On most construction sites, efficiency and accuracy are of high importance. One component that often goes unnoticed yet plays a crucial role in achieving both of these goals is the cardboard void former.
Used beneath concrete structures, these tubes are one of the simplest yet effective ways to manage material usage, reduce weight, and form precise cavities within slabs or foundations.
In this blog, we will explain exactly what cardboard void formers are, why they’re commonly used in concrete construction, and how they help contribute to stronger, more sustainable construction projects.
What Are Cardboard Void Formers?
Cardboard void formers are a type of cardboard tube used in concrete construction to shape and support wet concrete until it sets and hardens. They act as a temporary formwork system, keeping a structure secure during the curing process, while also helping to create hollow spaces that reduce the amount of concrete required.
Made from layers of high-strength cardboard, each tube is manufactured to withstand the pressure of wet concrete without deforming. Once the concrete mix has solidified, the void former can either remain in place or be removed.
They’re available in a wide range of diameters and wall thicknesses, and are used on everything from foundation work to major infrastructure builds, offering businesses a cost-effective, clean, and sustainable solution for shaping concrete.
Why Are Cardboard Void Formers Used in Construction?
Cardboard void formers are commonly used in concrete construction because they make the job easier, faster, and more efficient. Here’s why they’re used on so many construction project sites across the UK:
- Save materials and money: Less concrete is needed, helping to cut down on overall costs.
- Prevent damage from ground movement: Helps protect slabs and foundations built on clay or soft ground.
- Reduce weight: Creates hollow sections, making the structure lighter yet still strong.
- Simple to use: Quick to install, easy to remove, and clean to work with.
- Fits any job: Available in a variety of sizes, perfect for foundations, columns, walls, and bridges.
- Better for the environment: Made from recyclable materials, perfect for sustainable builds.
Key Benefits of Cardboard Void Formers
1. Lightweight and Easy to Handle
Each tube is light enough to be carried and positioned by hand, helping to reduce the need for the use of lifting equipment. This will help save time on site and reduce labour costs.
2. Cost-Efficient
By reducing the amount of concrete that is needed, void formers will help to lower both material and delivery costs. They also help to limit waste disposal fees and speed up the project turnaround.
3. Environmentally Friendly
As they are made from recyclable and biodegradable cardboard, these tubes help to support greener building practices. This helps site contractors meet their sustainability goals without having to change their construction methods.
4. Versatile in Size and Strength
These tubes are available in a wide range of diameters and wall thicknesses, making them suitable for almost any concrete construction design. From foundation piles to bridge columns, they provide a reliable solution that can be tailored to the specific load and shape required for your project.
5. Clean and Precise Formwork
Their smooth internal surface allows for a smooth and even finish once the concrete sets. This helps reduce the time spent on finishing and patching.
Here’s how cardboard void formers compare to other void former materials commonly used in UK construction:
Material Type | Weight | Recyclable? | Cost | Installation Speed | Typical Use |
Cardboard | Very light | Yes | Low | Quick | Foundations, slabs, columns |
Plastic | Medium | Partially | Medium | Average | Retaining walls, ducts |
Metal | Heavy | Yes | High | Slow | Permanent formwork, high-load areas |
Common Applications in Modern Projects
Cardboard void formers are widely used across various construction projects in the UK. This is largely due to their flexibility in both size and strength, which allows them to be adapted to almost any design or structural requirement. You will often find them used in:
- Building foundations and slabs to create hollow sections that reduce weight and material use.
- Bridge supports and motorway posts for forming round columns and structural piers with smooth, consistent finishes.
- Basement walls and retaining structures to shape complex reinforcement layouts while keeping formwork simple and accurate.
Void formers, ranging from 50mm to 500mm in diameter, are frequently used in both commercial and infrastructure projects, demonstrating their adaptability to site conditions and varying scales.
Installation and Handling Best Practices
Installing cardboard void formers correctly is the key to achieving a clean, reliable concrete finish. By following a few simple steps, you can help prevent damage and ensure you achieve the best results on site.
Before pouring concrete:
- Store your tubes in a dry, covered area to prevent any moisture damage.
- Cap both ends of the tube to prevent water or debris from entering.
- Check the alignment and bracing to ensure each void former remains secure and level during the pouring process.
- Avoid overloading before concrete placement to prevent distortion.
The Importance of Choosing the Right Void Former
Choosing the right cardboard void former can make a real difference to how efficiently and accurately concrete work is carried out on site. These tubes help conserve materials, improve sustainability, and produce cleaner, more reliable results across a wide range of construction projects.
At Essex Tubes, we manufacture durable, high-quality cardboard void formers designed to perform in all conditions. Each tube is made in-house and can be tailored to suit your exact specifications, whether for foundations, slabs or structural columns.
If you’re looking for a practical, sustainable solution for your next concrete project, our team can help you find the right size and strength for the job.
Get in touch with us today to discuss your requirements and see how our UK-manufactured void formers can support your next construction project.