Retaining Wall Guidelines for Victoria

As a general guide in Victoria:

• A building permit is generally required for retaining walls 1 metre or more in height.
• Retaining walls less than 1 metre high may not require a building permit where they are not associated with other building work or the protection of adjoining property.
• A retaining wall on or near a property boundary may require a building permit regardless of its height where the work could affect the stability of adjoining property.
• A planning permit may also be required depending on the property, planning controls and local council requirements.

Always check with your local council or a registered building surveyor before commencing work.

Retaining walls should be designed to suit the specific site conditions. Factors that may affect the design include:

• Overall retained soil height
• Soil type and ground conditions
• Post spacing
• Post size and section
• Footing diameter and depth
• Concrete strength
• Drainage conditions
• Groundwater
• Sloping ground
• Driveways or vehicle loads behind the wall
• Buildings, sheds, pools or other structures nearby
• Fences installed above the retaining wall
• Other surcharge loads

For higher walls, boundary walls, walls supporting significant loads or other complex installations, appropriate engineering advice should be obtained.

The correct post size, post spacing, footing diameter and footing depth should be selected according to the wall design and site conditions.

• Simply increasing the size of the steel post does not necessarily make a retaining wall suitable for a particular height.
• The posts, footings, sleepers, soil conditions and loads all work together as part of the retaining wall system.

Correct drainage is an important part of retaining wall construction. Water should not be allowed to build up behind the retaining wall. A typical drainage system may include:

• Agricultural drainage pipe
• Free-draining aggregate
• Geotextile or filter fabric
• Suitable backfill material
• A suitable legal discharge point

Poor drainage can increase pressure behind a retaining wall and may contribute to movement or failure.

Concrete sleepers should be suitable for retaining wall applications and installed in accordance with the applicable design and engineering requirements.

• The required sleeper thickness, strength and reinforcement will depend on factors including wall height, post spacing and loads behind the wall.

Extra care should be taken when constructing retaining walls close to property boundaries.

• Excavation, filling or construction work must not adversely affect the stability of neighbouring land or structures.
• Building permits, engineering and protection work requirements may apply depending on the circumstances.