Retaining walls do more than just hold back soil—they shape the landscape, prevent erosion, manage water runoff, and in many cases, turn a steep or unusable section of your yard into something practical and even beautiful. But not all retaining walls are created equal. Depending on your site conditions, the height of the wall, and even your budget, the type of retaining wall you choose can make a big difference to how long it lasts and how well it performs.
Over the years, I’ve worked with all kinds of retaining walls in Mornington Peninsula—some built for structural strength, others purely for landscaping appeal—and one thing’s clear: picking the right wall type from the start saves you a lot of headaches down the track. In this article, I’ll walk you through the most common types of retaining walls, how they work, and when you should consider each one. Whether you’re tackling a sloped block, dealing with drainage issues, or planning a garden redesign, this guide will help you understand your options and make an informed decision.
If you’re planning to build a retaining wall—whether it’s for structural support, improving drainage, or simply to tidy up the look of your yard—there are a few important things you should think through before you pick a wall type or start construction. Getting these basics right makes all the difference in how your wall performs over time and how much effort (and money) you’ll spend down the line.
Not all soil is equal when it comes to retaining walls. Clay-heavy soils retain water and expand, putting more pressure on the wall, while sandy soils drain better but may shift or erode easily. If you’re building on a steep slope, gravity becomes a bigger challenge, and you’ll likely need a more engineered solution like a cantilever or anchored wall.
In areas with poor soil stability, you might need to dig deeper footings or incorporate geogrid reinforcement behind the wall to prevent movement over time. If you're unsure, it’s worth investing in a proper site assessment or speaking to a contractor who’s familiar with local soil conditions.
One of the biggest causes of retaining wall failure is poor drainage. When water builds up behind the wall—especially in heavy rain or if the soil has poor permeability—it creates hydrostatic pressure that pushes hard against the structure. Over time, this can lead to bowing, cracking, or collapse.
Good drainage design is non-negotiable. This usually includes:
It might not be the part you see, but proper drainage is what keeps your wall standing strong for years.
The taller the wall, the more pressure it needs to resist—and that changes everything from footing depth to reinforcement. As a general rule in Australia, walls over 600mm to 1 metre in height usually need engineering certification and council approval.
It’s not just the soil weight you need to think about. If you’re planning to build a driveway, patio, shed, or even just have a parked vehicle above or near the wall, you’re dealing with what's called a surcharge load. This extra weight can significantly affect the wall’s design. Not all wall types are built to handle this, so it’s crucial to factor in what’s going above or behind the structure.
While the structural needs come first, looks still matter—especially if the wall’s in a visible spot. You’ll want to choose a material and finish that complements your home or garden. For example:
Retaining walls can be purely functional, or they can double as seating, feature walls, or garden beds—so don’t be afraid to factor design into your decision.
Your budget will influence both the type of wall and the materials used. But it’s also worth looking at long-term value, not just upfront cost.
Some walls may need resealing or occasional re-pointing. Others, like dry-stacked stone or block systems, might shift slightly over time and need adjustment. Think about how much maintenance you’re willing to take on, and how important longevity is in your case.
Most local councils require approval for retaining walls over a certain height—often 600mm to 1m—and especially if they’re close to a boundary, carry a surcharge load, or affect drainage or neighbouring properties. You might also need a structural engineer to certify the plans.
Skipping this step can lead to fines or having to pull the wall down later, so it’s best to check with your local council early in the process. If you're working with a contractor, they should handle the approvals for you or at least guide you through it.
Once you’ve figured out what your property needs—considering things like soil, drainage, and budget—the next step is choosing the type of retaining wall that suits. Each type has its own strengths, ideal use cases, and construction requirements. Some are better for heavy loads and steep slopes, while others are great for landscaping and smaller applications.
Let’s break down the most common types of retaining walls and where each one works best.
How it works:
Gravity walls rely purely on their own weight to resist the pressure from the soil behind them. They’re thick at the base and taper towards the top, using mass to hold everything in place.
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Cantilever walls are usually made of reinforced concrete and shaped like an upside-down “T.” They use leverage to balance the soil pressure and transfer the load to the ground below via a wide base slab.
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Thin, vertical sheets (usually steel, vinyl, or timber) are driven deep into the ground to form a wall. The soil holds the sheets in place, and they’re often used where space is tight.
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Anchored walls include additional reinforcement in the form of cables or rods driven deep into the ground and anchored with concrete or mechanical plates. These tiebacks help the wall resist large forces.
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These walls are made from interlocking concrete blocks designed to stack without mortar. The blocks have lips or tongues that lock them in place, and they can be built with or without reinforcement, depending on height and load.
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Gabion walls are built by stacking wire mesh cages filled with stone or rubble. The mass and flexibility of the cages help absorb and distribute pressure from the soil.
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Treated timber sleepers are stacked or anchored into the ground to hold back soil. Timber walls are common in residential backyards for low-height applications.
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With all the different types of retaining walls out there, it’s not always obvious which one to choose. The right option depends on your site conditions, what you need the wall to do, and how much you’re willing to invest—both financially and in terms of time and maintenance.
Here’s how to narrow it down and make a decision that’ll work for the long haul.
Start by thinking about why you need a retaining wall. Is it to support a sloping block and prevent erosion? To level off a space for a garden or driveway? Or purely for aesthetic reasons, like building raised garden beds or adding structure to your landscaping?
It’s easy to focus on upfront costs, but a retaining wall is a long-term structure—it needs to hold up for years, ideally decades.
Also factor in local conditions. In termite-prone areas, timber walls might not be the best idea unless well-treated and protected. In coastal areas, steel or mesh materials like those used in sheet pile or gabion walls need to be corrosion-resistant.
If your wall is going to be front and centre—say, bordering your driveway or visible from your entertaining area—you’ll want it to look the part. Thankfully, many materials now come with decorative finishes. Concrete sleepers, for example, are available in smooth, textured, or even timber-look finishes, giving you both strength and style.
Natural stone and gabion walls offer a more rugged, earthy look that suits bush settings or homes with more natural landscaping.
If visual appeal is important, choose a material that complements your home’s architecture and garden design—but make sure it still ticks the structural boxes.
Even if you’re planning a DIY wall, it’s worth having a chat with a landscaper, builder, or structural engineer—especially if the wall is going to be over 1 metre high, carry load, or sit near property boundaries. They can help with things like:
A properly designed wall will not only last longer—it’ll save you from expensive fixes or rebuilds later on.
While it’s tempting to go for the cheapest option, make sure you weigh the upfront cost against how long the wall will last and what maintenance it will need. A wall that costs a bit more now might end up saving you money over the years, especially if it avoids issues like shifting, leaning, or water damage.
Also consider access—if your site is hard to reach, labour and equipment costs can rise, regardless of the wall type. Sometimes a more modular solution like segmental blocks is more practical in these situations than something that needs large machinery or poured concrete.
Choosing the right retaining wall comes down to more than just looks—it’s about making sure the wall does its job, lasts the distance, and suits your property’s needs. Whether you’re dealing with a sloped block, drainage issues, or just want to add structure to your garden, the type of wall you go with should be guided by the conditions on site, the loads it needs to handle, and how much maintenance you're happy to take on.
If you’re working with soft soils or building something substantial, a reinforced solution like a cantilever or anchored wall might be necessary. For smaller landscaping jobs or raised beds, timber or modular block walls can do the trick without breaking the bank. And if you’re after something a bit more rugged and sustainable, gabion baskets or stone walls can give you that natural feel with solid performance.
At the end of the day, a well-planned retaining wall will not only solve practical problems like soil retention and water runoff—it can also become a defining feature of your outdoor space. If you’re unsure where to start, talking to someone with experience in your local area can help make sure you end up with a solution that’s safe, compliant, and built to last.
