Building Consent Exemptions NZ: 6 Key Rules, Sizes & Limits

Planning to replace a garage door, add a carport, or put up a small shed—and not sure if you need a building consent? Getting it wrong can cost time and money. While New Zealand’s Building Act 2004 (Schedule 1) lets some low‑risk work proceed without a consent, those exemptions only apply if you meet specific size, height and design limits. Even when consent isn’t needed, all work must still comply with the Building Code and your district plan, and councils may require notification or have local processes you need to follow.

This guide cuts through the jargon with six essential exemption areas, the key sizes and limits, and simple next steps. We cover when garage door projects are exempt, like‑for‑like repairs and maintenance, the 30 m2 rule for detached single‑storey buildings, carports/awnings/verandas/pergolas, decks, and fences/retaining walls. For each, you’ll see what’s covered, where the thresholds sit, when consent is still needed, and how to confirm with your council using MBIE’s Schedule 1 guidance and tools. Let’s begin with garage door projects and when they’re exempt.

1. When your garage door project is exempt (DoorsNZ guide)

Most garage door swaps are simple maintenance jobs and often fall under Schedule 1 building consent exemptions NZ, provided you don’t alter structure or weathertight details. Think like-for-like replacement in the same opening, with the door and hardware installed to manufacturer instructions and the Building Code still met.

What this covers

Typical exempt work includes straightforward replacement and upkeep that doesn’t change the opening or structure:

• Like-for-like replacement of a garage door in the same opening.
• Repair or replacement of tracks, springs, rollers and seals.
• Minor flashings/seal renewal that restores existing weathertightness.
• Servicing or replacing an automatic opener unit (separate electrical rules still apply).

Key sizes and criteria

There’s no specific m2 threshold for doors—the test is risk and impact on structure and weathertightness:

• Same size, same location, no new or enlarged openings.
• No changes to lintels, bracing or primary structure.
• Work maintains or improves existing weathertight details.
• Installed by a competent person to manufacturer specifications.

When consent is still needed

Consent is likely required if the work goes beyond maintenance:

• Creating, enlarging or relocating the opening.
• Altering structural supports or wall bracing.
• Work that could affect external weathertightness performance.
• Replacing a door installed within the last 15 years that has failed (MBIE notes this requires consent).

What to do next

Confirm your project against MBIE’s Schedule 1 guidance or the Buildit tool, then check any local plan rules with your council. If borderline, ask about a Schedule 1(2) discretionary exemption. Ready to proceed? Measure accurately, keep product specs/installation instructions on file, and use licensed trades where required.

2. General repairs, maintenance and like-for-like replacement (Schedule 1)

For day‑to‑day upkeep and simple swaps, Schedule 1 allows a wide range of low‑risk work to proceed under building consent exemptions NZ, as long as you’re not touching primary structure or compromising fire or external moisture performance. The principle is “repair, maintain, or replace in the same form and position” while still meeting the Building Code.

What this covers

Typical exempt activities include work that restores what’s already there without increasing risk:

• Like‑for‑like interior fixes: wall linings, trims, cabinetry, flooring.
• Non‑structural hardware: door furniture, locks, tracks and similar fittings.
• Exterior upkeep: resealing joints/flashings and replacing deteriorated components to maintain existing weathertightness.
• Windows/doors: like‑for‑like replacement in the same opening for existing dwellings/outbuildings.

Key sizes and criteria

The trigger isn’t area so much as impact:

• No change to structure or bracing: no larger openings, no lintel changes.
• Same location and dimensions: replacement, not relocation/enlargement.
• Weathertightness maintained or improved: details reinstated to Code.
• Competent installation: follow manufacturer instructions; keep records.

When consent is still needed

You’ll likely need consent if:

• Openings change: new, larger, or relocated windows/doors.
• Structure is altered: lintels, framing, or wall bracing affected.
• External moisture risk increases: cladding/system changes beyond maintenance.
• Recent failures: MBIE notes replacing a window/roof window/door that has failed within 15 years requires consent.

What to do next

Check your scope against MBIE’s Schedule 1 guidance or the Buildit tool, then confirm any district plan constraints with your council. Borderline? Ask about a Schedule 1(2) discretionary exemption. Photograph existing details, keep product specs/installation instructions, and use licensed trades where required by law.

3. The 30 m2 rule for detached, single-storey buildings (sheds and sleepouts)

This is the headline building consent exemptions NZ rule many DIYers care about. Certain simple, single‑storey detached buildings up to 30 m2 can be built without a building consent if you meet strict conditions. It’s ideal for small sheds, cabins and basic sleepouts, but the exemption is not a free‑for‑all—competency and scope limits apply, and all work must still comply with the Building Code and your district plan.

What this covers

Use this pathway for small, low‑risk structures that stand alone:

• Small sheds, workshops, studios and hobby rooms.
• Basic sleepouts or home offices without plumbing.
• Greenhouses and similar light utility buildings.

Key sizes and criteria

To qualify under Schedule 1 you must stay within these limits:

• Maximum floor area: up to 30 m2.
• Form: detached and single‑storey.
• Who designs/builds: either
  • Kitset/prefab up to 30 m2 where the design is carried out or reviewed by a Chartered Professional Engineer, or
  • Site‑built up to 30 m2 where a Licensed Building Practitioner (LBP) carries out or supervises design and construction.
• No plumbing/drainage: no kitchen, bathroom or laundry connections.
• Code compliance: structure, weathertightness and fire safety to the Building Code still apply, including external fire spread requirements near boundaries.
• Local rules: district plan setbacks/heights still apply (separate to building consent).

When consent is still needed

You’ll need a building consent if any of the following apply:

• Over 30 m2, multi‑storey, or attached to another building.
• No LBP/CPEng involvement as required by the exemption.
• Includes plumbing/drainage (kitchen, bathroom, laundry).
• Design/placement can’t meet Code or plan rules (for example, boundary fire requirements you can’t achieve).

Note: A separate government proposal to allow “granny flats” up to 70 m2 without consent is not yet law. Until legislation changes, stick to the 30 m2 rules.

What to do next

Map your project to one of the two compliant pathways: kitset/prefab with a Chartered Professional Engineer design/review, or site‑built under LBP design/supervision. Confirm there’s no plumbing, check boundary/setback rules, and use MBIE’s Schedule 1 guidance or the Buildit tool to double‑check eligibility. Keep plans, engineering/LBP documentation and product specs on file. If you’re close to the line, talk to your council about a Schedule 1(2) discretionary exemption or proceed with a building consent.

4. Carports, awnings, verandas and pergolas

Adding shade or weather cover is a common project, and many simple carports, awnings, verandas and pergolas can proceed under Schedule 1 building consent exemptions NZ if they stay within the prescribed size/height limits and are low‑risk. Remember: even when exempt, the work must still comply with the Building Code and any district plan rules (setbacks, height in relation to boundary, heritage overlays).

What this covers

These exemptions typically capture small, simple structures used for shelter or shade:

• Carports and shelters: basic open‑sided roof structures for vehicle cover.
• Awnings and verandas: lightweight roof projections attached to a building.
• Pergolas: open slat/lattice frameworks providing shade (usually unroofed).

Minor like‑for‑like repairs or maintenance to existing structures generally remain exempt when they don’t alter structure or weathertightness.

Key sizes and criteria

Specific caps and conditions apply under MBIE’s Schedule 1 guidance (sections on porches/verandas/pergolas and on shelters/shades/carports). Common threads include:

• Area/height limits apply: if you exceed the stated caps for that structure type, consent is required.
• Low‑risk design and fixings: simple connections that don’t compromise the host building’s primary structure or bracing.
• Code compliance: meet B1 Structure, E2 External moisture (for roofed work), and boundary fire requirements.
• Who does the work: some pathways for exempt work rely on competent/licensed people (for example, certain 2020 exemptions reference LBP or engineering involvement).

When consent is still needed

Expect to need consent if:

• You exceed the size/height caps for the relevant exemption.
• You enclose spaces (for example, closing in a veranda or patio) or materially alter cladding/weathertight details.
• You affect primary structure/bracing of the existing building.
• You can’t meet boundary/fire or district plan rules at the proposed location.

What to do next

Measure the proposed footprint and height, sketch fixings to the existing building (if any), and check MBIE’s exempt building work guidance or the Buildit tool against your scenario. Confirm district plan setbacks/heights with your council. Borderline? Ask the council about a Schedule 1(2) discretionary exemption or proceed with a building consent. Keep product specs, installation instructions and photos of existing conditions on file, and use licensed trades where required.

5. Decks and platforms

New outdoor living is a classic DIY job, and many simple decks and platforms are covered by building consent exemptions NZ if you stay within MBIE’s Schedule 1 “Platforms, decks and bridges” limits. The trick is keeping risk low: modest height, simple structure, no impact on bracing or weathertightness, and full Building Code compliance (structure, durability, and barriers where required).

What this covers

Use the exemption for straightforward work that doesn’t increase risk or alter primary structure:

• New low‑level decks and platforms serving a dwelling.
• Like‑for‑like deck surface/joist replacement in the same footprint.
• Minor repairs to steps and landings returning them to original condition.

Key sizes and criteria

Schedule 1 sets specific height thresholds and conditions for platforms and decks. To remain exempt:

• Stay within MBIE’s height limits for decks/platforms; exceeding them triggers consent.
• Keep designs simple (single level, straightforward fixings) and avoid compromising wall bracing or cladding.
• Meet the Building Code: B1 Structure, B2 Durability, and barriers/handrails where required.
• Observe district plan rules (setbacks, height in relation to boundary, overlays).

When consent is still needed

Plan for a consent if:

• Your deck or platform exceeds the Schedule 1 height thresholds.
• You enclose spaces below, add significant structure (for example, heavy canopies), or affect primary bracing or weathertightness.
• You’re creating complex multi‑level arrangements or can’t meet Code/district plan requirements at the chosen location.

What to do next

Measure finished deck height above ground across the site, sketch fixings to the house, and check your design against MBIE’s “Platforms, decks and bridges” guidance or the Buildit tool. Confirm any district plan constraints with your council. If borderline, discuss a Schedule 1(2) discretionary exemption; otherwise apply for consent. Keep product specs, installation instructions, and photos of existing conditions on file, and use licensed trades where required.

6. Fences and retaining walls

Boundary tidy-ups are popular DIY jobs, and many straightforward fences and small retaining walls can proceed under Schedule 1 building consent exemptions NZ if they stay within MBIE’s stated height limits and don’t create extra risk. Remember: pool barriers have separate rules, and district plan controls (setbacks, height in relation to boundary, heritage/visual overlays) still apply even when building consent isn’t needed.

What this covers

Use the exemption for simple, low‑risk work that restores or provides basic separation/retention:

• Fences: standard timber or panel fences, gates, and like‑for‑like repairs in the same line.
• Retaining walls: short, free‑draining walls not supporting additional loads (for example, garden terraces).
• Maintenance: replacing posts/rails/boards or renewing finishes without changing height/location.

Key sizes and criteria

Eligibility depends on limits and risk factors set out in MBIE’s guidance:

• Height caps apply: exceed the stated fence or wall height and you’ll need consent.
• No surcharge for retaining walls: the exemption does not cover walls that support extra loads (for example, driveways, buildings, slopes).
• Stay clear of primary structure and services: don’t undermine foundations or alter building bracing/performance.
• Code compliance: ensure structural adequacy, durability, and drainage for retaining walls.

When consent is still needed

Plan for consent if:

• You exceed MBIE’s height limits for fences or retaining walls.
• A retaining wall supports a surcharge or is close enough to affect a building or public land.
• Pool barriers are involved (separate compliance obligations apply).
• You can’t meet district plan rules (for example, boundary height controls).

What to do next

Measure accurately, note ground levels and any nearby loads (driveways, slopes, buildings), and sketch drainage details for retaining walls. Check your scenario against MBIE’s Schedule 1 “Fencing and restrictions” guidance or the Buildit tool, then confirm district plan rules with your council. Borderline? Ask about a Schedule 1(2) discretionary exemption or apply for consent. Keep product specs, installation details and photos on file, and use competent installers.

Final checks and next steps

You’ve now got the big six exemption areas and the key limits. Before you pick up the drill, sanity‑check your project against Schedule 1 so you don’t stray over a threshold. Remember: exempt doesn’t mean unregulated—your work must still comply with the Building Code and your district plan, and councils can ask for notification or documentation.

• Measure twice: footprint, finished height above ground, and distances to boundaries.
• Protect structure: don’t alter bracing, lintels or cladding beyond maintenance.
• Stick to 30 m2 rules: detached, single‑storey, no plumbing; use LBP/CPEng where required.
• Doors/windows: same size and position; failed units under 15 years generally need consent.
• Meet Code and plan rules: structure, weathertightness, fire, setbacks/overlays.
• Keep records: drawings, specs, install instructions, LBP/engineering evidence, photos.
• Borderline? Use MBIE guidance/online tools and ask your council about Schedule 1(2).

If your project involves a garage door, we can help you get it right first time—accurate measuring, compliant specs, NZ‑made product and nationwide supply. Start your project with DoorsNZ and keep your build on budget and on the right side of the rules.