Board type CMP-C
Capped composite decking
Capped composite is a wood and plastic core wrapped in a tough polymer shell. The shell is what stops rain, red wine, bird droppings and wet leaves soaking in, and it is why capped boards hold their colour far longer than the first generation of composite.
Fitted on a proper frame, it typically costs £120 to £220 per square metre. It is the board we suggest for most Leeds gardens.
- Fitted price
- £120 to £220 per m²
- Lasts
- 25 years or more
- Upkeep
- A wash twice a year
- Joists
- 300 to 400 mm centres
Capped against the other boards
Capped composite sits in the middle on price and near the top on how little work it asks of you afterwards.
| Fitted, per m² | £120 to £220 | £95 to £160 | £150 to £250 | £60 to £130 |
|---|---|---|---|---|
| What it is | Wood fibre and recycled plastic, wrapped in a polymer shell | Wood fibre and plastic with hollow channels, often uncapped | Cellular PVC, no wood fibre at all | Pressure-treated pine or spruce |
| Joist spacing | 300 to 400 mm centres | 300 to 350 mm centres | 300 to 400 mm centres | 400 mm centres is common |
| Upkeep | Wash in spring and autumn | Wash, plus a stain treatment if grease or leaves mark it | Wash in spring and autumn | Clean and oil or stain every year or two |
| Board warranty | Often 25 years or more | Often 10 to 20 years | Often 20 to 30 years | Treatment guarantee, often 15 years |
| Fire | Combustible | Combustible | Combustible, slow to ignite | Combustible |
| Best for | Most Leeds back gardens, shady or sunny | Ground-level decks on a tighter budget | Damp, shaded plots and around hot tubs | The lowest upfront cost, sunny open spots |
Capped composite prices by size
Level ground, capped boards on a treated timber or aluminium frame, hidden fixings and edging boards. No steps or balustrade.
| Deck | Area | Fitted price |
|---|---|---|
| Small, 3 × 3 m | 9 m² | £1,100 to £2,000 |
| Medium, 4 × 3.5 m | 14 m² | £1,700 to £3,100 |
| Large, 6 × 4 m | 24 m² | £2,900 to £5,300 |
| Very large, 8 × 4.5 m | 36 m² | £4,300 to £7,900 |
Typical UK fitted prices from published price lists we reviewed, October 2026, rounded to £100. National figures; a guide, not a quote. An aluminium frame instead of timber typically adds £20 to £45 per m².
What the cap actually does
Every composite board has a core made of wood fibre or rice husk bound with recycled polyethylene or PVC. On an uncapped board that core is the surface you walk on, so its wood fibre takes up water, swells slightly, and holds stains from anything that sits on it.
A capped board is co-extruded: a thin polymer layer, usually about 0.5 mm, is bonded round the core as the board is made. Some makers cap three sides and leave the underside open; the best cap all four. The cap gives you:
- Stain resistance. Barbecue fat, red wine and leaf tannin wipe off rather than leaving a mark.
- Colour that lasts. UV stabilisers in the cap slow fading. Expect a slight lightening in the first year, then very little change.
- Less water uptake. The core stays drier, so the board moves less and is less likely to grow mould in the grooves.
- A more convincing grain. The cap carries an embossed, multi-tone pattern that looks closer to real timber.
Why capped suits Leeds gardens
Leeds is wetter and greyer than the south of England, and a lot of its gardens are narrow plots between houses, shaded for much of the day. That is exactly where timber decks turn green and slippery, and where older uncapped composite stains under trees.
A capped board shrugs most of that off. It still gets dirty, especially under sycamores and birches, but a brush and warm soapy water in spring and autumn brings it back. There is no sanding, oiling or staining, ever.
In north-facing gardens choose a mid or light colour: dark boards show every water mark and leaf print. In full sun on a south-facing deck, the opposite applies: very dark boards get hot underfoot in July, so a mid grey or a warm brown is the safer choice.
How a capped deck is built
The board is only as good as what holds it up. Most problems people blame on composite are really frame problems: boards that sag between joists set too far apart, or decks that move because posts sit on soft ground.
| Stage | What happens | Time |
|---|---|---|
| Ground | Turf or old decking lifted, ground levelled, weed membrane and gravel laid | Day 1 |
| Frame | Joists at the board maker's spacing, usually 300 to 400 mm, on pads, posts or ground screws | Day 1 to 2 |
| Boards | Fixed with hidden clips, with the expansion gaps the maker specifies at ends and edges | Day 2 to 3 |
| Finish | Fascia boards over the frame, edge trims, steps and any lighting | Day 3 to 4 |
Treated timber joists are the usual choice. Aluminium joists cost more but never rot, so they suit decks you never want to lift, and decks laid straight onto old paving where a timber frame would sit in standing water.
Colours and finishes
Capped boards come in greys, browns and a few near-blacks, usually with a wood-grain face on one side and a grooved or brushed face on the other. A few points that save regret later:
- Ask for a physical sample and look at it wet, in your own garden, at different times of day. Colours on screens are unreliable.
- Mixed-tone boards hide dirt and wear far better than flat, single-colour boards.
- Fascia boards and step nosings come in matching colours. Check they exist for the board you like before you commit.
- Fixings with colour-matched heads are used at the edges where clips cannot go. Hidden clips everywhere else give the cleanest finish.
What to expect over 25 years
A capped deck on a sound frame should look much the same in year ten as in year two. The cap may dull slightly and pick up fine scratches from furniture, which is why felt pads under chair legs are worth having. Deep gouges cannot be sanded out as they can on timber, so a damaged board is replaced, which is simple with clip fixings.
Over 20 years a capped deck usually costs less than a timber one once you add the cost of treating timber every year or two and replacing boards. We set out the numbers in composite vs timber decking.
Where our information comes from
- BSI, BS EN 15534-4: wood polymer composite decking profiles and tiles
- GOV.UK, permitted development rights for householders: technical guidance
- GOV.UK, Approved Document K: protection from falling, collision and impact
- Typical UK fitted prices from published price lists we reviewed, October 2026 (national figures)
Capped composite questions
01How much does capped composite decking cost in Leeds?
Typically £120 to £220 per m² fitted. A 14 m² deck off the back of a semi usually costs £1,700 to £3,100. Use the composite decking cost calculator for your own size.
02Is capped composite better than uncapped?
For most gardens, yes. The cap resists staining and fading and stops the core taking up water. Uncapped boards cost less but mark easily and fade faster.
03Does capped composite get hot?
Dark capped boards can get uncomfortably warm in direct summer sun. Lighter greys and browns stay noticeably cooler. In Leeds this matters on a few days a year, mostly on south-facing decks.
04How long does capped composite decking last?
Most makers give a 25-year warranty on the boards, and many give longer. The frame needs to last as long: use treated timber rated for ground contact or aluminium joists.
05Can I pressure wash capped composite?
Gently, with a fan nozzle, held well back and moving along the boards. Most makers recommend a soft brush and warm soapy water, which is all a capped board usually needs.
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