Dual occupancy · Ku-ring-gai Council
Duplexes in Ku-ring-gai
What a house block in Ku-ring-gai Council's area needs before it can carry two homes: the LEP minimum (not permitted in R2 under the LEP), whether the state 450 m² / 12 m Low and Mid-Rise rule reaches here, and how the two homes can be titled. Read from the LEP text; the address check applies it to your lot.
The minimums under the LEP
Dual occupancies are not in the R2 land-use table of the Ku-ring-gai LEP, so outside the state Low and Mid-Rise catchment they are not permitted; inside it, cl 4.1A (inserted 2025) sets 1,015 m² and a split into two titles needs 507.5 m² per lot (cl 4.1B) — a planner confirms how the state rule and the LEP figure interact on your lot.
Low and Mid-Rise
Inside the state Low and Mid-Rise area — within about an 800 m walk of a listed town centre or station — the Housing SEPP overrides the LEP: a dual occupancy on a lot of 450 m² with a 12 m frontage at the building line, FSR 0.65:1, 9.5 m high, in any R2 zone. Block Checker reads the centre layer on the Planning Portal and tells you which side of the line your lot is on. Bushfire-prone, flood-control and heritage land is carved out and the LEP figures come back.
Can I split it into two titles?
Inside the Low and Mid-Rise area (an 800 m walk of the listed centres), the state rule (Housing SEPP s 169) lets a duplex approved on or after 28 February 2025 be split onto two Torrens lots of at least 225 m² each, 6 m wide at the front building line — one home on each, both fronting the street, no battle-axe lots. So the 450 m² / 12 m minimum lot splits side by side into two 225 m² / 6 m lots. It does not cover strata subdivision.
Outside that area, or on bushfire-prone or heritage land, the council decides. Under the LEP: inside it, cl 4.1A (inserted 2025) sets 1,015 m² and a split into two titles needs 507.5 m² per lot (cl 4.1B). The address check tells you which applies to your block.
What the blocks here actually measure
We ran 25 real addresses in each of these Ku-ring-gai suburbs through the engine. Median lot and frontage, and how many of the blocks we checked could carry two homes today. A spread of the addresses the NSW geocoder returns, not a census of the suburb.
| Suburb | Median lot | Median frontage | Two homes | Granny flat |
|---|---|---|---|---|
| Gordon | 945 m² | 18.7 m | 8 of 25 | 25 of 25 |
| Wahroonga | 974 m² | 18.5 m | 7 of 25 | 25 of 25 |
| Lindfield | 925 m² | 18.4 m | 5 of 25 | 25 of 25 |
| Warrawee | 935 m² | 18.4 m | 5 of 25 | 25 of 25 |
| Roseville | 846 m² | 18.3 m | 4 of 25 | 20 of 25 |
| Pymble | 942 m² | 19.9 m | 3 of 25 | 24 of 25 |
| Turramurra | 982 m² | 19.7 m | 3 of 25 | 23 of 25 |
| St Ives | 933 m² | 19.8 m | 1 of 25 | 23 of 25 |
Getting it approved
A DA to Ku-ring-gai Council is the universal route and the only one on heritage or constrained lots. A CDC from a private certifier under the Low Rise Housing Diversity Code fast-tracks a code-compliant pair (the greater of 400 m² and the council minimum, and 15 m at the building line — 12 m only where the parking comes off a lane or secondary road, no heritage, no bushfire). The Pattern Book pathway uses a pre-approved NSW design on a level lot that meets its tests — subject to survey (slope). Splitting the pair onto two titles is covered above.
What catches owners out here
- Frontage at the building line — the state rule measures width where the homes sit, not at the kerb; a splayed block can lose a metre.
- Just under — 449 m² is not 450 m². The area shown is the deposited-plan area; a registered survey settles it.
- Constraints — bushfire-prone, flood-control and heritage land takes the lot out of the state rules and the fast-track routes and back to the LEP figures and a DA.
- Easements and sewer — not on the public maps; order the section 10.7 certificate and the sewer diagram before you design.
Questions owners ask
What is the minimum lot size for a duplex in Ku-ring-gai?
It depends on the zone and the LEP; run the address. Inside the state Low and Mid-Rise area, within about an 800 m walk of a listed centre or station, the test is 450 m² with a 12 m frontage at the building line instead.
Can I build a duplex on a 450 m² block in Ku-ring-gai?
Only inside the Low and Mid-Rise area, on R2 land that is not bushfire-prone, flood-controlled or heritage, and only with 12 m of frontage at the building line. Outside that area the council minimum applies.
Can I subdivide a duplex in Ku-ring-gai into two titles?
Inside the Low and Mid-Rise area, yes, for a pair approved on or after 28 February 2025: Torrens lots of at least 225 m² each with 6 m of frontage, no battle-axe. Outside it, the LEP and its Lot Size Map decide.
Do I need a DA for a duplex in Ku-ring-gai?
A DA to Ku-ring-gai Council is the universal route. A code-compliant pair on a clear lot can go through a private certifier as a CDC under the Low Rise Housing Diversity Code, and a level lot that meets the tests can use a Pattern Book design, subject to survey.
More: the Ku-ring-gai Council guide (granny flats, C4, links) · granny flats in Ku-ring-gai · duplex rules across NSW · the Low and Mid-Rise policy · the Pattern Book.
Enter the address — lot, frontage, zone, the Low and Mid-Rise line and the LEP minimum, in about ten seconds.