Building Code Compliance for Alterations

When you own your home, it is tempting to think you can do whatever you like with it. In one sense, this is true; it is your property and your decisions. But New Zealand's building consent system exists for good reasons. It ensures that building work is safe, sanitary, and durable. Work that affects the structure of your home, its ability to keep water out, or its fire safety needs to be done correctly, and the consent process provides oversight to help ensure that happens.

The question most homeowners face is not whether the consent system matters, but whether their particular project requires consent. This is where things can get confusing, because the rules are not always intuitive.

When Is Building Consent Required?

Building work generally requires consent unless Schedule 1 or another statutory exemption applies. Exemptions have detailed limits and conditions, so check the proposed work against current MBIE guidance and confirm uncertain cases with the council.

• Structural alterations: Removing or modifying walls, changing roof lines, adding extensions.
• New plumbing and drainage: Adding bathrooms, relocating kitchens, changing drainage connections.
• Significant electrical work: While much electrical work is covered by electrical regulations, some triggers building consent.
• Adding bedrooms: New habitable rooms typically require consent.
• Decks and balconies: Those over one metre high require consent.
• Retaining walls: Those over 1.5 metres high or supporting buildings or infrastructure.
• Swimming pools: In-ground pools and many above-ground pools require consent.

Consent and inspection requirements vary with the work and relevant Building Code clauses. Check structural, weathertightness, plumbing, drainage, fire-safety, barrier and site risks for the actual design.

Exempt Building Work

Schedule 1 of the Building Act lists work that may be done without a building consent. Each exemption has conditions, and other approvals or authorised trades may still be required.

• Single-storey detached buildings up to 30 square metres (subject to conditions).
• Ground-level decks with no roof.
• Pergolas, carports, and shade structures (with limitations).
• Internal non-structural walls and partitions.
• Like-for-like replacement of windows, cladding, and roofing.
• Kitchen and bathroom renovations that do not change the layout or add fixtures.
• Repair and maintenance using comparable materials.

Exempt work must still comply with the Building Code. Being exempt from consent does not mean you can do whatever you like. It simply means you do not need council approval before starting. If you do exempt work badly and it fails to meet the Building Code, you can still be required to fix it or face consequences when selling the property.

Detached-building exemptions up to 30 square metres differ by design, construction and supervision pathway and include conditions about matters such as height, boundaries, sanitary facilities, cooking and sleeping use. Check the exact current exemption rather than relying on floor area alone.

The Consent Process

If the project requires consent, apply to the local building consent authority with the plans, specifications and supporting information required for that work. Fees and required documents are authority- and project-specific.

The building consent authority assesses whether the proposed work will comply with the Building Code and may request further information. A consent lapses if the work does not commence within 12 months after issue unless the authority allows a further period.

Book the inspections specified in the consent and follow the authority's instructions about when work can continue or must remain visible. Inspection requirements depend on the approved work.

Code Compliance Certificates

When consented work is complete, the owner applies for a Code Compliance Certificate. The building consent authority decides whether it is satisfied on reasonable grounds that the work complies with the building consent; keep the decision and supporting records.

Apply for the Code Compliance Certificate when consented work is complete and respond to any requests for records or remedial work. If an older consent remains open, check its status with the council and obtain property-specific legal or insurance advice where needed.

Dealing With Unconsented Work

If work may have been done without required consent, first establish what was built, when, and what council records exist. A certificate of acceptance may be available in defined circumstances, but it is not retrospective building consent.

For a certificate of acceptance, the council assesses the parts of the work it can reasonably inspect and verify. It may request plans, records, expert evidence or exposure of concealed work, and the certificate can be limited to the matters it was able to assess.

Certificate-of-acceptance fees and evidence requirements are council- and project-specific. The council may refuse the application or issue a limited certificate, and obtaining one does not remove the original obligation to have obtained consent before the work.

Working With Licensed Building Practitioners

For restricted building work, which includes most structural and weathertightness-related construction, you must use licensed building practitioners (LBPs). These are tradespeople and designers who have demonstrated competence and are accountable through a licensing system.

Check that restricted building work is designed or carried out or supervised by LBPs holding the appropriate licence class, and retain Certificates of Design Work and Records of Building Work. The Building Practitioners Board can discipline an LBP but cannot award compensation or order defective work to be fixed.

Building consent, inspections and LBP requirements each have defined roles, but they do not guarantee an outcome. Use clear contracts, keep records and follow the council and licensed-practitioner requirements for the project.