Home Extension Builder Collaroy Plateau — From $150K Fixed Price
Fixed-price home extensions in Collaroy Plateau 2097. Rear extension $150K–$300K, second storey $300K–$500K. Northern Beaches Council approvals managed. Free site consult.
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MBA NSW0476 300 300Quick Answer
A home extension in Collaroy Plateau costs $150,000–$600,000+. Rear extension from $150K, second-storey addition from $300K. Buildana manages design, Northern Beaches Council approvals, and construction under one fixed-price contract.
Extending Homes in Collaroy Plateau
Up on the Plateau, a home extension has one obvious direction: toward the water. Collaroy Plateau's 1950s–1980s brick homes on 500–800m² blocks sit on an eastern fall with ocean views available one storey up — views the original single-level builds never claimed. A first-floor addition here isn't vanity; on a $2.4M–$3.8M street it's often the single highest-return build you can do.
The sandstone underneath helps and hinders. Excavating for a ground-floor extension can hit rock at $40K–$100K, which quietly tilts the economics toward building up instead — and that same rock gives a first-floor addition a rock-solid base, literally. Post-war brick from this era usually carries the load once an engineer verifies the footings. Price both directions with us before you assume the cheaper one.
Buildana manages the complete home extension process in Collaroy Plateau — 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 Collaroy Plateau from $150K
- Northern Beaches Council DA and CDC approvals managed
- Ground floor, rear and second-storey additions
- Hawkesbury Sandstone — structural engineering included
- 1950s–1980s + premium contemporary-era homes assessed for extension suitability
- Connect new to existing — clean, matched finish
- 6-year structural warranty
- Free design consultation — near B-Line bus to CBD (Collaroy interchange) station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
Toward the water
The Plateau's eastern fall puts the ocean one storey up — a view the original single-level builds never claimed, and on a $2.4M to $3.8M street often the single highest-return build available.
The first-floor addition is designed to claim it without overbearing the neighbours.
The rock tilts the maths
Excavation can hit sandstone at $40K to $100K, which quietly favours building up — and the same rock gives the addition a base that will not move.
The post-war brick usually carries the load once the footings are verified. All priced upfront.
Home extension builder in Collaroy Plateau — key facts
- Suburb
- Collaroy Plateau, NSW 2097
- Council / LGA
- Northern Beaches Council (Northern Beaches)
- Primary zoning
- R2 Low
- Typical lot size
- 500–800m²
- Soil class
- Hawkesbury Sandstone
- Median house price
- $2.4M–$3.8M
- Home era
- 1950s–1980s + premium contemporary
- 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. Collaroy Plateau homes from the 1950s–1980s + premium contemporary 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
Collaroy Plateau home extension specialists: we work on your home while you live in it, weatherproof the site nightly, finish clean.
Cost Guide
| Item | Estimated Range |
|---|---|
| Simple rear extension (single wall removal, no roof change) | $102,000 – $230,000 |
| Moderate extension (multiple openings, roof extended) | $230,000 – $430,000 |
| Complex extension (structural steel portals, re-roofing) | $430,000 – $680,000 |
| Second-storey tie-in (existing house re-engineered) | $400,000 – $730,000 |
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
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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
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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
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Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Collaroy Plateau 2097. Northern Beaches Council regulations and local controls are covered on each page.