When hiring a retaining wall builder in New Zealand, checking their insurance cover is just as important as checking their workmanship. Retaining walls can involve significant earthworks, structural risk, and potential liability if something goes wrong — so the right insurance protects both you and the tradesperson. Here's what to look for before signing any contract.
Why Insurance Matters for Retaining Wall Work
Retaining walls are structural elements that hold back soil and manage water pressure. A failure can cause serious property damage, injury, or even threaten neighbouring properties. In New Zealand, retaining walls over 1.5 metres in height (or those retaining a surcharge such as a driveway or building) typically require a building consent — and with that comes greater accountability. Even for exempt walls, the financial and legal consequences of a collapse can be severe.
For this reason, any professional retaining wall builder should carry adequate insurance before they set foot on your site.
Key Types of Insurance to Ask About
1. Public Liability Insurance
Public liability insurance is the most essential cover for any tradesperson working on your property. It covers third-party bodily injury and property damage caused by the builder's work or negligence. For example, if excavation damages a neighbouring fence, underground services, or causes a slip onto an adjoining property, public liability insurance should respond.
As a guide, most reputable NZ builders carry a minimum of $1 million to $2 million in public liability cover, though larger or more complex projects may warrant higher limits. Always ask to see a current certificate of currency — a one-page document from the insurer confirming the policy is active.
2. Professional Indemnity Insurance
If your retaining wall builder also provides design advice, engineering input, or project management services, professional indemnity (PI) insurance becomes relevant. PI insurance covers claims arising from errors, omissions, or negligent advice in a professional capacity.
Note that structural retaining wall design in New Zealand often requires input from a chartered structural engineer, and certain restricted building work on consented walls must be carried out or supervised by a licensed building practitioner (LBP). If your builder is providing design services, confirm they hold appropriate PI cover. You can verify LBP status at Licensed Building Practitioners.
3. Statutory Liability Insurance
Statutory liability insurance covers fines and legal costs arising from unintentional breaches of New Zealand statutes — such as the Building Act, Resource Management Act, or Health and Safety at Work Act. Given that retaining wall work can intersect with resource consent requirements and WorkSafe NZ obligations around excavation safety, this cover is a sensible addition to any builder's policy.
4. Employers Liability Insurance
If the builder employs staff or subcontractors on your site, employers liability insurance covers claims from workers injured during the job that fall outside ACC cover. While ACC handles most workplace injury claims in NZ, gaps can exist — particularly for self-employed contractors.
5. Contract Works Insurance (Material Damage)
Contract works insurance (sometimes called construction all-risk insurance) covers the physical work in progress against damage from events like fire, storm, flood, or accidental damage during construction. This is especially relevant for retaining wall projects that may take several weeks and involve exposed excavations.
Clarify with your builder whether they carry contract works cover, or whether you need to notify your own home insurer that construction is underway — some home policies require this.
A Quick Checklist: What to Ask Your Builder
| Insurance Type | Why It Matters | What to Request |
|---|---|---|
| Public Liability | Covers damage to your property or neighbours | Certificate of currency, minimum $1–2M cover |
| Professional Indemnity | Covers design/advice errors | Relevant if builder provides design services |
| Statutory Liability | Covers unintentional legal breaches | Confirm it's included in their policy |
| Employers Liability | Covers workers beyond ACC | Ask if they employ staff or subbies |
| Contract Works | Covers work in progress | Confirm who holds this cover |
NZ Building Code and Consent Considerations
Under the NZ Building Code, retaining walls that exceed certain height thresholds or support a surcharge require a building consent from your local council. MBIE Building Performance provides guidance on when consent is required and what Schedule 1 exemptions may apply — but always confirm with your council, as requirements can vary by district.
A builder working on consented retaining wall work may need to be a Licensed Building Practitioner for certain restricted building work. Check LBP licensing to verify credentials. BRANZ also publishes useful technical guidance on retaining wall construction standards.
When to Call a Professional
Always engage a qualified, insured retaining wall builder for:
- Walls over 1 metre in height, or any wall requiring building consent
- Sites with poor ground conditions, high water tables, or steep slopes
- Walls adjacent to boundaries, buildings, or public land
- Any project where failure could affect neighbouring properties
Ask for proof of insurance before work begins — not after. A reputable builder will have no hesitation providing documentation. If a builder can't or won't show you a current certificate of currency, that's a red flag.
You can find qualified, insured retaining wall builders in your area through tradedirectory.co.nz.
Licensed Building Practitioner (LBP)
