Search for retaining wall builders, contractors, installers or specialists and you will find everyone from landscapers to civil contractors. The difference between a good one and a bad one usually shows up a few winters later, when a cheap wall starts to lean. Here is what to check before you choose.
1. The right licence
In NSW, residential building work over $5,000 (including GST) must be done by someone with the right contractor licence, and work over $20,000 generally needs home building compensation (HBCF) insurance. Check the licence on the NSW Government licence check and make sure it covers the work.
2. Insurance
Ask for public liability and workers compensation certificates. Retaining walls involve excavation next to boundaries, buildings and services, so this matters.
3. Drainage in the quote
Drainage is the number one cause of retaining wall failure. A proper quote should list ag pipe, aggregate backfill, geotextile and where the water will discharge. If drainage is missing or vague, ask why. Our guide to retaining wall drainage explains what to look for.
4. Engineering where needed
Walls over about a metre, on boundaries, or supporting driveways, pools or buildings should be designed by an engineer. A good contractor will tell you when engineering is needed rather than avoiding it to win the job.
5. Approvals handled
Many walls need a CDC or DA. Ask whether the contractor checks council controls and prepares the paperwork, and who is responsible if a wall is built without approval.
6. An itemised quote
- Excavation and spoil removal.
- Footings, post sizes and depths.
- Wall materials and finish.
- Drainage and backfill.
- Engineering and approval fees.
- Site clean-up and any exclusions.
7. The right wall for your site
A good retaining wall specialist recommends the wall that suits your soil, slope and budget, whether that is concrete sleeper, sandstone, gabion, timber or reinforced block.
Questions to ask
- Will you visit the site before quoting?
- What drainage are you including and where does it discharge?
- Does this wall need engineering or approval?
- What size and depth are the posts or footings?
- What warranty applies?
Talk to licensed retaining wall builders
See our retaining wall services or book a free site assessment.
Frequently asked questions
Do I need a licensed builder for a retaining wall in NSW?
For residential building work over $5,000 including GST, the contractor must hold the appropriate NSW licence. Always check the licence before signing.
Should a retaining wall contractor visit the site before quoting?
Yes. Slope, soil, access, drainage and services all affect the design and price. A quote without a site visit is a guess.
What should a retaining wall quote include?
Excavation, footings, wall materials, drainage, backfill, engineering, approvals, clean-up and any exclusions, listed separately.
