Can I build a duplex or granny flat in Kings Langley?

The typical Kings Langley block

The middle block of the 25 we checked is 698 m² with 18.4 m of street frontage. The smallest was 674 m² and the largest 935 m². Zones in the sample: R2 (25).

What homes sell for in postcode 2147

Median sale prices for the whole of postcode 2147, January to March 2026. These cover every suburb sharing the postcode, not Kings Langley alone, and they are not a value for any one block.

• Houses: $1.31m (77 sales)
• Units and apartments: $1.05m (11 to 30 sales, a small sample)

Source: NSW Government Rent and Sales Report (Department of Communities and Justice), sales tables by postcode, NSW Government. Updated each quarter.

A granny flat

24 of the 25 blocks we checked could take one. Blacktown LEP cl 5.4(9) — the greater of 60 m² or 5% of the house’s total floor area, parking excluded. Separately, the state Housing SEPP allows a granny flat of up to 60 m² through the ten-day complying-development route on a lot of 450 m² or more with a 12 m frontage, where the land is not flood, bushfire or heritage constrained.

Dual occupancy (duplex) rules in Kings Langley

25 of the 25 blocks we checked could carry two or more separate homes today.

Under Blacktown Local Environmental Plan 2015 a dual occupancy needs 500 m² — this LEP sets no frontage minimum, so Council's DCP governs width.

Of the 25 ordinary R2 blocks in our sample sitting outside the Low and Mid-Rise area, 25 had the 500 m². There is no LEP frontage test to pass here, but Council's DCP still judges width, setbacks and private open space, so clearing the area alone does not settle it.

Low and Mid-Rise

None of the 25 blocks we checked fell inside the state Low and Mid-Rise area, so in this part of Kings Langley the LEP minimums are what count. The boundary is a walking distance from a listed centre, so it can cut through a suburb — the checker reads which side of it your own address sits on.

What else turned up

None of the blocks we checked came back bushfire-prone, flood-mapped or heritage-listed. Any of those takes a block out of the fast-track routes and into a full DA, so it changes the answer more than the lot size does.

How we got these numbers

We took 25 real Kings Langley street addresses from the NSW geocoder and ran every one through the same engine this site runs for you, reading the planning controls live. Nothing here is modelled or estimated.

It is a sample, not a census. The addresses are a spread across what the geocoder returns, so treat these as "of the 25 blocks we checked" rather than a figure for every block in Kings Langley. Your own block is the only one that answers for itself — that is what the box on the right is for.