Composite decking quotes can vary wildly for what looks like the same job, and that leaves a lot of homeowners unsure whether they are being fairly priced. The honest answer is that the boards are rarely the biggest part of your bill. Here is how the cost actually breaks down, based on the kind of gardens we work in across Bolton and the surrounding towns.
For a straightforward, supplied and fitted composite deck at ground level on reasonably flat ground, most homeowners in the Bolton area should expect somewhere between £120 and £200 per square metre. A typical 20 square metre deck therefore lands roughly in the £2,400 to £4,000 bracket.
That is a wide spread because it covers a lot of ground. The lower end reflects budget hollow-core boards on a simple timber frame. The upper end reflects premium capped solid boards, an aluminium subframe, hidden fixings and proper edge trims. Both are legitimate jobs, but they will not last the same length of time or look the same in five years.
A great many Bolton gardens sit on a slope, which is simply what happens when you build on the edge of the West Pennine Moors. If your lawn drops away, the deck needs posts, bearers and often a balustrade, and that changes the job entirely. A raised deck over 600mm high adds structural work, handrails and sometimes building regulations considerations, and can easily add £1,000 to £2,500 to a project.
Drainage matters too. Much of the local soil is heavy clay, which holds water and moves with the seasons. Skimping on the base is the single most common reason a deck starts to feel spongy or uneven within a couple of years. Expect proper concrete pads or ground screws rather than boards laid onto soil, and expect that to appear as a real line on the quote.
Removing an old deck or patio is another genuine cost. Lifting rotten timber, breaking out concrete and paying for skip hire and tipping typically runs £300 to £700 depending on volume.
Composite is sold by the board, but a finished deck needs more than boards. Fascia and corner trims, starter clips, joist tape, ventilation gaps and a matching step or two all add up, and they are the difference between a deck that looks fitted and one that looks assembled.
Lighting is worth deciding early. Recessed step or post lights are much cheaper to run while the frame is open than to retrofit afterwards, and inset LEDs usually add £200 to £600 including cabling. The same goes for balustrade choice; glass or aluminium panels cost considerably more than composite spindles.
Composite usually costs 30 to 60 per cent more than a softwood deck up front. What you get back is the maintenance. Greater Manchester rainfall is hard on treated timber, and a softwood deck realistically needs cleaning and re-oiling every year or two, plus board replacements as the years pass. Composite needs a wash down and very little else.
Over a 15 to 20 year view, the figures tend to even out or favour composite. Over a three year view, they do not. If you are planning to move soon, be honest with yourself about which of those you are actually buying.
One last thing worth knowing: quotes that come in dramatically below everyone else usually differ in the frame, not the boards. Ask what the subframe is made of, how far apart the joists are, and what the fixings are. A 300mm joist spacing on a board rated for 400mm is where most failures begin.
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