How to Build a Retaining Wall

Retaining walls do more than hold back soil; they prevent erosion, tame sloping blocks, and create usable space in your yard. From concrete sleepers and timber to rocks and interlocking blocks, there are plenty of DIY options if you’ve got the tools and patience. But if you’d rather skip the hard work, Ecovolve has been building strong, lasting, QBCC-licensed retaining walls in Brisbane since 2005.

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A retaining wall is more than just a neat way to hold back soil. It’s a practical structure that helps stop erosion, manage sloping land, and create level spaces in your yard. If you’ve ever looked at a steep block and thought it could use a little bit of taming, then a retaining wall is your answer. 

Retaining walls are a common element of landscaping. Here’s how to build a retaining wall in Australia, step by step, with different options depending on your style, budget and site conditions.

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Building Different Types of Retaining Walls

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1. How to Build a Concrete Sleeper Retaining Wall

Wondering how to build a sleeper retaining wall with steel posts? These walls are strong, low-maintenance, and ideal for both residential and commercial projects. They are often used where you want durability without constant upkeep. The sleepers slot neatly between steel posts, which makes the whole system ultra-sturdy.

Materials you need:

• Concrete sleepers
• Steel posts (H or C channel)
• Gravel for drainage
• Concrete mix
• Drainage pipe
• Shovel, string line, spirit level

Steps involved:

1. Mark out the wall line with pegs and string.
2. Dig post holes to the right depth, making sure they’re evenly spaced.
3. Place steel posts in holes and set them with concrete.
4. Allow posts to set before moving on.
5. Slot the concrete sleepers into position between the posts.
6. Backfill with gravel and install a drainage pipe to prevent water build-up.
7. Finish with soil and compact the area.

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2. How to Build a Retaining Wall on a Slope With Sleepers

Building on a slope adds a few more challenges. But don’t worry; it can definitely be done!  Sleeper walls on sloped blocks are stepped so they follow the rise of the land. This makes them different from flat ground installations. Proper drainage and alignment are critical to avoid movement over time. Building on a slope takes more care, but if you follow the steps carefully, the end result will be a sturdy wall you can count on. 

Materials you need:

• Concrete sleepers
• Steel posts
• Concrete mix
• Gravel and drainage pipe
• Shovel, level, tape measure

Steps involved:

1. Plan where your steps in the wall will go based on the slope.
2. Dig post holes at varying depths to match the slope.
3. Set posts in concrete, making sure each step in height is consistent.
4. Slot sleepers into place, one section at a time.
5. Lay drainage pipe and backfill with gravel behind each stepped section.
6. Compact the soil to secure everything.

And that’s how to build a retaining wall with concrete sleepers that effectively controls all that soil movement. 

3. How to Build a Timber Retaining Wall

Timber retaining walls are popular because they look natural and are easier to build compared to concrete options. They work well for smaller walls and garden edging. But here’s the catch: you’ll want to keep in mind that timber will not last as long as concrete or stone options. 

Materials you need:

• Treated pine or hardwood sleepers
• Posts (treated timber or steel)
• Concrete mix
• Screws or bolts
• Gravel and drainage pipe
• Shovel, drill, saw

Steps involved:

1. Mark the wall line and dig post holes.
2. Place posts and set them with concrete.
3. Cut sleepers to size and fix them horizontally behind the posts.
4. Secure each sleeper with bolts or screws.
5. Add a drainage pipe and backfill with gravel.
6. Finish with soil behind the wall.

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4. How to Build a Rock Retaining Wall

Now we can’t deny that rock walls are all about character, which brings instant personality to any space. They blend into natural surroundings and can look like they’ve always been part of the landscape. While it takes more time and patience to build these types of walls, the results are totally worth it.

Materials you need:

• Large rocks or boulders
• Gravel for base and backfill
• Drainage pipe
• Shovel, mattock, wheelbarrow

Steps involved:

1. Excavate a trench for the first course of rocks.
2. Place the largest, flattest rocks at the bottom for stability.
3. Stagger each row so joints do not line up.
4. Backfill with gravel and install a drainage pipe as you go.
5. Keep checking the wall for level and alignment.
6. Fill gaps with smaller rocks for strength and looks.

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5. How to Build a Block Retaining Wall

Block retaining walls use interlocking concrete blocks, which makes them incredibly easy to use for DIY projects. You’ll love how they come in different styles, so whether you prefer a clean modern look or something more textured, there’s something that’ll match your aesthetic vision. 

Materials you need:

• Interlocking concrete blocks
• Gravel for base and backfill
• Drainage pipe
• Compactor
• Shovel, level, string line

Steps involved:

1. Mark the wall line and dig a trench for the base.
2. Fill the base with compacted gravel.
3. Lay the first row of blocks, checking the level carefully.
4. Stack each row, offsetting the joints for strength.
5. Place a drainage pipe behind the wall and backfill with gravel.
6. Finish the top row with cap blocks for a neat edge.

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Stop Hitting Walls As You Build. Just Call Ecovolve. 

Since 2005, Ecovolve has been shaping Brisbane landscapes with a mix of smart design, sustainable style and family-run service. We focus on creating solutions that last. No quick fixes here. Fully licensed by the QBCC, our team can manage everything from the first sketch to the final build. Our retaining walls don’t just hold the ground; they hold their strength and style for years to come. 

Ready to start your project? Contact Ecovolve today.

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Our services:

• Landscape architecture and design
• Landscape construction
• Garden maintenance
• Horticulture consultation
• Living walls and vertical gardens 
  
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