A retaining wall is far more than a row of sleepers. It is a structural system designed to safely retain soil, create usable land, prevent erosion and protect your property.

When built correctly, a retaining wall can provide decades of reliable service. When shortcuts are taken, however, retaining walls can fail, sometimes causing costly damage to fences, driveways, sheds and even nearby buildings.

At Crawfords Fencing, we specialise in timber sleeper retaining walls and concrete sleeper retaining walls, using quality materials and proven installation methods designed to stand the test of time.

What Does a Retaining Wall Do?

Retaining walls are commonly used to:

• Create level outdoor areas.

• Prevent soil erosion.

• Maximise usable backyard space.

• Support boundary fences.

• Improve landscaping.

• Protect existing structures.

• Manage sloping blocks safely.

Every retaining wall is different, and every property presents its own unique engineering challenges.

Choosing the Right Retaining Wall

Timber Sleeper Retaining Walls

Timber sleeper retaining walls provide a natural appearance and are a cost-effective solution for many residential properties.

Quality H4-treated pine or hardwood sleepers, installed correctly, can provide decades of reliable service.

Concrete Sleeper Retaining Walls

Concrete sleeper retaining walls are extremely durable, resistant to termites and rot, require very little maintenance and are an excellent long-term investment.

Every Retaining Wall Starts Below Ground

The most important part of any retaining wall is the part you’ll never see.

Strong foundations determine whether your wall remains straight for decades or begins moving after only a few years.

At Crawfords Fencing, we don’t believe in guesswork.

Every retaining wall is individually assessed before excavation begins.

How We Determine How Deep to Dig

There is no standard hole depth that suits every retaining wall.

Every project is individually assessed based on:

• Overall retaining wall height.

• Soil conditions.

• Groundwater.

• Drainage requirements.

• Steel H-beam size.

• The weight of the retained soil.

• Any surcharge loads.

As the retained height increases, so do the forces acting on the wall.

At Crawfords Fencing, our retaining wall post depths can vary dramatically depending on the project.

While smaller retaining walls may require comparatively shallow footings, larger structural retaining walls commonly require post depths extending to 2 metres or more, depending on the engineering design, retained height, soil conditions and structural loads.

There is no shortcut when it comes to foundations.

The depth of every footing must be appropriate for the loads it will carry. Saving money below ground is one of the quickest ways to create expensive problems above ground.

What Is a Surcharge Load?

One of the first questions we ask isn’t:

“How high is the wall?”

It’s:

“What is the wall supporting?”

The retained soil isn’t always the only weight acting on a retaining wall.

Many retaining walls also support:

• Boundary fences.

• Driveways.

• Garden sheds.

• Swimming pools.

• Concrete slabs.

• Houses.

• Garages.

• Carports.

• Large trees.

• Parked vehicles.

These are known as surcharge loads.

A retaining wall supporting only soil is completely different from one supporting your neighbour’s carport or part of a house foundation.

Every additional load increases the pressure placed on the wall and must be considered before construction begins.

When Does a Retaining Wall Need Engineering?

Not every retaining wall requires engineering.

However, retaining walls over 1 metre in height, or walls supporting structures and significant surcharge loads, commonly require engineering and building approval.

This process may include:

• Structural engineering design.

• Soil classification and geotechnical (soil) testing where required.

• Engineering calculations.

• Building permit application.

• Construction in accordance with the engineer’s specifications.

Engineering doesn’t simply determine the size of the steel posts.

It considers:

• Soil type.

• Retaining height.

• Groundwater.

• Drainage.

• Wind loading.

• Surcharge loads.

• Long-term structural performance.

At Crawfords Fencing, we work closely with qualified engineers and building surveyors where required to ensure every retaining wall is designed and constructed safely and in accordance with all applicable requirements.

Drainage Is Critical

The biggest cause of retaining wall failure usually isn’t the sleepers or steel posts.

It’s water.

Without proper drainage, rainwater becomes trapped behind the retaining wall.

As Director Tyrone Crawford often explains to clients:

“If you don’t have drainage behind your retaining wall, you’ve got the beginnings of a swimming pool. The water has nowhere to escape, and as it builds up, the force pushing against the wall becomes enormous.”

Water is incredibly heavy. As it builds up behind a retaining wall it creates hydrostatic pressure, placing enormous force on the wall in addition to the weight of the retained soil.

This pressure can cause walls to bow, lean, crack or even fail if they haven’t been designed and drained correctly.

Every retaining wall should include a drainage system that allows water to escape rather than build up behind the structure.

Depending on the project, this may include:

• Agricultural drainage pipe (Agi pipe).

• Free-draining scoria backfill.

• Geotextile drainage fabric.

• Suitable drainage outlets.

At Crawfords Fencing, we believe drainage is every bit as important as the steel, sleepers and concrete. A retaining wall is designed to retain soil—not water.

Quality Foundations Matter

At Crawfords Fencing, we don’t believe in shortcuts.

Depending on the project, our retaining walls may include:

• Galvanised steel H-beams.

• H4-treated timber sleepers or concrete sleepers.

• Footings designed specifically for the structural requirements of the wall.

• 40 MPa concrete.

• Agricultural drainage.

• Free-draining scoria backfill.

• Geotextile drainage fabric.

Everything below ground is designed to maximise the lifespan of the wall above it.

Why Retaining Walls Fail

Most retaining walls don’t fail because of the sleepers.

They fail because of:

• Poor drainage.

• Inadequate footing depth.

• Poor workmanship.

• Incorrect post spacing.

• Inferior materials.

• Ignoring surcharge loads.

• Lack of engineering where required.

• Water pressure building behind the wall.

Almost every retaining wall failure begins below ground long before movement becomes visible.

Our Installation Process

Every Crawfords Fencing retaining wall follows a structured process.

1. Site inspection.

2. Measure retaining height.

3. Assess soil conditions.

4. Identify surcharge loads.

5. Determine whether engineering is required.

6. Calculate footing depth.

7. Select the appropriate galvanised H-beam size.

8. Excavate footings.

9. Install posts using 40 MPa concrete.

10. Install agricultural drainage, geotextile fabric and free-draining scoria.

11. Install sleepers.

12. Complete backfilling and final clean-up.

Every retaining wall is different.

Every retaining wall deserves its own assessment and construction method.

Why Choose Crawfords Fencing?

We don’t simply build retaining walls.

We build retaining walls designed to remain standing for decades.

As Director Tyrone Crawford often says:

“A retaining wall doesn’t know whether it’s holding back dirt or your neighbour’s carport. It only knows the weight pushing against it. That’s why every wall deserves the right foundations.”

Our philosophy is simple:

Build it once. Build it properly. Build it to last.

Need a Retaining Wall?

Whether you’re replacing an old retaining wall or building a new one, Crawfords Fencing can help.

We proudly service Ringwood, Ringwood East, Ringwood North, Croydon, Heathmont, Blackburn, Mitcham, Vermont, Doncaster, Doncaster East, Templestowe, Warrandyte, Bayswater, Wantirna, Ferntree Gully, Boronia, Lilydale, Mooroolbark, Chirnside Park, Montrose, Coldstream, Yarra Glen and surrounding suburbs throughout Maroondah, Whitehorse, Manningham, Knox and the Yarra Ranges.

Contact Crawfords Fencing today for a free, no-obligation quote and let us build a retaining wall that’s designed, engineered where required, and built to stand the test of time.