Retaining Walls: When is building approval required?

Retaining walls are a crucial aspect of many construction projects, providing the necessary support and stability to protect your property and surrounding structures. Whether you’re looking to build on a hillside or level out an excavated area, a retaining wall is an easy and effective solution. But what exactly is a retaining wall and when is it necessary?

In this article, we’ll delve into the basics of retaining walls, what they are, the different materials they can be made from, and the important considerations that go into designing and building a retaining wall, including building approvals. By the end, you’ll better understand how retaining walls can be an important solution for your property, and what you should consider before beginning your own retaining wall project.

What is a retaining wall?

A retaining wall is a structure that holds back soil or supports excavations when the natural ground level has been altered. Retaining walls are needed to prevent soil movement or protect nearby buildings and structures. They can be made of boulders, concrete sleepers, timber sleepers, or blockwork. The materials used should be chosen based on the specific site and local government requirements and must be designed by a qualified person such as a structural engineer. Drainage is essential to retaining wall design as it prevents water from getting trapped behind the wall.

When do you need approval?

When it comes to building a retaining wall on your property, it’s important to understand the specific regulations and requirements that apply in your area. Depending on where you live, different rules and standards may be in place regarding the construction of retaining walls.


For example, in Queensland, building approval is required for retaining walls that are taller than 1 meter or located within 1.5 meters of a building or another retaining wall, or if there is a surcharge loading present.

Surcharge loading

Surcharge loading refers to the weight or pressure that is applied to a retaining wall from sources other than the soil or earth that the wall is retaining. In the context of building regulations, surcharge loading is a factor that is taken into consideration when determining if a retaining wall requires building approval or not. The ‘zone of influence’ refers to the area around the wall that could be affected by the wall’s failure, so the absence of surcharge loading over the zone of influence means that the wall is not subjected to any additional forces other than the soil it retains, which makes it less likely to fail and thus it does not require building approval.

New South Wales 

In New South Wales, building approval is required for retaining walls that are taller than 600mm or located closer than 2 meters from another retaining wall, or closer than 1 meter to a lot boundary, or within 40 meters of a water body, or within 1 meter of a registered easement, sewer, or water main.

Additional local government planning requirements may apply to your property and affect the type of approval needed.

Get Professional Assistance with Building Approvals

Don’t navigate the complex world of building approvals alone. Trust certified to guide you through the process and ensure your project complies with all industry regulations.

Our team of accredited private building certifiers are available to assist you on the Gold CoastBrisbane and Sunshine Coast in Queensland.

Don’t wait to start your building approvals process. Contact us by calling 1300 899 078 or filling out our online enquiry form. We’ll be happy to discuss your needs and help you move forward with your project.