Granny Flat Pricing Guide 2025–26

The short version: 2025–26 starting prices

Design	Size	Starting price	What's included
The Darkinjung	1 bed, 1 bath, 50m²	$130,000	Slab to paint, kitchen, bathroom, electrical, plumbing. Excludes site prep, approvals, services connection.
The Biripai	1 bed + studio, 1 bath, 60m²	$145,000	As above + 16m² studio with separate entry, extra power circuits, polished concrete studio floor.
The Awabakal	2 bed, 1 bath, 60m²	$155,000	As above + second bedroom, separate laundry.
The Gringai	2 bed, 1 accessible bath, 65m²	$165,000	As above + Level 2 Livable Housing compliance: widened doorways, step-free entry, accessible bathroom, reinforced walls for grab rails. NDIS SDA-ready.
The Wonnarua	2 bed + study, 2 bath, 70m²	$175,000	As above + second bathroom (ensuite), separate study nook with built-in desk and data cabling.
The Worimi	3 bed, 2 bath, 80m²	$220,000	As above + third bedroom, walk-in pantry, 4.2kW split system in living, ceiling fans in all bedrooms. This is a proper small house.

What drives the final cost?

These are the six things that push a granny flat from the starting price to the final invoice. Not all apply to every job — but understanding them helps you budget.

1. Site preparation ($5k–$35k+ depending on block)

If your block is flat, well-drained, and already cleared, site prep is cheap — maybe $5k to scrape topsoil, compact the pad, and pour a slab. If your block slopes, has rock, needs retaining walls, or requires cut-and-fill, site prep can hit $25k–$35k. We can't quote this without seeing the block.

What's included in site prep: excavation, retaining walls (if needed), pad compaction, termite barrier, slab pour, and all earthworks to get the site level and ready for framing.

Central Coast reality check: Wyong/Tuggerah/Lake Haven blocks are often flat — site prep is usually $5k–$10k. Gosford/Terrigal/Avoca/Copacabana blocks are often sloping — site prep can be $15k–$25k. Lake Macquarie/Newcastle/Cessnock blocks vary wildly — we've done $8k jobs in Morisset and $30k jobs in Redhead. Call 0448 368 354 with your address and we'll give you a ballpark over the phone.

2. Services connection ($3k–$12k depending on distance)

Every granny flat needs sewer, water, and power. If your main house is 10m away and you can tap into its services easily, connection is cheap — $3k–$5k. If your main house is 50m away, or you need to trench under a driveway, or you need to upgrade your main switchboard to handle the extra load, connection can be $8k–$12k.

What's included: plumber to connect sewer and water from the granny flat to your main house (or street if that's closer/cheaper), electrician to run power from your main switchboard (or street pole if you need a separate meter), and all trenching/conduits/labour.

Separate meter or not? Most clients don't bother — they keep the granny flat on the same meter as the main house. If you're renting it out long-term and want the tenant to pay their own power, you'll need a separate meter — add $1.5k–$2.5k for the meter application and switchboard upgrade (Ausgrid if you're Central Coast/Lake Mac/Newcastle; Essential Energy if you're Hunter). Talk to your sparky and your accountant.

3. Council approval ($3.5k–$12k depending on CDC vs DA)

Most granny flats under 60m² habitable area qualify for Complying Development (CDC) — 10-day approval instead of 3-month DA. CDCs cost $3,500–$4,500 all-in (private certifier fee + Council notification fee + plans). If your block is bushfire-prone, flood-affected, heritage-listed, or your granny flat is over 60m², you'll need a full DA — $8k–$12k and 8–12 weeks.

Koori does the approval legwork: We organise the CDC or DA for you. You don't chase the certifier or the Council. We handle it. The fee is separate from the build cost — we quote it after we see your block and confirm CDC/DA eligibility.

Which of our designs need a DA? The Darkinjung (50m²), Biripai (60m²), and Awabakal (60m²) almost always qualify for CDC. The Gringai (65m²), Wonnarua (70m²), and Worimi (80m²) usually need a DA unless your block is large, flat, and unconstrained. We'll tell you which path you're on after the site visit.

4. Upgrades ($0–$30k+ depending on taste)

Our standard spec is good — laminate benchtops, vinyl plank flooring, BIRs, Colorbond roof, Hebel or weatherboard cladding, basic tap/light/powerpoint selection. Most clients are happy with it. Some want upgrades:

• Stone benchtops: +$3k–$5k (reconstituted stone like Caesarstone or Quantum Quartz)
• Timber or hybrid flooring: +$4k–$7k (depends on m²)
• Upgraded appliances: +$1.5k–$3k (dishwasher, better oven, induction cooktop)
• Better bathroom fixtures: +$1k–$2k (rainfall showerhead, wall-hung vanity, better tapware)
• Extra insulation (ceiling + walls): +$2k–$3k
• Ducted air con instead of split system: +$6k–$10k
• Solar panels (3kW system): +$4k–$6k after rebates
• Deck or patio: +$5k–$12k depending on size and material

We never upsell. If you're happy with standard spec, we build standard spec. But if you want to live in the granny flat yourself (not rent it out), or you're targeting the premium Airbnb market, upgrades can make sense. We'll talk you through the ROI.

5. Driveway, fencing, landscaping ($3k–$15k+ depending on scope)

Most clients want a driveway or path to the granny flat, some fencing for privacy, and basic landscaping (turf, garden beds, maybe a clothesline). We can do all of it, or you can DIY/get your own landscaper. Typical costs:

• Concrete driveway (15m × 3m): $5k–$7k
• Gravel driveway (same size): $2k–$3k
• Colorbond fencing (20m run): $4k–$6k
• Basic landscaping (turf, garden beds, retaining): $3k–$8k

We quote this separately — it's not part of the granny flat build cost, but we can include it in the same contract if you want one invoice and one builder coordinating everything.

6. Slope, access, and "your block is weird" factors ($0–$20k+)

Some blocks are easy. Some blocks are nightmares. If your block has any of these, expect extra cost:

• Rock: If we hit rock during excavation, we need a rock breaker or an excavator with a hammer attachment — add $3k–$8k depending on how much rock.
• No vehicle access: If we can't get a truck or excavator to the build site (e.g. your granny flat is behind your house and there's no side access), we need a crane or a smaller machine — add $5k–$10k.
• Steep slope (>1m fall across footprint): You'll need retaining walls or piers/stumps instead of a slab — add $10k–$20k.
• Contaminated soil or asbestos: If your block has old fill or building materials, we need to remove and dispose of it safely — add $5k–$15k depending on volume.
• Bushfire Attack Level (BAL) 12.5 or higher: You'll need bushfire-rated cladding, ember guards on vents, and tempered glass — add $8k–$15k.

We spot these issues during the site visit and quote them upfront. No surprises halfway through the build.

Real-world pricing examples (Central Coast, Lake Mac, Newcastle, Hunter)

These are real jobs we've quoted or built in 2024–25. Addresses changed for privacy, but the numbers are real.

How to get an accurate quote (it's faster than you think)

1. Call or email Brad: 0448 368 354 or brad@kooriconstructions.com.au. Tell us: (1) your address, (2) which design you like (or "not sure yet"), (3) whether you're renting it out or living in it, (4) rough timeframe (e.g. "want to start in 3 months").
2. We do a site visit (free): Brad or a site supervisor visits your block, takes photos, checks slope/access/services, and measures up. Takes 30–45 minutes. You don't need to be there (but it helps if you are).
3. We send you a fixed-price quote within 48 hours: Broken down into: (1) granny flat build cost, (2) site prep, (3) services connection, (4) approvals, (5) driveway/fencing/landscaping if you want it, (6) upgrades if you want them. One total number. Valid for 30 days.
4. You say yes, we lock in the price and start: 10% deposit, we organise the CDC/DA, order materials, lock in the build schedule. You pay progress payments at each stage (slab/frame/lockup/fit-out/handover). No variations unless you change the scope.

Payment structure (how it works, when you pay)

We use the HIA Renovations, Extensions and Alterations Contract — the industry-standard contract for residential building work in NSW. It's fair, it's transparent, and it protects both of us. Here's the typical payment schedule for a granny flat:

1. 10% deposit on contract signing: Secures your build slot, covers our preliminary costs (approvals, plans, materials ordering).
2. 15% on slab pour: After we pour the slab and it's cured (usually week 2–3 of the build).
3. 30% on frame-up: After the frame, roof trusses, and roof sheeting are complete (usually week 5–6).
4. 25% on lockup: After windows, doors, external cladding, and roofing are complete — the granny flat is "locked up" and weatherproof (usually week 9–10).
5. 15% on fit-out complete: After internal linings, kitchen, bathroom, flooring, painting, and electrical/plumbing rough-in are done (usually week 13–14).
6. 5% on handover: After final inspection, Occupation Certificate issued, and you've done the walk-through with us. We hand over keys, warranties, and manuals.

Total: 10% + 15% + 30% + 25% + 15% + 5% = 100%.

We never ask for payment upfront for the full job. We never ask for payment before we've done the work for that stage. If we don't finish a stage, you don't pay for it. That's the HIA contract working as designed.

Frequently asked questions

Can I get a granny flat for under $130k?

Not from a licensed NSW builder in 2025–26. Materials cost what they cost. Labour costs what it costs. Anyone quoting under $130k for a liveable granny flat is either: (1) unlicensed (you have no warranty protection and no insurance coverage), (2) quoting a shell-only price (you still need to pay for kitchen, bathroom, flooring, paint), or (3) about to go broke halfway through your job. We've seen all three. If $130k is out of reach, consider: (1) waiting 12–18 months and saving more, (2) building a smaller studio or sleepout instead (not a granny flat, but cheaper), or (3) applying for an NDIS home modification grant if the granny flat is for someone with disability (The Gringai qualifies).

Why are granny flats so expensive compared to a house per-square-metre?

Because the fixed costs (slab, kitchen, bathroom, plumbing, electrical, roof) don't scale down. A 50m² granny flat has the same kitchen and bathroom as a 150m² house — but the house spreads those costs over 3× the area. That's why granny flats cost $2,600/m² and houses cost $1,800–$2,200/m². It's not a rip-off, it's just economics. The only way to make granny flats cheaper is to build 100 of them a year (factory-style) and reduce labour costs — and even then, you're still looking at $2,200–$2,400/m² after site costs.

Do I need a separate meter for the granny flat?

Not legally, no. Most clients keep the granny flat on the same meter as the main house (cheaper, simpler). If you're renting it out long-term and want the tenant to pay their own power bill, you'll need a separate meter — add $1.5k–$2.5k for the meter application and switchboard upgrade. Talk to your accountant about the tax treatment (if you're claiming the granny flat as an investment property, a separate meter makes expense tracking easier).

Can I claim the granny flat cost on tax if I'm renting it out?

Yes — if you're renting the granny flat out (including Airbnb), you can claim depreciation on the build cost over 40 years (2.5% per year), plus claim interest on any loan, plus claim a portion of your rates/insurance/maintenance. Talk to your accountant — this is not tax advice. But yes, granny flats are a legitimate investment property tax deduction. You'll need a depreciation schedule from a quantity surveyor (costs $400–$700, pays for itself in year 1).

How long does a granny flat build actually take?

12 to 16 weeks from slab pour to handover, weather permitting. Add 6–10 weeks for CDC approval + site prep if you're starting from scratch. So 18–26 weeks total if you call us today with an empty backyard and no approvals yet. If you need a DA (not a CDC), add another 4–8 weeks to the approval timeline. We'll give you a locked-in handover date in your contract (subject to weather delays and material availability — but we've never missed a handover date by more than 2 weeks in 4 years).

What's your warranty?

Structural warranty: 6 years (required by law under Home Building Act 1989). Non-structural warranty: 2 years (plumbing, electrical, painting, joinery). Manufacturer warranties on appliances (ovens, cooktops, hot water systems) pass through to you — typically 1–5 years depending on the product. All covered by Home Building Compensation Fund insurance (you get a certificate on handover). If we go out of business (we won't, but insurance is insurance), the fund covers up to $340,000 for incomplete or defective work.