Researchers at ETH Zurich, commissioned by the Nova Fundaziun Origen cultural foundation, have constructed Tor Alva, the world’s tallest 3D-printed concrete tower.
The 30-metre, four-storey modular structure showcases the potential of robotic fabrication, computer-aided design, and resource-efficient construction methods for future sustainable building practices.
The project, completed in May 2025, involved multiple ETH departments and spin-offs, with support from the ETH Foundation, the Surses community, private donors, and industry partners like Sika, BASF, and Knauf.
Tor Alva stands as the first multi-storey structure with load-bearing columns entirely created through 3D printing, complete with integrated reinforcement.
The 3D concrete printing method uses two coordinated robots: one extrudes concrete layer by layer, while the other places reinforcement.
A specially designed fine-grain concrete hardens quickly due to a custom additive, eliminating the need for traditional formwork.
Horizontal steel rings were embedded during printing, with vertical rods added post-printing and filled with self-compacting mortar to enhance structural integrity.
The tower’s design, created with parametric scripting, allows for adjustments, visualisation, and production simulations within the robotic 3D printers’ limits.
The modular design facilitates disassembly and relocation, aligning with circular construction principles.
Dry connections and prestressed joints promote component reuse, minimising waste and extending material lifespan.
While the specialised concrete mix has a higher carbon footprint than conventional alternatives, the team incorporated measures to reduce environmental impact, such as using corrosion-resistant stainless steel and designing the tower to accelerate carbonation.
The construction of Tor Alva follows other recent innovations in 3D printing for sustainable housing development.
Architect Hedwig Heinsman is presenting the Tiny Penthouses project at the 19th International Architecture Exhibition – La Biennale di Venezia, proposing modular living units on existing buildings’ rooftops to address urban challenges.
Additionally, Hassell, an international design studio, has completed a 3D-printed community building in Hope Village, Tanzania, using locally sourced earth, as part of a broader effort to create a safe space for vulnerable young girls.
