Should I choose composite or timber decking?

The honest comparison is not composite against timber but composite against a timber deck that actually gets maintained. Most timber decks are not maintained, which is why they look tired in five years — and why composite feels like a revelation to people who have owned one.

Step by step

1. Be honest about maintenance.A timber deck needs a clean each spring and a coat of oil every year or two. If that will not happen, composite is the better answer regardless of the price comparison.
2. Compare over the life, not the invoice.Add the cost of oil, cleaner and a day's work every couple of years to the timber figure, and the replacement cost at the end of its life. Over 15-20 years the gap narrows sharply.
3. Check the sun exposure.Dark composite in full south-facing sun gets hot enough to be uncomfortable barefoot. Timber stays cooler. If the deck is used by children or dogs in summer, this matters.
4. Think about expansion.Composite moves more with temperature than timber does. It needs the manufacturer's specified end gaps and fixing method — usually hidden clips that allow movement — and closer joist centres.
5. Consider grip when wet.Both get slippery with algae. Composite tends to hold less moisture and grows less algae, but a shaded composite deck still needs cleaning.
6. Think about repairs.A scratched or gouged timber board can be sanded. A damaged composite board cannot, and matching a discontinued colour years later is often impossible. Buy spares with the deck.
7. Check the substructure either way.Both are usually laid on a treated softwood frame, which is the part that rots first. Some composite systems use aluminium joists, which changes the life expectancy of the whole deck.
8. Decide on total cost and honest habits.Timber if you will look after it or want it cheap now. Composite if you want to do nothing to it for twenty years and can accept the upfront cost.

Tips

• Buy two spare boards whichever you choose. Colours and profiles are discontinued constantly.
• Ask for a physical sample and leave it outside for a month before committing. Colour changes on both materials.
• A composite deck on a softwood frame still has a softwood-frame lifespan. If the deck is meant to last 25 years, the joists need to as well.

Common mistakes

• Treating composite as maintenance-free — It needs washing, and shaded composite grows algae like anything else. It is low-maintenance, not no-maintenance.
• Fixing composite with standard decking screws through the face — It expands and contracts more than timber and face-screwing without the specified gaps causes buckling. Use the manufacturer's clip system and gaps.

If it doesn't work

Alternatives

• Treated softwood: Cheapest to buy and easy to work. Needs cleaning annually and oiling or staining every one to two years. Realistically 10-15 years with maintenance, much less without.
• Hardwood (balau, ipe, oak): Dense, durable and good-looking, with a life of 25 years or more. Expensive, heavy, hard on tools, needs pre-drilling for every fixing, and oiling to keep the colour.
• Wood-plastic composite: No oiling, no splinters, consistent colour and around 25 years of life. Two to three times the timber cost, gets noticeably hot in sun, expands and contracts more, and cannot be sanded back if it is scratched.
• Capped composite: Composite with a bonded polymer shell. Better stain and fade resistance than uncapped composite and more expensive again. The current default for a low-maintenance deck.

Questions people ask