Lay composite decking patio.

Composite decking — boards made from recycled plastic mixed with wood fibre — has gone from a fringe product 20 years ago to one of the UK's best-selling outdoor surfaces. The pitch is simple: looks like wood, doesn't rot, doesn't splinter, no annual oiling. This guide covers what composite actually costs in 2026, the brands worth buying, and the honest limitations (it's not as natural as real timber, and some early formulations have aged badly).

Premium brands include Trex, Millboard, Composite Prime, and Ecodek. Cheap unbranded composites should be avoided — they fade and warp.

What Does the Work Involve?

• Same sub-structure as timber decking — concrete pad foundations, joist frame.
• Joist centres typically 300–400 mm (composite sags more than hardwood at wider spans).
• Boards fixed with hidden clips that slot into board grooves (most premium systems).
• Edge trims and fascia boards in matching composite.
• Expansion gaps designed in — composite expands and contracts more than wood with temperature.

Typical Costs

Most premium brands offer 25-year residential warranties — significantly longer than any natural wood.

How Long Does It Take?

• 15 m² composite deck: 2–3 days (faster than timber).
• 20 m² with steps: 3–4 days.
• Annual maintenance: ~30 minutes (sweep + wash).

DIY or Professional?

Composite is very DIY-friendly — the hidden-clip systems are easier than face-screwing timber, and you can't ruin a board with a poor screw alignment. Most brands provide step-by-step install guides. For raised decks or large areas, professional install still saves time.

Choosing the Right Tradesperson

• Confirm they're an approved installer for the brand you want (gives best warranty).
• Look at installs aged 5+ years — how do they look?
• Ask about board expansion — they should leave 3–4 mm end gaps minimum.
• Discuss the hidden clip system — premium brands have their own; budget composites use generic.

UK Regulations

• Same planning rules as timber decking — under 300 mm height permitted development.
• Raised decks over 600 mm need balustrade per Building Regs.

Common Problems

• Heat in summer — dark composite gets hot to bare feet on south-facing patios. Choose lighter colours or capped boards.
• Sagging between joists — wider joist centres or budget boards. Stick to 300 mm centres.
• Fading with low-grade boards — uncapped composites fade noticeably. Capped boards have a colour-fast wrap.
• Surface scratching — softer composites scratch from furniture drag. Felt feet help.
• Cleaning of food / oil stains — composite is mostly stain-resistant but BBQ grease can mark uncapped products.

Frequently Asked Questions