Licensed Home Extension Builder Greenwich
NSW licensed extension specialist. Greenwich 2065 extensions on 1880s–1940s heritage-era homes require structural sign-off, Class M footings, and matched connection — we engineer and document properly.
HIA Member
MBA NSW0476 300 300Quick Answer
A home extension in Greenwich costs $150,000–$600,000+. Rear extension from $150K, second-storey addition from $300K. Buildana manages design, Lane Cove Council approvals, and construction under one fixed-price contract.
Greenwich Home Extensions & Additions
A home extension in Greenwich is usually a conversation about the harbour. This peninsula falls hard to the water between Greenwich Point, Manns Point and Bay Road, and a well-placed upper level on the Federation mansions and inter-war homes here can claim a harbour outlook that commands a serious premium in a $3.5M to $8M market. The 500 to 1,200m² blocks give room, but the slope and the heritage set the terms.
Heritage Conservation Areas blanket most streets, so street-facing changes get examined closely while rear and set-back upper work moves more freely. The ground is sandstone-dominant with substantial harbour fall, so extensions regularly mean suspended slabs, engineered piers and rock excavation rather than a simple pour. At these values, engineering it properly is the only sensible approach.
What I would check first on your Greenwich block: the heritage status, the harbour fall and how the addition sits on it, and the sandstone in the dig. Those three decide the design and the budget.
We build these fixed-price, licence HBL 487805C. Show us your fall and we will design to it.
Buildana manages the complete home extension process in Greenwich — 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 Greenwich from $150K
- Lane Cove Council DA and CDC approvals managed
- Ground floor, rear and second-storey additions
- M — structural engineering included
- 1880s–1940s heritage-era homes assessed for extension suitability
- Connect new to existing — clean, matched finish
- 6-year structural warranty
- Free design consultation — near Wollstonecraft (1.5 km, ferry) station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
A conversation about the harbour
This peninsula falls hard to the water, and a well-placed upper level on the Federation mansions and inter-war homes can claim a harbour outlook that commands a serious premium in a $3.5M to $8M market.
The 500 to 1,200m² blocks give room, though the slope and the heritage set every term.
Slope and sandstone
Heritage Conservation Areas blanket most streets, so street-facing changes get examined while rear and set-back upper work moves more freely.
The ground is sandstone-dominant with heavy harbour fall, so extensions regularly mean suspended slabs, engineered piers and rock excavation rather than a simple pour.
Home extension builder in Greenwich — key facts
- Suburb
- Greenwich, NSW 2065
- Council / LGA
- Lane Cove Council (Lane Cove)
- Primary zoning
- R2 Low Density
- Typical lot size
- 500–1,200m²
- Soil class
- M
- Median house price
- $3.5M–$8.0M
- Home era
- 1880s–1940s 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
The first job on an extension is finding out what you're extending onto. Greenwich homes from the 1880s–1940s heritage 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.
⏱Quality Promise
We extend Greenwich homes with a structural engineer on every job. Second storey, rear addition, multi-room — engineered and priced upfront.
Cost Guide
| Item | Estimated Range |
|---|---|
| Simple rear extension (single wall removal, no roof change) | $115,000 – $260,000 |
| Moderate extension (multiple openings, roof extended) | $260,000 – $490,000 |
| Complex extension (structural steel portals, re-roofing) | $490,000 – $770,000 |
| Second-storey tie-in (existing house re-engineered) | $450,000 – $830,000 |
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
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
Start a Greenwich Home Extension
Free design consultation for Greenwich 2065. We'll assess your home, design the extension, and provide a fixed-price quote.
Start Your ProjectMore in Greenwich
Other Buildana services in Greenwich
Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Greenwich 2065. Lane Cove Council regulations and local controls are covered on each page.