Building a deck around an above-ground pool takes you a weekend or two and roughly 50 to 120 euros per m² in materials. You lay a foundation of paving slabs or concrete piers, build a substructure of joists at a maximum of 40 cm centre to centre, and screw decking boards onto that with 5 to 8 mm of space between them. You build the deck exactly level with the pool rim, so you step straight in and out of the water.
Sounds manageable. And it is, if you go about it the right way.
In this article I’ll walk you through everything. From design and height to foundation, substructure, material choice and the mistakes you really don’t want to make.
Grab a coffee. We’re building.
Why a deck around your above-ground pool?
An above-ground pool is lovely, but that blue rim in the middle of the lawn looks a bit bare. And the little ladder always wobbles.
A deck fixes all of that at once.
- You step into the water neatly and safely.
- You have room for a lounger, towels and a cold drink.
- Suddenly the pool looks like it belongs there.
- The space under the deck hides the pump and the hoses.
And the best part: you build it yourself, made to measure, for a fraction of what a ready-made surround costs.
How high should the deck be?
The floor of your deck comes level with the top rim of your pool. Not higher, not lower.
So first measure the exact height of your pool, filled and ready. An above-ground pool can sink a little once the water is in it.
Work from the top down. The top of your decking board has to land on the rim of the pool.
From that measurement, subtract:
- the thickness of your decking board (usually 21 to 28 mm);
- the height of your substructure (joist of 45 x 70 or 45 x 95 mm);
- the height of your foundation (slab plus possibly a slab support).
All of it together determines how high your foundation needs to come. That way the deck sits flush later on.
Tip: leave 1 to 2 cm of space between the decking board and the pool wall. That keeps the wood from rubbing against the liner and lets the pool breathe.
All the way around or just one side?
You don’t have to wrap the whole pool right away. Pick what suits your garden.
On one side (platform)
A deck one or two metres wide along the entry point. Quick to finish, little material, perfect as a first project.
Half-round or L-shape
Around the entry point and a stretch beyond it, with a lounge corner. A nice compromise between effort and result.
All the way around
The pool sits built into a large terrace. The prettiest picture, but also the most work. And watch out: you then really have to think hard about access to the equipment (more on that below).
The round shape: here’s how to tackle it
Most above-ground pools are round. You build a deck with straight joists and boards. Those two clash. How do you solve it?
You have two options.
Option 1: straight deck with a round cut-out
You build a square or rectangular frame and saw the boards that meet the pool into a curve. Mark out the curve with a length of string and a pencil from the centre of the pool. Cut the curves with a jigsaw.
This is the neatest solution. But a bit more sawing.
Option 2: follow a polygon
Instead of a perfect circle, you build an octagon or hexagon around the pool. Straight sections that together approximate the curve. Less sawing, a slightly bolder shape.
With both options, leave at least 1 cm of clearance to the pool wall.
Foundation: what does your deck stand on?
The base determines whether your deck still lies dead straight in five years or sinks out of level. No wood on bare ground. Never.
You have three good options.
1. Concrete slabs (30 x 30 or 40 x 40 cm)
The classic. Lay slabs on a layer of sharp sand, level, every 40 to 50 cm. Your joists come to rest on those.
Cheap, quick, fine for a low deck.
2. Adjustable slab supports
Plastic feet that you twist up and down. Ideal if your ground isn’t flat or if you need to hit a specific height to come level with the pool rim.
You adjust them individually, so your deck comes perfectly level without endless shovelling of sand.
3. Concrete piers
For a high or heavy deck, you dig holes about 40 cm deep, fill them with concrete and set piers. The sturdiest of all.
Necessary if your pool stands high and a lot of weight comes onto the structure.
Always lay landscape fabric
Landscape fabric goes under the whole deck, with 10 cm of overlap. Otherwise weeds will grow up between your boards later on. Annoying and hard to remove once the deck is in place.
Substructure: the skeleton of your deck
Your bearing joists go on top of the foundation. This is the most important part, so read along carefully.
Joist size
Use pressure-treated joists of 45 x 70 mm or 45 x 95 mm. For a larger span or a lot of weight, choose the taller joist.
Centre-to-centre spacing
This is the distance between the middle of one joist and the middle of the next. Stick to:
| Decking material | Centre-to-centre spacing |
|---|---|
| Hardwood / softwood | 40 cm |
| Thermowood | 40 cm |
| Composite | 30 to 35 cm |
Composite deflects faster, so you lay those closer together. In doubt? Choose the smaller spacing. An extra joist is never wasted money.
Direction of the joists
Lay your joists at right angles to the direction the boards will run.
Ventilation underneath
Let air flow under the structure. Wood that can’t dry out will rot. That’s why everything stands on slabs or piers and not on the ground.
Fix the joists to the foundation with stainless steel brackets or angle pieces. And keep checking with your spirit level.
Level and fall: how do you set it up?
You lay a deck around a pool dead level. Not with a fall like an ordinary terrace.
Why? Because you want it flush with the pool rim all the way around. A fall would leave a gap on one side.
Water between the boards simply drains away through the gaps, that’s what those 5 to 8 mm of space do. You don’t need a fall for that.
Do lay the foundation underneath so rainwater can drain into the ground. Hence the sharp sand and the landscape fabric.
Which wood or material do you choose?
At a pool you’re dealing with a lot of moisture, wet feet and sometimes chlorine or salt water. So choose wisely.
| Material | Lifespan | Price per m² | Maintenance |
|---|---|---|---|
| Treated softwood | 10 to 15 years | 25 to 45 euros | Oil or stain yearly |
| Thermowood | 15 to 20 years | 45 to 70 euros | Little, but greying |
| Hardwood (bangkirai, ipé) | 20 to 30 years | 60 to 110 euros | Oil against greying |
| Composite | 20 to 30 years | 60 to 130 euros | Hardly any |
Treated softwood
Cheapest. Fine to start with, but wants regular maintenance and lasts the shortest.
Thermowood
Heat-treated softwood or pine. Stable, good-looking and affordable. Takes on little moisture, so pleasant near water.
Hardwood
The top choice for looks and lifespan. Ipé and bangkirai are rock hard and virtually indestructible. But pricey and heavy to work with.
Composite
Made from wood fibres and plastic. No splinters, no rot, no oiling. Naturally grippy, so safe around a pool. Most expensive to buy, cheapest to maintain.
For around a pool, composite, thermowood and hardwood are the smartest choices. They stand up to moisture best.
Decking screws or clips?
Two ways to fix your boards.
Stainless steel decking screws
You screw through the board into the joist. Two screws per board per joist. Pre-drilling prevents splitting, especially with hardwood.
Important: use stainless steel (A2 or A4). Ordinary steel screws rust and leave black streaks in your wood. With salt water pools, always A4.
Countersink the screw heads just below the surface. Protruding screw heads at a pool cut into your foot. You really don’t want that.
Clips (hidden fixing)
Small clamps between the boards that click into a groove on the side. You see not a single screw on the top.
Advantage: a smooth, screw-free floor and the clips set the correct gap between the boards straight away. Perfect around a pool, because not a single head sticks out.
Downside: a bit more expensive and slower to work with.
My advice: with composite you use clips (that’s often the manufacturer’s system). With wood either works, but clips give the safest barefoot result.
Space between the boards
Leave 5 to 8 mm of space between the decking boards. That’s not sloppiness, that’s deliberate.
- Water drains away instead of standing.
- Air circulates, so the wood can dry.
- Wood moves with the weather. Without space, boards will cup and bow.
With wood that still has to dry out, you leave a little less space, because the board will still shrink. With composite you follow the manufacturer’s specification.
Access to the pool equipment
Most people forget this. And then you’re stuck with a demolished deck when the pump breaks down.
The pump, filter and hoses will sit under or beside your deck. You have to be able to reach them.
Solve it like this:
- Make one section of the deck a hatch you can lift. Screw those boards onto a loose frame and don’t fix it down.
- Or leave an open side on the equipment side, so you can crawl underneath.
- Keep the hose feed-through generous, so you can disconnect them later.
Mark in where your pump goes before you build. Then you know exactly where your hatch needs to be.
Safety around the water
A few extra rules apply around a pool.
- Anti-slip. Choose grippy material or decking boards with a grooved side. Wet wood is slippery. Composite and grooved hardwood score best here.
- No protruding screws. Countersink everything, or use clips.
- Rounded edges. Sand off the outer edge of your deck, so nobody gashes their shin.
- Sturdy edge at the entry point. Make sure the board along the pool is fixed extra well, because that’s where you step on with your full weight.
- Child-safe. Consider a low edge or railing on the outside if there are small children around.
What does a deck around your pool cost?
Reckon on these amounts, including substructure and foundation.
| Component | Cost per m² |
|---|---|
| Treated softwood (complete) | 45 to 65 euros |
| Thermowood (complete) | 65 to 95 euros |
| Hardwood (complete) | 85 to 140 euros |
| Composite (complete) | 90 to 160 euros |
A 15 m² deck in thermowood therefore costs you roughly 1000 to 1400 euros in materials. A ready-made surround is quickly double that.
The biggest saving? Your own hours.
Which tools do you need?
- Cordless drill and driver
- Jigsaw (for the round cut-out)
- Circular saw or mitre saw
- Spirit level (long, at least 1 metre)
- Tape measure and pencil
- String for marking out the circle
- Pilot drill bit for hardwood
- Rubber mallet
- Screws or clips (stainless steel)
- Landscape fabric and sharp sand
- Work gloves and good safety goggles
Step-by-step in brief
- Measure and mark. Determine the shape, width and the exact height of your pool rim.
- Prepare the ground. Level it, lay landscape fabric with overlap.
- Place the foundation. Slabs, slab supports or piers, every 40 to 50 cm, level.
- Build the substructure. Joists at the right centre-to-centre spacing, fixed with stainless steel brackets.
- Plan the equipment. Decide where your hatch or open side goes.
- Lay the boards. From the pool rim outwards, 5 to 8 mm between them, countersink screws or click clips.
- Saw the curve. Mark out the curve with string, cut with the jigsaw.
- Finish off. Sand the edges, oil the wood, fit the hatch.
Common mistakes
Laying wood directly on the ground.
Rots within a few years. Always on slabs or piers with air underneath.
Joists too far apart.
The deck springs and flexes. Stick to the centre-to-centre table.
No space between the boards.
Water stands, wood cups. Always 5 to 8 mm.
Ordinary steel screws.
Rust streaks within one season. Only stainless steel, and A4 for salt water.
Boxing in the equipment.
No access to the pump means demolition when something fails. Plan a hatch.
Deck tight against the liner.
The wood rubs the wall to bits. Leave 1 to 2 cm of space.
Forgetting the pool sinks.
Measure the height with water in the pool, not empty.
Do I need a permit?
In most cases, no. A deck or terrace at ground level in your back garden is permit-free as long as it stays low.
But do watch these points:
- If the deck rises above roughly 1 metre or you turn it into a raised terrace, check your local council’s rules.
- With a shared terrace on the property boundary, it can be different.
- If you live in a listed building or a protected townscape, always check beforehand.
In doubt? One phone call to your council is soon made. Better that than trouble afterwards.
Frequently asked questions
How high should a deck around an above-ground pool be?
Exactly level with the top rim of your filled pool. Work back from the top down: board thickness plus joist height plus foundation has to add up to that rim height. Always measure with the pool full, because an above-ground pool sinks a few centimetres once the water is in it.
Which wood is best for a deck by a pool?
Hardwood (like bangkirai) and composite last longest with that constant moisture and splashing. Hardwood lasts around 20 to 25 years, composite 25 years or more and it doesn’t splinter, which is pleasant for bare feet. Treated softwood is cheaper but needs more maintenance and lasts a shorter time.
At what spacing do you lay the joists (centre to centre)?
With wooden decking boards you keep 40 cm centre to centre, with composite 30 to 35 cm because that material deflects more. Around the pool, where there’s a lot of walking, you can happily lay the joists closer for a sturdier feel.
Does a deck around a pool need a fall?
No, you lay a deck around your pool dead level, so it sits flush with the rim everywhere. The water simply drains away between the boards. Do provide 5 to 8 mm of space between the boards for drainage and ventilation.
What does a deck around an above-ground pool cost?
Reckon on about 60 to 150 euros per square metre in materials, depending on the type of wood. For a deck of 15 m² that works out to 900 to 2,250 euros in materials. Do it yourself and you save the labour cost of 50 to 90 euros per m².
How do I make sure I can reach the pool pump?
Plan a hatch or an open side into your deck in advance, right above or beside the filter pump and the hoses. Forget it, and you’ll be unscrewing boards at every service later on. This is one of the most commonly made mistakes.
Get started
A deck around your above-ground pool is one of the most rewarding jobs there is. You see results right away, it saves a lot of money and you swim the rest of the summer like a king.
Take your time over the foundation and the substructure. That’s where the secret lies. Laying the boards on top is the fun, fast part.
Want to build your deck entirely to measure, with a worked-out drawing and materials list? Then have a look at the building plans on fredsdiyplans.com. There you’ll find clear plans for garden projects that let you get going without guesswork. Good luck building.