Delivering void protection for infrastructure at the Queensferry Crossing
End User: DFCBC (Forth Crossing Bridge Contractors)
Location: Queensferry Crossing, East Scotland
Sector: Civil engineering – transport infrastructure
Challenge: Provide a lightweight, sustainable solution for structural separation around concrete bridge elements
Solution: Clayboard supplied via SIG to support void protection
Outcome: Enabled controlled separation and reduced structural pressure within Scotland’s largest modern infrastructure project
Void protection for infrastructure: smart ground separation for complex bridge engineering
Void management was a critical element in the delivery of this record-breaking bridge. Given the project’s sheer scale and complexity, the engineering teams required a proven solution that could create a separation between the structure and surrounding groundworks without adding unnecessary weight or environmental impact. That’s where Dufaylite’s Clayboard came in, providing a compressible layer that performed predictably under pressure while supporting tight construction timelines.
Spanning 1.7 miles across the Firth of Forth, the Queensferry Crossing forms a central part of a £1.35 billion upgrade to the cross-Forth transport corridor. It stands today as a symbol of innovation, resilience, and long-term thinking in national infrastructure delivery.
About the Queensferry Crossing project
Opened in September 2017, the Queensferry Crossing is now the longest three-tower cable-stayed bridge in the world. The scale of the structure is remarkable:
- 150,000 tonnes of concrete
- 35,000 tonnes of steel
- 23,000 miles of cabling
Commissioned by Transport Scotland and delivered by the FCBC joint venture (Forth Crossing Bridge Contractors), the bridge was designed to enhance transport links, replace the ageing Forth Road Bridge, and future-proof connectivity between Edinburgh and the north of Scotland.
Transport Scotland described it as the biggest infrastructure project in Scotland for a generation.
Collaborative material supply for transport infrastructure
To ensure the right construction accessories were available throughout the project, FCBC worked with SIG Construction Accessories of Glasgow, a specialist distributor with deep expertise in delivering materials for high-performance builds.
As part of this supply chain, Dufaylite’s Clayboard system was specified and supplied to support void separation requirements around key concrete sections of the bridge. With both performance and practicality in mind, the product needed to be lightweight, sustainable, and reliably engineered to suit the technical demands of large-scale infrastructure.
Curious how void formers work in major builds? Read our guide on what a void former is used for.
“This project showcased how Clayboard can deliver exceptional performance in infrastructure environments. By working closely with SIG and FCBC, we ensured the right solution was delivered – on time and to spec – for one of Scotland’s most iconic builds.”
Lightweight formwork for civil engineering applications
While Clayboard is widely used in housing, schools, hospitals, and commercial developments, it also offers valuable benefits when applied to civil engineering infrastructure, particularly in situations where structural isolation and compressible formwork are required.
In this application, the product wasn’t used for classic ground heave scenarios but rather as a sacrificial void former, creating controlled separation within certain areas of the bridge’s concrete construction.
- Lightweight construction for easy handling on site
- Sustainably manufactured using a recycled paper honeycomb core
- Predictable performance – engineered to collapse in a controlled way when required
- No waste extraction – Clayboard remains in situ post-installation
- BBA-certified for peace of mind and compliance
This made it an ideal fit for Scotland’s most significant transport structure, one where durability, technical certainty, and environmental responsibility were all in focus.
Why Clayboard was the right fit for the Queensferry Crossing
- Supports large-scale infrastructure with smart structural separation
- Easily handled and installed in tight project schedules
- Reduces environmental impact with recycled materials
- Delivers precise performance with no post-installation waste
- Proven in both UK and international civil engineering applications
Learn more about our full range of ground heave solutions and structural separation solutions.
Versatile structural separation beyond heave management
There are many examples of Clayboard being successfully used in civil engineering, including water treatment works, harbours, and bridge decks. But none are as iconic – or as ambitious – as the new road bridge across the Forth: the Queensferry Crossing, the centrepiece of a major upgrade to the cross-Forth transport corridor in the east of Scotland, officially opened in September 2017.
Beyond Scotland, Clayboard has also been specified in:
- A multi-storey development over a live subway tunnel in New York
- A car park built over a tunnel in Gibraltar
- A power station project in Sudan
See how Clayboard protected a subway tunnel in Brooklyn, NY.
These examples show how the product continues to evolve, enabling engineers and contractors to meet sustainability goals, reduce labour and transport costs, and protect critical structures with confidence.
Let’s talk infrastructure-ready void forming solutions
If you’re planning a civil engineering, bridge, or transport infrastructure project where structural separation, vibration control, or lightweight formwork is required, Dufaylite’s Clayboard system offers a proven, sustainable solution.
Contact our technical team today to find out how we can tailor Clayboard to suit your next void protection for infrastructure challenge.
