Composite decking cost per m² in the UK: boards, frame and fitting

Composite decking prices are usually quoted per board, which tells you nothing until you have worked out how many boards a deck needs. This guide converts our prices into a cost per square metre, then builds up the full material cost for three common deck sizes, including the subframe, clips and trims that the board price never mentions. All prices include VAT and are correct at the time of writing.

The short answer

Our composite decking boards work out at roughly £46 per m² for the boards alone, in any of the eight colours. Add the subframe, fixings and trims and a complete DIY deck comes to around £75 to £95 per m² in materials. Fitted by a landscaper, budget £150 to £220 per m² all in, depending on where you are and how much groundwork is needed.

Board cost per square metre

Our boards are 150mm wide and 25mm deep, in 3.6m and 4.8m lengths. With the 6mm expansion gap between boards, each one covers about 0.56m² per metre run.

Board	Price	Coverage per board	Cost per m²
3.6m woodgrain board	£25.00	0.54m²	£46.30
4.8m woodgrain board	£34.00	0.72m²	£47.20

The two lengths cost almost the same per square metre, so choose by your deck dimensions rather than price: 4.8m boards mean fewer joins on a long deck, 3.6m boards mean less waste on a short one. All eight colours are the same price, so the choice in our colour guide costs nothing.

What else a deck needs

Item	Our price	Typical quantity per 10m²	Cost per 10m²
Hidden fixing clips, 100 per pack	£16.50	About 220 clips (one every 350mm per board)	£37
Fixing screws, 100 per pack	£12.00	One per clip	£27
Composite joist 40 × 30mm, 3.6m (onto concrete)	£17.19	About 30 linear metres at 350mm centres	£145
Recycled plastic joist 50 × 100mm, 3m (onto ground, raised)	£44.95	About 30 linear metres	£450
Treated timber joist 47 × 100mm (merchant price)	£4 to £6 per metre	About 30 linear metres	£120 to £180
Fascia board to hide the frame	£22.99	Perimeter on show, typically 2 to 3 boards	£46 to £69
End caps for exposed board ends	£1.49	10 to 20	£15 to £30

The subframe is the big variable. A deck laid onto an existing concrete or slab patio only needs low composite battens and comes in cheapest. A deck raised off soil needs proper 100mm joists, posts and ground fixings, and if you want the frame to last as long as the boards, the recycled plastic framework is the rot-proof option at roughly double the price of timber.

Three worked examples

A 3.6m × 3m patio deck onto existing slabs, 10.8m²

• 20 × 3.6m boards (18 needed plus waste): £500
• Composite battens onto the slabs, 9 lengths: £155
• Clips and screws: £70
• Fascia, 2 boards, and 6 end caps: £55
• Materials total: about £780, or £72 per m²

A 4.8m × 4m garden deck raised on timber joists, 19.2m²

• 28 × 4.8m boards (27 needed plus waste): £952
• Treated timber joists and posts, about 55 linear metres: £280
• Post fixings, joist hangers, coach screws: £60
• Clips and screws: £130
• Fascia on two sides, 4 boards, plus end caps: £110
• Materials total: about £1,530, or £80 per m²

The same 19.2m² deck with a rot-proof recycled plastic frame and a balustrade

• Boards, clips, fascia as above: £1,192
• Recycled plastic joists, 50 × 100mm, about 55 linear metres: £825
• Two 1.5m balustrade kits for the open edge: £320
• Materials total: about £2,340, or £122 per m²

The third example costs 50% more than the second and will not need a single joist replaced in twenty years. Whether that is worth it depends on how long you plan to be in the house.

Labour

A landscaper or decking fitter in most of England charges £40 to £60 per m² for a straightforward ground-level deck on a prepared base, and £70 to £110 per m² where there is groundwork, steps or a raised frame. In London and the South East add a third. Two people can lay a 20m² deck on a built frame in a day; building the frame takes another day. Our installation guide gives the joist centres, gaps and clip spacing for anyone doing it themselves.

Composite against timber, per m²

Treated softwood decking boards are £18 to £28 per m² at a merchant, so composite boards cost around £20 to £28 per m² more up front. Timber then costs £4 to £7 per m² per year in cleaner, stain and the occasional replacement board. The break-even is around year five; over ten years composite is cheaper in materials alone. The full comparison, with the maintenance table, is in composite decking vs timber.

How to keep the cost down

• Size the deck to the board. A 3.6m or 4.8m dimension in one direction means no cuts and no waste along that edge.
• Lay onto an existing patio if you have one. It removes the joists, posts and groundwork, which are a third of the cost.
• Run fascia only on the sides you can see. A deck against a fence needs no fascia on that edge.
• Use a picture-frame border only if you want the look; it adds cuts and a few boards.
• Order everything at once, from one batch, so the colour matches and the delivery is one charge. Standard delivery is 2 to 4 working days across mainland UK, kerbside.

Get an exact figure

Put your deck's two dimensions into the calculator for a board count in either length. Order free decking samples before you commit to a colour. If your deck has steps, a curve, or a raised section, call 0161 399 1792 with the dimensions and we will price the whole list, frame included.