Two files used to land on my desk in the same week with almost the same question, and different answers. One was a Thorndon owner wanting to raise a battered bank behind a 1910s villa into a stepped retaining wall. The other was a neighbour three doors down wanting to remove a self-seeded macrocarpa that had started leaning over a shared fence. Both people used the same word — “consent” — as if it meant one thing. After years assessing outdoor work for a city council, I can tell you it does not. There are two separate systems, asking two separate questions, and outdoor work is where they collide most often.
Two different questions, not one
A resource consent sits under the Resource Management Act. It asks whether an activity is acceptable in this location, given the effects on neighbours, the street, and the environment — outlook, shading, runoff, and notable trees among them. A building consent sits under the Building Act 2004. It asks a narrower question: will this structure stand up and perform safely over its life. A garage that meets every building code clause can still need a resource consent if it sits too close to a boundary under the district plan. A garden wall that raises no planning objection at all can still need a building consent if it retains enough soil to fail dangerously. The two assessments run on separate tracks, against separate documents, and a project can need one, both, or neither.
What tends to trigger a building consent outdoors
For work outside the house, building consent questions usually turn on height and load. A retaining wall holding back more than around 1.5 metres of ground, or carrying a surcharge such as a driveway or another structure above it, generally needs a design from a chartered professional engineer and a building consent to go with it, because the wall is doing structural work and the council wants evidence it will not fail. Decks above a certain height, and structures with a roof over a minimum floor area, tend to sit in the same category. MBIE’s building consents guidance sets out the general thresholds a building team works from, though your own council still applies them to your specific site. Below those thresholds, some outdoor work sits inside Schedule 1 of the Building Act, which exempts certain low-risk work from needing a consent at all — but the exemption still expects the work to meet the building code, and it is narrower than most people assume.
What tends to trigger a resource consent outdoors
Resource consent questions turn on effects rather than engineering. Earthworks past a certain volume, or on a slope steeper than the district plan allows, cuts or fills close to a boundary, work that changes how surface water leaves a section and lands on a neighbour’s, and removing a tree that is scheduled or otherwise protected in the district plan can all trigger a resource consent, independent of whether the same job needs a building consent. A low garden wall might be structurally trivial and consent-free under the Building Act, and still need resource consent if it sits on a steep site within a special character area. This pairing is what catches people out — they check the building rules, get a clean answer, and never look at the planning ones.
Reading the exemption correctly
Schedule 1 exists because not every fence post or garden feature needs a file at the council. But it lists specific work under specific conditions — a certain wall height, a certain deck height, a certain floor area — and it does nothing to switch off the Building Act’s underlying requirement that the work still perform, and it does nothing to the resource consent question, which sits in a different Act entirely. I would see owners build something correctly exempt from building consent and still receive an abatement notice under the district plan, because nobody had checked the planning side. Once a consent is in hand, the process moves on to site inspections, covered separately in what a council inspector actually checks on an outdoor job. Treat the two systems as two checks, run early, on the same project.
Frequently asked questions
Can a project need both a building consent and a resource consent? Yes. A tall retaining wall close to a boundary is the classic example — the height triggers the building side and the proximity triggers the planning side, and each is assessed on its own criteria.
Does an exemption from building consent mean the work is unregulated? No. Exempt work under Schedule 1 still has to meet the building code; the exemption removes the paperwork step, not the performance standard.
Who can tell me which consents a specific job needs? Rules vary by council and by district plan, so a duty planner or building consents officer at your own council is the right first call before work starts.