Yes. You need approval. There's no version of this where you stick a second dwelling up the back, hang a curtain in the window and call it sorted — that's how people end up ripping things out two years later.
The better news is NSW built a fast track for granny flats, and a fair few blocks around the Gong sail straight through it without ever landing on a council desk.
I get asked about this most weeks. Usually it's a homeowner who's had a builder's quote in their hand and wants to know what they're really signing up for before they commit. So here's the lay of the land. The honest version, not the brochure one.
Two paths: CDC or a full DA
A granny flat in NSW lives under the Affordable Rental Housing SEPP — the secondary dwelling rules. Nobody calls it that. Everyone says the granny flat code. It exists so councils aren't drowning in paperwork over what's a fairly bog-standard build.
Two ways in.
First is Complying Development — a CDC. The fast track. Tick every box in the code and a private certifier can sign the whole lot off without it ever touching council. I've seen these land in a few weeks instead of a few months. Costs less, too.
Second is a full Development Application — a DA through Wollongong, Shellharbour, Kiama or Shoalhaven. You're on this road when your block trips one of the CDC rules. Too small, dodgy setbacks, heritage overlay, whatever it happens to be. A DA drags on longer and costs more. It's not the end of the world — heaps of granny flats get built this way every year.
Which path you're on comes down entirely to your block. That's the bit people get wrong before they've even started.
The rough numbers (don't take these as gospel)
A few figures get thrown around so much they start sounding like law. They're not. The code shifts, and your block has its own quirks.
- Block size: you generally want around 450sqm or more for the CDC fast track.
- Granny flat size: the secondary dwelling caps out around 60sqm of internal floor, give or take, and a patio or carport doesn't count against that.
- It stays on the same lot as the main house. You can't carve it off and sell it on its own.
I'd lean hard on generally there. A 449sqm block isn't dead in the water — it might just mean a DA instead of a CDC. And that 60sqm has a bit of give around verandahs and the like. Your certifier is the one who nails it down for your exact address, so get that sorted early. Before anyone draws a line.
Why you need a certifier (or council)
You can't approve your own granny flat. Neither can we. That sign-off is a legal job, and it belongs to a registered certifier or the council — not the chippy nailing up the wall frames.
For a CDC, a private certifier is usually the play. They check your plans against the code, issue the construction certificate, come out and inspect at the key stages, then hand over an occupation certificate at the end so the place is legal to live in. If you haven't got one, Dave can point you at certifiers we've worked alongside round the Illawarra. Same with the surveyor you'll probably need to mark setbacks and flush out any easements.
And I'll say this plainly, because it matters: we do the carpentry, not the certification. A granny flat is a real build with wet trades running all through it — plumbing, electrical, waterproofing, tiling — and those are licensed jobs done by licensed people. Our side is the building. Subfloor and framing, wall and floor structure, decks and external timber, linings, doors, the cabinetry and vanity install, the fit-out. The carpentry behind the whole thing, working in with the trades who handle the rest.
The gotchas that catch people out
Most granny flats that fall over at approval do it for dull, predictable reasons. Worth knowing them before you fall in love with a floor plan you can't build.
Setbacks. The code sets minimum distances off your boundaries and the existing house. Tight blocks and battleaxe blocks run out of room quick.
Easements. Sewer main or drainage easement running across the back of your block? A surprising number of older Wollongong blocks have one, and you generally can't build over it. That on its own can rule out the exact spot you'd pictured.
Bushfire. A lot of the Illawarra backs onto the escarpment, which means bushfire-prone land. If your block's mapped that way you're up for a bushfire assessment and maybe upgraded construction. Doesn't kill the project. Changes the build and the budget, though.
Heritage. Some of the older suburbs carry heritage listings or conservation-area controls. That usually bumps you off the CDC fast track and into a DA, with more design back-and-forth.
Slope. Sloping blocks are everywhere down here. A steep fall won't stop a granny flat, but it can mean a suspended floor, more structural work, and a different number altogether.
None of this is a reason not to build. It's a reason to get your certifier and a surveyor onto your actual block early — before you've sunk money into plans that were never going to fly.
Where we fit
Weighing up a granny flat and after a straight answer on the carpentry side — what the framing, subfloor, decking and fit-out involve, and roughly what it runs? That's the conversation we're happy to have. We'll be upfront about what's ours and what belongs to the certifier, the plumber and the sparky, and we can point you at trades we trust around Wollongong, Shellharbour and Kiama.
Give Dave a call on 0414 007 351, or send the form through for a free quote. Licensed, insured, local — and honest about who does what.
Want a hand with this at your place? Get a free quote or call 0414 007 351.