Cheap composite decking: how to buy on a budget without regretting it

Cheap composite decking is either the smartest buy in the garden or a mistake you live with for ten years, and the board itself is rarely what decides which. This guide is about buying composite on a budget without regretting it: what a genuinely cheap board should and should not compromise on, where the price of a deck actually goes, and the three ways people make a cheap deck expensive.

The short answer

A cheap composite board is fine if it is a proper wood-plastic composite with a groove for hidden clips, a written ten-year warranty, a matching trim range and published fitting figures. Ours are £25 for 3.6m, about £46 per square metre, and tick all four. What you should not buy cheaply is the frame: a £150 timber frame under £500 of boards is the false economy that costs the whole deck. Put the saving from the boards into rot-proof battens or joists and the deck will outlast a premium board on a rotten frame.

What "cheap" buys you, and what it does not

Composite boards in the UK run from about £20 to £90 for a 3.6m length. The price differences come from four things:

• Hollow or solid. Cheap boards are hollow. They are lighter, cheaper to ship and fine on joists at 350mm centres. Solid boards are quieter underfoot and heavier; that is most of what the middle of the market charges for.
• Capped or uncapped. A capped board has a plastic skin that shrugs off red wine and barbecue fat. An uncapped board wipes clean if you do it that day. Capping is the main thing the top of the market charges for.
• Colour blend. Premium boards mix two or three tones for a streaky, timber-like grain. Budget boards are one tone with an embossed grain. From the kitchen window, nobody can tell.
• Brand. Some of the price is the name. It buys nothing in the garden.

What cheap should never mean: no clip groove (face-screwed boards buckle), no warranty, no matching fascia or trims, no fitting guide. If a seller cannot tell you the joist centres, walk away whatever the price. Our seven checks apply at £20 a board as much as at £90.

Where the money in a deck actually goes

For a 3.6m by 3m deck on a patio, in our boards:

Item	Cost	Share
20 boards at £25	£500	63%
Composite battens, 9 lengths	£155	20%
Clips and screws, 3 packs each	£85	11%
L-trim, 3 lengths	£60	7%
Total	£800

The boards are less than two thirds of the job. Saving £5 a board by going cheaper still saves £100; skipping the battens saves £155 and puts the boards on a base that holds water under them. The full workings for three deck sizes are in the cost guide.

Three ways a cheap deck gets expensive

1. A rotten frame. Treated softwood on damp ground lasts eight to twelve years; the boards last twenty-five. When the frame goes, the boards come up. Composite battens on a hard base or recycled plastic joists on soil cost more on day one and nothing after. The subframe guide compares them.
2. Joists too far apart. Hollow boards on 450mm or 600mm centres bounce, creak and work their clips loose. Fewer joists saves £30 and ruins the deck. 350mm, no more.
3. Open board ends. An uncapped hollow end lets water into the core; a hard frost cracks it. End caps are £1.49. The trims guide shows where they go.

Where it is safe to save

• Buy 3.6m boards, not 4.8m, unless the deck is over 3.6m in that direction. £25 against £34 for 1.2m less board.
• Size the deck to the board. A 3.6m by 3m deck uses whole boards with no offcuts. A 4m by 3m deck wastes 20% of every board or needs the dearer 4.8m length.
• Fit it yourself. A patio-level deck on battens is a weekend with a drill, a saw and the installation guide. Labour is £300 to £500 on a deck this size.
• Skip the balustrade on a deck under 600mm high; building regulations do not require one and it is £160 per 1.5m.
• Choose a mid-tone colour. Not a saving in money, but dark boards run hot and pale ones show dirt, and both get replaced sooner by people who tire of them. Grey, oak and teak are the ones that stay.

Cheap composite against cheap timber

Budget treated decking boards are £10 to £15 for a similar length, so timber wins on day one by about £250 on this deck. It loses it back in staining or oiling every other year (about £60 in product and a weekend each time), and it needs replacing at year twelve to fifteen. Over fifteen years composite on a good frame is the cheaper deck, and it is the one that does not give you splinters. The composite vs timber guide has the numbers side by side.

Before you buy the cheapest board you can find

1. Order free samples and leave them outside for a week, wet one, stand on it.
2. Price the whole deck, frame and trims included, not the board.
3. Check the four things a cheap board must still have: clip groove, warranty, matching trims, fitting figures.
4. Send us the size and base and we will list the lot, including the frame, in one order. Free delivery over £190, with you in 2 to 4 working days.