Every planning control identified for any lot | Every planning rule & overlay cross-referenced in one query | Approval likelihood scored for every control | Conflicts and overrides resolved automatically | Every answer cited to the source clause | Ask planning questions in plain English | Results in under 1 second | Every planning control identified for any lot | Every planning rule & overlay cross-referenced in one query | Approval likelihood scored for every control | Conflicts and overrides resolved automatically | Every answer cited to the source clause | Ask planning questions in plain English | Results in under 1 second |
Suburb planning guide · Updated 2026-04-27

Thornleigh, NSW 2120 Zoning, development potential & planning controls

Low Density Residential dominant. Median sale $1.58M over the last 24 months. 88% of decided DAs approved.

Dominant zone
R2
Low Density Residential
Median sale (24m)
$1.58M
270 sales
DA approval rate
88%
126 of 144 approved
Total lots
2,624
Marketplace

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Zoning

What you can build in Thornleigh

Thornleigh is dominated by R2Low Density Residential. Land use rules, height, FSR, and permitted developments are set per zone in the Local Environmental Plan and refined by the Development Control Plan.

R2
Dominant
R2 Low Density Residential 94.0%
E4 General Industrial 2.3%
R4 High Density Residential 1.4%
E3 Productivity Support 1.3%
RE1 Public Recreation 1.0%
Avg max height
8.3 m

Limit varies by lot — check your address for the exact figure.

Avg max FSR
0.88:1

Floor Space Ratio — total floor area as a multiple of lot area.

Use mix
Residential94%
Commercial4%

Location

Where Thornleigh sits

Thornleigh 2120 covers an undefined area within The Council of the Shire of Hornsby.

Overlays © NSW Government
Council
The Council of the Shire of Hornsby
Postcode
2120
Area
Total lots
2,624

Drill into any lot in Thornleigh

Open the interactive map — click any address to see its zone, height, FSR, overlays, and approval likelihood.

Open interactive map

Development potential

Where the upside is in Thornleigh

We score every lot for development signal — under-built relative to the controls, eligible for a granny flat, or sized for subdivision.

Underdeveloped
56

lots with remaining GFA capacity

granny flat eligible
2,431

under SEPP (Housing) 2021

Subdivision potential
1,900

lots that may support subdivision

Site assembly
5

adjoining lots with combined upside

Total dev potential
114 lots

show at least one development signal

Transport Oriented Dev
17 lots

within a TOD corridor (uplift expected)

Rezoning signal score
30.5 /100

average uplift signal across the suburb

Theoretical capacity if every lot built to its limit: 4,309 dwellings, with 233,960 m² of unused GFA across the suburb.

Own a property in Thornleigh?

Check your lot's exact development potential — height, FSR, granny flat, subdivision, dual-occ.

Run a report on your address

Constraints & risks

What could stop you in Thornleigh

39% of lots are bushfire-prone — a bushfire assessment is likely required; also: 2% of lots carry heritage controls; 2.4% of lots intersect a Threatened Ecological Community.

Suburb-wide percentages — your specific lot may have all, some, or none of these.

Flood-affected None

Mapped flood-prone land

Bushfire-prone 38.9%

RFS bushfire-prone land mapping

Heritage controls 1.7%

Heritage item or Conservation Area

Near contaminated land 0.2%

Within 100 m of EPA-listed site

Threatened ecology (TEC) 2.4%

Mapped TEC vegetation

Sea-level rise exposure None

Coastal hazard mapping

Flight noise contour None

ANEF / aircraft noise

All Round Conveyancing

Conveyancer · serves Thornleigh, NSW

Shop 1/293 Pennant Hills Rd, Thornleigh NSW 2120

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Market

Thornleigh property market

Sales, rent, and yield data drawn from NSW Property Sales Information and rental bond data over the past 24 months.

Median sale price (24m)
$1,580,000
270 sales · land value $1.28M
Median rent (house)
$755 / wk
Houses
Gross rental yield
2.3%
House, gross of costs

DA activity

Development applications in Thornleigh

144 development applications for Thornleigh addresses were decided by The Council of the Shire of Hornsby over the past 24 months. 126 approved — a 88% approval rate.

88%
Approved
DAs lodged (24m)
144
Approved
126
New dwelling DAs
134
Building approvals (12m)
14

Demographics & lifestyle

Who lives in Thornleigh

ABS Census 2021 population data combined with lot-level amenity, healthcare, lifestyle, and crime indices.

Green cover
47%
Amenity score
92.1 /100

Walkable amenity within 1 km

Healthcare access
93.5 /100

GP / hospital / pharmacy proximity

Lifestyle score
90.7 /100

Cafés, parks, schools, transport

FAQs

Common questions about Thornleigh

What's the zoning in Thornleigh 2120?

Thornleigh is dominated by the R2 (Low Density Residential) zone, which covers 2,431 of 2,624 lots (94%). The full mix is: R2 Low Density Residential (94%), E4 General Industrial (2%), R4 High Density Residential (1%), E3 Productivity Support (1%), RE1 Public Recreation (1%).

What's the height limit and FSR in Thornleigh?

Across Thornleigh, the average maximum building height is 8.3 m and the average maximum Floor Space Ratio (FSR) is 0.88:1. Individual lots can vary materially — height and FSR are set per zone in the Local Environmental Plan (LEP) and can be modified by overlays. For an exact figure on a specific address, generate a planning report.

Can I build a granny flat in Thornleigh?

Yes — 2,431 lots in Thornleigh appear eligible for a granny flat under SEPP (Housing) 2021, based on lot size, zoning, and frontage. Eligibility is lot-specific: get a planning report on your address to confirm.

What's the median property price in Thornleigh?

The median sale price in Thornleigh over the past 24 months is $1,580,000, across 270 sales. Median unimproved land value is $1,280,000.

What's the median rent in Thornleigh?

Median weekly rent for a house in Thornleigh is $755. Gross rental yield works out to 2.3%.

What's the development application approval rate in The Council of the Shire of Hornsby?

The Council of the Shire of Hornsby decided 144 development applications for Thornleigh addresses over the past 24 months, with 126 approved (88% approval rate). Processing time depends heavily on application complexity, council backlog, and whether the application requires referral to other agencies.

What planning constraints apply in Thornleigh?

Across Thornleigh, 2% with heritage controls, 38.9% bushfire-prone, 0.2% near contaminated sites. These are suburb-wide percentages — every lot has its own combination. A planning report on a specific address shows exactly which controls apply.

What's the development potential of Thornleigh?

114 of 2,624 lots in Thornleigh show identifiable development potential — under-developed for the planning controls, eligible for a granny flat, or capable of subdivision. 17 lots fall within a Transport Oriented Development corridor. Average rezoning signal score: 30.5 / 100.

Allen & Sheppard Real Estate

Real estate agent · serves Thornleigh, NSW

270 Pennant Hills Rd, Thornleigh NSW 2120

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Get a planning report for any address in Thornleigh

Suburb-wide stats are useful for context. For a buy-or-walk decision on a specific lot, you need every control, every constraint, and every clause cited to source.

Run a report — from A$29

14-section report · LEP + SEPP + DCP cross-referenced · cited to source

Methodology & sources

Zoning, height, FSR, and overlays parsed from the The Council of the Shire of Hornsby Local Environmental Plan, applicable State Environmental Planning Policies, and the Development Control Plan. Property sales drawn from NSW Property Sales Information. DA history aggregated from the NSW Planning Portal. Heritage, flood, bushfire, contaminated land, TEC, sea-level rise, and aircraft noise overlays from the NSW Spatial Services and EPA registers. Population, age, income, and tenure from ABS Census 2021. Aggregated by ZoneDSS · last updated 2026-04-27.

Suburb-wide statistics — your specific lot may vary. Always run a planning report on the actual address before making a decision. How ZoneDSS works →