Researchers at ETH Zurich have developed an alternative method for constructing concrete floors with a significantly reduced environmental impact. The “Unfold Form”, created by PhD student Lotte Scheder-Bieschin, is a reusable formwork system designed to optimize material use, particularly in resource-constrained environments.

Efficient Use of Materials
Concrete floors traditionally require large amounts of concrete and steel reinforcement, contributing to high carbon emissions during production. The Unfold Form system reduces material usage by employing geometry to create thin, vaulted floor structures. This approach results in up to 60% less concrete and 90% less steel compared to conventional reinforced concrete slabs.

The formwork is composed of thin plywood strips connected by textile hinges. When unfolded, these strips form a zigzag pattern, enhancing structural rigidity without significant weight increases. The system can support up to a tonne of concrete while weighing only 24 kilograms.

Sustainability and Reusability
The design emphasizes reusability and accessibility. Unlike conventional formwork, which often uses single-use materials such as Styrofoam, the Unfold Form is foldable, compact, and lightweight. It can be assembled and disassembled easily without specialized tools or expertise. Materials for the prototype cost approximately CHF 650, demonstrating its potential for cost-effective production.

This system also contributes to reducing construction waste, as it can be reused multiple times without compromising quality. Its reliance on renewable materials like plywood supports circular construction practices.

Field Testing and Applications
The Unfold Form system has been tested in Switzerland and South Africa, demonstrating its versatility. In South Africa, a local construction firm used bio-concrete made from shredded invasive vegetation to create a prototype, highlighting the compatibility of the formwork with alternative concrete mixtures. This project showed the system’s effectiveness for producing durable and sustainable structures in diverse contexts.

Research and Development
Scheder-Bieschin is continuing to refine the Unfold Form system as a postdoctoral researcher, with plans for broader application and commercialization. Parallel to this, ETH Zurich will launch a Master of Advanced Studies (MAS) in Computational Structural Design in 2025. This programme will focus on developing innovative and sustainable solutions for the architecture, engineering, and construction industries, further advancing research in this field.

Source: ETH Zurich
Photos: Lotte Scheder-Bieschin / Andrei Jipa / ETH Zurich, BRG