Short answer, because that's what you came for: a granny flat in NSW usually lands between $120,000 and $250,000 all up. Big gap, I know. The reason it's that wide is the whole point of this post.
We get asked about this a lot around the Gong. Usually it's someone who's seen a kit advertised at $90k, then a builder up the road quoted them more than double, and they want to know who's having a lend. Truth is both numbers can be right. It comes down to what's actually in the price, and what your block does to the job once you start digging.
What you're really paying for
A budget kit or prefab, dropped on a flat block with easy access and basic finishes, sits around $120k to $150k. A custom build, proper kitchen and bathroom, slab poured on a site that isn't dead flat, you're looking at $180k to $250k. Start picking nice tiles and stone and joinery and it climbs from there.
Here's what shifts the number around the most:
- The block itself. Half the lots around the escarpment have a fall on them. A sloping site means engineered footings, a stepped slab or a suspended floor, sometimes retaining and piers before you've framed a single wall. This is the cost people don't see coming, and it's different on every site.
- Access. If a concrete truck and a couple of utes can pull straight up the side, beautiful. If every barrow load has to go down the side passage or get craned over the house to the back yard, that's days and dollars you won't get back.
- Services. Power, water and sewer to a second dwelling is rarely simple. How far the flat sits from what's already there, whether the existing sewer's at the right depth, whether your stormwater can take more roof. A messy connection can be five figures on its own.
- Size and finishes. A studio costs less per square metre than a two-bedder. Laminate and a builder's-range bathroom versus stone and full-height tiling. Same footprint, very different invoice.
One more, and it matters down here. Salt air. Near the water you want exterior timber, fixings and flashing that'll actually cope, and decent eaves to keep the weather off. The southerlies that come through Wollongong aren't gentle. Saving a grand on the build envelope is the kind of thing that bites you in five years.
Build cost vs the carpentry
This is the bit where I'll be straight with you, because plenty of mobs won't.
We're chippies. All Round Carpentry does the carpentry and building side of a granny flat, not the full turnkey job. Framing, subfloor or deck structure, wall and floor structure, linings, doors, the fit-out, cabinetry and vanity install. The bones, and a fair whack of the finish.
What we don't touch, and won't pretend to, is the wet trades and the paperwork. Plumbing, electrical, waterproofing and tiling are licensed trades in their own right. A carpenter isn't a plumber or a sparky, and certification is the certifier's job. On a granny flat those bits get handled by the relevant licensed trades and we work in alongside them. No own people lined up? Dave can put you onto blokes we've used for years.
So a turnkey quote is the lot bundled together, and the carpentry is one slice of it. Often a big slice. Still a slice. Knowing that helps you read a quote and see where the money's really going. If you're project-managing it yourself and lining up your own trades, you can bring us in for just the carpentry, and that changes how you budget the whole thing.
Decks and fencing are different. Those we do end to end, the full job, whether it's spotted gum, merbau, treated pine or a composite board. If your plan's got a deck off the flat or a run of fencing to split the yard, that part's squarely ours.
CDC or DA, and why your wallet cares
Quick version, because the approval path sets your timeline and a chunk of your cost.
Most granny flats in NSW (the proper term is a secondary dwelling) go through a Complying Development Certificate, or CDC. Tick the boxes under the state housing policy and a private certifier signs it off without it ever going near council. Faster, usually a few weeks, and far more predictable.
If your site doesn't comply, that's a Development Application through your council, whether that's Wollongong, Shellharbour, Kiama or Shoalhaven. Odd lot size, heritage, flood or bushfire land will all push you down this road. A DA takes longer and stacks up more in fees and reports. Worth finding out which path you're on before anything else, because it shapes the rest of it.
We don't do approvals or certification, that's the certifier's, but get it sorted before anyone swings a hammer.
The honest takeaway
Want one number? Budget $150k to $200k for a solid granny flat in the Illawarra. Well under that is a kit on an easy site. Well over is a custom build or a hard block, sometimes both. Get a couple of real quotes, ask flat out what's in and what's out, and make sure the site work and the services are actually costed instead of buried in a footnote.
If it's the carpentry you're after, or you just want a hand reading where the build cost sits before you commit to anything, call Dave on 0414 007 351 or send the form through for a free quote. We're local, fully licensed and insured, Helensburgh down to Nowra, and we'll talk it through straight before you spend a cent.
Want a hand with this at your place? Get a free quote or call 0414 007 351.