What is Expanded Polystyrene and How Is It Used in Construction?
Expanded Polystyrene (EPS) is a lightweight, durable, and cost-effective thermoplastic foam widely used in a variety of industries, particularly construction. It is made from solid polystyrene beads, which are polymerised from styrene monomer. These beads contain pentane, a gas that helps them expand when exposed to steam, forming a rigid and closed-cell structure.
This material’s unique properties—insulation, strength, and water resistance—make it a crucial component in modern building and insulation systems.
HOW EXPANDED POLYSTYRENE IS MADE
The process of making EPS begins with small polystyrene beads that contain the hydrocarbon gas pentane. When these beads are heated with steam, they expand up to 40 times their original size, forming the familiar lightweight foam. The expanded beads are then moulded into blocks or sheets that can be cut to size for various applications.
The rigid and closed-cell structure of EPS provides exceptional thermal insulation, which is why it’s so widely used in building construction.
Key uses of expanded polystyrene in construction
EPS is widely recognised for its thermal insulation properties. It can be found in:
- Walls and Roof Insulation: EPS panels are used within cavity walls and roofs to improve energy efficiency in residential and commercial buildings. It prevents heat transfer, reducing energy bills by maintaining a comfortable indoor climate.
- Floor Insulation: Expanded Polystyrene is often placed beneath concrete slabs or suspended floors to create a thermal barrier. Its lightweight nature ensures it doesn’t add unnecessary load to the structure while still providing high insulating performance.
EPS is commonly used as a lightweight fill material in construction projects such as:
- Roadways and Bridge Embankments: Due to its low weight, EPS is used to reduce the overall load on soft soil or embankments, preventing subsidence.
- Void Forming in Concrete Structures: In construction, EPS is often used as a void form to reduce the amount of concrete required, saving both weight and cost. This is particularly useful for large buildings or complex structures like bridges.
While EPS is best known for its thermal properties, it can also contribute to soundproofing in buildings. Its closed-cell structure absorbs sound, reducing noise transfer between floors and walls. EPS panels are often integrated with other materials to provide enhanced acoustic insulation in residential and commercial properties.
Benefits of using expanded polystyrene in construction
EPS is resistant to moisture, mould, and rot, making it ideal for long-term use in construction. Once installed, it can last the lifetime of the building without degrading or losing its insulating properties.
Compared to other insulation and fill materials, EPS is affordable and offers excellent value for money. Its ease of installation can also reduce labour costs on-site.
EPS can be recycled and repurposed, reducing its environmental impact. It is a chemically stable material that doesn’t emit harmful gases once installed, contributing to healthier indoor air quality.
The adaptability of EPS makes it a go-to material in construction. It can be moulded into various shapes and sizes to meet the needs of specific projects, whether for insulation, void forming, or load reduction.
The eFloor Plus advantage
At Floorspan we use Expanded Polystyrene in our eFloor Plus system. eFloor Plus uses pre-stressed concrete T-beams with expanded polystyrene (EPS) infill panels between each beam and a variable depth closed-cell expanded top layer.
eFloor Plus is a high-quality alternative to traditional block & beam flooring, with numerous advantages, which make it perfect for home-builders.
