Fitting garden decking is a great way to make full use of your garden space. Especially, when a concrete or paving patio becomes slippery in wet weather. Also, if your garden slopes away from the house it’s difficult to install a level patio anyway. This is where decking comes in handy. Usually, it tidies up muddy and slippery grass outside your patio doors by laying boards onto level joists with handrails around.
The average cost of decking is pretty reasonable too. Often, hardwood timber decking prices are about £75/m2 to buy and £25/m2 to install, while composite decking costs slightly more. Furthermore, assume a typical deck measures about 15m2. Usually, it’ll take between 1 and 3 days to install. These prices include the cost of decking legs, joists and fittings.
Timber decking is the most common material available but composite board, although more expensive, has added benefits. We’ll talk about these later.
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Main Topics
Decking Prices: Installation & Fitting Comparison
The best way to compare prices for all types of decking is to look at the price per metre of an average–sized decking area, say 15m2. Almost certainly, your area won’t be the same size. So, just measure the length and width of your proposed deck area (in metres) and multiply them together. Then, this will give you the area (in m2). Next, multiply your area by the decking cost per m2. Finally, the answer will give you an approximate cost for installing the decking. This doesn’t take into account the cost of decking legs, joists or fittings, as these are dependent on your site conditions. But, it’s a start.
| Deck material | Decking cost (£/m) | Decking cost (£/m2) | Labour cost (£/day) | Labour cost (£/m2) | Total decking installation price (£/m2) |
|---|---|---|---|---|---|
| Softwood timber (120mm wide) | £1.50 to £2.50 | £12 to £21 | £150 | £20 | £32 to £41 |
| Hardwood timber (90mm wide) | £5.20 to £18 | £57 to £200 | £150 | £20 | £77 to £220 |
| Wood/plastic composite (146mm wide) | £8.50 to £15 | £58 to £120 | £150 | £20 | £78 to £140 |
| Antislip (120mm wide) | £9 to £22 | £75 to £183 | £150 | £20 | £95 to £203 |
Usually, the labour cost will increase by about 20% if you live in London and the surrounding area. Also, prices exclude VAT, which at time of writing is also 20%.
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Estimated Labour Time & Rates
Although a decking installer will charge about £150/day to build a raised decking area, it’s very easy for you to install decking in your back garden as a DIY project. However, it’ll probably take longer than the 1.5 to 3 days needed for a professional to finish the job.
So, let’s look at the installation sequence to see if it’s really difficult.
Preparation
Measure out your decking area and hammer a peg into the ground at each corner. Then, mark out the perimeter using a string tied to each peg. Within the area, remove all vegetation, weeds and turf. Next, use a spirit level to check for unevenness. Lastly, cover the area with weed control fabric and gravel.
Build subframe
Arrange joist timber around the perimeter, cut to length and screw together to form the outer boundary. Next, mark the positions of the joists, ensuring the centres are about 450mm apart.
Screw all joists to the perimeter frame. Now, if the joists are more than 1m long (its span), insert a small length of joist timber (a noggin) between the joists to prevent them from bending and flexing when walked upon.
Coat the decking boards with a coat of clear wood preserver, and leave to dry while building the subframe.
Next, check with the spirit level that the subframe is horizontal. If not, you can pack underneath with paving slabs or a concrete block until it is level.
If the amount of packing needed to make the subframe level is greater than 100mm, cut some legs to the required length and screw these to the subframe at appropriate positions. Then, place pieces of paving slab onto the geotextile for the legs to stand on. Also, dig a hole for each of the perimeter legs and bed these in concrete.
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Lay the timber decking
Start at one corner and lay the decking boards across the joists, leaving a 5mm expansion gap between each board. Next, screw the deck to the joists using two screws at each joist. Make sure you drill pilot screw holes in the boards at 20mm from the outside edges and 15mm from the end of the board. Dab the cut end grain with wood preserver and make sure it soaks in well. Ensure you stagger the joints and finish each board at the centre of a joist. Screw each board as you go, keeping the 5mm expansion gap. Countersink the screws below the surface of the boards.
Finishing off
Smooth all edges using a belt sander. Use a paintbrush to give the entire deck another coat of clear wood preserver. When dry you can apply a finish of your choice. Such as wood paint, decking stain or oil.
Important
If you have a sloping garden and intend using decking legs, or plan to have multiple levels joined by steps, you must make sure the deck is safe for people to walk on. Also, don’t forget to put a guardrail around the deck.
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Additional Quotation Extras
So far, we’ve only talked about the joists and decking boards. But, there’s a lot more to installing a deck than just that. Let‘s go through the list of other components and see how they add up.
- A handrail sells for between £4 and £8 each, and are vitally important if you have a raised deck.
- Balusters are the thin pieces of timber that reach from the handrail to the deck to make a barrier. They cost from £1 to £5 each.
- Decking post is a strong timber post that supports the handrail. Also called a newel post, these will set you back by £8 to £12 each.
- A railing kit provides everything you need to build a safe and secure barrier along the edge of your decking. There’s a selection of handrail, balusters and fixing brackets. These range from £80 to £140 per kit.
- You need a membrane to stop grass and weeds from growing up through your decking. They cost from £20 to £30 for about 40m2.
- Decking comes in a variety of thicknesses, widths and materials to suit your preferences. On average, budget boards cost about £12 to £15/m2, medium quality boards cost between £35 to £50/m2. While, premium boards can range from £60 to £100/m2, or even higher.
- Preservative stops the timber from rotting and costs between £5 and £10 per litre.
- Decking oil gives the timber a beautiful sheen and costs from £20 to £30 per litre.
- Depending on how much turf you have to lift, you might have to hire a waste skip.
Decking Accessories
Additionally, if you’re having a brand new deck, why not buy some new garden furniture too? Tables, chairs, barbeque, and outdoor lighting all add to the atmosphere and are well worth buying. Remember that if you want to install lighting, you’ll require a qualified electrician to install a separate consumer unit, wiring and a circuit breaker.
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Supply-Only Decking Options
If you don’t want to use a qualified installer, you could install the decking yourself. Alternatively, use your local gardener or handyman to do it. In these cases, you’ll only need to know the costs of decking components from your local supplier. We discussed the average costs of ‘supply only’ components in the previous section, so we won’t repeat those here.
However, you will need to plan the decking in detail to make sure you have enough of each component to ensure a strong and safe installation. Some of the major points to consider are:
- The thickness of decking boards to prevent splitting and collapse. Budget boards tend to be thinner than the premium type.
- How many joists you need to build the subframe. Additionally, calculate the dimensions of each joist and their distance apart.
- The type of screws you need to prevent corrosion and rust stains on the wood.
- Strength and height of handrail, number of balusters and newel posts.
- Make sure you or your handyman can do the work to a good standard. Otherwise, seriously consider using a professional installer.
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Benefits of Decking Your Garden
Decking has many benefits when compared to other garden ground coverings such as a patio, lawn or gravel.
- Timber decking provides a free draining garden covering that is independent of the ground contours. So, you can build a horizontal deck even if the ground slopes or has significant level changes. Also, rain won’t collect on the deck, unlike the other ground coverings.
- It provides a comfortable surface on which to walk, sit, play or entertain.
- The wooden surfaces seem to blend in with the rest of the garden, unlike other coverings.
- Wooden decking is a ‘warm’ material, just right for summer evenings with a glass of wine.
- You can build the deck over inspection manholes, drains and other unsightly features. However, remember to provide a removable hatch so you can access these if necessary.
- You can extend a small decking area or modify it quite easily.
- Rather than major excavation and preparing the ground, you can build a square decking just by covering up whatever ground you already have.
- All decking timber comes from sustainable forests rather than non-renewable stone materials.
Should You Go With Ground Level or Raised Decking?
It depends on your preferences. However, there are a few considerations to take into account.
- Ground–level decking only needs paving slabs for the subframe to rest on. Whereas raised deck will need legs concreted into the ground and spaced across the subframe to provide suitable support.
- Is the garden flat or sloping? A flat garden doesn’t need a raised deck, whereas a sloping one requires legs to keep the deck level.
- Where is the decking being built? If it’s adjacent to the house, do you need steps to access the doors? Is it worth building steps or build the decking higher?
- Decking more than 600mm from the ground must be designed by a structural engineer and constructed by a builder.
- Some elevated decks will need planning permission. Check before you start building.
- Raised decking will always need a guard rail and balusters.
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Garden Decking Maintenance
To keep your deck looking good, you must look after it.
Most times, your deck only needs a sweep with a stiff broom to remove grit, mud and leaves. But, now and again it will need something more. It’s a good idea to jetwash the decking after winter and before using it in the summer. And, do it in the autumn before you put your garden to bed for the winter.
If you have a particularly muddy day in the summer, use a stiff broom with hot soapy water to clean everything ready for the family barbeque at the weekend.
In the spring, after you’ve jet washed the deck. Allow it to dry and then give it another coat of your chosen finish. This could be paint, oil, stain or sealer. This will ensure it looks good before the outdoor season starts.
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Planning Permission & Building Regulations
You need planning permission to erect platforms in your garden if the decking is more than 300mm above ground level. In addition to this, if the area of the decking, other extensions and outbuildings total more than 50% of the garden area, you must also apply for permission.
Furthermore, some houses may be limited by restrictions that prevent decking of any sort. If you are in doubt, check with your local planning department before you start.
Every deck needing planning permission also need Building Regulations approval. But, even if it doesn’t need planning approval, a decking will have to comply with the Building Regulations as set out in the Approved Documents. If you aren’t sure, contact the Building Control department for advice.
Garden Decking Q&A
Is it cheaper to lay a patio or decking?
Depending on the quality of construction, a patio will have a lifespan of about 10 years, compared to 15 to 30 years for a decking. The price to construct both ground coverings depends on the landscape and quality of materials and construction. So, either could be cheaper depending on your preferences.
Is Paving cheaper than decking?
Usually, decking materials cost less than paving. However, these may be offset depending on the ground conditions and decking maintenance requirements.
Does decking attract rats?
Although you’ve probably seen articles in the press about decking attracting rats and mice, this is a view not necessarily shared by others. The Timber Decking and Cladding Association suggests that if the deck is properly constructed, the underneath is very inhospitable to rodents. Alternatively, The English Garden, a popular garden design publication, gives tips to prevent your decking from becoming a home for rodents. Our view is that if you follow the advice given in The English Garden, you probably won’t play host to unwanted guests.
What is the average lifespan of a deck?
If you regularly apply wood preserver to your deck, it should last about 15 to 20 years.
What is the best material to put under a deck?
First lay a weed–suppressing fabric sheet on the ground, followed by a thick layer of gravel to help keep light out.
How do I know if my deck needs replacing?
Keep an eye out for damaged boards and posts, loose boards, rusting hardware and loose railings. Furthermore, you’ll notice when you give the deck its regular clean that it’s looking worse for wear and needs significant repair. If you have an unsafe deck, you should always remove it and replace with new.
Get Decking Quotes
A timber decking in your garden will give you somewhere to relax and entertain friends. You can build one yourself if you have the skills. But it’s probably easier to have a professional install one for you. Complete the form on this page and you’ll receive 2 or 3 quotes from decking installers near you, making it easy for you to compare the costs of decking fitting in your area.
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