Home Extension Builder Baulkham Hills — From $150K Fixed Price
Fixed-price home extensions in Baulkham Hills 2153. Rear extension $150K–$300K, second storey $300K–$500K. The Hills Shire Council approvals managed. Free site consult.
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MBA NSW0476 300 300Quick Answer
A home extension in Baulkham Hills costs $150,000–$600,000+. Rear extension from $150K, second-storey addition from $300K. Buildana manages design, The Hills Shire Council approvals, and construction under one fixed-price contract.
Baulkham Hills Home Extensions & Additions
Out or up? That's the first question for any home extension in Baulkham Hills, and the block usually answers it. On 600–900m² of R2 land you've got genuine room to push a ground-floor extension rearward without eating the whole yard — cheaper per square metre than a first-floor addition and no scaffolding over your kitchen for four months. The 1970s–1990s brick homes here take it well.
Some do go up, and the era mostly cooperates — brick veneer from these decades can carry a first floor once an engineer confirms the footings, which on Wianamatta Shale generally behave. With the median at $1.6M–$2.4M, moving to a bigger house in the same school catchment costs six figures in friction before you gain a room. Ask us to price both options against your floor plan.
Buildana manages the complete home extension process in Baulkham Hills — 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 Baulkham Hills from $150K
- The Hills Shire Council DA and CDC approvals managed
- Ground floor, rear and second-storey additions
- M — structural engineering included
- 1970s–1990s-era homes assessed for extension suitability
- Connect new to existing — clean, matched finish
- 6-year structural warranty
- Free design consultation — near Bus to Castle Hill Metro (3 km) / T-Way station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
The block answers out-or-up
Baulkham Hills' 600 to 900m² blocks usually vote for out — the rear wing lands cheaper per square metre and keeps the family living downstairs through the build — while the brick veneer carries a first floor where the yard matters more.
I run both options against your floor plan before you commit either way.
Shale junctions engineered
The Wianamatta Shale moves with moisture, so the junction where new footings meet the 1970s-1990s originals gets engineered — new moves with old or the join cracks.
Era materials get the licensed check where the tie-in disturbs them. All priced upfront.
Home extension builder in Baulkham Hills — key facts
- Suburb
- Baulkham Hills, NSW 2153
- Council / LGA
- The Hills Shire Council (The Hills)
- Primary zoning
- R2 Low
- Typical lot size
- 600–900m²
- Soil class
- M
- Median house price
- $1.6M–$2.4M
- Home era
- 1970s–1990s
- 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. On-site assessment of your 1970s–1990s-era home in Baulkham Hills. We check structural condition, block dimensions (600–900m²), setback availability, and The Hills Shire Council's DCP requirements. Written feasibility and cost estimate provided. 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.
⏱The Baulkham Hills construction phase. Fixed price, programmed, supervised. We lodge your extension approval — CDC for eligible designs or DA through The Hills Shire Council. Full documentation including structural engineering for Class M soil, BASIX, and shadow diagrams. CC issued before works start. 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.
⏱The job isn't done when the site's clean; it's done when you have keys, certificates and warranties. Final inspection, Occupation Certificate, 6-year structural warranty. Your Baulkham Hills home now has the space your family needs.
⏱Quality Promise
Our Baulkham Hills 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
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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
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
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Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Baulkham Hills 2153. The Hills Shire Council regulations and local controls are covered on each page.