05 Jan 2018

Step-by-step guidance to building your own decking

A deck is the perfect way to extend your living area to the outdoors – creating what is essentially an open-air extension.


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Decking is flexible, perfect for lazy summer evenings watching the sunset or cosy winter nights under a multitude of blankets drinking a hot beverage – they really are a year-round living area. Building your own deck shouldn’t be a daunting task, so if you’re a fearless DIY-er, who doesn’t mind getting their hands dirty, below is a step-by-step guide to help you create your dream decking.

Plan, plan, plan!

Before you reach for the power tools there are some things you need to consider before even attempting to begin building your new garden deck. It’s advised to check for underground cables and pipes in the area you plan to build and it’s a good idea to decide on the overall design of your deck as early on as possible. It’s a good idea to do a dry run of the decking first too, so you know you have enough deck board.

Top tip: Timber deck boards require a 5 to 8mm expansion gap along the length of the deck boards and a 3mm gap along the ends of the deck boards.

Prepare the site

With the planning phase complete, it’s time to set out your deck. Using your plans, mark out the site with pegs and string. Make sure you clear the site of vegetation including any turf. A top-tip is to lay a weed killer in the area to ensure no pesky weeds are going to ruin all your hard work. This whole phase is crucial, so take your time – if you get your measurements wrong your deck could end up being a disaster. Measure your deck frame and cut to size.

Next step

Make two pencil marks on each end of the deck frame’s two outer joists as a guide to where the coach screws will go. Make the marks to align with the centre of the adjoining outer joist. You will need to make a total of eight marks – two in each corner of the outer joist frame.

Next, use a flat wood bit to drill recesses into each of the eight marks you previously made. These should be the depth of the screw’s head.These recesses ensure the screw heads will be flush with the joist surface for a neat and professional looking finish.


You’ll need a thinner drill bit than your coach screw’s shank for the next step. Line up the neighbouring outer joists and drill a pilot hole as a guide hole to help direct the screws through the centre of the recess, from the outer joist into the adjoining outer joist. With the pilot holes drilled, it’s now time to fit the coach screws. Once the outer frame is assembled and in position, it’s time to secure the inner joists.

Laying the decking

Start in one corner of the frame you’ve built and position the first board across the inner joists, so that the deck board is in the opposite direction to the inner joists. Make sure that board is flush with the frame. Mark a cutting line for the end of the first board and cut it.

The deck board has to be secured to every joist it covers over the sub-frame with the decking screws into the pilot holes.

Top tip: If laying grooved deck boards facing upwards, pop the screws at the bottom of a groove.

Finishing touches

Use sandpaper to smooth over any cut ends and once smoothed down, add water- and weatherproofing products to protect the timber from rot and decay.

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