When excavation work goes wrong and a neighbour's property is damaged — whether it's a collapsed fence, cracked foundation, or disturbed landscaping — the question of who foots the bill can get complicated quickly. In most cases, the excavation contractor carries primary liability, but your own responsibilities as the property owner commissioning the work also come into play. Understanding how liability works in New Zealand can save you a great deal of stress and money.
How Liability Is Generally Determined
In New Zealand, liability for property damage caused during excavation typically hinges on a few key factors:
- Who engaged the contractor — as the homeowner commissioning the work, you have a duty of care to ensure the job is carried out safely and competently.
- Whether the contractor is licensed and insured — a reputable excavation contractor should hold public liability insurance and, where relevant, be a Licensed Building Practitioner.
- Whether proper consents were obtained — some excavation work requires a building consent under the NZ Building Code. Failing to get consent when required can shift liability toward you as the property owner.
- Whether the contractor followed safe work practices — under the Health and Safety at Work Act 2015, contractors have obligations to manage risks on site. WorkSafe NZ sets out these duties clearly.
Generally speaking, if a professional contractor caused the damage through negligence or poor workmanship, their public liability insurance should cover the cost of repairs to your neighbour's property. However, if you hired an uninsured or unlicensed operator, or if you directed the work in a way that caused the damage, you may find yourself personally liable.
Your Responsibilities as the Property Owner
Even though you're not operating the excavator yourself, commissioning excavation work comes with real responsibilities:
- Check your contractor's credentials before work begins. Ask for proof of public liability insurance (typically a minimum of $1 million cover, though many reputable contractors carry more) and confirm they have relevant experience.
- Obtain any required building consents from your local council before work starts. Excavation near boundaries, retaining walls, or foundations often triggers consent requirements under the NZ Building Code. Schedule 1 of the Building Act lists some exemptions, but always confirm with your council — don't assume.
- Notify your neighbour before work begins, especially if excavating near the boundary. This is good practice and can prevent disputes.
- Check for underground services — gas, water, electrical, and telecommunications lines must be located before any digging. Use a service locator and contact WorkSafe NZ guidelines on safe excavation practices.
What the Contractor Is Responsible For
A professional excavation contractor is responsible for:
- Carrying out work to an acceptable standard of care
- Holding adequate public liability insurance
- Complying with health and safety obligations on site
- Following the engineer's or designer's specifications
- Avoiding damage to neighbouring structures, services, and land
If the contractor's negligence directly caused the damage — for example, excavating too close to a boundary without adequate shoring, causing a neighbour's retaining wall to collapse — their insurer should respond to a claim. BRANZ provides useful guidance on best practice for excavation near existing structures.
What Happens If There's a Dispute?
If your contractor disputes liability or is uninsured, the situation becomes more difficult. Here's a general process to follow:
| Step | Action |
|---|---|
| 1 | Document all damage with photos and written descriptions immediately |
| 2 | Notify your contractor in writing and request their insurance details |
| 3 | Contact your own home and contents insurer — they may pursue the contractor on your behalf |
| 4 | Seek independent legal advice if the contractor refuses to engage |
| 5 | Consider the Disputes Tribunal for claims up to the current jurisdictional limit (confirm the current threshold at www.disputestribunal.govt.nz) |
Your neighbour may also have grounds to make a claim directly against your contractor, or against you if they believe you directed the work. Open communication with your neighbour throughout the process is strongly recommended.
The Role of Engineers and Designers
For significant excavation projects — particularly those near boundaries, on sloped sites, or involving deep cuts — a geotechnical or structural engineer may be required to design the works. If an engineer specified the method and the contractor followed those specifications correctly, liability for any resulting damage may shift toward the engineer. This is why it's important to keep all documentation, plans, and correspondence.
When to Call a Professional
Always engage a qualified, insured excavation contractor for any significant digging work near property boundaries. If excavation is required near foundations, retaining walls, or slopes, have a structural or geotechnical engineer assess the site first. For any work that may require a building consent, speak with your local council or a Licensed Building Practitioner before breaking ground.
If you're unsure whether your planned excavation requires consent, MBIE Building Performance has helpful guidance, but your local council is the definitive authority.
You can find qualified, local excavation contractors on tradedirectory.co.nz — always ask for proof of insurance and references before work begins.
Licensed Building Practitioner (LBP)
