Guide
How much does decking cost in the UK?
Updated October 2026
Quick answer: Typical UK supplied-and-fitted decking ranges are around £90–£160 per m² for softwood, £140–£240 for hardwood and £130–£250 for composite. A simple 4m × 3m softwood deck therefore suggests roughly £1,080–£1,920 fitted. Boards are only part of the project: the supporting frame, fixings and ground preparation can substantially change the total.
Decking prices per square metre
These October 2026 figures are typical UK planning ranges, not quotes, including VAT where normally charged. Board-only prices exclude joists, posts and fittings. Fitted ranges assume a straightforward low deck with an ordinary frame; raised construction, steps and balustrades need a separate scope. Do not add a second frame allowance to a fitted package that already includes it.
| Material | Boards supply only, per m² | Supplied and fitted, per m² | 12m² fitted deck |
|---|---|---|---|
| Treated softwood | £25–£45 | £90–£160 | £1,080–£1,920 |
| Hardwood | £60–£110 | £140–£240 | £1,680–£2,880 |
| Composite | £55–£120 | £130–£250 | £1,560–£3,000 |
Compare boards by usable coverage, not price per length. A narrow board, a grooved fixing system and a large required gap can alter how many boards you buy. Composite fascias, starter clips and end caps also vary by system. An attractive board price may exclude accessories that are essential to the finished edge.
What does the substructure cost?
| Item | Supply-only planning range | Scope |
|---|---|---|
| Frame timber | £15–£35 per m² of deck | Ordinary joists and bearers |
| Fixings and connectors | £5–£12 per m² | System and exposure affect specification |
| Ground preparation and supports | £10–£30 per m² | Simple accessible site; difficult ground costs more |
| Balustrade | £45–£120 per linear metre | Material only; fitting extra |
Frame cost depends on span, height, support spacing and board requirements. Composite boards often need a different joist spacing from the timber they replace. Posts and foundations must suit the site and loading. On a sloping garden or raised platform, the support design matters more than the surface-area calculation.
Budget separately for clearing vegetation, removing old decking, spoil disposal and access. A wheelbarrow route through a narrow side passage can slow deliveries and excavation. Avoid assuming that a flat-looking lawn provides a stable foundation or adequate drainage beneath the deck.
Worked example: a 4m × 3m deck
Use the decking cost calculator to reproduce an area-based board allowance. Its effective board width includes the planned gap and its board count includes 5% waste. For a 12m² rectangle, take an effective width of 0.144m and 3.6m stock boards priced at £14.50.
- Board rows: 3 ÷ 0.144 = 20.83, rounded up to 21 rows, each 4m long, giving 84 linear metres.
- Add 5%: 84 × 1.05 = 88.20 linear metres.
- Divide by 3.6m stock: 88.20 ÷ 3.6 = 24.50, rounded to 25 boards.
- Boards cost 25 × £14.50 = £362.50.
- Add £210 for frame timber and £65 for fixings and feet: the calculator total is £637.50.
Allow a further £120 for the example's ground preparation and support materials to make a DIY material estimate of £757.50. That final allowance sits outside the displayed total unless you include it in the frame input. At an illustrative £125 per m² fitted rate, the same 12m² deck is £1,500, subject to a clearly agreed specification.
The board count is an estimating quantity, not a cutting plan. Four-metre runs built from 3.6m stock require supported joins and staggered cuts, or a different board direction. Draw each row before ordering; a longer stock length may cost more per board yet reduce labour and leftover pieces.
Softwood, hardwood or composite?
Softwood usually wins on initial cost. It suits a simple DIY project if the user is comfortable inspecting, cleaning and maintaining timber. Treatment quality, drainage and protecting cut ends matter. A cheap board on a damp, poorly supported frame can fail sooner than its price suggests.
Hardwood offers a different appearance and may need more care with drilling and fixings. Species, sourcing and movement characteristics vary, so buy a specified product rather than relying on the word “hardwood”. Maintenance choices affect whether the finish keeps its colour or weathers naturally.
Composite generally costs more than softwood upfront and avoids routine timber staining, but it still needs cleaning and inspection. Expansion gaps, ventilation, permitted spans and installation temperature details matter. Do not treat a product warranty as a promise that every deck or supporting frame lasts the same number of years.
Waste and labour
Five percent is a useful minimum for a simple square layout using suitable stock lengths. Allow 8–10% for diagonal boards, picture-frame borders and awkward joins; complex curves can need 12–15%. The calculator's fixed 5% means those extra cuts need a separate purchasing check. Keep board waste separate from a cash contingency for hidden ground problems.
Professional fitting can be worthwhile where levels, foundations or balustrades need careful construction. Ask for the frame specification, board brand or technical reference, gaps, steps, disposal and treatment of cut ends in the written scope. A day rate without a programme does not establish the finished price.
Check the alternatives before committing
Compare the usable area and maintenance with the cost to lay a patio. For deciding which parts you can reasonably tackle, read DIY versus hiring a tradesperson. Check local planning requirements where height, coverage, a listed property or other restrictions may apply.
Frequently asked questions
How much does composite decking cost?
Typical October 2026 UK ranges are £55–£120 per m² for boards alone and £130–£250 per m² supplied and fitted for a straightforward deck.
How much does a 4m by 3m deck cost?
At 12m², typical fitted ranges are £1,080–£1,920 for softwood and £1,560–£3,000 for composite, before unusual site work or extras.
Is the frame included in decking prices?
It depends on the price. Board-only prices exclude it, while the fitted ranges in this guide assume an ordinary frame. Check the written scope.
Does composite decking need maintenance?
Yes. It needs appropriate cleaning, drainage and checks to fixings and supports, even where routine staining is unnecessary.