Zigzag Formwork: A Game Changer for Greener Construction
Concrete, one of the most widely used construction materials globally, is often reinforced with steel to enhance its performance, especially under tensile stress. However, the production of both concrete and steel generates significant carbon emissions, making it a major contributor to climate change. Furthermore, the traditional formwork used to mold concrete is often wasteful, requiring the use of single-use materials, many of which are made from petroleum-based substances like Styrofoam.
At ETH Zurich, Professor Philippe Block’s team has consistently focused on innovative methods to reduce the carbon footprint of construction materials. One such breakthrough is vaulted concrete floors that use geometry to create stronger, thinner concrete elements without the need for steel reinforcement. This method has already begun to be commercialized through ETH-spinoff VAULTED AG.
However, the next step in achieving sustainable construction is to address the formwork used to mold the concrete. Traditionally, formwork is bulky, single-use, and difficult to transport, resulting in significant waste. In a move toward more sustainable solutions, Lotte Scheder-Bieschin, a doctoral student at ETH Zurich, has developed a unique foldable formwork system called Unfold Form.
The Unfold Form System: Sustainable and Efficient
The Unfold Form system consists of thin, flexible plywood strips connected by textile hinges, which can be unfolded like a fan to create sturdy, zigzag-shaped molds for poured concrete. This formwork, once the concrete cures, can be easily removed, folded away, and reused multiple times. The prototype weighs only 24 kilograms but can support up to 1 metric ton of concrete.
The system is simple to assemble, requiring just four compact units to create a zigzag mold, providing a significant reduction in material usage. Scheder-Bieschin’s aim was to design a system that could be easily used worldwide, even in regions with limited resources. Currently, creating non-standard concrete shapes typically requires digital fabrication and specialized equipment, which can be costly and challenging to access, especially in developing countries.
By focusing on simplicity and cost-effectiveness, the Unfold Form system can be produced for just 650 Swiss francs using easily available materials. This approach makes it accessible to a global market, particularly in areas where there is a high demand for affordable and sustainable construction.
Reducing Waste in Construction: The Environmental Benefits
The environmental impact of Unfold Form is significant. Traditional concrete formwork, especially for non-standard shapes, is often made from petroleum-based products like Styrofoam, and is typically single-use, contributing to high levels of waste. The Unfold Form system, by contrast, is reusable and requires fewer resources in its production, aligning with the sustainability goals of the construction industry.
Unfold Form reduces the amount of concrete and reinforcement steel used by up to 60% and 90%, respectively. This is achieved through the formwork’s clever geometry—the zigzag structure that increases the strength and rigidity of the mold without significantly increasing its weight. The addition of curved-crease folding (CCF) technology enhances this effect, allowing the formwork to maintain high stability under load with minimal material input.
Inspiration from Nature: Nature-Inspired Design
The design of the Unfold Form system draws inspiration from natural structures, particularly the zigzag patterns found in seashells. This biomimetic approach creates a formwork system that is both lightweight and strong, providing added stability without increasing material usage. The structural design also transfers to the concrete poured onto it, resulting in a ribbed pattern that enhances load distribution.
Real-World Applications: A Test in South Africa
One of the most exciting aspects of the Unfold Form system is its potential to make a global impact, especially in regions with limited access to traditional construction methods. A prototype was sent to Cape Town, South Africa, where local construction partners used the formwork to build a concrete structure using bio-concrete, made from invasive vegetation. This test demonstrated the versatility of the system, showing that it works with non-premium concrete materials and is suitable for use in sustainable housing projects.
The success of this test not only proved the formwork’s functionality but also showcased its portability—the folded formwork was transported in surfboard bags, illustrating the system’s ease of transportation and scalability.
Building Dignified Housing with Unfold Form
One of the primary goals of the Unfold Form system is to support the construction of affordable, sustainable housing in regions that need it most. By making the formwork simple to assemble and reusable, it provides communities with the tools to build their own structures without relying on expensive or resource-intensive materials.
In South Africa, this approach could provide a long-term solution to the housing challenges faced by residents in townships. The use of low-cost, sustainable materials for construction not only benefits the environment but also empowers local communities to participate in the building process.
Next Steps: Scaling Up and Global Impact
The future of Unfold Form looks promising, with Scheder-Bieschin planning to continue developing the system as a postdoctoral researcher at ETH Zurich. The next step is to bring the product to market, and training programs are already in development to teach local communities how to build their own formwork and use it for construction.
Scheder-Bieschin’s work highlights the importance of localizing sustainable solutions and making innovative technologies accessible worldwide. By focusing on simplicity and resource efficiency, the Unfold Form system offers a blueprint for the future of green construction.
