Licensed Granny Flat Specialist Mosman
NSW licensed builder delivering SEPP-compliant granny flats across Mosman 2088. BASIX, engineered slab (Class M), full certifier sign-off and 6-year structural warranty.
HIA Member
MBA NSW0476 300 300Quick Answer
A granny flat in Mosman costs $150,000–$300,000+ depending on size and finishes. 1-bed from $150K, 2-bed from $200K. CDC fast-track approval in 10–15 business days. Buildana manages design, Mosman Council approval and fixed-price construction.
Mosman Granny Flat Construction — Fixed Price
A granny flat in Mosman is a premium, family-driven build, not a yield exercise. On 500 to 1,000m² blocks worth $4.5M to $8M, a secondary dwelling is guest accommodation, a studio, staff quarters or multigenerational space — the lot clears the 450m² Housing SEPP threshold comfortably, so size is rarely the question.
Two things decide the job. First, heritage: Heritage Conservation Areas cover virtually all the older streets, so a secondary dwelling almost always goes through a full DA rather than the fast CDC path. Second, the ground: sandstone-dominant with substantial fall on the Mosman Bay and Sirius Cove streets, which means deep rock excavation, engineered slabs and substantial retaining.
So I scope the heritage and the rock first. This is architect-led work built to the standard the address demands — a discreet, beautifully made second dwelling that answers the main house and the streetscape.
We build to that standard, fixed-price, licence HBL 487805C. Heritage and rock scoped before design starts.
Buildana manages the full granny flat process in Mosman — from site assessment and CDC fast-track approval through to fixed-price construction and handover. We build studio, 1-bedroom, and 2-bedroom designs up to the NSW maximum of 60m².
Read our Complete Granny Flat Guide or explore granny flat builds across Sydney.
- Granny flats in Mosman from $150K
- CDC fast-track approval (10–15 business days)
- 500–1,000m² blocks — most qualify for 60m² granny flat
- Mosman zoned R2 Low Density / R3 Medium pockets
- Fixed-price contract — design to handover
- M — engineered slab included
- Rental yield $800–$1,200/week in Mosman
- Free site assessment — near North Sydney (4 km, ferry from Mosman Bay) station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
Premium, family-driven
On 500 to 1,000m² blocks worth $4.5M to $8M, a Mosman secondary dwelling is guest accommodation, a studio, staff quarters or multigenerational space — not a weekly-rent play. The lot clears the 450m² Housing SEPP threshold comfortably.
It's built to the standard the address demands, answering the main house and streetscape.
Heritage and deep rock
Heritage Conservation Areas cover virtually all older streets, so a secondary dwelling almost always goes through a full DA — I scope that first.
Sandstone-dominant ground with substantial fall on the bay streets means deep rock excavation, engineered slabs and substantial retaining, scoped off a real geotech.
Granny flat builder in Mosman — key facts
- Suburb
- Mosman, NSW 2088
- Council / LGA
- Mosman Council (Mosman)
- Primary zoning
- R2 Low Density
- Typical lot size
- 500–1,000m²
- Soil class
- M
- Median house price
- $4.5M–$8.0M
- Home era
- 1880s–1940s heritage
- Typical price range
- $150,000 – $300,000+
- Typical timeline
- 4–6 months design to handover
- Approval pathway
- CDC via NSW Affordable Rental Housing SEPP (10–15 days)
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 |
|---|---|
| Rental income model (Mosman 1-bed) | $240,000 – $300,000 |
| Family member (dependent living) | $260,000 – $340,000 |
| Teenager retreat / adult child | $220,000 – $290,000 |
| Home office / short-stay | $210,000 – $280,000 |
| Future main dwelling (build granny first, big house later) | $280,000 – $360,000 |
Prices are indicative for Western Sydney (2025). Actual costs depend on site, specifications, and approvals.
How It Works
From First Call to Final Key
Site visit to your Mosman block to check feasibility — lot dimensions, sewer and stormwater locations, driveway access, and Mosman Council's setback and landscape requirements. Written feasibility report within 3 business days.
⏱Design pulls from a library of plans we've refined over years of Mosman-area builds, then adapts to your specific block constraints. Faster than starting from scratch, better than buying a stock plan that doesn't suit the site.
⏱Most Mosman granny flats qualify for CDC — faster and simpler than DA. Buildana prepares all documentation, lodges with the certifier, and obtains the Construction Certificate.
⏱Construction in your back yard means coordinating site access, material delivery, and trade movement around the existing house. Buildana plans the build to keep main-house disruption to a few hours per week, not constant noise and dust.
⏱Final inspection, Occupation Certificate, keys, and maintenance guide. Ready for tenants or family.
⏱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 July 2025
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Free site assessment for Mosman 2088. We'll check your block, recommend the best design, and provide a fixed-price quote.
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Costs, approval pathway and fixed-price contract detail for every other build type we deliver in Mosman 2088. Mosman Council regulations and local controls are covered on each page.