Composite Decking
An outdoor decking material manufactured from a blend of wood fibres and recycled plastic, designed to look like natural timber while requiring less maintenance.
Composite decking is an engineered outdoor flooring material made from a mixture of wood fibres (or wood flour) and recycled plastic (typically polyethylene or polypropylene). It is designed to provide the appearance of natural timber decking while offering significantly better resistance to weathering, rot, and insect damage — and with far less ongoing maintenance.
Composite vs. timber decking
| Composite | Natural timber | |
|---|---|---|
| Maintenance | Minimal — occasional wash | Annual sanding, oiling, or staining |
| Lifespan | 25-30+ years | 10-15 years (with regular maintenance) |
| Rot / insect resistance | Excellent — does not rot or attract insects | Vulnerable without regular treatment |
| Upfront cost | Higher | Lower |
| Lifetime cost | Lower (no maintenance products needed) | Higher (treatment products + time/labour) |
| Appearance | Realistic but uniform | Natural grain variation |
| Heat | Can get hotter in direct sunlight | Stays cooler underfoot |
Types of composite decking
- Capped composite — the core material is wrapped in a protective polymer shell on all sides. The most durable type, with the best resistance to staining, scratching, and fading. Premium pricing.
- Uncapped composite — the wood-plastic blend is exposed on all surfaces. More affordable but more susceptible to staining and moisture absorption over time.
- Hollow core — lighter and cheaper, with a hollow centre. Less rigid, may feel slightly different underfoot.
- Solid core — heavier, more rigid, and more closely mimics the feel of real timber. Higher price point.
Installation considerations
Composite decking boards are fixed to a subframe of timber or aluminium joists. Key points to discuss with your contractor:
- Subframe material — aluminium subframes last as long as the composite boards. Timber subframes are cheaper but may need replacing sooner.
- Ventilation — the area beneath the deck needs airflow to prevent moisture buildup
- Expansion gaps — composite expands and contracts with temperature changes. Your installer should leave appropriate gaps between boards and at edges.
- Hidden fixings — clip systems that fix boards from below give a clean, screw-free surface
Budget planning
Composite decking costs more upfront than timber, but the total cost of ownership over 15-20 years is typically lower because you avoid annual maintenance costs. When reviewing quotations, check whether the price includes the subframe, fixings, edge trims, and any ground preparation — these are sometimes listed separately and can significantly affect the total.