Can You Recycle Insulation Offcuts?

When working with insulation materials, one of the most common questions is whether the insulation offcuts can be recycled. As we all strive to reduce waste and move towards more sustainable practices, we must know how our materials impact the environment, even in their smallest forms. This blog will explore the recycling potential of two prominent insulation materials: Expanded Polystyrene (EPS) and mineral wool. We’ll look specifically at how companies like SPI (Styrene Packaging & Insulation) and Rockwool handle their offcuts and manufacturing waste to minimise their environmental footprint.

What is EPS made from?

EPS (Expanded Polystyrene) is made from synthetic aromatic polymer polystyrene. The key ingredient is styrene, a liquid hydrocarbon commercially derived from petroleum and natural gas. The process to make EPS involves several key steps:

1. Pre-expansion: Small beads of polystyrene are heated with steam. This causes the beads to expand as the pentane gas trapped inside them is released. The beads increase in size, often by 40 to 50 times their original volume.
2. Conditioning: The expanded beads are then allowed to rest, stabilising as the air fills the spaces left by the released gas. This process makes the beads more rigid.
3. Moulding: The expanded beads are placed in moulds where they are further heated, causing them to expand again and fuse together into the desired shape. This creates the familiar foam structure of EPS.
4. Final product: The final result is a lightweight, durable, and thermally insulating material comprising about 98% air and only 2% plastic.

We source our EPS from SPI (Styrene Packaging & Insulation Ltd), which operates with an extremely advanced environmental policy. This policy focuses on recycling EPS and lowering their emissions.

Can you recycle EPS insulation offcuts?

SPI operates under the ISO 14001 Environmental Management System, a rigorous standard that governs all aspects of its business, from manufacturing and transport to office management. This system ensures that SPI complies with the latest environmental regulations, and it undergoes regular audits by an independent certification body, The British Assessment Bureau, to maintain its certification. These audits provide assurance that SPI consistently meets the highest standards of environmental responsibility. SPI’s state-of-the-art factory follows strict quality control standards to ensure top-quality products. A major advantage of this process is that no solid waste is generated. Any faulty or broken products are simply ground up and reintroduced into the manufacturing process, further reducing waste. All SPI EPS products are 100% recyclable, and the company has developed a comprehensive waste collection service for customers. Waste collected from customer sites is returned to SPI’s factory, where it is inspected for contamination before being ground up and reintroduced into the manufacturing process. This closed-loop recycling system significantly reduces the amount of EPS waste that would otherwise end up in landfills. SPI customers can benefit from this service by contacting the company directly to arrange waste collection. SPI’s EPS products are extremely lightweight, making them easier to handle and reducing the environmental impact associated with transport. Less fuel is used in transportation, meaning a smaller carbon footprint. Importantly, SPI’s EPS products are free from CFCs (chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), and HBCDs (brominated flame retardants), making them an environmentally friendly choice. With zero Ozone Depletion Potential (ODP) and Global Warming Potential (GWP), EPS is safe to use and produces no toxic particles during its life cycle. This contrasts with alternative insulation materials that release harmful gases or particles.

How is Rockwool's mineral wool manufactured?

Rockwool’s mineral wool, also known as stone wool, is made from natural volcanic rock, primarily basalt and diabase. The manufacturing process involves several key stages that transform these raw materials into a versatile and sustainable insulation material.

1. Melting the Rock

. At this temperature, the rock melts into molten lava-like material.

2. Fibre Formation

The molten rock is then passed through spinning wheels or similar devices that rapidly spin the material, turning it into thin fibres. This process is somewhat similar to how candy floss is made. As the molten rock cools and solidifies, it forms fine, fibrous strands of stone wool.

3. Binding and Curing

Next, a binding agent and, in some cases, oils are added to the fibres to hold them together and improve handling properties like water repellence. The binder compresses and forms these fibres into mats, boards, or rolls, depending on the desired product shape. The binder is cured in an oven to harden, giving the insulation its characteristic structure.

4. Cutting and Shaping

Once the product is cured, it is cut into the required dimensions. Depending on the application, Rockwool produces a variety of thicknesses and densities for different insulation needs, including building, industrial, and technical insulation.

How does Rockwool recycle insulation offcuts?

Rockwool follows a highly sustainable manufacturing process by incorporating recycling at multiple stages, ensuring minimal waste and a reduced environmental footprint. The focus on recycling begins right at the production level. Both post-industrial and post-consumer materials are reintroduced into the production cycle.

1. Use of Recycled Raw Materials

A significant portion of the raw materials used in Rockwool’s production comes from recycled sources. The company incorporates stone wool offcuts and other industries' waste into its manufacturing process. Using recycled content, Rockwool reduces its reliance on virgin resources, such as basalt and diabase, and contributes to the circular economy.

2. Reintroduction of Manufacturing Offcuts

During production, any offcuts or excess stone wool generated are immediately collected, ground down, and returned to the furnace to be melted again. This means almost no solid waste is produced during the manufacturing process. The reintroduced material is blended with the molten raw rock and spun into new fibres, ensuring nothing is wasted. This closed-loop recycling system helps reduce the environmental impact of the production process and maximises the use of raw materials.

3. Internal Recycling Systems

Rockwool’s factories are designed with internal recycling systems that make recycling production waste seamless. The company has invested in advanced machinery and infrastructure that enable efficient stone wool collection, grinding, and reprocessing. This ensures that production runs efficiently without generating unnecessary waste, and any faulty or off-spec material is immediately returned to the system for reuse.

4. Recycling Post-Consumer Stone Wool

In addition to recycling during production, Rockwool offers services for collecting and recycling post-consumer stone wool products. When buildings are demolished or renovated, stone wool insulation can be recovered and reintroduced into manufacturing, reducing the need for new raw materials. This further supports a circular economy by ensuring that stone wool products can be recycled at the end of their life cycle.