Hiring the right retaining wall builder is one of the most important decisions you can make for your property. A poorly built retaining wall can fail catastrophically, causing damage to your home, neighbouring properties, and even posing a serious safety risk. Taking the time to thoroughly check a builder's previous work and references before signing anything will give you real confidence in your choice.
Why Checking References Matters for Retaining Walls
Retaining walls are structural elements — they hold back soil and manage water pressure. In New Zealand, walls over 1.5 metres high (or in some cases lower, depending on surcharge and soil conditions) typically require a building consent from your local council. Walls that fail can trigger landslips, damage foundations, and create legal liability. This means the quality and compliance of a builder's past work is not just about aesthetics — it's about safety and legal accountability.
Always confirm consent requirements with your local council before work begins. You can also check guidance from MBIE Building Performance on what triggers consent obligations.
Ask for a Portfolio of Completed Projects
Any reputable retaining wall builder should be able to show you a portfolio of completed jobs. Look for:
- Photos of finished walls — ideally before, during, and after construction
- A variety of wall types — timber, concrete block, concrete panel, stone, or gabion, depending on what you need
- Projects similar in scale and complexity to yours — a builder who has only done small garden walls may not be the right fit for a large engineered retaining structure
If possible, ask to visit a completed project in person. Seeing a wall up close lets you assess the quality of workmanship, drainage details, and how well it has held up over time.
Request and Actually Contact References
Don't just ask for references — use them. A good builder will happily provide contact details for past clients. When you speak with references, ask:
- Was the work completed on time and within budget?
- Did the builder obtain the necessary building consents?
- Were there any issues with drainage or wall movement after completion?
- How did the builder handle problems or unexpected site conditions?
- Would you hire them again?
Aim to speak with at least two or three past clients, ideally for projects completed more than a year ago so you can gauge how the wall has performed over time.
Check LBP Licensing and Council Records
In New Zealand, certain retaining wall work must be carried out or supervised by a Licensed Building Practitioner (LBP). Specifically, restricted building work (RBW) — which includes structural work — must involve an LBP. You can verify a builder's licence status on the Licensed Building Practitioners register.
You can also search your local council's building consent records to confirm that a builder's past projects were properly consented and received a code compliance certificate (CCC). A CCC confirms the work was inspected and met the NZ Building Code. If a builder's past jobs don't have CCCs, that's a significant red flag.
Look for Professional Memberships and Insurance
Check whether the builder belongs to a recognised trade body such as Registered Master Builders or Certified Builders. Membership doesn't guarantee quality, but it does mean the builder has agreed to a code of conduct and may offer additional warranties.
Also confirm the builder holds:
- Public liability insurance — covers damage to your property or neighbours during the build
- Contractors all-risk insurance — covers the work itself during construction
Always ask for proof of current insurance, not just a verbal assurance.
Red Flags to Watch For
Be cautious if a builder:
- Cannot provide references or is reluctant to share past project details
- Has no LBP licence for structural work
- Suggests skipping the building consent process to save time or money
- Offers a quote significantly lower than all others — this may indicate corners will be cut
- Has negative reviews or unresolved complaints on platforms like Google or Builderscrack
You can also check the Consumer NZ website for general advice on hiring tradespeople and resolving disputes.
Check Online Reviews and Industry Reputation
Search the builder's business name online and look for reviews across multiple platforms. A pattern of positive feedback about communication, quality, and compliance is a good sign. One or two negative reviews aren't necessarily a dealbreaker, but pay attention to how the builder responded — professionalism in handling complaints says a lot.
When to Call a Professional
If your retaining wall is over 1.5 metres high, is near a boundary, or is on a steep or unstable site, you will almost certainly need a geotechnical engineer or structural engineer involved in the design. This is separate from the builder — the engineer assesses soil conditions and designs the wall to meet NZ Building Code requirements. A good retaining wall builder will welcome this involvement rather than resist it.
For complex or high-risk sites, BRANZ provides technical guidance that both builders and homeowners can reference.
If you're ready to find a qualified retaining wall builder in your area, you can search for local professionals on tradedirectory.co.nz.
Licensed Building Practitioner (LBP)
