NSW Granny Flat Approval Process: Step-by-Step Guide for Homeowners 2026
Author: giantA Pty Ltd — Sydney Architects & Building Designers
Published: 17 July 2026 | Reading time: 8 min
Related: Complete Granny Flat Guide · Cost Breakdown · DA & CDC Guide
Getting Your Granny Flat Approved in NSW
Building a granny flat in NSW is one of the fastest ways to add value to your property and generate rental income. The approval process has been streamlined significantly under the Housing SEPP 2021, with two main pathways: Complying Development Certificate (CDC) and Development Application (DA).
This guide walks you through every step of the approval process — from eligibility checks to obtaining your Construction Certificate.
Step 1: Confirm Your Property is Eligible
Before spending money on design or documentation, verify these requirements:
Lot Size Requirements
| Pathway | Minimum Lot Size | Notes |
|---|---|---|
| CDC (fast-track) | 450m² | Must meet all SEPP standards |
| DA (council) | No fixed minimum | Council discretion applies |
Zoning Requirements
Your property must be zoned under the Housing SEPP: - R1 (General Residential) - R2 (Low Density Residential) - R3 (Medium Density Residential) - R4 (High Density Residential) - R5 (Large Lot Residential) - RU5 (Rural Living)
Special Considerations
- Bushfire-prone land: Must meet Bushfire Attack Level (BAL) requirements
- Flood-prone land: May require raised slab design
- Heritage conservation areas: Usually DA-only, heritage assessment required
- Western Sydney Airport zone (July 2026 update): Ban reversed — granny flats now allowed up to 85m² in Wollondilly, Fairfield, Camden, Liverpool, and Penrith
Quick Eligibility Check
Use the NSW Planning Portal's exempt and complying development tool to check if your property qualifies for CDC. You'll need your property address and lot number.
Step 2: Engage a Building Designer or Architect
Once eligibility is confirmed, engage a licensed professional to prepare your documentation. At giantA, we provide:
Required Documentation Package
| Document | Purpose | Who Prepares |
|---|---|---|
| Site plan | Shows existing + proposed dwelling | Architect / Building Designer |
| Floor plans (scale 1:100) | Layout, room sizes, door/window locations | Architect / Building Designer |
| Elevations (scale 1:100) | External appearance, materials, heights | Architect / Building Designer |
| Sections | Cross-sections showing construction | Architect / Building Designer |
| BASIX certificate | Energy & water efficiency compliance | BASIX Accredited Assessor |
| Structural engineering certificate | Foundation and frame design | Structural Engineer |
| Soil report (if required) | Geotechnical assessment | Geotechnical Engineer |
Design Requirements for SEPP Compliance
Your design must meet these standards:
- Maximum floor area: 60m² internal (85m² in Western Sydney Airport zone)
- Setbacks: Front ≥ 3m, side ≥ 0.9m, rear ≥ 3m
- Height: Maximum 4.5m (single storey) or 5.5m (two storey with restrictions)
- Site coverage: Maximum 50% of lot area (including main dwelling)
- Parking: 1 space for granny flat + existing parking for main dwelling
- Private open space: Minimum 24m² with 3m minimum dimension
Step 3: Obtain Your BASIX Certificate
Every granny flat in NSW requires a BASIX certificate confirming compliance with the Building Sustainability Index.
2026 BASIX Requirements for Granny Flats
| Category | Target | How to Achieve |
|---|---|---|
| Energy | 7-star minimum | Insulation, efficient glazing, solar PV |
| Water | Reduction targets | Water-efficient fixtures, rainwater tanks |
| Thermal comfort | Heating/cooling limits | Orientation, shading, ventilation |
| Materials (new 2026) | Embodied carbon index | Sustainable materials, mass timber |
BASIX Cost for Granny Flats
- DIY via NSW Planning Portal: ~$50–$100
- Professional BASIX assessment: $800–$1,500 (includes optimisation advice)
- giantA BASIX service: Included in our design package
Tip: The new Materials Index introduced in 2026 measures embodied carbon. Choosing timber framing over steel can reduce your materials score by 30–40%, making compliance easier and cheaper.
Step 4: Choose Your Approval Pathway
Pathway A: Complying Development Certificate (CDC)
Timeline: 10–20 days
Cost: $2,000–$5,000 (certifier fees)
Best for: Standard designs on eligible lots
Advantages: - No council involvement — private certifier handles everything - No neighbour notification required - Faster approval (10–20 days vs 6–12 weeks) - Lower fees - Can start construction sooner
Requirements: - Must meet ALL Housing SEPP standards - Lot ≥ 450m² - Standard setbacks and heights - Not on bushfire-prone land (or BAL ≤ 29) - Not in heritage conservation area - Not on flood-prone land (or FFL ≤ 0.5m AHD)
Pathway B: Development Application (DA)
Timeline: 6–12 weeks
Cost: $3,000–$8,000 (council fees + consultant time)
Best for: Complex sites, non-standard designs, heritage areas
Advantages: - More design flexibility - Can seek variations to standards - Works for any lot size (council discretion) - Can include landscaping and driveway in same application
Process: 1. Prepare Statement of Environmental Effects (SEE) 2. Submit via NSW Planning Portal to your local council 3. Council assesses against Local Environmental Plan (LEP) and Development Control Plan (DCP) 4. Neighbour notification (14–30 days) 5. Council determination (approve / refuse / conditions)
Step 5: Lodge Your Application
For CDC (Private Certifier)
- Choose an accredited certifier: Find certifiers via NSW Building Professionals Board
- Submit documentation: Upload all plans, BASIX certificate, engineering certificates
- Pay certifier fee: $2,000–$5,000 depending on complexity
- Certifier assessment: 10–20 days (may request clarifications)
- Receive CDC: Start construction within 12 months
For DA (Local Council)
- Complete application form: Via NSW Planning Portal
- Upload documents:
- Site plan + architectural drawings
- BASIX certificate
- Statement of Environmental Effects
- Structural engineering certificate
- Consultation report (if required)
- Pay council fees:
- Application fee: $500–$1,500
- Construction cost levy: ~0.5% of construction value
- Long service levy: ~0.35% of construction value
- Council assessment: 6–12 weeks
- Receive determination: With conditions (if approved)
Step 6: Obtain Construction Certificate (CC)
Before any construction begins, you need a Construction Certificate confirming your building plans comply with the Building Code of Australia (BCA).
Who issues: - Same private certifier (if CDC pathway) - Council or accredited certifier (if DA pathway)
Required inspections during construction:
| Stage | What Certifier Checks |
|---|---|
| Slab/foundations | Concrete strength, reinforcement, levels |
| Frame | Timber/steel framing, bracing, tie-downs |
| Roof | Structural integrity, waterproofing |
| Waterproofing | Wet areas — bathrooms, laundry |
| Final inspection | Complete build, safety, BCA compliance |
Step 7: Build and Obtain Occupation Certificate
Construction timeline: 3–6 months
Typical Build Sequence
- Site preparation (1 week): Clear, level, set out
- Slab/foundations (1–2 weeks): Concrete slab or piers
- Frame (2–3 weeks): Timber or steel frame erected
- Roof + external (3–4 weeks): Roofing, cladding, windows
- Services (2–3 weeks): Plumbing, electrical, HVAC
- Internal fit-out (3–4 weeks): Gyprock, flooring, kitchen, bathroom
- Final touches (1 week): Painting, landscaping, driveway
Final inspection: Certifier conducts final inspection → issues Occupation Certificate → you can legally occupy or rent the granny flat.
How long does the entire process take?
| Phase | CDC Timeline | DA Timeline |
|---|---|---|
| Design & documentation | 2–4 weeks | 2–4 weeks |
| BASIX certificate | 1–2 weeks | 1–2 weeks |
| Approval (CDC/DA) | 10–20 days | 6–12 weeks |
| Construction Certificate | 5–10 days | 5–10 days |
| Construction | 3–6 months | 3–6 months |
| TOTAL | 5–8 months | 7–11 months |
How much does granny flat approval cost?
| Cost Item | CDC | DA |
|---|---|---|
| Design & documentation | $5,000–$15,000 | $5,000–$15,000 |
| BASIX certificate | $50–$1,500 | $50–$1,500 |
| Approval fees | $2,000–$5,000 | $3,000–$8,000 |
| CC fees | Included or $500–$1,000 | $500–$1,000 |
| Council levies | N/A | $1,000–$3,000 |
| Approval total | $7,550–$22,500 | $9,550–$28,500 |
| + Construction | $100k–$200k | $100k–$200k |
Why Use giantA for Your Granny Flat Approval?
At giantA Pty Ltd, we handle the entire approval process end-to-end:
✅ Eligibility assessment — Check your property for CDC or DA suitability
✅ Architectural design — Custom plans that maximise your 60m²
✅ BASIX certification — 7-star energy rating, including Materials Index optimisation
✅ CDC/DA lodgement — We prepare all documentation and submit on your behalf
✅ Private certifier liaison — We know the best certifiers in Sydney
✅ Construction Certificate — Structural engineering included
✅ Council liaison — We handle DA assessments and variations
📞 Call: +61 488 880 787 | 📧 Email: info@gianta.com.au
📍 Visit: Parramatta CBD, Western Sydney
Frequently Asked Questions
Can I convert an existing shed or garage into a granny flat?
It depends. If the structure meets BCA requirements (ceiling height, insulation, waterproofing, fire safety), a Section 4.55 modification or CDC for alterations may be possible. However, most existing sheds don't meet habitable building standards. A new build is usually more cost-effective.
What happens if my CDC application is refused?
If your CDC is refused, you can either: 1. Modify your design to meet SEPP standards and re-apply for CDC 2. Switch to the DA pathway with your local council 3. Seek a Section 4.6 objection if you believe the refusal was incorrect
Can I build a two-storey granny flat?
Yes, but with restrictions. Under the Housing SEPP, a secondary dwelling can be two-storey if: - Total floor area still ≤ 60m² (or 85m² in Western Sydney Airport zone) - Height ≤ 5.5m - Does not overshadow neighbouring properties - Meets all setback requirements
Most granny flats are single-storey due to the 60m² limit.
Do I need a separate water and electricity meter for my granny flat?
Not required by law, but highly recommended for rental properties. Separate meters: - Allow individual billing for tenants - Simplify BASIX compliance calculations - Cost: $2,000–$4,000 for separate electricity; $1,500–$3,000 for separate water
How do I know if my property is in the Western Sydney Airport zone?
Check your property address against the Aircraft Noise Ombudsman map or contact your local council. The July 2026 reversal applies to: - Wollondilly Shire - Fairfield City - Camden Council - Liverpool City - Penrith City
If you're in these areas, you can now build granny flats up to 85m² (increased from 60m²).
Resources
- NSW Planning Portal — Secondary Dwellings
- Housing SEPP 2021 — Full Policy
- giantA Complete Granny Flat Guide 2026
- giantA BASIX & NatHERS Services
- giantA Cost Estimating
Last updated: 17 July 2026. Information accurate at time of publication. Always verify current regulations with NSW Planning and your local council.
giantA Pty Ltd | Licensed Building Designer | BASIX Accredited Assessor