Home Extension Builder Mortlake — From $150K Fixed Price
Fixed-price home extensions in Mortlake 2137. Rear extension $150K–$300K, second storey $300K–$500K. City of Canada Bay Council approvals managed. Free site consult.
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MBA NSW0476 300 300Quick Answer
A home extension in Mortlake costs $150,000–$600,000+. Rear extension from $150K, second-storey addition from $300K. Buildana manages design, City of Canada Bay Council approvals, and construction under one fixed-price contract.
Second-Storey & Rear Additions in Mortlake
A home extension in Mortlake is riverside work on a peninsula that mixes its eras. The stock runs Federation through to post-war on 400 to 800m² blocks, so there is no single template — the wing is read to the particular home, and wherever the block has a river orientation the design turns to make the most of it.
On the conservation streets the frontage is kept and the work goes behind it; on the post-war stock the wing extends more freely. Pre-war fabric has its lead and asbestos stripped under licence wherever the work touches it.
At a $1.9M to $3.5M median, a wing beats the cost of upsizing off the peninsula — the wharf and the Breakfast Point amenity next door are the lifestyle you would be paying to give up.
We build these fixed-price, licence HBL 487805C. Get our extension scope, with the heritage position checked, before you commit.
Buildana manages the complete home extension process in Mortlake — 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 Mortlake from $150K
- City of Canada Bay Council DA and CDC approvals managed
- Ground floor, rear and second-storey additions
- M–H — structural engineering included
- 1900s–1960s-era homes assessed for extension suitability
- Connect new to existing — clean, matched finish
- 6-year structural warranty
- Free design consultation — near North Strathfield (2 km) / Mortlake ferry to Putney station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
Read per home, built for the river
Mortlake's mixed eras get the read first — conserved frontages on the heritage streets, freer wings on the post-war stock — with the river orientation rewarding a design that faces the water.
The wharf and the Breakfast Point amenity hold every metre you add.
Fabric handled properly
Pre-war walls on the peninsula can hold both asbestos and lead paint, and both come out under licence.
That work, with the era checks, sits in the quote before we start.
Home extension builder in Mortlake — key facts
- Suburb
- Mortlake, NSW 2137
- Council / LGA
- City of Canada Bay Council (City of Canada Bay)
- Primary zoning
- R2 Low
- Typical lot size
- 400–800m²
- Soil class
- M–H
- Median house price
- $1.9M–$3.5M
- Home era
- 1900s–1960s
- 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
We assess your Mortlake home — existing structure, block size (400–800m²), R2 Low 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 Mortlake home's streetscape. Multiple design options presented.
⏱Documentation pack covers structural engineering for the new footings sized to match existing depths on Class M–H 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 M–H soil, structural connection to existing home, frame, fit-out, and finishes.
⏱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
Buildana's Mortlake home extension process: assess the existing structure, design the addition, approve, build. Fixed price throughout.
Cost Guide
| Item | Estimated Range |
|---|---|
| Adding a master suite (1900s–1960s Mortlake home) | $120,000 – $270,000 |
| Kitchen/living open-out to backyard | $140,000 – $330,000 |
| Second storey for teenagers/office | $270,000 – $520,000 |
| Extension + bathroom (growing family) | $190,000 – $380,000 |
| Full rear + roof tie-in (entertainer's zone) | $330,000 – $570,000 |
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
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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
Extend, Don't Move — Mortlake
Free design consultation for Mortlake 2137. We'll assess your home, design the extension, and provide a fixed-price quote.
Start Your ProjectMore in Mortlake
Other Buildana services in Mortlake
Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Mortlake 2137. City of Canada Bay Council regulations and local controls are covered on each page.