Home Extension Builder Hornsby — From $150K Fixed Price
Fixed-price home extensions in Hornsby 2077. Rear extension $150K–$300K, second storey $300K–$500K. Hornsby Shire Council approvals managed. Free site consult.
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MBA NSW0476 300 300Quick Answer
A home extension in Hornsby costs $150,000–$600,000+. Rear extension from $150K, second-storey addition from $300K. Buildana manages design, Hornsby Shire Council approvals, and construction under one fixed-price contract.
Extending Homes in Hornsby
A home extension in Hornsby holds a house on land the CBD keeps re-rating. R3 and R4 redevelopment rings the town centre, Westfield and the hospital front the station, and the 1960s to 1990s brick veneer homes on the surrounding 600 to 900m² R2 blocks are becoming the scarce commodity. At a roughly $1.8M to $2.6M median, improving what you own beats trading up as the towers rise.
Hawkesbury Sandstone bedrock is the line item to respect, with rock excavation typical, so we test the dig before pricing groundwork. The brick veneer era extends best at ground level and needs steel to go up, so out usually wins on these generous blocks, and the hospital and CBD keep tenant demand strong for any extra bedroom you add.
What I would check first on your Hornsby house: where the sandstone starts under a rear addition, and the frame's capacity if you are set on going up. Those set how we build it and what it costs.
We build these fixed-price, licence HBL 487805C. Ask us for a feasibility figure priced on a test dig.
Buildana manages the complete home extension process in Hornsby — from design consultation and structural engineering through to DA or CDC approval, and fixed-price construction to handover. Extend your home without the stress.
Read our Home Extension Cost Guide 2026 or explore extension approval pathways in NSW.
- Home extensions in Hornsby from $150K
- Hornsby Shire Council DA and CDC approvals managed
- Ground floor, rear and second-storey additions
- Hawkesbury Sandstone bedrock — structural engineering included
- 1900s–1940s Federation heritage (Beecroft/Cheltenham/Pennant Hills/Wahroonga boundary) + 1960s–1990s brick (Cherrybrook/Asquith/Mount Colah/Mount Kuring-gai) + 2010s+ R3/R4 redevelopment around Hornsby/Asquith/Waitara stations-era homes assessed for extension suitability
- Connect new to existing — clean, matched finish
- 6-year structural warranty
- Free design consultation — near Hornsby station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
Hold land near the CBD
R3 and R4 redevelopment rings the town centre, and the 1960s to 1990s brick veneer homes on the surrounding 600 to 900m² R2 blocks are becoming scarce.
At a roughly $1.8M to $2.6M median, improving what you own beats trading up as the towers rise, and the hospital and CBD keep tenant demand strong.
Respect the sandstone
Hawkesbury Sandstone bedrock means rock excavation is typical, so we test the dig before pricing groundwork rather than guessing.
The brick veneer era extends best at ground level and needs steel to go up, so out usually wins on these generous blocks.
Home extension builder in Hornsby — key facts
- Suburb
- Hornsby, NSW 2077
- Council / LGA
- Hornsby Shire Council (Hornsby Shire)
- Primary zoning
- R2
- Typical lot size
- 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe)
- Soil class
- Hawkesbury Sandstone bedrock
- Median house price
- $1.8M–$2.6M Hornsby/Asquith/Mount Colah; $2.4M–$3.6M Cherrybrook/Beecroft/Pennant Hills; $3.0M–$8.0M+ Galston/Arcadia acreage
- Home era
- 1900s–1940s Federation heritage
- Typical price range
- $150,000 – $600,000+
- Typical timeline
- 6–12 months design to handover
- Approval pathway
- CDC for most rear extensions, DA for second-storey
Want a real number for YOUR block — not a generic estimate?
Free site assessment, fixed-price contract, line-itemised quote within 48 hours. No high-pressure sales — just a real builder talking real numbers.
How It Works
From First Call to Final Key
On-site assessment of your 1900s–1940s Federation heritage (Beecroft/Cheltenham/Pennant Hills/Wahroonga boundary) + 1960s–1990s brick (Cherrybrook/Asquith/Mount Colah/Mount Kuring-gai) + 2010s+ R3/R4 redevelopment around Hornsby/Asquith/Waitara stations-era home in Hornsby. We check structural condition, block dimensions (700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe)), setback availability, and Hornsby Shire Council's DCP requirements.
⏱Designing an extension is half about the new space and half about how it joins the old one. Doorway position, ceiling height transition, floor level matching, light wells — the junction makes or breaks how the finished home feels.
⏱We lodge your extension approval — CDC for eligible designs or DA through Hornsby Shire Council. Full documentation including structural engineering for Class Hawkesbury Sandstone bedrock soil, BASIX, and shadow diagrams.
⏱For ground-floor rear extensions you usually stay in the house during the build, with temporary weatherproofing at the junction wall until the new section is locked up. Second-storey additions need a 4–8 week relocation during the roof-off and frame-up phase.
⏱Final inspection, Occupation Certificate, 6-year structural warranty. Your Hornsby home now has the space your family needs.
⏱Quality Promise
We extend Hornsby homes with a structural engineer on every job. Second storey, rear addition, multi-room — engineered and priced upfront.
Cost Guide
| Item | Estimated Range |
|---|---|
| Adding a master suite (1900s–1940s Federation heritage (Beecroft/Cheltenham/Pennant Hills/Wahroonga boundary) + 1960s–1990s brick (Cherrybrook/Asquith/Mount Colah/Mount Kuring-gai) + 2010s+ R3/R4 redevelopment around Hornsby/Asquith/Waitara stations Hornsby home) | $130,000 – $280,000 |
| Kitchen/living open-out to backyard | $150,000 – $350,000 |
| Second storey for teenagers/office | $280,000 – $550,000 |
| Extension + bathroom (growing family) | $200,000 – $400,000 |
| Full rear + roof tie-in (entertainer's zone) | $350,000 – $600,000 |
Prices are indicative for Western Sydney (2025). Actual costs depend on site, specifications, and approvals.
Our Team
Oliver Alameri
Founder / Director / Builder · MPropDev · PhD Student
Ahmad Alameri
Accounts Manager
Claire Wendell
Project Manager
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Liverpool, NSW
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Last updated: 1 April 2026
Hornsby Extension — Free Consultation
Free design consultation for Hornsby 2077. We'll assess your home, design the extension, and provide a fixed-price quote.
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Other Buildana services in Hornsby
Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Hornsby 2077. Hornsby Shire Council regulations and local controls are covered on each page.