If you are pricing up a new deck, you will quickly find that composite decking quotes vary wildly, sometimes by thousands of pounds for the same size garden. Most of that difference comes down to board quality, groundwork and access rather than anyone pulling numbers out of thin air. Here is an honest breakdown of what composite decking really costs in the UK, based on what we see on jobs around Bolton and Greater Manchester.
For the boards alone, budget composite decking starts at around £30 to £45 per square metre, mid-range boards sit at roughly £50 to £80, and premium capped or co-extruded boards can run £90 to £120 or more. Capped boards have a protective plastic shell bonded around the core, which is what stops the fading and staining that gave early composites a bad name, so the extra spend is usually worth it if the deck gets heavy use or full sun.
Supply and fit is a different figure altogether. Once you add the subframe, fixings, labour and waste removal, a professionally installed composite deck in the North West typically lands between £140 and £250 per square metre. So a fairly standard 20 square metre deck might come in anywhere from £2,800 to £5,000 depending on the spec and the state of the ground underneath it.
Two decks of identical size can be quoted very differently, and it is nearly always down to what is happening below the boards and around them. The subframe is the big one: composite boards need closer joist spacing than timber, usually 300 to 400mm centres, so the frame costs more than people expect. A deck built over an existing solid patio is far cheaper than one needing excavation, ground screws or a raised frame on a sloping Bolton garden.
Access matters too. If materials have to be carried through the house or up a steep terraced back yard, labour time climbs. It is worth getting any contractor to break their quote down so you can see where the money is going.
Softwood timber decking is cheaper up front, often £90 to £150 per square metre installed, so composite can cost 40 to 80 percent more on day one. The case for composite is what happens afterwards. Timber in the Greater Manchester climate needs cleaning, sanding and re-staining or oiling every year or two, and even well-maintained boards tend to need replacing within 15 to 20 years, often sooner.
Good composite boards typically carry 20 to 25 year warranties and need little beyond a wash with soapy water a couple of times a year. Over a 15 year period the total cost often evens out or tips in composite's favour, especially once you factor in your own weekends spent on maintenance. If you plan to move house within a few years, timber may still make more financial sense.
Always get quotes broken down into boards, subframe, groundwork, extras and labour, and make sure everyone is pricing the same specification. A quote using hollow economy boards on a widely spaced frame is not comparable with one using solid capped boards on 300mm centres, even if the headline figures look similar.
Ask what the subframe is made of. Treated timber joists are common and perfectly acceptable, but aluminium or composite subframes last longer and add a few hundred pounds on a typical deck. Finally, check the quote includes waste removal and VAT, as these are the two items that most often appear as surprises later.
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