A homeowner’s guide to building consents for renovation projects

Before you start knocking down walls or building that new deck, there’s one thing you need to know: Does this project require building consent? It’s not the most exciting part of a renovation, but it’s one of the most important!

The tricky part is that some projects clearly need consent, some clearly don’t, and others sit somewhere in between. In this guide, we’ll break down the rules and walk through the most common home upgrades, so you can move forward with clarity and confidence.

Table of Contents

• What is Building Consent?
• Building Consent Rules for Common Renovation Projects
  • Do You Need Building Consent for a Bathroom or Kitchen Renovation?
  • Do You Need Building Consent for a Deck?
  • Do You Need Building Consent for a Retaining Wall?
  • Do You Need Building Consent for a Fence?
  • Do You Need Building Consent for a Garage Conversion or New Garage?
  • Do You Need Building Consent for a Louvre Roof or Pergola?
  • Do You Need Building Consent for Artificial Grass or Landscaping?
• What Happens If You Don’t Get Building Consent?
• The Building Consent Process

A building consent is approval from your local council confirming that your planned work complies with the New Zealand Building Code. While your local council manages the process, the rules themselves are set nationally under the Building Act 2004.

Building consent forms part of a national system designed to ensure homes across New Zealand are built safely and to a consistent standard. Under the Building Act 2004, the law sets out:

• What counts as building work
• When consent is required
• How applications are assessed
• What inspections must occur

The technical standards sit within the New Zealand Building Code. The Code doesn’t tell you exactly how to build; it sets the performance standards your project must achieve.

Whether building consent is required for kitchen and bathroom renos depends on whether the work is classified as “building work”. Under Section 40 of the Building Act, building work must not be carried out without building consent unless it is exempt under Schedule 1.

Schedule 1, Part 1 allows exemption for general maintenance and like-for-like replacements. This typically includes:

• Replacing sanitary fixtures in the same position
• Installing new cabinetry or benchtops
• Replacing tiles or wall linings
• Regrouting or resurfacing

If you are not altering plumbing, drainage, or structure, building consent is generally not required.

Consent is required where the renovation involves work that must demonstrate compliance with the New Zealand Building Code, including:

• Adding or relocating toilets, showers, or sinks (Clause G12 – Plumbing and Drainage)
• Modifying drainage systems (Clauses G12 and E1 – Surface Water)
• Removing or altering load-bearing walls (Clause B1 – Structure)
• Creating new wet areas or altering floor levels affecting moisture control (Clause E3 – Internal Moisture)
• Converting a non-wet area into a bathroom, which may trigger change-of-use considerations under Section 115

If your project changes the layout, plumbing location, drainage, or structure, a building consent will be required before work begins

You generally won’t need building consent if:

• The deck is 1.5 metres high or lower.
• It’s not part of a larger structural alteration.
• It’s built to comply with the New Zealand Building Code.

This exemption covers most standard ground-level and low-elevation decks.

You generally will require a building consent if:

• The deck is more than 1.5 metres above ground level (Clause B1 – Structure).
• The deck supports a roof or forms part of a covered outdoor area (Clauses B1 – Structure and B2 – Durability).
• It ties into the structural bracing of the house (Clause B1 – Structure).
• There is a fall of more than 1 metre requiring safety barriers (Clause F4 – Safety from Falling).

It’s also worth noting that safety barriers are required where there’s a fall of more than 1 metre, regardless of whether building consent is required.

As a simple rule: if your deck is low and standalone, you’re usually fine. If it’s higher, covered, or structurally integrated with your home, you’ll need consent before you start.

• The wall is 1.5 metres high or lower.
• It’s holding back the garden soil only.
• There’s no driveway, building, or vehicle load above it.

• The wall retains more than 1.5 metres of ground (Clause B1 – Structure).
• The wall supports a surcharge load, even if it is under 1.5 metres (Clause B1 – Structure).
• The design requires engineered structural support or specific durability performance (Clauses B1 – Structure and B2 – Durability).

Once a retaining wall starts holding back significant height or weight, it moves firmly into consent territory. It’s far easier to confirm the requirements upfront than to fix a non-compliant wall later.

In most cases, you won’t need building consent for a standard residential fence. The key factor is height, and once you know the threshold, the rule is straightforward.

• The fence is 2.5 metres high or lower.
• It’s a typical standalone boundary or privacy fence.
• It’s not supporting another structure.

That covers the vast majority of timber boundary fencing around Kiwi homes.

• The fence is higher than 2.5 metres.
• It forms part of a larger building structure.

Standard fencing is usually straightforward. Once you start pushing height limits, consent comes into play. It’s also worth checking your local district plan for height or boundary restrictions; those are planning rules rather than building consent rules, but they still matter.

Garages are where building consent rules can shift quickly, especially if you’re changing how the space is used. There’s a big difference between building a simple detached garage and converting an existing garage into a living space.

If you’re converting a garage into a bedroom, office, or any habitable room, building consent is required. Why? Because you’re changing how the space is used. Under Section 115 of the Building Act 2004, a change of use must ensure the building complies, as nearly as reasonably practicable, with the Building Code for its new purpose.

• Convert the garage into a bedroom or living space (Section 115 – Change of Use).
• Add insulation to meet current standards (Clause H1 – Energy Efficiency).
• Install plumbing for a bathroom or kitchenette (Clause G12 – Plumbing and Drainage).
• Modify structural elements (Clause B1 – Structure).
• Alter fire separation requirements (Clause C – Fire Safety).

Once a garage becomes a habitable room, it must meet the same performance standards as the rest of the home. If the space is being used for sleeping or living, consent needs to be in place before work begins.

For new garages, size and plumbing are the deciding factors.

A detached, single-storey garage may be exempt from consent if it:

• Is no larger than 30 square metres.
• Does not contain sanitary plumbing.
• Meets boundary and height limits.
• Complies with the Building Code.

If the garage exceeds 30m², is attached to the house, includes plumbing, or involves structural complexity, building consent will be required (Clauses B1 – Structure and B2 – Durability).

Once a garage moves beyond simple standalone storage, it shifts into consent territory, and it’s best to confirm the requirements before construction starts.

Louvre roofs and pergolas sit in a grey area. The deciding factor isn’t what you call it, it’s how it’s built, its overall size, and whether it becomes part of the house.

• The structure is an open pergola (not fully roofed or enclosed) and under 30sqm in size.
• It does not significantly affect the structural integrity of the house.
• It complies with the Building Code.

Simple, standalone garden pergolas will often fall into this category.

• The structure is over 30sqm in size.
• The louvre roof system is attached to the dwelling and transfers structural loads (Clause B1 – Structure).
• The structure is fully roofed and creates a covered outdoor area (Clauses B1 – Structure and B2 – Durability).
• The design requires specific engineering for wind or structural loading (Clause B1 – Structure).
• The structure forms part of the building envelope and must manage weather tightness (Clause E2 – External Moisture).

Once a pergola becomes roofed and structurally integrated with the home, it moves into consent territory. It’s far easier to confirm requirements upfront than to retrofit compliance later so talk to your local authorities.

Artificial grass and basic landscaping are usually straightforward. In most cases, laying synthetic turf isn’t considered building work, but the structures underneath it can be.

• Installing small areas of artificial grass
• Minor ground preparation
• Basic paving
• General garden landscaping

If you’re not building structural elements or changing drainage, consent is typically not required.

• Constructing a retaining wall beyond the 1.5 metre threshold (Clause B1 – Structure).
  Carrying out significant earthworks that affect stability or drainage (Clause B1 – Structure).
  Installing drainage connected to stormwater systems (Clause E1 – Surface Water).
  Building structural platforms or decks (Clauses B1 – Structure and B2 – Durability).
  Installing large areas of artificial grass if the council deem it a non-permeable covering.

Once landscaping moves beyond surface-level work and starts altering structure, load, or drainage, it shifts into consent territory. It’s worth confirming the requirements before the ground is broken.
Similarly, some councils have differing views on artificial grass. Check with your local authority first.

If work is done without building consent when consent was required, it can cause issues later, often when you least expect it. Councils can issue a Notice to Fix, requiring the work to be inspected, altered, or formally approved through a Certificate of Acceptance. That process is usually more time-consuming and more expensive than getting consent sorted properly from the start.

Unconsented work can also complicate selling your home. Buyers and their lawyers often ask for consent documents and a Code Compliance Certificate (CCC). If they’re missing, it can delay settlement or affect the sale price.

If your project requires building consent, here’s what the process typically looks like from start to finish:

1. Confirm consent requirements: Before you begin, confirm whether your project requires building consent or falls under a Schedule 1 exemption. If there’s any uncertainty, it’s worth checking with your local council or getting professional advice early.
2. Prepare plans and supporting documentation: You’ll need drawings and specifications that show how the proposed work will comply with the New Zealand Building Code. For structural or more complex projects, this may include engineering calculations or documentation from a Licensed Building Practitioner (LBP).
3. Submit your application to the council: Your local council acts as the Building Consent Authority (BCA). Once your application is lodged and accepted as complete, it enters the formal assessment process.
4. Council assessment (up to 20 working days): By law, councils have 20 working days to process a complete application. If they request further information (often called an RFI), the processing clock pauses until that information is supplied.
5. Consent is issued: Once approved, you’ll receive your building consent documentation outlining approved plans and required inspections. Work can then begin.
6. Inspections during construction: Council inspections must be booked at key stages of the build, for example, foundations, framing, drainage, waterproofing, or final completion. Work must not proceed past certain stages without an inspection sign-off.
7. Code Compliance Certificate (CCC): After the final inspection is passed and all documentation is complete, the council issues a Code Compliance Certificate (CCC) confirming the work complies with the approved consent and the Building Code.

Handled properly, it’s a structured process designed to protect homeowners, not slow projects down.

Building consent doesn’t need to be complicated, but it does need to be handled properly. The key is understanding when consent is required, what the rules say, and getting clarity before work begins. If you’re planning an upgrade and aren’t completely sure where your project sits, it’s far easier to check early than to fix compliance issues later.

At The ProGroup, we work with these rules every day. We understand when consent applies and how to navigate the process properly when it does. If you’re unsure about your next project, get in touch. We’re happy to point you in the right direction before you (or we) pick up the tools.