Concrete Sleeper Retaining Walls
Concrete Sleeper Retaining Walls
What Are Concrete Sleeper Retaining Walls?
You'll notice a lot of new Brisbane and Gold Coast houses with concrete sleeper retaining walls, whereas homes built in the 60s through to 90s would have most likely had timber, now in need of replacement.
Concrete sleeper retaining walls are a popular choice for modern Brisbane and Gold Coast homes due to their low maintenance and durability.
Concrete sleepers are usually 200mm high and 75–80mm thick with either 2 or 3 pieces of rebar inside. This reinforcement helps the sleepers withstand the force of the soil acting behind them. Builders stack the sleepers vertically between steel posts. We concrete the steel posts into the ground, usually slightly deeper than the wall height. For example, if the wall is 1m high, we typically bury the posts at least 1m deep, depending on the soil type.
Many suppliers stock the posts and concrete sleepers, so it's worthwhile shopping around to find the best supplier.
These walls also come in a variety of textures, which cost slightly more but add value to your project, as many people prefer the timber-grain style, for example.
Learn more on our Retaining Wall Engineering page.
Key Benefits of Concrete Sleeper Retaining Walls
1. Durability
The sleepers themselves can last 40–50+ years, while the galvanised steel posts — up to 10mm thick — also last for decades. Although the posts may eventually rust, this usually takes a very long time. Most issues come from poor construction rather than materials. This is why selecting a quality wall builder who understands design requirements is important.
2. Low Maintenance
Once installed, these walls require essentially zero maintenance — unlike timber walls, which may need oiling or painting.
3. Aesthetically Pleasing
They come in a variety of textures, including timber-grain style, stone look, smooth finish, and multiple colours.
4. Cost Effective
Even though the materials cost more than timber, the walls remain cost-effective because they use off-the-shelf components mass-produced locally. We shop around to find the best-priced suppliers.
Construction Process
1. Design
Every quality project starts with a quality design. We check ground levels, dimensions, access, heights, possible underground services, and your future plans for the retained area. We then draft a plan and calculate the right quantity of materials.
2. Approvals (if required)
If the project requires engineering, we arrange soil testing, engineering design, and drafting for building approval. We handle the entire process for you.
3. Material Orders
We order materials only when the project is ready to start. This prevents clutter on your property. We buy from reputable wholesalers with strong pricing.
4. Site Preparation
We cut and fill the area using an excavator and bobcat. We dig the holes for the steel posts — generally 1.2m deep for a 1m wall and around 450mm in diameter. Soil conditions can affect these measurements. We remove or reuse excess soil on site.
We insert the posts carefully, set them plumb, and position them at the correct height and spacing. We pour the concrete using either wheelbarrows or a pump, depending on what is most suitable. This is the most critical part of the job.
6. Installation of Sleepers
After the concrete cures, we deliver the sleepers and lift them into position using machinery. We ensure the sleepers sit flush across the wall face.
7. Installing Drainage, Geofabric & Backfill
We begin drainage with an agi-pipe at the base of the wall, sloped toward an outlet. We place free-draining gravel above it, then wrap the materials in geofabric to prevent soil contamination.
We clean the site, remove rubbish, and spread or dispose of excess material.
For general retaining wall regulations, see QLD Building Guidelines.