Mount Kuring-gai Home Extension Builder — Live In, Build On
Buildana extends homes across Mount Kuring-gai 2080 while you stay in place. 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 structure, Hornsby Shire Council rules, weatherproofing during build — all managed locally from Fairfield.
HIA Member
MBA NSW0476 300 300Quick Answer
A home extension in Mount Kuring-gai 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.
Mount Kuring-gai Home Extensions & Additions
A home extension in Mount Kuring-gai is a bushfire job on generous land — 1960s-1990s brick on 700 to 1,200m² blocks against Ku-ring-gai Chase, where BAL ratings lead and the room is never the constraint.
The RFS assessment is mandatory on most projects, the sandstone is read before the dig, and the junctions are engineered.
At the $1.8M to $2.6M median, the wing beats the cost of upsizing on the bushland fringe.
We build these fixed-price, licence HBL 487805C. Get a BAL-literate number priced on a test dig.
Buildana manages the complete home extension process in Mount Kuring-gai — 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 Mount Kuring-gai 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 Mount Kuring-gai station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
BAL leads the design
Mount Kuring-gai sits against the national park — the RFS assessment and BAL rating specify every new window, deck and cladding sheet.
We build BAL-compliant across the Shire; it is a specification, not a stopper.
Room and rock
The blocks absorb a whole wing without the yard noticing, and the shallow sandstone makes a test dig worth doing before final costing.
The rock work is priced off that dig, in the scope from the outset.
Home extension builder in Mount Kuring-gai — key facts
- Suburb
- Mount Kuring-gai, NSW 2080
- Council / LGA
- Hornsby Shire Council (Hornsby Shire)
- Primary zoning
- R2 Low Density predominant
- Typical lot size
- 700–1,200m²
- 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
Everything that has to be right before we touch the ground. We assess your Mount Kuring-gai home — existing structure, block size (700–1,200m²), R2 Low Density predominant zoning, setbacks, FSR, and your space requirements. You'll know what's achievable before spending on detailed design. Design phase covers the extension layout, junction with existing structure, window and door placement, and external finish to match your Mount Kuring-gai home's streetscape. Multiple design options presented.
⏱The Mount Kuring-gai construction phase. Fixed price, programmed, supervised. Documentation pack covers structural engineering for the new footings sized to match existing depths on Class Hawkesbury Sandstone bedrock soil, BASIX 2025 compliance, shadow diagrams to neighbours' POS, hydraulic, and detailed sections through the wall-tie junction. Approval-grade, not concept-grade. Fixed-price construction of your extension. New footings engineered for Class Hawkesbury Sandstone bedrock soil, structural connection to existing home, frame, fit-out, and finishes. Weekly updates from your project manager.
⏱The job isn't done when the site's clean; it's done when you have keys, certificates and warranties. Handover documentation covers the new work specifically — OC for the extension, structural certs, BASIX certificate updates, and warranty for the new section plus the junction detailing. Existing house remains under whatever warranty position applied before.
⏱Quality Promise
Our Mount Kuring-gai home extensions connect old-to-new cleanly. Matched brickwork, tied roofline, no awkward transitions.
Cost Guide
| Item | Estimated Range |
|---|---|
| Small rear extension (up to 30m²) | $90,000 – $180,000 |
| Medium rear/side extension (30–60m²) | $180,000 – $320,000 |
| Large ground-floor extension (60–100m²) | $320,000 – $500,000 |
| Second-storey addition (60–120m²) | $280,000 – $550,000 |
| Wrap-around (ground + 1st floor) | $500,000+ |
| Structural engineering & tie-in | Included |
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
Estimate Your Build Cost
Use our free calculator to get an instant cost estimate for your project
Still got questions? Talk to Oliver directly.
30-min free call — bring your block, your brief, your budget. We'll map out feasibility, timeline, and realistic cost. No sales pitch.
Frequently Asked Questions
Buildana built our granny flat in just 12 weeks. Fast approvals, great communication, and a beautiful final product. Highly recommend.
Fatima Al-Rashid
Liverpool, NSW
We Build Across Sydney
Headquartered in Western Sydney's Fairfield. Active across all 28 metropolitan Sydney LGAs — from Penrith to the Eastern Suburbs, the Hills to the Sutherland Shire.
Last updated: 1 April 2026
Explore Related Topics
Add Space to Your Mount Kuring-gai Home
Free design consultation for Mount Kuring-gai 2080. We'll assess your home, design the extension, and provide a fixed-price quote.
Start Your ProjectMore in Mount Kuring-gai
Other Buildana services in Mount Kuring-gai
Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Mount Kuring-gai 2080. Hornsby Shire Council regulations and local controls are covered on each page.