Researchers at public university ETH Zurich, commissioned by the cultural foundation Nova Fundaziun Origen, have completed what is described as the world’s tallest 3D printed concrete tower: Tor Alva — a 30-meter, four-story modular structure in Mulegns, Switzerland. Constructed from 3D printed concrete elements, this project showcases how robotic fabrication, computer-aided design, and resource-efficient construction methods pave the way for sustainable building practices of the future.
Led by ETH Zurich, the initiative also received support from the ETH Foundation, the Surses community, private donors, and industry partners such as Sika, BASF, and Knauf. It brought together multiple ETH departments—including digital fabrication, structural engineering, and materials science—as well as two ETH spin-offs, Mesh and Saeki.
Engineering Innovation and Digital Workflow
Completed in May 2025, Tor Alva is the world’s first multi-story structure with load-bearing columns fully created through 3D printing, including built-in reinforcement. This 3D concrete printing method employs two coordinated robots: one robotic arm extrudes concrete layer by layer into intricate freeform shapes, while the other places reinforcement between the layers. Using a specially designed fine-grain concrete that hardens quickly due to a custom additive, structural components can be produced without the need for traditional formwork. This printing technology was developed by ETH Zurich in partnership with industry collaborators.
To enhance structural integrity, ETH researchers developed a hybrid reinforcement system. Horizontal steel rings were embedded during printing, with vertical rods added post-printing and filled with self-compacting mortar. The tower’s upper sections incorporate prestressed rods to improve crack resistance.
Researchers at ETH Zurich explained that the Tor Alva’s design was created entirely with parametric scripting—computer algorithms that produce a digital model for making adjustments, visualizing, and simulating production within the limits of robotic 3D printers.
Sustainability and Reusability
The modular design allows for disassembly and relocation, aligning with circular construction principles. Dry connections and prestressed joints facilitate component reuse, minimizing waste and extending material lifespan.
While the specialized concrete mix has a higher carbon footprint than conventional alternatives, the team incorporated measures to reduce environmental impact. Corrosion-resistant stainless steel replaced traditional rebar to improve durability, and the tower is designed to accelerate carbonation—a natural process where concrete reabsorbs atmospheric CO₂.
Key Structural and Fabrication Details of Tor Alva
Below are the essential details highlighting the tower’s architecture, printing specifications, and dimensions.
| Category | Details |
| Structure | Four stories, each with 8 double and quadruple columns (32), plus double dome with 8 triple and 8 single columns (16); Total: 48 load-bearing columns with fully integrated reinforcement |
| 3D Printing | Approximately 2,500 concrete layers, each 8 mm high and 25 mm deep; total printing time ~500 hours |
| Elements | 232 3D printed concrete elements, plus 104 prefabricated concrete parts with printed formwork |
| Dimensions | Total height: 30 meters (including base), diameter: 7 to 9 meters |
Advances in 3D Printing for Sustainable Housing Development
In May, Architect, artist and entrepreneur Hedwig Heinsman is presenting the Tiny Penthouses at the 19th International Architecture Exhibition – La Biennale di Venezia, held from 10 May to 23 November 2025. The project proposes placing modular living units on the rooftops of existing buildings to address urban challenges such as climate change, housing shortages, and social fragmentation. By building upwards instead of outwards, it offers a strategy for densifying cities without large-scale demolition or new construction.
In February, International design studio Hassell has completed a 3D printed community building in Hope Village, Tanzania, using locally sourced earth. The project is part of a broader effort to create a safe and supportive space for vulnerable young girls in Kibaha. Developed in partnership with fellow architect ClarkeHopkinsClarke, the plan also includes family housing, a school for 480 students, and facilities for childcare and skills training, extending its impact to the wider community.
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Featured image shows Close-up of Tor Alva. Photo via ETH Zurich.
