Short answer: in Auckland, a retaining wall usually does not need building consent if it holds back 1.5 metres or less of ground and has nothing extra loading it, like a driveway, a building, a fence or a slope above. Walls taller than that, or walls carrying extra load, usually need an engineer’s design and building consent. Separate Auckland Council rules on earthworks, boundaries and stormwater can also apply. Here’s how to tell which side of the line your wall is on.
This is general guidance from a North Shore landscaping company, not legal advice. Rules change, so always confirm your specific project with Auckland Council or a structural engineer.
The 1.5 metre rule, explained
Schedule 1 of the Building Act 2004 lists building work that doesn’t need building consent. It includes a retaining wall that retains not more than 1.5 m depth of ground and doesn’t support any surcharge or any load beyond the ground itself. Both conditions have to be true.
Two details trip people up:
- It’s the depth of ground retained, not the height of the visible wall. Measure the difference in ground level from the bottom of the wall to the top of the soil behind it. A wall can look 1.2 m tall and still be retaining more than 1.5 m if the ground behind it slopes up.
- “Surcharge” means anything adding weight near the top of the wall. That includes a driveway or parking area, a house, garage or shed, a deck or fence posts close to the edge, another retaining wall above it, or a steep slope of soil rising behind it.
An exempt wall still has to meet the Building Code. Being exempt from consent means nobody checks it, not that it can be built any way you like. The owner is still responsible if it fails.
Quick check: does my retaining wall need consent?
| Your wall | Building consent? |
|---|---|
| Garden wall retaining under 1.5 m, nothing above it but lawn or garden | Usually not needed |
| Wall retaining more than 1.5 m of ground | Needed, with engineer’s design |
| Wall of any height beside or below a driveway or parking area | Usually needed, with engineer’s design |
| Wall supporting a house, garage, deck or another structure | Needed, with engineer’s design |
| Terraced walls stepped up a slope | Depends on spacing. Closely spaced tiers can act as one taller wall, so get an engineer’s view |
| Wall with a fence on top | Check the combined height and loads. A fence on top adds load, and the total height near a boundary can bring in other rules |
Building consent isn’t the only rule
Even when a wall doesn’t need building consent, the Auckland Unitary Plan can still apply. These are the ones we see most often on the North Shore:
- Earthworks. Cutting into a bank or filling behind a wall is earthworks. Larger volumes or areas, work on steep or unstable land, or work near streams and the coast can need resource consent.
- Boundaries and height. Walls and fill close to a neighbour’s boundary can affect height-in-relation-to-boundary rules. They also affect your neighbour’s land if the wall ever moves, so talk to them early.
- Stormwater and overland flow paths. You can’t block or divert a natural flow path in a way that sends water onto someone else’s property. Where your wall’s drainage discharges matters.
- Protected trees and services. Digging near protected trees or underground pipes and cables brings its own rules. Services must always be located before digging.
What happens if your wall does need consent
- Engineer’s design. A structural or geotechnical engineer designs the wall for your soil, height and loads, and usually provides a producer statement for the design (PS1).
- Building consent application. The drawings, engineering and specifications go to Auckland Council. Processing time varies, so allow for it in your project timeline.
- Build and inspections. Council inspects key stages, such as footings and drainage, before they are covered up.
- Sign-off. The engineer confirms the wall was built to the design (PS4), and council issues a code compliance certificate.
Consent adds cost and time, but it protects you. A consented, signed-off wall is a selling point when you sell the house. An unconsented wall that should have been consented can come up in a buyer’s LIM report or building inspection.
Exempt doesn’t mean easy: build it to last
Most retaining wall failures we’re called out to on the North Shore are walls under 1.5 m that were never inspected. The cause is almost always the same: no drainage behind the wall, or posts that were too small or too shallow for the clay. Whether or not your wall needs consent, it should have:
- A perforated drainage pipe with a filter sock at the base, falling to a proper outlet
- Free-draining aggregate behind the wall, wrapped in filter cloth, not clay backfill
- H5-treated posts (for timber walls) set in concrete to a depth suited to the height and soil
- A plan for where the water goes, so it doesn’t end up on your neighbour’s section
If you’re weighing up costs, our retaining wall cost guide for Auckland breaks down what drives the price, including driveway walls.
Frequently asked questions
Do I need consent for a retaining wall under 1.5 m in Auckland?
Usually not, as long as the wall retains 1.5 m or less of ground and nothing extra is loading it, such as a driveway, building, fence or slope above. It still has to meet the Building Code, and other Auckland Council rules on earthworks, boundaries and stormwater can still apply.
Does a retaining wall next to a driveway need consent?
In most cases, yes. Cars add extra load (surcharge) near the top of the wall, so the Building Act exemption no longer applies even under 1.5 m. Expect an engineer’s design and building consent.
How is the 1.5 m measured?
By the depth of ground the wall retains: the difference in ground level from the bottom of the wall to the soil surface behind it. It isn’t just the height of the visible wall face.
Can I build two 1.2 m walls instead of one 2.4 m wall to avoid consent?
Not necessarily. Terraced walls that are close together can act as a single taller wall, and the upper wall adds load to the lower one. An engineer needs to assess the spacing and soil before you rely on this.
What happens if I build a retaining wall that needed consent without one?
Council can require you to apply for a certificate of acceptance, modify the wall or remove it. It can also show up during a sale, through a LIM report or a buyer’s building inspection, and affect the price.
Who applies for the consent?
Usually the builder or landscaper coordinates it with a structural engineer, who designs the wall. At Xtra Landscaping we arrange the engineering and consent process for walls that need it and include it in the quote.
Not sure about your wall?
We build retaining walls across the North Shore and can tell you at a free site visit whether yours is likely to need consent. Where it does, we work with a structural engineer and handle the process for you. Get in touch or call 027 207 7887.