Retaining walls are an important part of many residential and commercial properties across Sydney. They can be used to manage sloping land, create usable outdoor areas, support driveways and landscaped areas, form boundaries, and protect properties from soil movement and erosion. 

Choosing the right retaining wall system is an important decision because every property has different site conditions, access restrictions, soil types, wall heights and structural requirements. 

The four retaining wall systems commonly used by CANDO VIEW Landscaping & Construction are concrete sleeper retaining walls, block retaining walls, timber sleeper retaining walls and Dincel wall systems. 

Each system has advantages and is suited to different applications. This guide explains how each retaining wall system works, the main differences between them and the factors homeowners, builders and developers should consider before construction begins. 

What Is a Concrete Sleeper Retaining Wall?

Concrete sleeper retaining walls are constructed using precast reinforced concrete sleepers installed horizontally between galvanised steel posts. 

The steel posts are installed into concrete piers, with the post size, spacing, pier diameter and pier depth determined by the wall height, soil conditions, surcharge loads and engineering requirements. 

Concrete sleeper retaining walls are widely used throughout Sydney for residential properties, boundary retaining walls, landscaping projects and developments. 

Concrete sleepers are available in various colours, textures and finishes, including smooth concrete, timber-look and stone-look designs. 

Advantages of Concrete Sleeper Retaining Walls 

Concrete sleeper retaining walls offer several advantages: 

• Long service life.  

• Resistant to termites, rot and moisture damage.  

• Low ongoing maintenance requirements.  

• Suitable for straight retaining walls and stepped wall configurations.  

• Available in various colours and finishes.  

• Suitable for residential and commercial projects.  

• Fencing can often be installed above the retaining wall when appropriately designed.  

• Individual sleepers may be replaced if damaged.  

• Suitable for taller walls when designed by a structural engineer.  

Things to Consider 

Concrete sleepers are heavy and suitable machinery may be required for excavation, post installation and sleeper placement. 

Site access can significantly affect the cost and construction method. 

Depending on the wall height, location, nearby structures and surcharge loads, structural engineering and council approval may also be required. 

Correct subsoil drainage and backfilling are important to reduce water pressure behind the retaining wall. 

What Is a Block Retaining Wall?

Block retaining walls can be constructed using reinforced concrete masonry blocks, commonly known as Besser blocks, or purpose-designed segmental retaining wall systems. 

The construction method depends on the type of block system, wall height and structural requirements. 

Reinforced Besser block retaining walls typically require excavation, reinforced concrete footings, starter bars, steel reinforcement, block installation and concrete core filling. 

Segmental retaining wall systems may use interlocking blocks installed over a prepared foundation and can incorporate geogrid reinforcement depending on the wall design. 

Advantages of Block Retaining Walls 

Block retaining walls offer: 

• Excellent durability when correctly constructed.  

• High structural capacity when reinforced and engineered.  

• Suitable for straight, curved and stepped retaining walls.  

• Wide range of architectural finishes.  

• Can be rendered, painted or capped.  

• Suitable for retaining walls integrated into landscaping and building works.  

• Can be used where a more architectural finished appearance is required.  

• Reinforced block walls can accommodate significant structural loads.  

Things to Consider

Block retaining walls generally require more labour and construction time than concrete sleeper retaining walls. 

Depending on the wall design, construction may involve reinforced concrete footings, steel reinforcement, core filling, concrete pumping, waterproofing, drainage and architectural finishes. 

Restricted access can increase labour and material handling costs. 

What Is a Timber Sleeper Retaining Wall?

Timber sleeper retaining walls are generally constructed using treated structural timber sleepers supported by timber or galvanised steel posts. 

They are commonly used for smaller residential retaining walls, garden beds, landscaping areas and properties where a lower initial construction cost is preferred. 

Advantages of Timber Sleeper Retaining Walls

Timber retaining walls offer: 

• Generally lower upfront construction costs.  

• Natural appearance that integrates well with landscaped gardens.  

• Relatively fast installation.  

• Easier material handling on properties with restricted access.  

• Suitable for low retaining walls and garden areas.  

• Timber sleepers can be cut and adjusted easily during construction.  

Things to Consider 

Timber retaining walls generally have a shorter service life than concrete sleeper, reinforced masonry or Dincel walls. 

The lifespan of a timber retaining wall depends heavily on timber treatment, drainage, soil conditions, termite exposure and ongoing moisture. 

Proper drainage and the use of suitable structural treated timber are important for improving the service life of the wall. 

Timber may not be the most suitable option for taller retaining walls or walls carrying significant structural loads. 

What Is a Dincel Retaining Wall?

Dincel is a permanent polymer formwork system used to construct reinforced concrete walls. 

The lightweight Dincel panels are assembled on site, reinforced with steel according to the structural engineering design and filled with concrete. 

Unlike conventional concrete formwork, the Dincel panels remain permanently in place after the concrete is poured. 

Dincel wall systems can be used for retaining walls, basement walls, boundary walls, OSD tanks and other structural applications. 

Advantages of Dincel Retaining Walls

Dincel walls offer: 

• Reinforced concrete structural construction.  

• Excellent durability.  

• Suitable for tall retaining walls and heavily loaded applications when appropriately engineered.  

• Suitable for basement walls and OSD tank construction.  

• Permanent formwork reduces the need for conventional formwork installation and stripping.  

• Lightweight panels before concrete placement.  

• Efficient construction method for long or high structural walls.  

• Compatible with engineered reinforcement and concrete specifications.  

• Low ongoing maintenance requirements.  

Things to Consider 

Dincel wall construction is generally more complex than standard timber or concrete sleeper retaining walls. 

Construction may require: 

• Detailed excavation and site preparation.  

• Reinforced concrete footings.  

• Starter bars.  

• Structural reinforcement.  

• Installation and bracing of Dincel panels.  

• Concrete pumping and placement.  

• Waterproofing where specified.  

• Subsoil drainage.  

• Engineering inspections and certification.  

• Suitable site access for excavation equipment, concrete trucks and concrete pumps.  

Dincel walls should always be constructed in accordance with approved structural engineering drawings and manufacturer requirements. 

Comparing Retaining Wall Systems

The best retaining wall system depends on the specific property and project requirements. 

Which Retaining Wall Is the Most Affordable?

Timber sleeper retaining walls generally have the lowest upfront construction cost. 

They can be suitable for smaller residential retaining walls, garden beds and projects where budget is the main consideration. 

Concrete sleeper retaining walls typically have a higher initial cost than timber but provide better resistance to termites, moisture and deterioration. 

Block retaining walls can be more expensive due to the labour, reinforced concrete footings, steel reinforcement and concrete required during construction. 

Dincel retaining walls generally have a higher construction cost and are typically selected where structural requirements justify reinforced concrete wall construction. 

However, comparing retaining walls based only on the cost per lineal metre can be misleading. 

Wall height, excavation requirements, soil disposal, site access, drainage, engineering, concrete quantities and nearby structures can significantly affect the final project cost. 

Which Retaining Wall Lasts the Longest?

Concrete sleeper, reinforced block and Dincel retaining walls can all provide excellent long-term durability when correctly designed, constructed and drained. 

These systems are resistant to termites and decay and require relatively little ongoing maintenance. 

Timber retaining walls can also provide many years of service, but their lifespan is more dependent on timber treatment, drainage, soil conditions and moisture exposure. 

The quality of construction and drainage system can be just as important as the retaining wall material itself. 

Which Retaining Wall Looks Best?

The best-looking retaining wall depends on the property and surrounding landscape. 

Concrete sleepers are available in various finishes and colours and can provide a modern appearance. 

Block retaining walls offer significant design flexibility and can be rendered, painted, capped or integrated into other landscape features. 

Timber sleepers provide a natural appearance that works particularly well in gardens. 

Dincel walls are generally selected for structural reasons but can receive architectural finishes, cladding or other treatments depending on the project design. 

Which Retaining Wall Is Best for Sloping Properties?

There is no single retaining wall system that is suitable for every sloping property. 

The appropriate system depends on: 

• Wall height.  

• Property slope.  

• Soil conditions.  

• Drainage requirements.  

• Surcharge loads.  

• Nearby buildings.  

• Swimming pools.  

• Driveways and vehicle loads.  

• Boundary conditions.  

• Available construction access.  

• Engineering requirements.  

• Council and planning requirements.  

Concrete sleeper retaining walls are commonly used for residential properties and boundary walls. 

Reinforced block retaining walls are suitable where structural capacity and architectural finishes are important. 

Timber retaining walls can be suitable for smaller landscaping applications. 

Dincel retaining walls can be considered for tall walls, basement construction, OSD tanks and projects requiring reinforced concrete structural walls. 

Can a Fence Be Installed Above a Retaining Wall?

Fences can often be installed above retaining walls when the additional loads are considered during the retaining wall design. 

Concrete sleeper walls can incorporate extended steel posts or purpose-designed fence brackets. 

Fencing can also be installed above reinforced block and Dincel walls using appropriate structural connections. 

The wind loads created by the fence can significantly increase the forces applied to the retaining wall. 

For this reason, retaining walls and fencing should be designed together where required. 

Why Is Drainage Important Behind Retaining Walls?

Water pressure is one of the biggest risks to retaining wall performance. 

When water accumulates behind a retaining wall, hydrostatic pressure increases the load applied to the structure. 

Depending on the retaining wall design, appropriate drainage may include: 

• Agricultural drainage pipes.  

• Free-draining aggregate.  

• Geotextile fabric.  

• Suitable backfill material.  

• Drainage cells.  

• Waterproofing systems.  

• Connections to approved stormwater discharge points.  

Correct drainage should be incorporated during retaining wall construction rather than added after problems occur. 

Do Retaining Walls Need Engineering Approval?

Engineering requirements depend on several factors, including: 

• Retaining wall height.  

• Property boundaries.  

• Nearby buildings.  

• Swimming pools.  

• Driveways.  

• Vehicle surcharge loads.  

• Soil conditions.  

• Wall type.  

• Location of underground services.  

• Local council requirements.  

Some retaining walls may be constructed without development approval when they meet applicable planning requirements, while others require engineering, certification or council approval. 

Requirements vary between properties and councils across Sydney. 

Homeowners should obtain professional advice before commencing retaining wall construction. 

What Affects the Cost of Building a Retaining Wall? 

The final cost of a retaining wall project depends on much more than the wall material. 

Major cost factors include: 

• Total wall length.  

• Retaining height.  

• Excavation requirements.  

• Rock excavation.  

• Soil disposal.  

• Site access.  

• Machinery requirements.  

• Concrete quantities.  

• Steel reinforcement.  

• Drainage.  

• Backfilling materials.  

• Engineering.  

• Council approval.  

• Traffic control.  

• Fencing above the retaining wall.  

• Demolition and disposal of existing retaining walls.  

For this reason, accurate retaining wall quotations should generally be based on a site inspection and review of the available engineering documentation. 

How Do You Choose the Right Retaining Wall?

Before selecting a retaining wall based only on price or appearance, consider the following questions: 

• How much soil needs to be retained?  

• What is the maximum wall height?  

• Are there buildings near the wall?  

• Is there a driveway or vehicle loading above the wall?  

• Will a fence be installed above the retaining wall?  

• Is there a swimming pool nearby?  

• What are the soil conditions?  

• How will subsoil drainage be managed?  

• Can excavation equipment access the property?  

• Is concrete pump access available?  

• Does the project require structural engineering?  

• Are council approvals required?  

• What service life do you expect from the retaining wall?  

A professional site inspection can help identify these factors and determine the most appropriate retaining wall system. 

Retaining Wall Construction Services in Sydney

CANDO VIEW Landscaping & Construction provides retaining wall construction services for homeowners, builders, developers and property managers across Sydney. 

Our retaining wall services include: 

• Concrete sleeper retaining walls.  

• Reinforced Besser block retaining walls.  

• Segmental block retaining wall systems.  

• Timber sleeper retaining walls.  

• Dincel retaining walls.  

• Dincel OSD tanks and structural walls.  

• Retaining wall demolition and replacement.  

• Excavation and detailed site preparation.  

• Pier drilling and excavation.  

• Reinforced concrete footings.  

• Concrete placement and pumping coordination.  

• Subsoil drainage.  

• Backfilling and compaction.  

• Fencing above retaining walls where included within the project scope.  

Get a Quote for Retaining Wall Construction in Sydney 

Every retaining wall project is different. 

The correct wall system depends on the property, retaining heights, soil conditions, drainage requirements, site access, structural loads and intended use of the surrounding area. 

CANDO VIEW Landscaping & Construction can review your project, inspect the site and provide a detailed quotation based on the required scope of works. 

Whether you require a concrete sleeper retaining wall, reinforced block wall, timber sleeper wall or Dincel wall system, our team can help you understand the available options and plan the appropriate construction solution. 

Contact CANDO VIEW Landscaping & Construction today to arrange a site inspection or request a quotation for your retaining wall project.