Frequently Asked Questions
Our Frequently Asked Questions page provides clear explanations about retaining wall design, engineering requirements and common site conditions in Queensland. Because of this, homeowners and builders can understand the key steps before work begins. In addition, the page outlines when approvals are required for different wall heights and construction methods. Each answer is written in simple language, which makes the process easier to follow.
For example, we describe typical soil issues, drainage requirements and the site assessments engineers usually complete. Moreover, we explain how engineering drawings support safe and compliant retaining wall construction. The information also highlights important factors that influence cost, timelines and overall project planning. As a result, you can quickly identify which details may apply to your specific property.
Therefore, you can prepare for your retaining wall project with greater confidence. In the same way, the guidance helps you communicate more clearly with contractors and engineers. Consequently, you can avoid delays, prevent approval issues and reduce the risk of unexpected changes. Ultimately, this page is designed to guide you through each stage with clarity. However, if you need additional support, our team can provide tailored advice based on your site, goals and retaining wall requirements.
Retaining Wall Engineers – Frequently Asked Questions
When does a retaining wall need building approval in Queensland?
Building approval is required when the retaining wall (including retained soil) is over 1 metre, supports a surcharge load (driveway, building, structure), sits within 1.5 m of another wall/building, or forms part of a pool barrier.
If unsure, Retaining Wall Engineers can confirm approval requirements for your site.
Do I always need council approval to build a retaining wall in Queensland?
Not always. Walls under 1 metre with no surcharge load and that sit fully on your property may not need approval. If you’re unsure, our engineers can assess compliance quickly.
Do I ever need planning approval (not just building approval)?
Yes. Planning approval may apply if your property is affected by overlays like flood, landslide risk, waterways, coastal hazard, or environmental protection zones.
What standards or codes must retaining walls comply with in Queensland?
All walls must meet Queensland Development Code (QDC) requirements and engineering standards for structural integrity, drainage, and setbacks.
Retaining Wall Engineers design to full QDC compliance.
Who must design, build, or certify a retaining wall?
Any regulated retaining wall (over 1 m or carrying load) requires:
• A structural engineer for design,
• A QBCC-licensed builder for construction,
• A building certifier for approvals.
What documents are required for retaining wall approval?
Approval typically requires:
• Engineering drawings,
• Soil/geotechnical report,
• Survey or site plan,
• Drainage design,
• Structural calculations.
Are there boundary or setback rules for retaining walls in Queensland?
Yes. Walls must sit fully on your property. Setbacks may apply near boundaries, easements, or unstable soil areas depending on wall height and site conditions.
Does my retaining wall need drainage?
Yes. Proper drainage (agg pipe, gravel backfill, weep holes) is essential to prevent water pressure buildup and avoid damage or failure.
If my retaining wall is under 1m, can I build without any approvals?
Only if:
• It is under 1 metre,
• No surcharge load exists,
• It is not near other structures,
• It is not part of a pool area,
• Proper drainage is installed.
What happens if I build a retaining wall without the required approval?
You may face:
• Council enforcement,
• Orders to modify or demolish the wall,
• Liability for neighbour disputes,
• Higher repair or reconstruction costs later.
How much does a retaining wall engineer cost in Queensland?
Engineering fees vary based on wall height, materials, and soil conditions. Retaining Wall Engineers provide fixed-price quotes for most residential retaining walls.
Do you design concrete sleeper retaining walls?
Yes. We specialise in concrete sleeper retaining wall engineering, including design, certification, and drainage requirements for Brisbane and South East Queensland sites.
Can you assess or certify an existing retaining wall?
Yes. We provide structural inspections, reports, and remediation recommendations for failing or non-compliant walls.
What is a surcharge load on a retaining wall?
A surcharge load is any extra weight above or behind the wall—such as a driveway, slab, pool, or building. Walls with surcharge loads always require engineering design.
Do you work with builders, contractors, and landscapers?
Yes. We regularly provide engineering plans for builders, landscapers, concreters, and retaining wall contractors across Queensland.
How long does retaining wall engineering take?
Most residential retaining wall designs are completed within 3–5 business days once all site information is provided.
Are timber retaining walls still compliant in Queensland?
Yes—if engineered and built to QDC standards. We design timber, block, sleeper, and masonry retaining walls based on site and soil conditions.
Do you provide retaining wall designs for sloping or difficult sites?
Yes. We specialise in sloped sites, cut-and-fill sites, narrow boundaries, and properties with soil instability.
Can you design retaining walls over 1 metre or multi-tiered walls?
Yes. We provide engineering for walls over 1m, tiered retaining systems, and complex load-bearing structures.
Do you service all areas of Brisbane and South East Queensland?
Yes. Retaining Wall Engineers provides retaining wall engineering across Brisbane, Gold Coast, Sunshine Coast, Ipswich, Logan, Moreton Bay, Redlands, and wider South East Queensland.
Our residential retaining wall design and engineering services help Queensland homeowners understand the process so they can build safely and confidently.