How to install a SuperSleeper Retaining Wall

Whether you're taming a sloped yard, building a raised garden bed or adding structure to your landscape, SuperSleepers are a practical, DIY-friendly option for your retaining wall project that can handle Australia’s tough conditions.

Installing Your SuperSleepers

Made from a fibre-reinforced polymer composite, SuperSleepers are lighter than concrete and tougher than timber – and best of all, they’re easy to install yourself. In this guide, we’ll walk you through how to install a SuperSleeper retaining wall step by step, using simple tools and straightforward instructions.

Tools and materials you’ll need

SuperSleepers and many of the materials listed below are available directly from us, with delivery available across Queensland and beyond. Here’s what you’ll need before you start:

Essential materials

  • SuperSleepers (standard or premium)
  • Composite C‑posts (end‑posts) and H‑posts
  • Crushed rock or road base
  • Backfill soil
  • Agricultural drainage pipe (with sock)
  • Geo-fabric
  • Concrete (for setting posts)
  • Galvanised screws/ bolts & nuts (e.g., M12 SuperBolts/Nuts) 

Tools

  • Tape measure
  • Spirit or laser level
  • Shovel and spade
  • Post hole digger or auger
  • Drill or impact driver
  • Wheelbarrow
  • Gloves and safety gear

Optional extras

  • String line for accuracy
  • Tamper or compactor for base preparation
  • Circular saw

Step-by-step instructions

1. Plan your wall and check local regulations

  • What to do: Measure your wall’s height and length, then calculate how many sleepers and posts you’ll need. If your wall is over 1 metre high or near a boundary, check with your local council to see if approval is needed.
  • Why it matters: Proper planning ensures safety, compliance and a smoother install.
  • Tip: Always contact Dial Before You Dig at 1100 to avoid underground services.

2. Mark out your site

  • What to do: Use a string line and pegs to mark where your wall will go. For curves, spray paint works well.
  • Why it matters: Accurate marking helps ensure the wall is straight and fits the space properly.
  • Common mistake: Not allowing enough space for post widths. Always include the full sleeper and post width in your layout.

3. Excavate and level the base

  • What to do: Dig a trench around 200 mm wider than your sleeper width and deep enough to allow for drainage. Add a compacted 75–100 mm layer of crushed rock or road base.
  • Why it matters: A stable, level base prevents movement and ensures your wall stays solid over time.
  • Tip: Use a tamper or plate compactor to properly compact the base material before moving on.

4. Set your posts

  • What to do: Dig post holes every 1.5 to 2 metres, depending on sleeper length. Insert galvanised C or H-posts and set them in concrete. Check alignment and vertical level before the concrete sets.
  • Why it matters: Posts anchor your wall – they need to be level, aligned and deeply embedded to support weight over time.
  • Tip: Allow concrete to cure for 24–48 hours before continuing.

5. Install your sleepers

  • What to do: Slide SuperSleepers into the posts, starting from the bottom and stacking upwards.
  • Why it matters: Neat alignment and firm fitment help your wall perform well under pressure and look great.
  • Tip: Check for level after every row. If your wall curves, offset joints slightly for a tighter visual finish.

 

 

6. Backfill and add drainage

  • What to do: Place a socked ag pipe behind the base sleeper. Cover with free-draining material like gravel, then top up with soil about 300 mm from the surface. Ag pipe is available for purchase from our online store. 
  • Why it matters: Proper drainage prevents water buildup behind your wall, reducing long-term pressure and damage risk.
  • Common mistake: Skipping this step! Even small walls need drainage.

7. Add finishing touches

  • What to do: Add optional capping, landscape around your wall and slope the topsoil slightly away from the wall.
  • Why it matters: A tidy finish protects the wall and adds street appeal.
  • Tip: Use mulch or native plants for a low-maintenance, polished look.

 

Why SuperSleepers are a smart choice

No rot, no warping, no cracks

SuperSleepers are made from a fibre-reinforced composite that won’t rot, twist, split or crack like timber can over time. That means no need for ongoing maintenance or replacement due to water damage or natural decay, even in Queensland’s humid or coastal environments.

Lightweight and strong

Despite their strength, SuperSleepers are much lighter than concrete, making them easier to lift, carry and install without specialist tools or machinery. This saves time and labour costs, especially for DIYers looking for a weekend project that won’t require extra help or heavy lifting.

Eco-conscious materials

Manufactured using recycled content, SuperSleepers help reduce environmental impact. Choosing these sleepers means you’re supporting sustainable building practices without compromising on strength or appearance.

Weather and UV resistant

Designed for Australia’s extreme conditions, SuperSleepers stand up to scorching sun, heavy rain and high humidity. Their UV-stabilised surface ensures they won’t fade, crack or degrade when exposed to the elements, making them ideal for long-term outdoor use.

DIY and tradie approved

Built to meet the needs of both home renovators and professionals, SuperSleepers are engineered for easy installation while offering the durability and quality required on commercial job sites.

 

Ready to start building?

Installing a SuperSleeper retaining wall is a rewarding project that delivers long-term results. Whether you're tackling a brand-new garden design or updating an older outdoor space, SuperSleepers offer a smart, DIY-friendly solution that’s built for Australian conditions. Their composite construction means no rot, warping or cracking, and because they’re lightweight yet strong, you won’t need extra hands or heavy machinery to get the job done. 

With the right tools, a clear plan and our step-by-step guide, you’ll be ready to create a solid, attractive wall that stands the test of time. Explore our SuperSleepers range at Australian Landscape Supplies today!