How Much Does It Cost To Build a Retaining Wall?
Ballpark estimates for building retaining walls in Victoria cost around:
Depending on the size and complexity of your retaining wall, a small garden edging retaining wall can set you back just under $1000, while larger structural retaining walls can cost you well in excess of $10,000.
- $250 to $500 per sq/m for treated pine/treated timber/hardwood sleepers
- $300 to $550 per sq/m for besser blocks
- $550 to $700 per sq/m for concrete sleepers
Example of a small retaining wall project ~ $1200
Pictured: The Marina smooth-face concrete sleeper in charcoal, used for a small garden bed retaining wall project - Materials cost = ~$400; Labour cost = $800
Example of a large Retaining Walls will supply and install a concrete sleeper retaining wall as per the structural engineering documentation ~ $70,000
Pictured: Approximately 56 lineal meters of retaining wall using 80x 2400mm x 80mm Plain Marina Concrete Sleepers
Considerations to make when building a retaining wall
Below are just some of the factors to consider when you’re planning on building a new retaining wall:
- Do you have an existing retaining wall that needs to be replaced? If so, who will be responsible for demolishing and disposing of it, you or the retaining wall builder?
- What type of materials will you use for the new retaining wall?ย
- What is the Height of the new retaining wall? Heights generally dictate whether or not you will need council approvals, engineering certificates, and soil testing. Does the wall impact the neighbouring property? Does it need to carry additional load (e.g., driveway, fence, building, or surcharge)? If so, you may still need engineering plans, even if it’s below the council’s height requirements.
- Does your wall need to incorporate steps, curves or any other special features?ย
- Do you plan on building the retaining wall yourself, and if so, have you calculated the material costs and delivery costs?
If you plan to dig holes for posts, do you have a Before You Dig Australia (BYDA) plan (formerly known as Dial Before You Dig (DBYD))? You may also need to hire the services of an underground services locator before digging any new holes.
Different types of retaining walls
Retaining wall applications come in many forms.ย
Structural Retaining Walls
Garden Bed Retaining Walls
Under Fence Plinth Retaining Walls
Around the pool retaining walls
Boundary Wall Retaining Walls
Steps Retaining walls
Block Retaining Walls
Gabion Retaining Walls
The materials you choose for your retaining wall
In Australia, retaining walls are constructed from a variety of materials, depending on the budget, design preference, soil type, and whether the wall serves structural or purely decorative purposes.ย
Below are some commonly used materials for retaining walls:
- Concrete Sleepers (prices start from $32.00 per sleeper)
- Timber Sleepers (prices start from $20.00 per sleeper)
- Concrete Besser Blocks (prices start from $12.00 per 400 x 200 x 215mm block )
- Gabion Walls (prices start from $165 per 1m length by 500mm width and 800mm height)
- Composite Sleepers (prices start from $40.00 $60.00 per sleeper)
Pros & Cons
Future maintenance costs and longevity of your wall
One of the most important factors to consider when choosing the material type for your retaining wall is the ongoing maintenance cost and the longevity of the wall itself.ย
For example, consider timber as the preferred material choice for your retaining wall. In that case, it’s best to opt for treated timber, such as H4 timber, because it will offer slightly better resistance to rot and damage compared to regular unseasoned timber sleepers. However, even a treated wood like H4 won’t last as long as a concrete sleeper retaining wall, which is significantly more durable and can have a lifespan of 50 years or more.
Retaining Wall Drainage Considerations
A retaining wall with good drainage and backfill will last far longer than one without it. If you skip this step, rainwater can build up behind the wall and cause it to decay quicker over time. After a heavy rainfall, the water puts so much pressure on the wall that it may eventually collapse.
For drainage, you will need a full-length agi pipe to drain out the water, drainage gravel and also screenings to cover the Agi pipe with geofabric to wrap the screenings protect your drainage. You will also need FortiCon (builders plastic) to over the back of the wall and run it under the drainage.
Council Regulations for Retaining Walls
Each state and territory in Australia has its own rules and regulations regarding the construction of retaining walls and whether council approvals are required. The general rule of thumb is that if the wall is 1m or taller, you will need the services of a structural engineer to design the wall (and possibly further expenses like soil testing and underground services locating), or if the proposed retaining wall is going to be built near boundaries where there is a possible risk of damage to the adjoining property.
Removal of existing Retaining Walls
If your job requires the removal of an existing retaining wall, a few factors come into play. Firstly, will the retaining wall contractor be responsible for removing the existing retaining wall, or will you remove the wall and clear the site for the retaining wall contractor to build the new one?
If the retaining wall contractor is going to be quoting on removing the existing retaining wall, they need to know;
- What is the existing retaining wall made from (Timber, Concrete, etc)?
- Will the retaining wall contractor have to dig out any existing posts set in concrete?
- What is the access like to the retaining wall? Can you get an excavator in?ย ย
- Does the retaining wall have any complex drainage behind it?
- Does removing the wall need neighbours’ approval and access to their property?ย
- The removal of soilย
- The removal of any existing fencing (if applicable)ย
You can save a few thousand dollars if you choose to remove the existing wall yourself, but you will still need to factor in the costs of hiring a trailer to remove the existing wall (if you don’t own one), skip bin hire, dumping fees, transportation costs, and your time and effort.
A retaining wall contractor can charge anywhere between $2,000.00 and $4,000.00 for the complete removal of an existing 10-15m wall (again, many factors are involved, and each job is typically unique).
Calculating your retaining wall area
Before obtaining quotes for a new retaining wall installation, you will first need to calculate the total area of the retaining wall. We’ll use an example of a wall that’s 20 meters long and 600mm tall.ย
Step 1. Convert the units into the exact measurement
- Length: 20 metres
- Height: 600mm = 0.6 metres
Step 2. Multiply the length and heightย
- 20m (length) ร 0.6m (height) = 12mยฒ
Your total retaining wall area will be 12 square metres (mยฒ).
Calculating the materials needed for your retaining wall
- Wall area (mยฒ)
Area = Length (m) ร Height (m)
20 ร 0.6 = 12 mยฒ - Sleepers required using standard 2.0 m ร 0.2 m sleepers (2000mm x 200mm)
- Sleepers per bay = Wall Height รท Sleeper height โ 0.6 รท 0.2 = 3 bay
- Number of bays = Wall Length รท Sleeper length โ 20 รท 2.0 = 10
- Total sleepers = Number of Bays ร Quantity of sleepers per bay = 10 ร 3 = 30
- Steel posts (H/C posts / general rule-of-thumb, non-engineered)
- Number of steel posts = Number of bays + 1 โ 10 + 1 = 11
- Post length โ Wall height x 2 โ 0.6 x 2 โ 1.20m
- Concrete for posts (general rule-of-thumb, non-engineered)
- Hole for post depth โ Wall height + 0.10m โ 0.6 + 0,1 โ 0.7m
- Volume per hole, considering a hole ร of 350 mm โ ฯ ร radยฒ ร depth โย ฯ ร 0.17.5ยฒ ร 0.7m = 0.0673mยณ
- Total concrete = Volume per hole ร number of posts โ 0.0673mยณ x 11 โ 0.74mยณ (โ ยพ cubic meter)
- Qty of concrete bags = 1 Bag of 20kg of Rapid Set Concreteย makes 0.01mยณ โ Total Concrete รท bag capacity โ 0.74mยณ รท 0.01mยณ โ 74 bags
- Drainage & backfill (general rule-of-thumb, non-engineered)
- Agg pipe length โ wall length (e.g., 20 m) + length to drainage outlet.
- Geofabric area โ wall face area (12 mยฒ).
- Scoria volume (estimate): Wall Length ร Wall Height ร Backfill thickness (usually 300mm) โ 20 ร 0.6 ร 0.3 โ 3.6mยณ
- Permits & engineering (Victoria)
- If the wall is โฅ1.0 m or carries a surcharge (e.g., fence, driveway, building), obtain an engineering and building permit.
- Under 1.0 m with no surcharge: Typically, no permit is required, but please check with your local council.
Total Materials Estimate
The total cost of the materials in the example below is provided by Sunset Sleepers, using Concrete Sleepers as your preferred material for the retaining wall, and the price is effective as of February, 2026. Prices may have changed at the time of reading, so please visit our Shop section for the latest pricing on retaining wall materials.
Pitfalls to watch out for when building a new retaining wall
There are some issues you may encounter when deciding to build your new retaining wall and weโll cover a few below that some of our customers have experienced.
Neighbouring Property Issues
If your new retaining wall is neighbouring your neighbours property and your neighbour isnโt too happy with signing Form 7: Protection Work Notice and Form 8: Protection Work Response Notice because you could potentially be touching their land and putting some liability on them, then you may need to move the retaining wall inward to your own property so that itโs not damaging their land.ย
Real examples of retaining wall quotes
We engaged one of our experienced retaining wall installers to provide real-world examples of completed retaining wall projects including quotes. Below are selected projects offering insight into the typical inclusions and cost considerations involved in a retaining wall quote.
