Retaining walls are essential for many Gold Coast properties, especially with our region’s mix of sloping blocks, unstable soils, and heavy summer rains. Whether you’re building a wall to hold back soil, prevent erosion, or level out your yard for landscaping, your retaining wall should be built right. Unfortunately, too many walls fail early because of avoidable mistakes made during the construction process. And let’s be real, fixing or rebuilding a wall isn’t cheap. Whether you’re planning a DIY project or bringing in a contractor, this guide breaks down the most common mistakes when building a retaining wall, so you can steer clear of them and ensure a safer, longer-lasting structure.
Mistake #1: Poor Drainage Design
When it comes to retaining walls, water is the biggest threat to stability. Without proper drainage, water builds up behind the wall, creating hydrostatic pressure. Over time, this pressure can cause the wall to bulge, lean, or collapse which is a costly mistake that’s often avoidable with the right setup. This problem is rampant on the Gold Coast due to the heavy rains and sudden storms that can overwhelm a poorly drained wall.
How to avoid this:
- Install a perforated ag pipe at the base of the wall to redirect water away from the structure.
- Use coarse gravel or scoria as backfill behind the wall. These materials allow water to flow freely toward the drainage pipe.
- For taller walls, consider adding weeping holes or additional drainage features to relieve pressure buildup.
Failing to manage water flow risks your retaining wall and can also affect nearby landscaping, foundations, or other structures. A well-designed drainage system is essential for protecting your investment and maintaining the integrity of your property.
Mistake #2: No Engineering for Taller or Load-Bearing Walls
Retaining walls over 1 metre in height or those carrying extra loads like driveways or other built structures often require engineering approval. Without proper structural design, these walls are at risk of failure, which could lead to safety hazards, expensive repairs, or even legal action. On the Gold Coast, engineering requirements are guided by the local council regulations. Ignoring these rules might save time upfront, but you risk compliance issues, fines, or the need to rebuild the entire structure if it’s non-compliant.
To avoid this, you should always seek engineering specifications if you’re planning to build a wall that’s over 1 metre in height. You should also check with the Gold Coast City Council for any specific requirements regarding boundaries, setbacks, and load-bearing capacity. Working with an experienced retaining wall contractor on the Gold Coast who can manage the design and approval process will help keep the project completed smoothly and with minimal hassles.
Mistake #3: Using the Wrong Materials for the Site
Choosing the wrong material for your retaining wall can significantly shorten your wall’s lifespan. Material selection should be highly considered, especially on the Gold Coast where coastal humidity, heavy rains, and reactive soils can be tough on certain materials. For example, untreated timber or recycled sleepers might be a budget-friendly option, but they are prone to rot and warping, or failing early when subjected to moist environments. This means more maintenance, faster deterioration, and potentially needing a full rebuild earlier than expected.
To avoid this, choose materials that are designed to handle moisture, pressure, and local conditions. Concrete sleepers with galvanised steel posts are the gold standard for long-term durability. If you’re planning to build a retaining wall that’s higher than 1 metre, concrete is the go-to choice. For walls under 1 metre, you can still use H4-treated timber sleepers. These are budget-friendly, but will require more ongoing maintenance and overall a shorter expected lifespan.
Whatever you choose, always make sure that the materials you choose are rated for outdoor, in-ground use and suited to your specific soil type and weather conditions.
Mistake #4: Inadequate Footings or Post Embedment
If the posts aren’t properly embedded or the footings aren’t deep enough, your wall is at risk of tilting, sagging, or even collapsing. Shallow post installation or weak foundations won’t hold the wall in place, leaving it vulnerable to movement over time. Footing depth, drainage, and material placement all play a role in proper retaining wall installation, ensuring the structure stays secure and compliant from the ground up. To avoid issues with stability, follow the basic rule of thumb: half of the post’s height should be buried underground and set in concrete. While it might seem tempting to cut corners and save time, going deeper and ensuring a solid base is essential for a wall that will stand the test of time. If you’re unsure, always err on the side of caution and dig a little deeper.
Mistake #5: Building Without Considering Site Conditions
Every property is unique, and failing to consider site conditions can lead to major issues down the line. Whether it’s the slope of the land, soil type, or how water naturally flows through the yard, building a retaining wall without factoring these elements in can cause problems like blocked drainage, unstable ground, or even shifting foundations. For example, placing a wall that blocks natural water runoff or building too close to other structures can put undue stress on the wall and the surrounding areas. Always do a proper site assessment before starting your design. An experienced local builder will consider everything from slope direction to surface water flow, ensuring the wall works with the landscape rather than against it.
Mistake #6: Ignoring Council Regulations
It’s easy to assume that building a retaining wall is a simple project, but failing to check council regulations can lead to serious complications. Certain walls may be considered exempt development on the Gold Coast, but walls over 1 metre in height, near boundaries, or supporting extra loads typically require council approval and engineering certification. Skipping this step might save you time upfront, but it can result in fines, forced removal, or even a legal battle down the road. To avoid this, always check with your local council or work with a contractor who understands the rules and can handle the approval process. A little research now can save you a lot of headaches later.
Mistake #7: Hiring an Inexperienced or Unlicensed Contractor
Choosing the wrong contractor can be one of the most costly mistakes you make when building a retaining wall. Not every contractor is experienced or equipped to handle the complexities of retaining wall construction. Walls built by inexperienced or unlicensed contractors often fail quickly due to poor workmanship or cutting corners. Watch out for red flags like no QBCC licence, vague quotes, no written contracts, or lack of references. Always ask for recent work examples, check online reviews, and make sure the contractor is properly licensed and insured by using the QBCC licence search tool.
Build It Right the First Time
A retaining wall is a long-term investment in your property, and getting it right from the start is key to its success. By avoiding these common mistakes, you’ll ensure your wall will look great, function properly, and stand the test of time. Factors like material choice, site conditions, and regular maintenance all play a role in how long a retaining wall lasts. A well-built retaining wall adds value, stability, and beauty to your yard, so it’s worth taking the time to get it done properly.
If you’re thinking about building a retaining wall on the Gold Coast, don’t leave it to chance. Get in touch with our team today for a properly built and compliant retaining wall! We’ll guide you through the design process, ensure your wall meets all local council requirements, and provide expert installation that lasts for decades to come.
