Garden Structures

How To Lay Garden Decking: The Ultimate Guide

partially built decking with hammer drill laid on boards
Written by Chris Lee

There’s nothing better than relaxing on a deck chair, sipping a nice chardonnay, and watching the sunset.

That is, of course, unless you built the decking yourself. Then you get to add a feeling of smug satisfaction to the experience. And there really isn’t anything better than that.

raised decking with tables, chairs & bbq
Some stunning raised decking for inspiration

In this guide, we’re going to tell you how to lay garden decking. You’ll learn how to mark, prepare, and build the frame that supports your decking. Then, how to put the decking on top, and get everything ship-shaped.

And if you’ve got doubts about your carpentry skills, you can put your mind at rest. There are no particularly elaborate techniques in this guide.

What is a garden deck made of?

Not everyone has built a deck from scratch before, nor does everyone necessarily know how to put one together. Let us fill you in.

A deck usually consists of a sub-frame for support and structural integrity, on top of which decking boards are laid. The sub-frame is made of timber, most often 2x4s. Decking boards are available in many materials, and because they will be visible, they are more aesthetically appealing than the frame.

The sub-frame is made of a few components:

  • A ledger beam, which sits alongside any walls.
  • A bearer beam, which lines the outward-facing edge.
  • Joists, which provide structure and join the ledger beam to bearer beams.
  • Noggins, which strengthen the decking and sit between joists.
  • Maybe even a few chocks, to raise the deck where necessary.

Decking boards are laid on top. Everything is held together with screws to give it the strength required to support chairs, people, barbecues, hot tubs, and so on.

What you’ll need to lay your decking

This is a comprehensive list of what you’ll need to lay garden decking. A few things in the list you could probably do without, but we’ve included everything so you can decide for yourself.

Timber. This is what you’ll use to build your sub-frame, so it’s vital. We recommend 2×4 wood, either composite, redwood, or hardwood.

Decking boards. Again, these are vital. They’re the bit of your deck that you’ll look at and stand on.

Joist hangers. Specially designed brackets, renowned for making it much easier to keep joists aligned than it would be without them.

Wood varnish. This is used to cover any ends that are left untreated after cutting bits of wood down to size. It prevents damp or rot damaging the wood when it’s exposed to the elements.

Carpet or synthetic membrane. Placing this on the ground beneath your decking will reduce the amount of weed growth.

Wood screws. Vital for joining the various bits of wood together that will form your deck.

Rawl plugs. Necessary if you’re drilling into brickwork or similar.

A clamp. This helps hold bits of wood together, keeping them stable while you join them together permanently.

A tape measure. Useful for initially marking out the area of your decking, and measuring timber for cutting.

A pencil. A tape measure becomes much less useful if you don’t have anything to mark measurements with.

A spirit level. It’s a good idea to check things are aligned horizontally while building your deck.

A set square. Useful for checking that right-angled corners are correctly proportioned.

Stakes and string. A handy combination for marking out the area.

A jigsaw or a handheld saw. You’ll no doubt have bits of wood that need cutting. A handsaw is fine, but you’ll just have to put in more elbow grease!

A drill and bits. This is what you’ll use to put the deck together. Make sure you’ve got bits that match the screws you’re using.

A hammer. It’s much easier than using your bare hands!

Super-vigilant readers will notice the absence of chocks and noggins from this list. That’s because they’re just offcuts from the timber used to build your sub-frame, rather than specific standalone items.

How to lay garden decking

This section contains instructions to turn your deck from a pipedream into a reality. Always exercise care when working with tools, and don’t be afraid to ask for help if you need it!

beautiful composite decking with swing seat and other garden furniture
One more piece of visual inspiration before you start building

Prepare the ground beneath your decking

This guide presumes you’re laying the decking on hard, flat ground. If you’re building on grass or loose gravel, things are done slightly differently. Check out our ‘troubleshooting’ section at the end.

Remove any debris. Then cut your carpet or membrane down to size and lay it on the ground. Preventing weed growth will reduce the chance of pesky plants poking through your decking.

Mark the area where your decking will be laid

Hammer in a stake at each corner of your planned decking, then use string to connect them. Having a visual representation of where your deck will go provides a useful cue to work from.

Choosing the right timber for your decking

Tanalised wood is recommended, as it is designed to withstand the elements. Although you’ll only sit on your deck when it’s sunny, it will have to put up with wind, rain, snow, and everything else the British weather throws at it.

Create a sub-frame with your timbers

You’ll be creating a supporting frame to lay your deck on. A ledger beam will be placed alongside a wall, a bearer beam will be placed opposite, and joists will join the two together.

Cut your 2x4s to size, and set these aside.

Drill clearance holes in the ledger beam

The section of the sub-frame that will be attached to a wall is called the ledger beam. You need to prepare this for attachment by drilling clearance holes. Screws will be drilled through these holes later, and they help prepare the wall behind in the meantime.

The holes should be about 100mm apart, along the whole length of each part of the sub-frame that will join the wall.

Attach the sub-frame to the walls

Once clearance holes are drilled, align your sub-frame with the wall, then drill through the clearance holes into the wall. Then hammer a rawl plug into each new hole in the brickwork.

Then you can drill your bolts through the beam and into the rawl plugs behind. This should create a stable, sturdy connection.

Place the joists

These beams remove bounciness from the deck by supporting the middle. You should place a joist every half metre or so.

These should be perpendicular to the direction you want the decking to run.

You can use joist hangers or, for surfaces where you have access to drill into the joist through the frame, you can just use bolts. We recommend joist hangers because they make things easier.

Place your bearer beam

This runs along the front of your deck, opposite the ledger beam. The bearer beam should align with the marking string. Use screws to attach the timbers together: rawl plugs aren’t needed when drilling wood to wood.

a half built decking structure
Here you can see the bearer beam, joists, and ledger beam in place

Your joists and bearer beam can extend beyond the shape you want your decking to take – for example, if you want an angled section. This will be covered in more detail in a later section, but to briefly introduce what you’ll be doing: you’ll place another beam on top of the joists, mark them, then cut them down to size to allow you to fit the angled beam.

Place noggins between joists

This is another step to remove potential bounciness from the deck. Noggins are offcuts of timber that you place between joists, running perpendicular to the direction of the joists.

Simply cut the timber offcuts to size, wedge them in between joists, and screw them in place. To ensure you have enough access to screw the noggins in place, stagger them slightly.

Decking with noggins in place, staggered slightly for access
Here you can see noggins in place, staggered slightly for access

Cut decking to size

We mentioned earlier that once your joists and bearer beam are in place, you can deviate from the shape they mark out. If you want to add an angled section to your decking, this is the time.

Lay a 2×4 on top of the joists in the position you would like it to sit. Then, when it’s in place, mark its position on the joists below with a pencil. Remove the 2×4, then cut the joists along the marked lines.

After this, you can place the 2×4 as another bearer beam at ground level and attach it to the joists with screws, the same way you have been connecting the other beams.

It’s essential to rub wood varnish over the end of surfaces exposed by cutting wood to size. Varnish protects against damage and can give visible wood a finish consistent with the remaining pieces.

Attach decking to frame

Now it’s time to attach your decking!

Many professionals recommend mounting a piece of decking to all bearer beams, to provide a fascia board that is visually consistent with the decking to be placed on top of the frame.

If you decide to do this, use a clamp to hold it in place, then screw it in.

After attaching the fascia board, place the decking boards on top of the frame, making sure that joints are directly above the joists. This positioning ensures a secure attachment and prevents the decking from bowing if somebody steps on an unsupported joint.

Professionals also recommend laying decking beams a couple of millimetres apart, to allow for expansion as the wood starts to dry out and settle. You can buy special plastic spacers for this, but these aren’t vital, and the screws you’ve been using to join bits of wood are just as good. Just pop a screw between decking beams before you screw it down – one at each end – then remove them afterwards.

man drilling screws into decking frame
Make sure you have a steady hand when drilling!

Cut the decking to the right size and shape

As with trimming the joists earlier, you may need to trim bits of decking down to get rid of any sections that jut out beyond the sub-frame. This is simply a case of marking the decking and cutting off the relevant parts.

You can use your string to indicate where to mark your line, and your spirit level to ensure the decking is level.

Pull up a pew

If all has gone to plan, your deck should be ready to go. After removing the marking stakes and string and tidying away your tools, grab a chair, grab a beer or glass of wine, and give the deck a test run.

Troubleshooting

This section briefly covers some hurdles you may come up against while building and laying your deck.

What to do if levels are wrong

If the spirit level is showing a wonky decking, don’t despair. This can be fixed relatively easily.

What you’ll need to do is cut down some timber to make ‘chocks’, then use a crowbar to lift your decking slightly, and place a chock underneath. You can reposition chocks if the levels still aren’t quite right, or you can add more.

How do you lay decking on grass or gravel?

On soft surfaces, steps must be taken to ensure the decking doesn’t sink into the ground. You can place slabs or blocks of stone under the corners of the decking to absorb their weight, and because these will have a larger surface area, they will be less prone to sink.

What do I do about drainpipes and other obstacles?

Depending on where you’re laying your decking, you may find it comes into contact with drain pipes or similar wall-mounted ornamentation.

If this happens, mark out an area on the piece of decking board in question. Make sure it’s big enough to allow the drainpipe or other pesky obstacle through, then cut out the marked section. Now you should be able to lay the board and attach it to the frame without it making contact.

Thanks for reading!

There are few things more satisfying than kicking back and relaxing on a garden deck that you built and laid yourself. We hope that reading this guide has given you the knowledge you need to create your very own decking.

Your deck is only really limited by your creativity. This guide describes the fundamentals of building a basic deck on flat ground, but the sky is the limit. Some decks are built on multiple levels, others on slopes. Some have hot tubs built-in, others have pull-out awnings over the top.

Whatever decking vision you have for your garden, we wish you luck in achieving it!

About the author

Chris Lee

Chris is interested in nature and the good things that happen when people are in it. He is a freelance writer, with writing published about cycling, green living, and ways to make a difference without fundamentally restructuring your lifestyle.

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