Article
Most decking decisions start with the boards: composite or timber? It’s a fair question, and the answer matters. But after building decks across Hertfordshire and Essex, we’d argue the bigger question is what goes underneath them. A beautiful composite board on a poor subframe will fail just as surely as cheap timber.
Here’s an honest look at both materials, then the part most comparisons skip.
The short answer
- Choose timber if you want a natural look, a lower upfront cost and don’t mind regular maintenance.
- Choose composite if you want consistent colour, less upkeep and are happy to pay more at the start.
- Either way, insist on a properly treated, properly ventilated subframe.
Grip and slip: the UK problem
In a damp climate, slip resistance matters more than anything.
Timber decking gets slippery mainly because of what grows on it. An industry article on timber decking explains that timber holds moisture after rain, giving algae ideal conditions to take hold, especially in shade. The fix it recommends is anti-slip timber boards with a gritted insert, plus regular cleaning.
Composite is often sold as the non-slip option, but it isn’t immune. Timber manufacturers argue composite can become slippery too, and it can still collect algae and debris in shady, damp spots. Whichever you choose, ask for the board’s slip-resistance information and keep the surface clean, especially under trees.
Maintenance: what each really needs
| Timber | Composite | |
| Cleaning | Regular, to keep algae and grime down | Regular washing; less scrubbing |
| Treatment | Periodic oil, stain or preservative | Usually none |
| Colour over time | Weathers to silver unless treated | More consistent; some fading in strong sun |
| Splinters | Possible as boards age | No |
| Repairs | Easy to replace single boards | Possible, but matching colour can be harder later |
Neither is maintenance-free. Composite simply swaps annual treatment for occasional washing.
Look and feel
Timber looks and feels like wood because it is. It suits cottage gardens and period homes, and can be stained to match fences or garden buildings.
Composite offers sharper, uniform lines and colours that suit modern homes. Some homeowners love the consistency; others find it looks less natural up close. Ask to see and handle samples in daylight before deciding.
One practical point: timber manufacturers also point out that composite can get hotter underfoot in direct summer sun than timber. If the deck faces south and gets full afternoon sun, bear that in mind for bare feet.
Cost: upfront vs over time
Composite usually costs more to buy and install. Timber is cheaper at the start but needs ongoing treatment, cleaning products and time. Look at the cost over the years you plan to live in the house, not just the first quote.
What’s underneath matters most
This is where decks succeed or fail, whatever the boards.
The Timber Decking & Cladding Association’s builder’s guide is clear on the essentials:
- All substructure timbers (posts, beams and joists) should be treated to Use Class 4, the level for ground contact.
- Joists should be strength-graded timber, with C16 the minimum and C24 recommended.
- Internal timbers (Use Class 2) are not suitable
- Boards should be fixed with screws, and fixings should be of matching metal.
This applies to composite decks too, because many composite boards still sit on a timber subframe.
Ventilation and space matter for composite in particular. One composite manufacturer’s installation manual specifies a minimum gap between the ground and joists, open sides for airflow, and expansion gaps between boards, because composite absorbs moisture from beneath and moves with temperature. Requirements vary by product, so always follow the manufacturer’s instructions.
And don’t forget the ground: a deck built over soil that holds water will stay damp underneath, which shortens the life of any subframe. Weed membrane and drainage beneath the deck are part of a good build.
Do you need planning permission?
Usually not. The Planning Portal says decking is normally permitted development if it’s no more than 30cm above the ground, and together with other extensions and outbuildings covers no more than half the garden. Raised decks above that height, or decks on flats, listed buildings or in some protected areas, may need permission.
Which suits your garden?
Timber is often the better fit if:
- You want a natural, traditional look
- The budget for the initial build is tight
- You’re happy to clean and treat the deck regularly
Composite is often the better fit if:
- You want low upkeep and a consistent finish
- The deck is a long-term investment in a home you plan to stay in
- You prefer modern colours and clean lines
Consider a patio instead if the area is heavily shaded and damp all year. A patio can be easier to keep safe and clean in those conditions. If you’re also weighing up the lawn, our guide to artificial grass or real turf covers that decision.
Mistakes to avoid
- Joists or posts treated only to Use Class 3, or internal-grade timber
- No ventilation beneath composite boards
- Missing expansion gaps on composite
- Standard boards in deep shade where anti-slip boards are needed
- Building over waterlogged ground without drainage
Planning a new deck?
Paveline Drives and Patios designs and builds decking in timber and composite across Bishop’s Stortford, Braintree, Saffron Walden, Chelmsford and Stansted, often alongside landscaping and groundworks and drainage.
Get a free quote and we’ll bring board samples, check your sun and shade, and explain exactly how the frame underneath will be built.
FAQs
How long does decking last?
It depends far more on the subframe, ventilation and maintenance than on the board type. A well-built deck of either material will outlast a poorly built one.
Can you put composite boards on an old timber frame?
Only if the frame is sound, correctly treated and spaced to the composite manufacturer’s requirements. Old frames often fail one of those, so they’re usually replaced.