Home Extension Builder Hornsby Heights — Approved in 60 Days
Hornsby Heights 2077 extensions with tight approval timelines. CDC where eligible (~15 days), DA via Hornsby Shire Council in 40–60 days. Construction 12–24 weeks depending on scope.
HIA Member
MBA NSW0476 300 300Quick Answer
A home extension in Hornsby Heights 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 Heights
With 700–1,500m² under most houses, nobody in Hornsby Heights needs to build a second storey for space — the home extension question here is about compliance, not room. Berowra Valley National Park wraps the suburb on multiple sides, bushfire ratings run BAL-12.5 to flame zone, and an RFS bushfire assessment is mandatory on most projects. Every new window, deck and cladding sheet on an extension gets specified to that rating.
The 1960s–2000s brick homes take rear extensions well, and the block sizes mean you can add a whole wing without the yard noticing. Sandstone bedrock is the other line item — excavation gets expensive when the rock is shallow, so a test dig before final costing saves surprises. We build BAL-compliant across Hornsby Shire; get us up for a site assessment.
Buildana manages the complete home extension process in Hornsby Heights — 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 Heights 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 (3 km) station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
Compliance, not room
With 700 to 1,500m² under most houses, Hornsby Heights never lacks space — the extension question is bushfire compliance, with Berowra Valley wrapping the suburb and BAL running to flame zone.
An RFS assessment is mandatory on most projects, and every new external element is specified to the rating.
Rock read before pricing
The 1960s-2000s brick takes rear wings well, and the blocks absorb a whole wing without the yard noticing. Shallow sandstone makes excavation dear, so a test dig comes before final costing.
The rock read lands in the fixed price before we commit to a number.
Home extension builder in Hornsby Heights — key facts
- Suburb
- Hornsby Heights, NSW 2077
- Council / LGA
- Hornsby Shire Council (Hornsby Shire)
- Primary zoning
- R2 Low Density predominant
- Typical lot size
- 700–1,500m²
- 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 Hornsby Heights home — existing structure, block size (700–1,500m²), 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 Hornsby Heights home's streetscape. Multiple design options presented.
⏱The Hornsby Heights 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
Hornsby Heights home extension specialists: we work on your home while you live in it, weatherproof the site nightly, finish clean.
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
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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
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Last updated: 1 April 2026
Extend, Don't Move — Hornsby Heights
Free design consultation for Hornsby Heights 2077. We'll assess your home, design the extension, and provide a fixed-price quote.
Start Your ProjectMore in Hornsby Heights
Other Buildana services in Hornsby Heights
Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Hornsby Heights 2077. Hornsby Shire Council regulations and local controls are covered on each page.