Seven Hills Home Extension Builder — Live In, Build On
Buildana extends homes across Seven Hills 2147 while you stay in place. 1960s–1980s-era structure, Blacktown City Council rules, weatherproofing during build — all managed locally from Fairfield.
HIA Member
MBA NSW0476 300 300Quick Answer
A home extension in Seven Hills costs $150,000–$600,000+. Rear extension from $150K, second-storey addition from $300K. Buildana manages design, Blacktown City Council approvals, and construction under one fixed-price contract.
Extending Homes in Seven Hills
A home extension in Seven Hills builds on Class H clay, and the engineering respects it — new footings designed to move with the existing house, because a rear wing that fights the ground cracks at the junction.
The 1960s-80s stock on generous 550 to 700m² blocks takes the family addition well: second living, extra bedrooms, alfresco. The era's fibro gets the licensed strip-out where touched.
At the $900K to $1.15M median with the station and motorways close, the extend-versus-move maths lands on staying.
We build these fixed-price, licence HBL 487805C. Get our extension scope, with the footings engineered, before you commit.
Buildana manages the complete home extension process in Seven 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 Seven Hills from $150K
- Blacktown City Council DA and CDC approvals managed
- Ground floor, rear and second-storey additions
- Class H soil — structural engineering included
- 1960s–1980s-era homes assessed for extension suitability
- Connect new to existing — clean, matched finish
- 6-year structural warranty
- Free design consultation — near Seven Hills station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
The junction is everything
On Seven Hills' Class H clay, the extension's weakest point is where new meets old — so the footings are engineered to move together, off geotech, before any slab goes down. That is the difference between a clean wing and cracked cornices.
The generous blocks take the full family addition once the ground is respected.
Era and maths
The era's fibro gets the licensed strip-out where the addition touches it, and at the $900K to $1.15M median, the staying maths beats upsizing clearly.
The strip-out sits in the fixed price up front, and the maths is laid out before you commit.
Home extension builder in Seven Hills — key facts
- Suburb
- Seven Hills, NSW 2147
- Council / LGA
- Blacktown City Council (Blacktown City)
- Primary zoning
- R2 Low Density
- Typical lot size
- 550–700m²
- Soil class
- Class H
- Median house price
- $900K–$1.15M
- Home era
- 1960s–1980s
- 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.
Cost Guide
| Item | Estimated Range |
|---|---|
| Simple rear extension (single wall removal, no roof change) | $84,000 – $190,000 |
| Moderate extension (multiple openings, roof extended) | $190,000 – $350,000 |
| Complex extension (structural steel portals, re-roofing) | $350,000 – $560,000 |
| Second-storey tie-in (existing house re-engineered) | $330,000 – $600,000 |
Prices are indicative for Western Sydney (2025). Actual costs depend on site, specifications, and approvals.
How It Works
From First Call to Final Key
The first job on an extension is finding out what you're extending onto. Seven Hills homes from the 1960s–1980s were built to different standards — we open walls, check footings, verify load paths. The existing house has to carry the new work.
⏱Design follows the existing roof. A bad extension looks like a bolt-on; a good one reads as original. Matched brickwork or contrasting render (whichever the architecture calls for), tied-in roofline, continuous flooring where it should be continuous.
⏱Construction happens while you live in the house. That means weatherproofing every night, staging the works so kitchens and bathrooms don't disappear on the same week, and keeping the site clean of debris that doesn't belong in a family home.
⏱Finish is seamless. Paint match, floor match, roofline match, brick match where possible. The only way to tell the extension is new is the date on the plans.
⏱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
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Other Buildana services in Seven Hills
Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Seven Hills 2147. Blacktown City Council regulations and local controls are covered on each page.