Building a Retaining Wall on a Boundary: Rules and Responsibilities

Retaining Walls on Property Boundaries in Victoria

Building a retaining wall on or near a property boundary introduces additional legal, regulatory, and neighbourly considerations that do not apply to walls entirely within your property. In Victoria, specific rules govern boundary retaining walls, and understanding them before you start is essential to avoiding disputes and compliance issues.

Who Is Responsible for a Boundary Retaining Wall?

The question of responsibility often depends on who benefits from the wall and what created the need for it:

• If the higher property owner has filled or raised their land, they are generally responsible for retaining that fill and preventing it from affecting the lower property
• If the lower property owner has excavated or lowered their land, they are generally responsible for supporting the higher ground
• If the level difference is natural and neither party has altered the ground, responsibility can be shared or may need to be determined through negotiation or legal advice

These principles are not always black and white, and disputes over boundary retaining walls are common. Early communication with your neighbour is always the best first step.

Council and Permit Requirements

Retaining walls on a boundary are subject to the same building permit requirements as any other retaining wall in Victoria. Walls over one metre require a building permit, and the Victorian Building Authority (VBA) sets the standards. However, boundary walls often attract additional scrutiny from local councils because:

• They may affect drainage patterns on adjoining land
• Failure could cause damage to the neighbouring property
• Construction may require access to the neighbouring property
• The wall may affect the neighbour’s use or enjoyment of their land

Neighbour Notification

Your building surveyor will typically require you to notify adjoining property owners before a permit is issued for a boundary wall. This notification gives neighbours the opportunity to review the plans and raise any concerns. While neighbours cannot prevent you from building a compliant wall on your own land, addressing their concerns early prevents disputes during and after construction.

Setback Requirements

Some councils have specific setback requirements for retaining walls near boundaries. A setback means the wall must be built a minimum distance from the boundary line, typically 150mm to 500mm. This setback allows for maintenance access and prevents the wall from encroaching on the neighbouring property. Check with your local council for specific setback requirements in your municipality.

The Fences Act and Retaining Walls

In Victoria, the Fences Act 1968 covers dividing fences between properties but does not specifically address retaining walls. A retaining wall is generally considered a structure rather than a fence, so the Fences Act provisions for cost-sharing do not automatically apply. However, if a fence is built on top of a retaining wall, the fence component may fall under the Fences Act while the retaining wall does not.

Common Boundary Wall Scenarios

New Build on a Sloped Block

When a new house is built on a sloped block, the builder typically needs to cut and fill the site. Any cut or fill near the boundary that creates a level difference requires a retaining wall. The builder of the new house is usually responsible for these walls as part of the construction project.

Neighbour Excavates Below Your Property

If your neighbour excavates their land and exposes the side of your property, they are generally responsible for providing lateral support. This may involve building a retaining wall to support your land. If they fail to do so, you may have legal grounds to require them to provide support.

Shared Retaining Walls

Some properties have existing retaining walls that sit directly on the boundary and benefit both properties. Maintenance and replacement responsibilities for shared walls should ideally be agreed in writing between both parties. If no agreement exists, mediation through the Dispute Settlement Centre of Victoria can help.

Practical Tips for Boundary Walls

• Talk to your neighbour early and share your plans before engaging a builder
• Get a survey to confirm the exact boundary location before construction
• Document the existing condition of your neighbour’s property with photos before work begins
• Use a licensed builder with insurance that covers work on or near boundaries
• Keep written records of all communications with your neighbour regarding the wall

We connect you with licensed retaining wall builders experienced in residential boundary wall projects across Melbourne. Find a licensed builder who understands the requirements for boundary retaining walls in your area.