such as building temporary structures in areas with limited infrastructure.

The cupola serves as a performance space with 32 seats and a central stage. Photo by Benjamin Hofer, Nova Fundaziun Origen

Tor Alva in Numbers

Tor Alva rises 30 metres, about the height of a ten-storey building. It’s built from 124 3D-printed elements, including 48 fully structural columns and a domed cupola at the top. In total, over 2,500 layers of concrete were printed—each just 10 mm thick. The printing process took around 900 hours, equivalent to over a full month of continuous production. The tower spans up to 9 metres in diameter at its highest level where the viewing platform theatre seats 32 visitors.

Structural Engineering, Material Innovation and Technical Development

Tor Alva showcases major advancements in computational design, digital fabrication, structural engineering, and material science—made possible through close interdisciplinary collaboration across architecture, engineering, materials research, geodesy, and robotics. The Chair of Structural Engineering – Concrete Structures and Bridge Design (Prof. Dr. Walter Kaufmann) played a key role in developing and testing load-bearing, reinforced 3D-printed concrete columns. This research, conducted by Prof. Kaufmann, Dr. Alejandro Giraldo Soto, Dr. Lukas Gebhard, and Dr. Lucia Licciardello, deepened understanding of how reinforcement can be effectively integrated into concrete structures while printing. Since 2017, the Chair of Building Materials (Prof. Dr. Robert Flatt) has been working together with the Chair of Digital Building Technologies on suitable concrete mixes and printing processes to enable the fabrication of the highly customized elements with their high surface resolutions.

This integrated approach—merging design, engineering, material science, and robotic fabrication—is at the heart of the NCCR Digital Fabrication’s research culture. Tor Alva exemplifies how interdisciplinary collaboration enables architectural innovation and advances new methods of construction. It reflects NCCR DFAB’s core philosophy: cross-disciplinary integration, co-development of technology, and full-scale testing.

From Research to Real-World Application

The impact of this research extends beyond academia. Two spin-offs from NCCR DFAB—MESH AG and Saeki AG—played key roles in the project. MESH provided robotic reinforcement systems for the complex concrete geometries, while Saeki developed industrialised printed formwork solutions. Their involvement highlights how research at DFAB leads to applied technologies with market relevance, bridging the gap between experimental fabrication and scalable construction methods.

Credits

Nova Fundaziun Origen was building the Tor Alva in close collaboration with ETH Zurich, the construction companies Uffer Group and Zindel United and the engineering firm Conzett Bronzini Partner AG. The architects of the White Tower are Prof. Benjamin Dillenburger (Chair of Digital Building Technologies, ETH Zurich) and Michael Hansmeyer. The ETH professorships of Robert Flatt (Building Materials) and Walter Kaufmann (Structural Engineering), together with other researchers from the National Centre of Competence in Research Digital Fabrication (NCCR DFAB), have made significant contributions to the development. The construction of the White Tower is an architectural, engineering and financial challenge. The White Tower could only be realised thanks to the courageous commitment of generous foundations, companies and private individuals.