Development applications in Thornleigh, NSW 2120
42 development applications were lodged for properties in Thornleigh from Oct 2025 to Sep 2026. What is being built, how much of it is housing, and where each application stands.
Latest council activity:
Applications lodged
42
incl. 14 modifications
Decided
29
12 still in progress
New dwellings proposed
12
stated on applications
Declared construction value
$13.9M
across 25 applications
Applications lodged each month
Oct 2025 to Sep 2026. The latest month is month-to-date, and councils can publish applications a few weeks after lodgement.
- 4Oct
- 2Nov
- 4Dec
- 5Jan
- 2Feb
- 5Mar
- 3Apr
- 2May
- 5Jun
- 2Jul
- 2Aug
- 6Sep
What is being proposed
28 new applications by main type of work (modifications excluded).
- Alterations & additions11
- Commercial, industrial & community5
- New houses5
- Dual occupancy & semi-detached4
- Subdivisions2
- Granny flats1
Where applications stand
Status of the 42 applications lodged in the last 12 months.
- Approved
- 3
- Determined (outcome not stated)
- 26
- Refused
- 0
- Withdrawn or not accepted
- 1
- In progress
- 12
Many council records only say an application was "determined", without saying whether it was approved, so those are shown separately rather than counted as approvals.
Largest projects in the last 12 months
Ranked by dwellings proposed, then declared construction cost.
- In progress
12 Roach Avenue
Demolition, Erection of a new structure, Dual occupancy (detached)
Dual occupancy & semi-detached · Lodged 6 July 2026 · 2 dwellings · $1M–$5M
- Determined
8 Tillock Street
Dual occupancy, Demolition, Subdivision, Erection of a new structure, Dual occupancy (attached)
Dual occupancy & semi-detached · Lodged 16 Mar 2026 · 2 dwellings · $1M–$5M
- Approved
73 Duffy Avenue
Demolition, Erection of a new structure, Dual occupancy (attached)
Dual occupancy & semi-detached · Lodged 28 Apr 2026 · 2 dwellings · $1M–$5M
- Determined
35 Station Street
Secondary dwelling, Demolition, Dwelling house, Erection of a new structure
New houses · Lodged 21 Jan 2026 · 2 dwellings · $100K–$500K
- Determined
17 Morgan Street
Demolition, Dwelling house
New houses · Lodged 9 June 2026 · 1 dwelling · $1M–$5M
Most recent applications
The 30 most recent applications lodged in Thornleigh, newest first. Costs are shown as bands.
- In progress
115 Norman Avenue
Demolition, Recreation area
Commercial, industrial & community · Lodged 17 Sept 2026 · $20M–$100M · Modification
- In progress
8 Pritchard Street
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 14 Sept 2026 · $100K–$500K
- In progress
38 Norman Avenue
Dwelling house, Alterations or additions to an existing building or structure, Residential Accommodation
Alterations & additions · Lodged 13 Sept 2026 · $1M–$5M
- In progress
10 Janet Avenue
Dwelling house, Erection of a new structure
New houses · Lodged 8 Sept 2026 · 1 dwelling · $500K–$1M
- Determined
8 Tillock Street
Dual occupancy, Demolition, Subdivision, Erection of a new structure, Dual occupancy (attached)
Dual occupancy & semi-detached · Lodged 2 Sept 2026 · 2 dwellings · $1M–$5M · Modification
- In progress
18 Derribong Place
Demolition, Alterations or additions to an existing building or structure, Balcony, deck, patio, terrace or verandah (screened enclosures)
Alterations & additions · Lodged 1 Sept 2026 · Under $100K · Modification
- In progress
161 Dartford Road
Alterations or additions to an existing building or structure, Earthworks, retaining walls and structural support
Alterations & additions · Lodged 25 Aug 2026 · $500K–$1M
- In progress
23 Judson Road
Secondary dwelling, Demolition, Erection of a new structure
Granny flats · Lodged 6 Aug 2026 · 1 dwelling · $100K–$500K
- Determined
7 De Saxe Close
Alterations or additions to an existing building or structure, Balcony, deck, patio, terrace or verandah
Alterations & additions · Lodged 23 July 2026 · Under $100K
- In progress
12 Roach Avenue
Demolition, Erection of a new structure, Dual occupancy (detached)
Dual occupancy & semi-detached · Lodged 6 July 2026 · 2 dwellings · $1M–$5M
- In progress
52 Duffy Avenue
Demolition, Subdivision, Erection of a new structure, Driveways and hard stand spaces
Subdivisions · Lodged 20 June 2026 · Under $100K
- In progress
38 Duffy Avenue
Subdivision
Subdivisions · Lodged 12 June 2026 · $100K–$500K
- In progress
38 Norman Avenue
Dwelling house, Alterations or additions to an existing building or structure, Residential Accommodation
Alterations & additions · Lodged 10 June 2026 · $500K–$1M
- Determined
17 Morgan Street
Demolition, Dwelling house
New houses · Lodged 9 June 2026 · 1 dwelling · $1M–$5M
- In progress
11 Adamson Avenue
Dual occupancy, Demolition, Erection of a new structure, Dual occupancy (detached), Residential Accommodation
Dual occupancy & semi-detached · Lodged 5 June 2026 · 2 dwellings · $1M–$5M · Modification
- Determined
8 Coolabah Close
Dwelling house, Alterations or additions to an existing building or structure, Erection of a new structure
Alterations & additions · Lodged 27 May 2026 · Under $100K · Modification
- Determined
23 Vale Road
Dwelling house, Erection of a new structure
New houses · Lodged 6 May 2026 · Under $100K
- Determined
200-206 Pennant Hills Road
Signage, Advertising and signage, Advertising structure
Commercial, industrial & community · Lodged 28 Apr 2026 · $500K–$1M · Modification
- Approved
73 Duffy Avenue
Demolition, Erection of a new structure, Dual occupancy (attached)
Dual occupancy & semi-detached · Lodged 28 Apr 2026 · 2 dwellings · $1M–$5M
- Determined
50A The Esplanade
Demolition, Dwelling house, Erection of a new structure
New houses · Lodged 1 Apr 2026 · 1 dwelling · $500K–$1M · Modification
- Determined
1 Judson Road
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 30 Mar 2026 · $500K–$1M
- Determined
46 Wareemba Avenue
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 30 Mar 2026 · Under $100K
- Withdrawn
3 3-5 Chilvers Road
Place of public worship, Change of use of land or a building or the classification of a building under the Building Code of Australia
Commercial, industrial & community · Lodged 27 Mar 2026 · $100K–$500K
- Determined
28 Edmundson Close
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 24 Mar 2026 · $100K–$500K · Modification
- Determined
8 Tillock Street
Dual occupancy, Demolition, Subdivision, Erection of a new structure, Dual occupancy (attached)
Dual occupancy & semi-detached · Lodged 16 Mar 2026 · 2 dwellings · $1M–$5M
- Determined
182 Pennant Hills Road
Restaurant or cafe, Food and drink premise, Hours of operation and trading
Commercial, industrial & community · Lodged 4 Feb 2026 · Modification
- Determined
50 Duffy Avenue
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 4 Feb 2026
- Determined
15 Dartford Road
Dwelling house, Erection of a new structure
New houses · Lodged 29 Jan 2026 · 1 dwelling · $500K–$1M · Modification
- Determined
35 Station Street
Secondary dwelling, Demolition, Dwelling house, Erection of a new structure
New houses · Lodged 21 Jan 2026 · 2 dwellings · $100K–$500K
- Determined
18 Adamson Avenue
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 13 Jan 2026 · Under $100K · Modification
Application details as published by The Council of the Shire of Hornsby. The council's own register is the authoritative record for any individual application.
Suburb profile
Thornleigh market data
Median prices, rental yield, growth, vacancy and properties for sale in Thornleigh.
Sales
Recently sold in Thornleigh
What buyers actually paid, days on market and recent sale prices in Thornleigh.
Development in Thornleigh: frequently asked questions
How many development applications were lodged in Thornleigh in the last 12 months?
42 development applications were lodged for properties in Thornleigh from Oct 2025 to Sep 2026. 14 were modifications to an earlier application. The busiest month was Sep 2026, with 6 applications.
What kind of development is happening in Thornleigh?
Of the new applications lodged in the last 12 months, the most common were alterations & additions (11), commercial, industrial & community (5), new houses (5).
How many new homes are proposed in Thornleigh?
Applications lodged in Thornleigh in the last 12 months propose 12 new dwellings, counting new houses, granny flats, dual occupancies, townhouses and apartments where the application states a dwelling count. Withdrawn applications and modifications are excluded.
How many development applications in Thornleigh have been decided?
Of the 42 applications lodged in the last 12 months, 29 have a decision (3 recorded as approved, 26 recorded as determined without the outcome stated), 12 are still in progress and 1 was withdrawn or not accepted.
Which council assesses development applications in Thornleigh?
Applications for Thornleigh are lodged with The Council of the Shire of Hornsby. Its public register is the authoritative record for any individual application.