Building wooden garden steps doesn’t start with sawing, it starts with maths. First measure the total height difference you need to bridge. Divide that by the rise (the height per step) and you know how many steps you need.
For a garden or a slope you work with a lower rise and a deeper going than for an indoor staircase. Comfortable outdoors is a rise of 15 to 18 cm and a going (the depth your foot rests on) of 30 to 35 cm. Outside you walk in muddy shoes and sometimes with a plant pot in your hands, so gentler and deeper is nicer.
The rule of thumb that ties it all together is the step formula: 2 x rise + 1 x going = 57 to 63 cm. Stay inside that range and the steps feel natural to walk. An example: for a slope 90 cm high you pick 6 rises of 15 cm, with a going of 33 cm each. Further down I work it out for you in full.
On costs: a small self-build set of 3 to 5 steps costs roughly 150 to 500 euros in materials, depending on the timber. Having a complete set of wooden garden steps installed quickly climbs to 1,100 to 2,000 euros. Below you’ll read exactly how to build them yourself, from the calculation to the last anti-slip strip.
The step calculation: this is the heart of it
You spot uncomfortable steps straight away: you step too short or you have to lift your leg too high. That almost always comes down to a wrong ratio between rise and going. Get this part right and the rest is just screwing things together.
Rise and going: which is which?
Every step consists of two measurements.
- Rise: the height of one step, so how far you go up per stride.
- Going: the depth of the step, the horizontal surface your foot rests on.
On an indoor staircase the rise is often 18 to 20 cm and the going only 22 to 24 cm: steep and compact, because indoors space is expensive. Outside you turn that ratio around. A low rise and a deep going give calm, safe “lazy steps” that also walk nicely when it’s wet or slippery.
Guide values for garden steps:
| Measurement | Guide value outside | For comparison: inside |
|---|---|---|
| Rise (height per step) | 15 to 18 cm | 18 to 20 cm |
| Going (depth) | 30 to 35 cm | 22 to 24 cm |
| Minimum step width | 80 cm (comfortable) | 80 cm |
The step formula
The step formula matches the height and depth of your steps to the average stride length of a person (about 57 to 63 cm). The formula reads:
2 x rise + 1 x going = 57 to 63 cm
Two examples that land right inside it:
- Rise 15 cm, going 33 cm: (2 x 15) + 33 = 63 cm. Roomy and comfortable.
- Rise 17 cm, going 29 cm: (2 x 17) + 29 = 63 cm. A little steeper, but still perfectly fine.
Drop below 57 or go above 63 cm and the steps start to feel wrong. Too far below and you take small shuffling steps, too far above and you have to stride like a stork.
Working out the number of steps, step by step
Here’s how you calculate it for your own situation:
- Measure the total height difference. From the ground at the bottom to the top level, measured dead straight up (vertically, not along the slope).
- Divide by your desired rise. That gives the number of rises. Round to a whole number.
- Divide the height again by that whole number. This gives you the exact rise you need.
- Calculate the going with the step formula.
- Work out the horizontal length: number of steps (to stand on) x going.
Important detail: the number of steps you actually stand on is always one fewer than the number of rises. The top “step” is in fact the upper level itself (the garden, the patio or the top of the slope).
Worked example: a slope 90 cm high
Say you have a grassy slope that rises 90 cm to the higher part of your garden.
- Height difference: 90 cm.
- Desired rise: about 15 cm. Then: 90 ÷ 15 = 6 rises.
- Exact rise: 90 ÷ 6 = 15 cm (nicely round).
- Going via the formula: 63 – (2 x 15) = 33 cm.
- Number of steps to stand on: 6 – 1 = 5 steps.
- Horizontal length of the steps: 5 x 33 = 165 cm.
So: on a slope 90 cm high you build steps that reach 165 cm into the slope, with five treads 33 cm deep and 15 cm of height difference each time. Want them steeper and shorter? Then pick 5 rises of 18 cm and goings of 27 cm. Then they only reach 108 cm into the slope, but they walk less comfortably.
Are you allowed to just build garden steps? The rules
Good news: a free-standing set of garden steps or steps against a slope in your own back garden is usually permit-free. You’re not building a structure attached to the house and you’re mostly bridging a small height difference.
Even so, it’s smart to keep the safety guidance from the Building Regulations (in the UK, Approved Document K on protection from falling) as a guideline. It’s there for a reason.
- Handrail: steps that bridge more than about 1 metre of height difference and are steeper than 2:3 should have at least one handrail. The top of the handrail sits between 80 and 100 cm above the front edge of the tread.
- Edge protection: if your steps border an open side with a drop of more than 1 metre, a barrier (balustrade) against the risk of falling is sensible.
- A single flight: a single straight flight sensibly bridges at most 3 to 4 metres. Need to go higher? Then build in an intermediate landing (a resting point).
For low garden steps of 40 to 90 cm you’re not obliged to fit a handrail, but in slippery weather or with older users one never hurts.
Which timber do you choose for outdoors?
Your steps stand outside all year, in rain, sun and frost. Untreated softwood from the DIY store won’t survive two winters of that. So choose timber that can handle being outdoors.
| Timber type | Durability | Price | Note |
|---|---|---|---|
| Pressure-treated softwood (pine/spruce) | Good, as long as the treatment stays intact | Lowest | Most sold, fine for prefab stringers |
| Douglas fir or larch | Naturally durable, no treatment needed | Middle | Warm look, greys off nicely |
| Hardwood (e.g. balau, ekki) | Very durable, 25+ years | Highest | Heavy and slippery when wet, so anti-slip needed |
When fixing, watch out for two things:
- Use stainless steel or hot-dip galvanised screws and bolts. Ordinary steel rusts and draws ugly black streaks into your timber.
- With treated timber and many hardwoods, cut-end treatment may be needed. Treat fresh sawn faces with a wood preserver, because that’s where moisture gets in fastest.
For the treads themselves, decking boards work fine. A common decking board is about 14.5 cm wide, so with two boards side by side (plus a bit of gap) you reach a going of around 30 cm. Leave a 5 to 10 mm gap between the boards for drainage and for the timber to expand.
Construction types: which garden steps suit you?
There are roughly three ways to build wooden garden steps. Which one fits depends on the height difference and the ground.
1. Steps with stringers
This is the classic “free-standing set”: two angled beams on either side (the stringers) with the treads between or on top of them. Ideal when you’re bridging a clear change in level, for example from a patio down to a lower part of the garden.
You can saw the notches (the tread cut-outs) into the stringers yourself, but ready-made prefab cut stringers are far easier. You buy them with 2 to 6 steps already cut, in treated timber for about 25 to 61 euros each. You need two of them.
- Set the stringers 40 to 60 cm apart. With wider treads (or heavy use) you add a third stringer in the middle to stop sagging.
- Make sure your tread material is at least 27 mm thick, and preferably 40 mm, so it doesn’t bend.
2. Steps on a slope (block steps with cross beams)
For a gently curving slope, a “block step” often works better than a free-standing set. For each step you lay a horizontal beam or cross beam (for example a thick Douglas fir beam or a railway-sleeper-style block) across the slope, set behind two buried posts or ground anchors. Behind the beam you fill in with gravel and soil, and that becomes your going.
This is how you build the steps from the bottom up, step by step into the slope. This method is stable, looks natural and lets rainwater soak away well.
- Use timber posts of 6×6 or 7×7 cm and set them about 100 cm into the ground for grip.
- Reinforce with ground anchors or buried posts that you fix into the slope.
3. Floating steps
The smart variant: individual treads that seem to jut out of a wall or slope, carried by hidden steel supports or thick buried beams. Handsome, but the trickiest to build structurally and the least suited to the DIYer without experience. For most gardens, option 1 or 2 is more practical.
Building wooden garden steps yourself: step by step
Below is the approach for steps with (prefab) stringers. The block step follows the same principle, but then step by step into the slope.
Step 1: Measure and calculate
Measure the vertical height difference and the horizontal space available. Use the step formula to work out how many steps you need and how deep and high they become (see the worked example above). Sketch it out on paper.
Step 2: Foundation and base
Steps that sink or end up leaning are downright dangerous. The bottom is the most important part, because that’s where most of the weight rests.
- Dig a foundation under the lowest stringer: a paving slab on a bed of gravel, or a proper concrete footing for a heavy or tall set of steps.
- Make sure the timber doesn’t touch the ground. Direct ground contact will rot even treated timber over time. Set the stringers on slabs, footings or metal post supports.
- Lay a layer of gravel or hardcore under the foundation so rainwater drains away.
Step 3: Set the stringers, level and square
Lay the stringers in place and check with a spirit level. The treads later need to sit perfectly horizontal (or with a tiny fall to the front for drainage, see step 5).
- Fix the stringers at the top to the patio edge, a wall or a buried post.
- Check that the steps are square to the top edge, so they don’t run off crooked into the garden.
Step 4: Fit the treads
Screw the treads down, from bottom to top or the other way, it makes no difference.
- Fit the bottom and top tread first, check everything is still level and even, then fill in the rest. That stops you ending up crooked.
- Pre-drill for the stainless steel screws with a hole (Ø 6 to 10 mm in the top timber) so the wood doesn’t split. Use screws of 40 to 65 mm.
- Leave a 5 to 10 mm gap between the board sections of a tread.
Step 5: Sort out drainage
Water that sits on your tread turns into an ice rink in winter and speeds up wood rot.
- Give each tread a tiny fall to the front of 1 to 2% (so 3 to 6 mm over a going of 30 cm). Enough to let water run off, not enough to feel.
- The gaps between the board sections help too: that’s where the water drains through.
Step 6: Apply anti-slip
Wet wood, moss and frost make wooden steps glass-slippery. This is the most underrated step.
- Stick or screw anti-slip strips onto the treads, or use anti-slip tape.
- Alternative: rubber mats on the treads, or an anti-slip coating with a fine grit.
- Keep the treads free of moss and algae, especially on the shady side.
Step 7: Handrail (if needed)
Do your steps bridge more than 1 metre, or do children or older people use them? Then fit a handrail.
- Fix the handrail posts (6×6 or 7×7 cm) firmly, ideally buried or bolted to the stringers.
- Set the top of the handrail 80 to 100 cm above the front edge of the treads.
What do wooden garden steps cost?
The price mainly depends on the timber and whether you do it yourself. A rough guide:
| Situation | Cost (guideline) |
|---|---|
| Yourself, small set 3-5 steps, treated | approx. 150 to 350 euros in materials |
| Yourself, hardwood or a larger set | approx. 350 to 700 euros in materials |
| Fully installed, wooden garden steps | approx. 1,100 to 2,000 euros |
The big cost items in a self-build: the two stringers (25 to 61 euros each in treated timber), the tread material (reckon on two decking boards per step), posts, stainless steel screws, foundation and anti-slip. Hardwood pushes the price up sharply, but it lasts 25 years or more.
Always compare quotes on the same basis: with or without installation, and which timber. “Garden steps from 1,100 euros” is something quite different from a made-to-measure hardwood set with a handrail.
Common mistakes
- Copying the rise and going of an indoor staircase. Outside you want it lower and deeper. Steep garden steps are a fall waiting to happen.
- Uneven steps. If one step differs in height, you’ll trip for certain. Measure all the rises exactly equal.
- Timber on the ground. Direct ground contact rots your steps from the bottom up. Always on slabs or footings.
- Forgetting anti-slip. A handsome hardwood set with no anti-slip is unusable and dangerous in winter.
- Foundation too light. The bottom step carries the most weight. If it sinks, the whole set tips.
- No drainage. Flat treads hold water: rot, moss and ice.
- Using ordinary steel. Rusting screws draw black streaks and weaken the joint.
Frequently asked questions
What is a good rise and going for garden steps?
For comfortable garden steps you keep a rise (height per step) of 15 to 18 cm and a going (depth) of 30 to 35 cm. That’s lower and deeper than an indoor staircase, because outside you want to walk more calmly and safely. Always check your measurements with the step formula: 2 x rise + going should be between 57 and 63 cm.
How many steps do I need for my height difference?
Divide the total vertical height difference by the desired rise. A slope of 90 cm divided by a 15 cm rise gives 6 rises, so 5 steps to stand on. Round the number of rises to a whole number and divide the height by it again for the exact rise.
Which timber is best for garden steps?
Pressure-treated softwood is the cheapest choice and fine for prefab stringers. Douglas fir and larch are naturally durable and don’t need treating. Hardwood such as balau lasts the longest (25 years or more), but it’s dearer and slippery when wet, so anti-slip is then a must. Always use stainless steel or galvanised screws.
Do I need a permit for garden steps?
A free-standing set of wooden garden steps or steps on a slope in your own back garden is usually permit-free. If you’re in doubt with a tall set or a structure attached to the house, check with your local authority. For safety, keep to the Building Regulations guidance: with more than 1 metre of height difference a handrail is sensible.
When is a handrail required on garden steps?
Steps that bridge more than 1 metre and are steeper than 2:3 sensibly need at least one handrail, with the top 80 to 100 cm above the treads. For a low set of garden steps a handrail isn’t required, but in slippery conditions or with older users it’s always advisable.
How do I stop my wooden steps getting slippery?
Apply anti-slip strips, anti-slip tape or a coating with grit to the treads. Give each tread 1 to 2% fall to the front so water runs off, and leave gaps between the board sections. Keep the treads on the shady side free of moss and algae, because moss makes wood glass-slippery.
Ready to take your garden up a level? Wooden garden steps are a rewarding job: a day’s work that gives you years of pleasure and suddenly makes a slope or change in level safe to walk.
At www.fredsdiyplans.com you’ll find clear building drawings and step-by-step plans, so that with the right measurements, materials and calculations you start off right straight away. Measure, calculate, saw and enjoy. Good luck with the build!