Concrete sleepers have overtaken treated pine as the go-to retaining wall material across Melbourne. They don’t rot, termites can’t eat them, they are non-combustible (important in bushfire overlay areas), and they come in finishes that suit a modern garden. A sleeper is only as good as the steel post holding it, though. Here is what to know when you are buying concrete sleepers in Melbourne.
Standard concrete sleeper sizes
Most residential sleepers are 200 mm high and come in lengths of 1.6 m, 2.0 m and 2.4 m. Thickness is usually 75 mm or 80 mm for standard walls, with heavier 100 mm-plus units for taller or engineered walls. Sleeper length sets your post spacing: posts sit at the sleeper length centre to centre, so a 2.4 m sleeper needs fewer posts per metre of wall than a 2.0 m sleeper. Each post then carries more load, which can push you up a section size.
Finishes
- Smooth or off-form grey: clean and contemporary, and the most affordable.
- Timber look (woodgrain): cast with a timber texture, often in charcoal, sandstone or natural tones.
- Stacked stone or sandstone look: textured faces for feature walls.
See finished walls in our project gallery and the current range on the sleepers page.
Pairing sleepers with the right steel post
The sleeper slides into the space between the post flanges, so the flange gap must match the sleeper thickness. The post also has to resist the soil pressure. As a general guide:
- Walls up to about 600 mm: 100UC15 posts
- Walls around 800 mm to 1.2 m: 125UC or 150UC posts
- Walls 1.2 m to 1.8 m, or with driveway loads: 200UC or larger, engineer designed
These figures are indicative only. Soil type, slope and surcharge all change the answer, and walls over 1 m usually need a building permit in Victoria. Our steel post specifications guide and the UC vs UB post comparison explain sizing in more detail.
Tips for a wall that lasts
- Use hot-dip galvanised posts. Concrete sleepers last decades, and the posts must last as long.
- Install ag pipe and free-draining gravel behind the wall so water pressure does not build up.
- Pour footings to full depth and keep posts plumb with a string line.
- Order a spare sleeper or two for cuts and breakages.
Get sleepers and steel in one order
We supply concrete sleepers and cut-to-length galvanised posts together, delivered across Melbourne and regional Victoria. Send your wall dimensions through the quote form or get in touch for advice.