Granny Flat Rules and Sizes in NSW 2026 — What You Can Build

Granny Flat Rules in NSW 2026 — Sizes, Setbacks, and What You Can Build

NSW has some of the most permissive granny flat rules in Australia. Under the State Environmental Planning Policy (Affordable Rental Housing), you can build a secondary dwelling (granny flat) on any residential-zoned lot over 450 sqm — regardless of whether your council likes them or not. The SEPP overrides local council DCPs for granny flats that meet the specified standards.

Buildana (Lic. 487805C) builds granny flats across Fairfield, Liverpool, Cumberland, Canterbury-Bankstown, and Blacktown. Here are the rules, sizes, and practical considerations for 2026.

Size Limits and Configuration Rules

Maximum internal floor area: 60 sqm. This is measured as the internal floor area and does not include garages, carports, porches, verandahs, or balconies.

Practical layouts within 60 sqm:

• 1-bedroom (45–55 sqm): One bedroom, one bathroom, open plan living/kitchen/dining. Most popular for rental — compact but functional. • 2-bedroom (55–60 sqm): Two bedrooms, one bathroom, compact living/kitchen. Popular for families or sharing. Bedrooms may be smaller (approximately 3m × 3m). • Studio (30–40 sqm): Open plan living/sleeping area with bathroom and kitchenette. Suitable for single occupants or short-term accommodation.

The 60 sqm limit sounds small — but well-designed granny flats are surprisingly livable. Key design strategies: • Open plan living — combine kitchen, dining, and living into one flowing space • Built-in storage — wardrobes, kitchen pantry, bathroom cabinets designed into the layout • Indoor-outdoor connection — a covered verandah or patio (not counted in the 60 sqm) extends the living space • Natural light — windows on multiple walls and skylights if needed • Bathroom efficiency — combined laundry and bathroom saves space

Setbacks, Height, and Placement Rules

Under the NSW Complying Development Code (Housing Code), granny flat setbacks are:

• Front setback: behind the building line of the main dwelling (cannot be closer to the street than the house) • Side setback: 0.9m minimum from side boundaries • Rear setback: 3m minimum from rear boundary • Setback from main dwelling: 3m minimum from the primary dwelling

Height limit: Maximum 3.8m for a flat roof or 5.4m for a pitched roof. This means granny flats are single storey only.

Site coverage: The total site coverage (main dwelling + granny flat + garages) cannot exceed 60% of the lot area.

Private open space: The granny flat must have a minimum 24 sqm private outdoor area with a minimum dimension of 3m.

These rules are non-negotiable under CDC. You can vary them through a DA application to council — but this adds time and cost, and council may refuse the variation.

Approval Process — CDC vs DA

The vast majority of granny flats are approved via CDC (Complying Development Certificate):

• Timeline: 10–15 business days from lodgement to approval • Cost: $3,000–$5,000 (private certifier fees) • No neighbour notification required • Certainty: if your design meets all code requirements, approval is guaranteed

You need a DA (Development Application) when: • The granny flat does not meet one or more CDC setback or coverage requirements • The block is in a heritage conservation area • The block is flood-prone • You want to exceed the 60 sqm limit (some councils may consider this — but rarely approve over 60 sqm)

DA timeline: 40–90 days depending on council. Cost: $5,000–$12,000.

Documentation required for CDC or DA: • Architectural drawings (floor plan, elevations, site plan) • BASIX certificate • Structural engineering • Stormwater management plan • Survey of the property (if one does not exist)

Buildana manages the full approval process — from design through to certificate issue. For the costs of building a granny flat, see our granny flat cost guide. For rental income analysis, see our granny flat rental yield guide.

Construction Cost — Granny Flat 2026

Granny flat construction costs in Western Sydney (2026, Rawlinson adjusted):

• Budget (40 sqm, basic fit-out, fibro or weatherboard cladding): $90,000–$120,000 • Standard (50–60 sqm, medium fit-out, brick veneer): $130,000–$165,000 • Quality (60 sqm, full kitchen, quality bathroom, brick veneer/render): $165,000–$200,000

Additional costs: • Sewer connection (Sydney Water Section 73): $5,000–$15,000 • Electrical sub-board and separate meter: $3,000–$6,000 • Driveway or path access: $3,000–$8,000 • Rainwater tank (BASIX): $2,500–$4,500 • Landscaping: $3,000–$8,000

Total all-in cost: $135,000–$245,000 depending on size, spec, and site conditions.

Buildana's fixed-price granny flat contracts include all approvals, construction, connections, and basic external works. No provisional sums, no surprises.

For granny flat vs duplex comparison, see our granny flat vs duplex guide. For more on our granny flat services, visit /homes/granny-flats. Contact us at /contact for a free assessment.