Key Takeaways -

• Composite decking is made from recycled wood fibres and plastic, offering durability and low maintenance.
• It is resistant to rot, splintering, and fading, making it a long-lasting alternative to wood.
• Eco-friendly materials and a long lifespan reduce environmental impact.
• Available in various colours and finishes, it provides both aesthetic appeal and functionality.

Composite decking is a strong, low-maintenance alternative to wood. Made from recycled wood fibres and plastic, it creates a durable, long-lasting material for outdoor spaces. While every decking material has pros and cons, understanding composite decking helps you choose the best option.

This article will explain what composite decking is made of, how it's manufactured, and why it's a popular choice. You'll also learn about its benefits, including durability, sustainability, and ease of care.

Keep reading to discover how composite decking offers a practical and stylish solution for your home. Whether you're building a new deck or upgrading an old one, understanding its materials will help you make the best decision.

Composition of Composite Decking

Wood Fibres

Composite decking typically contains 60% recycled wood fibres, including sawdust, wood chips, and reclaimed hardwood. These materials give decking its natural look and texture while providing strength and stability.

Since the wood fibres are sourced from recycled materials, composite decking is an eco-friendly choice that reduces waste. Many manufacturers offer FSC-certified options, ensuring the wood comes from responsibly managed forests for a more sustainable product (1).

Plastic Materials

Around 40% of composite decking consists of recycled plastics like HDPE (High-Density Polyethylene) or PP (Polypropylene). These plastics improve durability, weather resistance, and structural integrity. Some brands may use virgin plastic, but recycled options are more sustainable.

• PE (Polyethylene): Lightweight, affordable, and widely used.
• PP (Polypropylene): Stronger, more heat-resistant, and offers better longevity.
• PVC (if used): Less eco-friendly but provides additional moisture resistance in some brands.

Other Additives

To enhance performance, manufacturers add bonding agents to hold materials together. UV inhibitors protect against sun damage and fading, while colour pigments give decking its desired look.

Anti-oxidants and anti-microbial agents help prevent mould, mildew, and deterioration, ensuring long-lasting quality with minimal maintenance.

How is Composite Decking Manufactured?

Extrusion Process

In the extrusion process, raw materials are mixed, heated, and melted to create a uniform blend. The heated mixture is then forced through a die, shaping it into decking boards.

This method produces high-quality, consistent products with precise dimensions and durability, making it the most commonly used manufacturing technique.

Compression Moulding

Compression moulding involves placing the wood-plastic mixture into a mould, where heat and pressure form the boards into the desired shape. This process creates a textured surface that closely resembles natural wood grain.

Additionally, compression moulding provides extra durability and strength, making the decking more resistant to wear and tear.

Co-extrusion (Capping Technology)

Co-extrusion applies a protective outer layer to composite decking during manufacturing. This capped layer improves resistance to stains, UV exposure, and general wear. It also helps prevent moisture absorption and fading, extending the deck’s lifespan while reducing maintenance needs.

Hollow vs. Solid Core Construction

Composite decking comes in hollow and solid core options, each with unique benefits depending on your needs.

• Hollow Core: Lightweight, cost-effective, and designed for better water drainage. However, it requires additional support for stability.
• Solid Core: Heavier, stronger, and more durable. It offers better sound absorption and increased structural integrity, making it ideal for long-term use.

Benefits of Composite Decking Over Traditional Materials

Environmental Benefits

Composite decking is made from recycled wood fibres and plastics, reducing landfill waste. Unlike timber decking, it does not contribute to deforestation. Its long lifespan means fewer replacements, further minimising environmental impact and making it a sustainable choice for outdoor spaces.

Durability & Low Maintenance

Designed to withstand the elements, composite decking is resistant to rot, splintering, and warping. It does not require staining, painting, or sealing, making upkeep easy. With a longer lifespan than traditional wood, it remains in excellent condition with minimal effort.

Aesthetic Appeal

Available in a variety of colours and finishes, composite decking can complement any outdoor space. It can mimic natural wood grain while offering modern design options, giving homeowners the look of wood without maintenance.

Safety Features

Composite decking includes slip-resistant surfaces, making it safer in wet conditions. Unlike traditional wood, it does not splinter, providing a comfortable and secure surface for children and pets.

Frequently Asked Questions

Is Composite Decking Waterproof?

Composite decking is highly water-resistant but not entirely waterproof. While it does not absorb water like traditional wood, prolonged exposure to moisture can still affect its performance. Proper installation with adequate spacing and drainage helps prevent water buildup.

Choosing a capped composite decking option can further enhance moisture resistance.

Can Composite Decking Be Installed Over an Existing Deck?

Yes, composite decking can be installed over an existing deck, but the underlying structure must be in good condition. The original deck frame should be stable, level, and free from rot or damage before installation. In some cases, reinforcing or replacing old joists may be necessary.

For the best results, always follow the manufacturer's installation guidelines.

Does Composite Decking Expand and Contract?

Yes, composite decking expands and contracts due to temperature changes. Like most materials, it responds to heat by expanding and contracts in colder conditions. To prevent warping or buckling, installers must leave proper spacing between boards during installation.

Following manufacturer recommendations ensures a stable and long-lasting deck.

Conclusion

Composite decking offers a long-lasting, easy-care, and environmentally friendly option compared to traditional wood. Made from a blend of recycled wood fibres and plastic, it offers long-lasting performance with minimal upkeep.

Its resistance to rot, splintering, and fading, combined with a variety of design options, makes it a practical choice for any outdoor space. Whether you're looking for sustainability, durability, or aesthetic appeal, composite decking provides a reliable and stylish solution.

By understanding its composition, benefits, and installation requirements, you can make an informed decision that ensures a beautiful and functional deck for years.

Sources -

1. https://www.cladcodecking.co.uk/blog/post/what-is-composite-decking