Development applications in Mount Colah, NSW 2079
31 development applications were lodged for properties in Mount Colah 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
31
incl. 4 modifications
Decided
20
10 still in progress
New dwellings proposed
10
stated on applications
Declared construction value
$9.4M
across 26 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.
- 3Oct
- 3Nov
- 3Dec
- 1Jan
- 2Feb
- 2Mar
- 2Apr
- 3May
- 3Jun
- 2Jul
- 1Aug
- 6Sep
What is being proposed
27 new applications by main type of work (modifications excluded).
- Alterations & additions13
- New houses6
- Pools, sheds, garages & decks4
- Dual occupancy & semi-detached2
- Commercial, industrial & community1
- Granny flats1
Where applications stand
Status of the 31 applications lodged in the last 12 months.
- Approved
- 0
- Determined (outcome not stated)
- 20
- Refused
- 0
- Withdrawn or not accepted
- 1
- In progress
- 10
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.
- Determined
19A Northumberland Avenue
Secondary dwelling, Dwelling house, Erection of a new structure
New houses · Lodged 14 Apr 2026 · 2 dwellings · $1M–$5M
- Determined
647 Pacific Highway
Demolition, Erection of a new structure, Dual occupancy (attached)
Dual occupancy & semi-detached · Lodged 8 Oct 2025 · 2 dwellings · $1M–$5M
- In progress
33 Lord Street
Dual occupancy, Erection of a new structure, Dual occupancy (detached)
Dual occupancy & semi-detached · Lodged 14 Sept 2026 · 2 dwellings · $500K–$1M
- Determined
14 Willarong Road
Dwelling house, Erection of a new structure
New houses · Lodged 8 Dec 2025 · 1 dwelling · $500K–$1M
- Determined
19 Northumberland Avenue
Dwelling house, Change of use of land or a building or the classification of a building under the Building Code of Australia
New houses · Lodged 10 Feb 2026 · 1 dwelling · $500K–$1M
Most recent applications
The 30 most recent applications lodged in Mount Colah, newest first. Costs are shown as bands.
- In progress
11 Varna Street
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 15 Sept 2026 · Under $100K
- In progress
25 Bimbil Avenue
Erection of a new structure, Balcony, deck, patio, terrace or verandah, Minor building alterations (external), Swimming pool
Alterations & additions · Lodged 15 Sept 2026 · $100K–$500K
- In progress
33 Lord Street
Dual occupancy, Erection of a new structure, Dual occupancy (detached)
Dual occupancy & semi-detached · Lodged 14 Sept 2026 · 2 dwellings · $500K–$1M
- In progress
17 North Street
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 9 Sept 2026 · $100K–$500K
- In progress
12 Yirra Road
Erection of a new structure, Balcony, deck, patio, terrace or verandah, Cabanas, cubby houses, ferneries, garden sheds, gazebos and…
Pools, sheds, garages & decks · Lodged 9 Sept 2026 · $100K–$500K
- In progress
14 Willarong Road
Erection of a new structure, Balcony, deck, patio, terrace or verandah, Earthworks, retaining walls and structural support, Swimming pool
Pools, sheds, garages & decks · Lodged 8 Sept 2026 · $100K–$500K
- In progress
1-3 Grey Gum Road
Erection of a new structure, Balcony, deck, patio, terrace or verandah, Swimming pool
Pools, sheds, garages & decks · Lodged 26 Aug 2026 · Under $100K
- In progress
26 Amaroo Avenue
Alterations or additions to an existing building or structure, Carport, Minor building alterations (external)
Alterations & additions · Lodged 9 July 2026 · Under $100K
- Determined
4A Poinciana Close
Alterations or additions to an existing building or structure, Residential Accommodation
Alterations & additions · Lodged 3 July 2026 · $100K–$500K
- In progress
17 North Street
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 30 June 2026 · $100K–$500K
- Determined
7 Murralong Road
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 9 June 2026 · Under $100K
- Determined
3 Landra Avenue
Alterations or additions to an existing building or structure, Residential Accommodation
Alterations & additions · Lodged 3 June 2026 · Under $100K
- In progress
3 Flora Avenue
Demolition, Dwelling house, Subdivision, Erection of a new structure, Residential Accommodation
New houses · Lodged 27 May 2026 · 2 dwellings · $1M–$5M · Modification
- Determined
21 Northumberland Avenue
Secondary dwelling, Erection of a new structure
Granny flats · Lodged 27 May 2026 · 1 dwelling · $100K–$500K · Modification
- Determined
1 Lord Street
Demolition, Dwelling house, Erection of a new structure
New houses · Lodged 6 May 2026 · 1 dwelling · $500K–$1M
- Determined
3 Parklands Road
Alterations or additions to an existing building or structure, Minor building alterations (external)
Alterations & additions · Lodged 24 Apr 2026 · Under $100K · Modification
- Determined
19A Northumberland Avenue
Secondary dwelling, Dwelling house, Erection of a new structure
New houses · Lodged 14 Apr 2026 · 2 dwellings · $1M–$5M
- Determined
31 Rupert Street
Demolition, Dwelling house, Subdivision, Residential Accommodation
New houses · Lodged 4 Mar 2026 · $100K–$500K
- Withdrawn
1 Ku-Ring-Gai Chase Road
Dwelling house, Erection of a new structure
New houses · Lodged 3 Mar 2026 · 1 dwelling · $500K–$1M
- Determined
19-21 Telopea Street
Signage, Advertising and signage
Commercial, industrial & community · Lodged 20 Feb 2026 · Under $100K
- Determined
19 Northumberland Avenue
Dwelling house, Change of use of land or a building or the classification of a building under the Building Code of Australia
New houses · Lodged 10 Feb 2026 · 1 dwelling · $500K–$1M
- Determined
21 Northumberland Avenue
Secondary dwelling, Erection of a new structure
Granny flats · Lodged 27 Jan 2026 · 1 dwelling · $100K–$500K
- Determined
44 Landra Avenue
Alterations or additions to an existing building or structure, Residential Accommodation
Alterations & additions · Lodged 10 Dec 2025 · Under $100K
- Determined
46B Lady Street
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 9 Dec 2025 · $500K–$1M
- Determined
14 Willarong Road
Dwelling house, Erection of a new structure
New houses · Lodged 8 Dec 2025 · 1 dwelling · $500K–$1M
- Determined
23 North Street
Dwelling house, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 25 Nov 2025 · $100K–$500K
- Determined
11 10 Playfair Road
Attached dwelling, Alterations or additions to an existing building or structure
Alterations & additions · Lodged 19 Nov 2025 · $100K–$500K
- Determined
7 Burra Close
Alterations or additions to an existing building or structure, Earthworks, retaining walls and structural support, Supporting Development
Alterations & additions · Lodged 16 Nov 2025 · Under $100K · Modification
- Determined
23 Amaroo Avenue
Erection of a new structure, Driveways and hard stand spaces, Shade structures of canvas, fabric, mesh or the like
Pools, sheds, garages & decks · Lodged 21 Oct 2025 · Under $100K
- Determined
4 Flinders Place
Dwelling house, Alterations or additions to an existing building or structure, Residential Accommodation
Alterations & additions · Lodged 19 Oct 2025 · $100K–$500K
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
Mount Colah market data
Median prices, rental yield, growth, vacancy and properties for sale in Mount Colah.
Sales
Recently sold in Mount Colah
What buyers actually paid, days on market and recent sale prices in Mount Colah.
Development in Mount Colah: frequently asked questions
How many development applications were lodged in Mount Colah in the last 12 months?
31 development applications were lodged for properties in Mount Colah from Oct 2025 to Sep 2026. 4 were modifications to an earlier application. The busiest month was Sep 2026, with 6 applications.
What kind of development is happening in Mount Colah?
Of the new applications lodged in the last 12 months, the most common were alterations & additions (13), new houses (6), pools, sheds, garages & decks (4).
How many new homes are proposed in Mount Colah?
Applications lodged in Mount Colah in the last 12 months propose 10 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 Mount Colah have been decided?
Of the 31 applications lodged in the last 12 months, 20 have a decision (20 recorded as determined without the outcome stated), 10 are still in progress and 1 was withdrawn or not accepted.
Which council assesses development applications in Mount Colah?
Applications for Mount Colah are lodged with The Council of the Shire of Hornsby. Its public register is the authoritative record for any individual application.