Dividing fences, retaining walls and trees are amongst the most common sources of dispute between neighbours. The responsibilities of each neighbour in relation to dividing fences and trees are clearly set out in the Neighbourhood Disputes (Dividing Fences and Trees) Act 2011 (Qld). However, the rules surrounding retaining walls are less clear, as they are not covered by this Act and are instead governed by a combination of common law principles, building regulations and local council requirements.
Understanding Property Boundaries in Queensland
Retaining walls are an important part of many construction projects, whether for erosion control, landscaping, or creating usable outdoor spaces on sloping properties. The QBCC, building certifiers, and local councils regulate these structures to ensure they are safe and durable.
A retaining wall requires planning and compliance with state and local standards. This involves understanding the roles of the QBCC, building certifiers and local councils.
Who Pays For a Retaining Wall?
Sometimes, a retaining wall does not only benefit one property, but a neighbouring property as well. This commonly occurs when ground levels between neighbouring properties have been altered.
In general, responsibility for a retaining wall is linked to who altered the natural ground level and created the need for the wall. Where a retaining wall benefits both properties, neighbours may be reasonable for neighbours to agree to share costs based on how much each property benefits from the wall. Ongoing maintenance and any future repairs should also be considered as part of any cost-sharing arrangement. However, cost sharing is not automatic and usually requires agreement between both parties.
What Happens if a Retaining Wall Fails?
In most cases, the owner of the land where the retaining wall is located is responsible for its repair and maintenance. This is because property owners are generally required to ensure structures on their land remain safe and do not pose a risk to neighbouring properties. This applies where the wall sits fully within private property boundaries and supports that land.
In some situations, a neighbour may be liable for repair or replacement costs if their actions have contributed to the failure of the wall. For example, if they install drainage that directs water toward the wall, use heavy machinery close to the boundary, or carry out landscaping that destabilises the structure, they may be legally responsible for the resulting damage.
Shared Responsibility vs Sole Responsibility
If a retaining wall is built along a shared boundary or provides lateral support, responsibility can become shared. In these cases, collaboration between neighbours must collaborate to resolve issues fairly. When a retaining wall collapses and causes damage or removes support from adjacent land, liability may extend beyond just the owner of the land where the wall is located.
In these situations, it is important to:
- Confirm ownership of the wall through property documents or a professional boundary assessment
- Understand the wall’s structural role, including whether it provides lateral support or erosion control
- Consult local council requirements, particularly if the wall presents a safety risk or requires urgent action
Ongoing responsibilities for property owners
To ensure a retaining wall remains safe and structurally sound, property owners are expected to take reasonable steps to maintain their retaining walls. This includes:
- Inspecting the wall regularly for signs of movement, cracking or erosion
- Repairing damage promptly to prevent further issues
- Ensuring appropriate drainage behind the wall to reduce pressure from water build-up
