Do I Need Council Approval for a Deck in NSW? The Rules, in Plain English

On almost every deck we quote, the first question from the homeowner isn't about timber or boards. It's: "Do I need council approval for this?"

The honest answer is: it depends on how high the deck sits, how big it is, where it sits on your block, and whether you're in a bushfire zone. There's no single number. But there are three clear tiers in NSW, and once you know them you can tell within a minute which one your project falls into.

Here's how we explain it on site.

The three tiers: exempt, complying, or full DA

NSW splits building work into three buckets:

1. Exempt development — no approval needed at all, as long as you stick to the rules.
2. Complying Development Certificate (CDC) — a fast-tracked approval, usually done through a private certifier in a week or two, no full council DA.
3. Development Application (DA) — the full council process, for anything that doesn't fit the first two.

Most residential decks land in tier one or two. Here's where the lines sit.

Exempt: the deck you can build with no paperwork

Under the NSW exempt development code, a deck, patio or verandah can go up without any approval if it meets all of these:

• Floor area no more than 25 square metres
• Floor height no more than 1 metre above existing ground level
• Total height no more than 3 metres at the highest point above ground
• Enclosing walls no higher than 1.4 metres (if any)
• Set back from the boundary, behind the building line, and not on heritage land or in a restricted zone

That's a small, low deck — think a 5m x 5m alfresco step-down off the back door. The moment you go bigger, higher, or closer to the fence, you move up a tier.

A quick note: people read "exempt" as "no rules". It's not. You still have to meet the balustrade, structural, and setback requirements — you just don't need a piece of paper first. And in our experience, certifiers and insurers still like to see a stamped drawing, even on an exempt deck, when you sell the house.

Complying Development: the middle ground for most decks

If your deck is bigger than 25m² or higher than 1 metre off the ground but still a standard residential job, it usually qualifies for a Complying Development Certificate. This is the path most of our decks take.

A CDC is a ticked-box approval — a private certifier checks your plans against a fixed set of rules (height, setback from the boundary, site coverage, distance to the building line) and signs it off, usually in one to two weeks. No neighbourhood notification, no council meetings, no months of waiting.

The rules a CDC deck has to meet include setback from the side and rear boundary (tighter the bigger you go), a height limit, and the standard fire and safety provisions. If your block is on a steep slope, within the front setback, or over a certain size, the certifier will tell you straight away whether CDC is an option or whether you're into DA territory.

Full DA: when council has to decide

A full Development Application is needed when the deck falls outside both the exempt and complying rules — too high, too close to the boundary, forward of the building line, on a heritage item, or in a zone with stricter controls (some bushfire-prone and foreshore lots on the Northern Beaches fall here).

A DA goes through council, gets advertised, and can take anywhere from six weeks to several months. We handle the drawings and the statement, but council makes the call.

The balustrade rule: where you need a rail

Regardless of which approval tier you're in, the same safety rule applies across Australia: if someone could fall more than 1 metre from your deck to the ground below, you must have a balustrade, and it must be at least 1 metre high (865mm on a stairway, measured to the nosing of the treads).

That's why almost every deck we build more than a step off the ground has a balustrade — it's not optional, and it's not a council thing, it's the National Construction Code.

If your deck is more than 5 metres off the ground, a second rule kicks in: the glass in any glass balustrade has to be laminated safety glass, not the single-pane toughened glass that's fine at lower heights. We've written a whole post on that one — the short version is, above 5m the glass has to fail safe.

Bushfire zones: the rule that catches Northern Beaches blocks

This is the one a lot of people miss, and it matters a lot where we work.

If your property is mapped as bushfire-prone land — which covers a good chunk of Terrey Hills, Ingleside, Duffys Forest, Church Point, Oxford Falls and the foreshore pockets — your deck has to meet a Bushfire Attack Level (BAL) rating. The rating (BAL-LOW through BAL-FZ) depends on slope, vegetation, and how close the deck is to the bush.

What that means in practice:

• Decking within 300mm horizontally and 400mm vertically of a window or glazed door has to be non-combustible or bushfire-resistant.
• At the higher BAL ratings, the whole deck frame and board selection is restricted — some hardwoods qualify, some composites don't, and steel framing becomes the safe choice.
• A high BAL can push an otherwise exempt deck into needing approval.

We always check the bushfire map for your lot before we quote. It's a five-minute check and it changes the materials list and sometimes the whole approval path.

Pergolas and carports are treated differently

One that trips people up: a pergola in the NSW code is an open, unroofed frame — beams and rafters, no solid covering. A roofed pergola, an awning, or a carport is a different structure with its own exempt and complying thresholds (usually larger allowable area, but with their own height and setback rules).

So if you're planning a covered deck with a roof over it, you're really building two structures in the eyes of the code — the deck and the roof — and each has to meet its own rules. We design them together but certify them against their own thresholds.

What we do for you

On every deck we build we work out the approval tier before we pick up a tool. If it's exempt, we'll tell you and keep going. If it needs a CDC, we prepare the drawings and engage the certifier as part of the build. If it needs a DA, we handle the application and the statement, and we liaise with council through to approval.

You shouldn't have to become a part-time planner to get a deck built. That's our job.

Planning a deck? Let's look at your block first

Book a free site measure and we'll tell you which approval tier your deck falls into, what the council will want to see, and what it'll cost — before you commit to anything.

Call us on 0482 088 410 or get a free quote online.

MJ Leckie Carpentry — Licensed Carpenters, NSW Licence 353438C