Building consent is one of the most misunderstood topics in the NZ trades. Homeowners think their tradie will sort it. Tradies assume the homeowner has checked. Councils wonder why nobody asked.
The result: work gets done without consent, it fails inspection, and somebody pays to have it ripped out and redone. That somebody is usually the tradie.
Here's what you actually need to know.
What Building Consent Is (and Why It Exists)
Building consent is written permission from your local council (Building Consent Authority, or BCA) to carry out specific building work. The process involves: 1. Submitting plans, specifications, and documentation 2. The council reviewing them against the New Zealand Building Code 3. Inspections during and after construction 4. A Code Compliance Certificate (CCC) once work is confirmed compliant
The Building Code is the standard everything must meet — regardless of whether consent is required. Even exempt work must comply with the Code. Consent is just the formal process for verifying that it does.
Work That ALWAYS Requires Building Consent
The Building Act 2004 defines work requiring consent broadly. In practice, it includes:
Structural work: - New buildings (except minor exempt structures) - Extensions or additions to existing buildings - Structural alterations (removing load-bearing walls, new openings) - Foundations and retaining walls over 1.5m high
Wet areas: - New bathroom, kitchen, or laundry plumbing installations - Relocating sanitary fixtures (toilets, showers, sinks) - New hot water cylinder installation (in most cases)
Electrical: - New switchboard installation - New electrical circuits - Fixed wiring installations (note: electrical work also requires a licensed electrician and Certificate of Compliance under separate regulations)
Other: - Decks more than 1.5m above ground - Swimming pools and spa pools (plus fencing requirements under the Fencing of Swimming Pools Act) - Sheds and outbuildings over 30m² (in most cases — see exempt work below) - Garages attached to a dwelling - Fireplaces and solid fuel heaters - Heat pumps in some councils (check locally)
Exempt Work — What Doesn't Need Consent
Schedule 1 of the Building Act lists exempt building work. Common exemptions include:
- Maintenance and repair that doesn't change the building's original design
- Garden sheds up to 10m² (single-storey, not habitable, not near boundaries)
- Driveways, paths, and fencing (with height limits)
- Painting, plastering, tiling (not structural)
- Interior fit-out that doesn't affect structure, fire safety, or weathertightness
- Replacing existing fixtures with like-for-like (same location, same function)
Critical point: Exempt from consent ≠ exempt from Building Code compliance. A garden shed still needs to be structurally sound and weathertight. You just don't need council permission to build it.
The Building Performance website has a full Schedule 1 list and guidance documents for each exemption category.
The Grey Zone: Work That's Hard to Call
Some work sits in between — technically exempt under one interpretation but potentially requiring consent under another. Common grey zones:
- Pergolas and carports — exempt if open-sided, may need consent if enclosed
- Sleepouts and minor dwellings — almost always need consent unless genuinely minor
- Bathroom renovations — like-for-like replacement is usually exempt; moving fixtures usually isn't
- Insulation — generally exempt; spray foam in cavities can raise weathertightness questions
When in doubt, call your local council's duty planner or BCA. A quick call costs nothing. Doing work that turns out to need consent and getting caught costs a lot.
Licensed Building Practitioners and Restricted Building Work
Some building work is classified as Restricted Building Work (RBW) — meaning it can only be carried out or supervised by a Licensed Building Practitioner (LBP).
RBW includes: - Structural work - External weathertightness (cladding, roofing, windows, exterior doors) - Certain fire safety work - Design of the above
If you're an LBP, you must provide a Record of Building Work to the homeowner and council at completion. This certifies that the work was carried out under your licence.
Doing RBW without an LBP, or allowing a non-licensed person to do RBW on your job, is an offence with fines up to $20,000.
Check LBP status at lbp.govt.nz.
How Building Consent Works in Practice
If consent is required, the typical process:
- Application — submit plans, specs, and documentation to your council
- Processing — councils have 20 working days once they have all information
- Grant — consent is issued (or declined with reasons)
- Inspections — you request inspections at specified stages (foundations, framing, pre-line, post-line, etc.)
- Code Compliance Certificate — issued when all inspections pass and documentation is complete
Costs vary by council and project complexity. Expect $500–$2,000+ for residential consents, more for complex projects.
Timeline: budget 4–8 weeks minimum from application to consent grant. More for complex or non-standard work.
What Happens If You Skip Consent
Building work done without required consent is illegal. Consequences include:
- Council can issue a notice to fix requiring compliance
- Work may need to be opened up for inspection (or demolished if the issue can't be resolved)
- A certificate of acceptance may be available (retrospective) but isn't guaranteed and is more expensive
- Property resale problems — LIM reports show unconsented work, affecting value and buyer confidence
- Insurance voidance — some policies don't cover damage from unconsented work
- Personal liability as the LBP or contractor if the work later causes harm
Key Takeaways
- Consent is required for most structural, plumbing, and electrical work — when in doubt, ask your council
- Exempt work still must comply with the Building Code
- Restricted Building Work can only be done by an LBP
- Budget 4–8 weeks for consent processing in most councils
- Skipping consent creates legal, insurance, and resale issues — not worth the risk
See our full guide on Getting Your LBP Licence in NZ if you're working towards restricted building work qualification.
NZ Tradie Tools provides free calculators, templates, and guides for New Zealand tradies. Building consent requirements vary by council and project — always confirm with your local BCA before proceeding.