Last Updated Sep 14, 2018 · Written by Craig Gibson
A retaining wall is defined as any structure built for the purpose of supporting soil that otherwise would not be self-supporting.
Because retaining walls have an impact on the surrounding environment and can be subject to collapse if not well-constructed, council approval is often required before you can build one. You may also need a professional to design and certify your plans.
Here's what you need to know about getting approval for your retaining wall, including:
When it comes time to choosing materials, there are a range suitable for building a retaining wall, including:
A concrete retaining wall can not only be built very quickly but it will be durable and extremely robust. This can be built using poured concrete or modular concrete besser blocks.
Here treated pine, hardwood or railway sleepers are commonly used, which all give an organic, rustic feel to your garden.
A gabion retaining wall uses a system of wire mesh "cages" that hold rocks or stones in place. You start with level reinforced concrete footings upon which the wall is built. The wire baskets are held together with steel wiring.
A number of factors will influence the cost of your retaining wall, specifically:
Small retaining walls could be built for under a thousand dollars and escalate to as much as ten thousand dollars. A low cost retaining wall can be built with untreated pine, but will have a limited lifespan and structural integrity. For superior longevity opt for treated hardwood, concrete, brick or stone. These options will cost more.
Also expect to pay more for retaining walls that require council approval and structural diagrams, all additional costs which you will be liable for. Other considerations that will affect overall cost include excavation and drainage requirements for your site. Expect to be quoted based on materials and labour, with materials calculated on a per square metre basis.
Learn more: How much does a retaining wall cost?
Regulations vary from council to council, so it is best to check before you start your project.
Generally speaking if the height of your retaining wall approaches 1 metre, you will need a structural engineer to design your project. The height of a retaining wall isn't the only consideration. Where you are building it could also be crucial. If it is on or near a building or the boundary of your property, you may need to get council permission regardless of its height. The reasoning behind this is simple: the higher your retaining wall the more safety becomes an issue.
Retaining walls can be erected without Council approval, as a Complying Development, if it meets certain criteria:
The key is to check with your local council before you commence building your retaining wall.
If council approval is required, it is because a retaining wall may pose a danger to people or the environment unless it is properly constructed.
The only way to ensure that it does not is to have the wall designed and approved by professionals. In some areas, you will need to engage the services of a structural engineer. In other parts of Australia, you may need to go through the same procedure you go through for a home renovation. In this case, you will need to:
If you think your retaining wall may need council approval, it is probably a job best left to the experts.
Building a gabion retaining wall is a job best left to a professional. Most states require retaining wall builders to be licensed. Depending on where you live this could be a builder, landscaper, bricklayer or stonemason. As mentioned, you may also need to consult a structural engineer.
When it comes time to hiring a retaining wall builder, take time to make sure they are right for your job. Some questions to ask then include:
A free and easy way to find out how much your retaining wall will cost is to get quotes from local businesses where you live.
When filling out the form, be sure to include any details that can help the builders determine if council approval is needed as well as details about the size and height of the wall. Also include information about the type of material you want your wall to be built from.
You can also browse our retaining wall photo gallery to get visual inspiration and design ideas for your project.