Let me guess how this started. Someone in your house needs their own space. Maybe it’s a teenager who thinks the lounge room is a “shared area” (it isn’t). Maybe it’s Mum or Dad, who’d like to be close but not that close. Or maybe you’ve looked at Wollongong rents and thought, “I’ve got a backyard. Why not?”
Good thinking. But before you fall in love with a floor plan, you need to know the rules. And in Wollongong, with its escarpment, creeks, coastal flats and the odd bushfire zone, the rules aren’t always as simple as “just build it.”
I’ll walk you through the granny flat rules in Wollongong in plain English: how big your granny flat can be, what kind of block you need, and how approval works. No jargon. Well, almost none. Planners love their jargon, so I’ll translate as we go.
First Things First: What Counts as a Granny Flat?
In council language, a granny flat is called a secondary dwelling. It’s a self-contained home that sits on the same block as your main house.
Self-contained means it has:
- somewhere to sleep and live
- a kitchen area
- a bathroom (shower and toilet)
- laundry facilities
It can be freestanding in the backyard, attached to your house, or built inside it (think a converted lower level or garage). Either way, it’s one lot, one owner, two homes.
And here’s the part people miss. A granny flat isn’t the same as a dual occupancy. A dual occupancy is two proper homes on one block, usually with a separate approval path and often a bigger budget. A granny flat is the smaller, “supporting act” dwelling. If you want a quick way to remember it: the granny flat is the sidekick, not the co-star.
Granny Flat Size Limits in Wollongong
Let’s start with the question everyone asks. How big can a granny flat be in Wollongong?
In NSW, a secondary dwelling is generally capped at 60 square metres of floor area. That’s roughly the size of a compact two-bedroom unit. Not huge, but you’d be surprised what a good designer can fit into 60 sqm.
Some things to know:
- The 60 sqm figure counts the dwelling itself. Verandahs and carports are usually treated differently, but always confirm how your plans are measured.
- If your plans go over the limit, you can’t use the fast-track path. You’d need a full development application, and council has to be happy with it.
- There’s only room for one granny flat per property.
| Rule | What it usually means |
| Maximum floor area | Around 60 sqm |
| Number allowed | One per property |
| Style | Freestanding, attached, or inside the main house |
| Bedrooms | Not capped on their own, but the size limit keeps it to one or two in practice |
My honest take: don’t treat 60 sqm as a challenge to squeeze in three bedrooms. A clever one-bedder with a proper living area feels bigger than a cramped two-bedder. Open-plan living, high ceilings, and big windows do more for a small home than an extra door ever will.
What Block Size Do You Need?
Next up: the block. This is where plenty of plans quietly die.
For the standard fast-track approval, NSW generally asks for a lot of at least 450 square metres. Many guides also mention a minimum width of around 12 metres, though you should check this against your own block, because the details can change from site to site.
That’s the minimum for the simple route. If your block is smaller, you might still get there, but it’ll likely mean a development application and more back-and-forth with council.
Here’s a quick cheat sheet:
| Your situation | What it likely means |
| Block 450 sqm or more | You may qualify for the fast approval path |
| Block under 450 sqm | Likely a development application, with no guarantee |
| Narrow block | Setbacks and access become the tricky part |
| Already has a granny flat | You can’t add a second one |
Wollongong blocks have their own quirks
I’ll say this gently: Wollongong isn’t a flat grid of identical rectangles. You’ve got steep blocks up the escarpment, flood-prone pockets near the creeks, coastal areas with their own rules, and plenty of bushland edges. All of that matters.
Before you get excited, check whether your land is affected by:
- Bushfire risk. You may need a bushfire-rated design, which affects materials and cost.
- Flooding. Floor heights and building materials can be restricted.
- Heritage. Some streets and homes are protected, and that can limit what you do out the back.
- Drainage easements and stormwater pipes. You generally can’t build over these.
- Slope. Steep land can still work, but earthworks and retaining walls add cost.
- Trees. Removing some trees needs approval, and neighbours’ trees can affect your footprint.
The easiest way to find out what applies to your land is a Section 10.7 planning certificate from council. It lists the rules attached to your block. It’s a small fee for a lot of clarity.
Setbacks, Height and the Boring-But-Important Stuff
Size and block are the headline acts. But the “supporting cast” can still sink your plans.
You’ll need to think about:
- Setbacks. How far the granny flat sits from your boundaries.
- Height. Single storey is the norm, but some blocks allow more. Check first.
- Private open space. Your main house must keep a decent backyard. You can’t swallow the whole garden.
- Parking. Requirements can vary. Check what applies to your site.
- Privacy and light. Councils care about your neighbours’ sunshine more than you’d think.
- Services. Water, sewer, power, and stormwater all need a plan.
I once heard a story (and I’ve seen the same thing a few times since) about a homeowner who had the perfect design, then discovered a sewer main running right through the spot they’d picked. Moving the flat 3 metres changed the layout, the cost, and the mood in the house for a week. A quick site check at the start saves that conversation.
Do You Need Approval? Yes. Here Are Your Two Paths.
Short answer: yes, you need approval to build a granny flat in Wollongong. There’s no “I’ll just pop one up on the weekend” option, tempting as it sounds.
There are two main paths.
Path 1: Complying Development Certificate (CDC)
This is the fast lane. If your plans tick every box in the state rules, you can apply for a complying development certificate. Instead of council debating your design, an accredited certifier checks that it meets a fixed list of standards.
Why people love it:
- It’s often faster. Council describes it as often just a couple of weeks once your application is ready.
- There’s less guesswork, because the rules are fixed.
- Neighbours generally aren’t asked for comments the way they are in a DA.
The catch? You must meet every requirement. Miss one, and you’re out of the fast lane.
Path 2: Development Application (DA)
If your plans don’t fit the fixed rules, or your block has constraints, you go through council with a development application.
- Council assesses your plans on their merits.
- Neighbours may be notified and can comment.
- It takes longer, and you may be asked for changes.
It’s not a bad road. It’s just a slower one. Some sites can only go this way, and plenty of those still get approved.
| CDC (fast path) | DA (council path) | |
| Who decides | Accredited certifier | Council |
| Speed | Usually quicker | Usually slower |
| Flexibility | Low, rules are fixed | Higher, assessed on merit |
| Neighbour comments | Generally not | Often yes |
| Best for | Simple, standard blocks | Tricky or non-standard sites |
Insert image of a person reviewing building plans at a kitchen table here.
Can You Subdivide or Sell a Granny Flat Separately?
Short answer: no.
In NSW, a lot with a secondary dwelling can’t be subdivided to sell the granny flat on its own title. It’s tied to the main house. If you’re dreaming of selling the back flat and keeping the front, that’s a dual occupancy conversation, and a much bigger project.
Can You Rent It Out?
Yes. Many people build a granny flat for exactly this reason. Whether it’s for family now and a tenant later, or purely an income stream, it’s allowed.
Just keep a few things in mind:
- Your rental income may be taxable. Speak to an accountant.
- There are landlord rules to follow, as with any rental.
- Your insurance and council rates may change.
Think of it like a second job for your backyard. A reliable one, if you build it right.
What Does It Cost? (And Where Does the Money Hide?)
I won’t throw a magic number at you, because the cost depends on size, finishes, slope, and services. But I can tell you where the surprises tend to appear:
- Site works. Slopes, rock, and drainage.
- Connections. Sewer, water, power, and stormwater.
- Bushfire or flood requirements. Special materials and design add cost.
- Approval fees. Certifier, council, and any reports you need.
- Landscaping and access. The things people forget until the end.
A fixed-price contract with clear inclusions is your best friend here.
A Simple Pre-Build Checklist
Here’s the order I’d tackle things, if it were my backyard:
- Check your block size and width. Is it 450 sqm or more?
- Order a planning certificate. Find out about flood, bushfire, heritage, and zoning.
- Check for pipes and easements. Know what’s underground.
- Decide the purpose. Family, rental, or both. It shapes the design.
- Get a design that fits the 60 sqm limit. Make every square metre earn its keep.
- Pick your path. CDC if you tick every box, DA if you don’t.
- Get a fixed-price quote. No guessing.
- Plan the build. Access for trucks, trees, and the neighbours.
Common Mistakes (So You Don’t Make Them)
- Assuming the rules are the same everywhere. Councils and sites differ.
- Ignoring flood or bushfire. It can change the design after you’ve paid for it.
- Building over pipes. It’s a quick way to get plans refused.
- Going over 60 sqm “just a little.” Councils measure it exactly.
- Skipping the legal check on titles. Easements or covenants can hide in the paperwork.
- Hiring on price alone. The cheapest quote often leaves things out.
Quick FAQs
How big can a granny flat be in Wollongong? Generally up to 60 sqm of floor area.
What size block do I need? Usually at least 450 sqm for the standard approval path, and many guides also look for a lot width of around 12 metres.
Can I build two granny flats? No. Only one secondary dwelling is allowed per property.
Do I need council approval? You need approval, either through a complying development certificate or a development application.
How long does approval take? A CDC can be quick, often a couple of weeks once everything is ready. A DA takes longer.
Can I subdivide the granny flat? No. It can’t be sold separately from the main house.
Can my family live in it? Absolutely. It’s the classic use, and renting it to a tenant is allowed too.
A Quick Note on 2026
Planning rules in NSW get tweaked regularly. What’s true today might shift next year, and each block has its own story. Treat this guide as a map, not a legal opinion. Always check the latest rules with Wollongong City Council, the NSW Planning Portal, or a qualified professional before you commit.
Final Thoughts: Measure Twice, Build Once
Wollongong is a great place to add a granny flat. The lifestyle’s there, the demand’s there, and the backyards are often just waiting for a purpose.
The rules come down to three things: keep it to about 60 sqm, check your block meets the minimum, and pick the right approval path. Get those right, and the rest is the fun part: choosing finishes, picking a layout, and imagining who’ll be sipping coffee out the back.
If you’d like a hand working out whether your block can take a granny flat, Modern View Constructions Pty Ltd can talk you through your options in plain English. Get in touch for a no-fuss chat about your site, your budget, and your plans. Your backyard has more potential than you think.