On a terraced Blue Mountains slope, stairs are often the detail that determines whether a series of retaining walls actually functions as a garden, rather than a set of level shelves nobody can get between comfortably. Getting from one terrace to the next, or down a steep side yard past a driveway cut, means either building steps into the wall itself or running a separate stair alongside it. Both are legitimate approaches, but they carry different design, drainage, and safety considerations worth understanding before you commit to a layout.
Two Basic Approaches: Integrated or Separate
Steps cut or notched into the wall itself. Where a retaining wall runs across a slope that also needs a pedestrian route through it, steps can be built directly into the wall structure, effectively a stepped opening through an otherwise continuous wall, with the wall’s structural elements continuing on either side of the stair opening. This works well for sandstone and concrete sleeper walls alike, and it keeps the stair visually integrated with the wall rather than reading as a separate, bolted-on element.
A separate stair running alongside or over the wall. Where terracing involves several stepped-down wall levels, it’s often simpler to build a dedicated stair, in sandstone, concrete, or timber, that runs down the slope adjacent to or over the top of the terraced walls, connecting each level via its own landing. This suits gardens with multiple terrace levels where a single continuous stair run is more practical than notching an opening into every individual wall.
Which approach suits your site usually comes down to how many terrace levels are involved and how much of a feature you want the stair to be. A single wall with one change of level often suits an integrated notch stair. A garden with three or four terraces usually works better with a dedicated stair run.
For broader design context around terracing a sloped garden, wall spacing, layout, and planting, see our Terraced Garden Retaining Wall guide.
Rise, Going and Landing Rules Worth Following
Garden and landscape stairs on a private residential property generally aren’t subject to the same mandatory certification as internal stairs in a building, but building them to a recognised, comfortable standard is still the sensible approach, both for everyday safety and because a poorly proportioned outdoor stair is a genuine trip hazard, particularly at night or in wet weather.
Rise (the height of each step). A comfortable outdoor rise is typically in the 150 to 180mm range. Rises much beyond this become tiring and awkward on a garden stair used regularly; rises below about 100mm can themselves become a trip hazard because they’re easy to misjudge underfoot.
Going (the depth of each tread). A minimum going of around 250 to 300mm is a reasonable starting point for outdoor stairs, and more generous goings, 300 to 350mm, are common in garden settings where the stair is also a design feature rather than a purely functional access route.
Consistency matters more than the exact numbers. The single most important safety principle for any stair, garden or otherwise, is that every rise and going in a single flight should be identical. An irregular stair, where one step is subtly taller or shallower than the rest, is one of the most common causes of trips and falls, because people’s stride adjusts to a consistent rhythm and a single inconsistent step breaks that rhythm without warning.
Landings on longer runs. Where a stair connects several terrace levels, breaking the flight with a landing every 10 to 14 steps or so gives a resting point and a place to change direction if the stair needs to turn to fit the site.
Handrails. For any outdoor stair of meaningful height, a handrail on at least one side is worth including for safety, even where it isn’t strictly mandated for a private garden stair. Where a stair serves a driveway or any part of the property with regular visitor access, we’d generally recommend a rail regardless of the formal requirement.
Materials for Retaining Wall Stairs
Sandstone steps. Natural sandstone is a strong aesthetic match for a sandstone retaining wall, and full sandstone blocks or slabs make durable, low-maintenance stair treads that develop a good non-slip surface texture with age and weathering. Sandstone steps integrate particularly well into a dry-stone wall design, since the stair opening can follow the same coursing logic as the wall itself.
Concrete sleeper or precast concrete steps. Where the retaining wall is concrete sleeper construction, precast concrete steps or a poured concrete stair with a broom or exposed-aggregate finish for slip resistance is a practical, cost-effective match. This suits a more contemporary garden aesthetic and pairs naturally with the wall material.
Timber steps. Hardwood timber treads on a stringer, or timber sleeper steps set into the slope, suit a more rustic garden character and can work well as a separate stair alongside a timber or concrete sleeper wall system. Timber requires more ongoing maintenance in the Blue Mountains’ high-rainfall environment than stone or concrete, and slip resistance needs specific attention, textured decking strips or embedded grit additives are a sensible addition.
Gravel or compacted base steps with timber or stone risers. For a lower-key garden stair, timber or stone risers holding back compacted gravel treads offer a more informal, lower-cost option, though they need more regular maintenance to keep the tread stable and non-slip after heavy rain.
Drainage Around Stairs
A stair opening through a retaining wall is also a potential water pathway, and it needs designing with that in mind. Water running down a stair during heavy rain can concentrate flow in a way a continuous wall face wouldn’t, so a few details matter:
- Cross-fall on each tread, a slight slope across the width of each step (rather than along its depth) sheds water off the side of the stair rather than letting it pool on the tread surface or cascade down the nose of each step.
- A drainage channel or grate at the base of the stair, particularly where the stair discharges onto a path, driveway, or paved area, to intercept concentrated runoff before it causes erosion or ponding.
- Keeping the wall’s ag pipe drainage system continuous around a stair opening, rather than interrupting it, so the stair doesn’t create a gap in the wall’s overall drainage performance.
See our Landscaping After a Retaining Wall guide for the wider picture on drainage maintenance and planting around a new terraced garden, stairs included.
Indicative Cost of Adding Stairs
Stairs add a genuine cost to a retaining wall or terracing project, since they involve extra excavation, structural detailing at the opening, and stair-specific materials and labour.
Indicative 2026 pricing for retaining wall stairs (Blue Mountains, per flight):
| Stair Type | Indicative Cost |
|---|---|
| Sandstone steps (integrated, 4-6 risers) | $2,500 – $5,500 |
| Concrete sleeper or precast concrete steps (4-6 risers) | $1,800 – $3,800 |
| Timber steps (4-6 risers) | $1,200 – $2,800 |
| Handrail (per flight, where included) | $600 – $1,800 |
These figures are indicative only and depend on total rise, material, and site access. See our Retaining Wall Cost Guide, Blue Mountains 2026 for the full pricing framework across wall types and materials.
Frequently Asked Questions
Do garden stairs through a retaining wall need council approval in the Blue Mountains? Generally, standalone garden stairs are considered alongside the retaining wall’s own approval pathway rather than assessed separately, but where a stair is part of a wall over the exempt-development height threshold, or affects a heritage-listed property, it can factor into the overall approval requirement. This is confirmed as part of the design and quoting process for your specific project.
What’s the most slip-resistant material for outdoor stairs in a high-rainfall climate? Textured or exposed-aggregate concrete and naturally textured sandstone both perform well wet. Smooth, honed stone or unsealed timber decking without added grip can become genuinely slippery in the Blue Mountains’ rainfall, and we’d generally steer away from smooth finishes for any outdoor stair tread.
Can stairs be added to an existing retaining wall, or do they need to be built in from the start? It depends on the wall’s construction. Adding a stair opening to an existing wall usually means partial demolition and reconstruction of that section with proper structural detailing around the new opening, which is a bigger job than incorporating the stair into the original design. It’s worth planning for stairs upfront wherever a terraced design is being considered.
How many steps can I have before I need a landing? There’s no single mandatory number for a private garden stair, but a landing every 10 to 14 risers or so is a sensible design convention that gives a resting point and keeps a long flight from feeling relentless or unsafe. For a stair connecting several terrace levels, a landing at each terrace is the usual approach rather than running straight through.
Do I need a handrail on a low garden stair with only two or three steps? Not usually a strict requirement for a very short flight, but for anything beyond a handful of risers, or where the stair sees regular use by visitors, elderly family members, or children, including a rail is a sensible safety measure regardless of whether it’s formally mandated for a private garden.
Thinking through stairs as part of a terraced garden or retaining wall project? The stair detail belongs in the wall design from the start, not as an afterthought. Request a free quote →