What the SEPP actually allows
Under the NSW Affordable Rental Housing SEPP, eligible blocks (typically 450m²+, residential zoning) can build a secondary dwelling up to 60m² internal floor area via the Complying Development Certificate (CDC) pathway — usually approved in 10–20 business days. Larger or non-compliant designs need a DA. See built examples on our granny flats page.
Setback and siting rules
Minimum 3m rear setback, 0.9m side setbacks (more on wider blocks), and the dwelling can't reduce private open space below 24m². Tree retention, easements and overshadowing all need checking before quoting.
Realistic budgets in 2026
A finished-to-main-house-standard 60m² granny flat in Sydney runs $220k–$340k turnkey, including services connection, kitchen and bathroom. Cheaper kit-style options exist but rarely match the finish or longevity owners actually want.
Rental yield vs family use
Sydney granny flats typically rent for $450–$700/week depending on suburb. We design for both — flexible layouts that work for family today and rent tomorrow without compromise. If a full additional wing makes more sense, see our extensions option.
Frequently asked
Quick answers
- What is the maximum granny flat size in NSW?
- 60m² internal floor area under the CDC pathway via the NSW Affordable Rental Housing SEPP. Larger dwellings require a Development Application.
- How long does CDC approval take for a granny flat?
- Typically 10–20 business days once a complete CDC application is lodged with a registered certifier.
- Can I subdivide and sell the granny flat separately?
- No — secondary dwellings under the SEPP cannot be separately titled or sold. They must stay on the same lot as the principal dwelling.
