Granny Flat Builder St Marys — Approval in 10 Days, Finished in 14 Weeks
St Marys 2760 secondary dwellings via the NSW Affordable Rental Housing SEPP. CDC fast-track (10–15 days), construction in 14–20 weeks. Free site check.
HIA Member
MBA NSW0476 300 300St Marys Secondary Dwellings
A granny flat in St Marys is often a strong investment, and it's about to get stronger. This is the LGA's secondary CBD with its own station and shopping precinct, older fibro and brick stock on side streets on 450 to 750m² blocks. Land is affordable, most blocks clear the 450m² Housing SEPP threshold, and the upcoming Western Sydney Airport rail link will lift tenant demand further.
Two things to check. The R3/R4 redevelopment ramping around the station is geared to apartments, so the granny flat suits the settled side streets, and the eastern-edge legacy precincts carry industrial contamination overlays that need managing on affected parcels. On many side streets the older stock is genuinely ripe for a studio in the backyard.
The soil is Wianamatta Shale grading M, so a stiffened-raft slab is engineered off a real geotech on the reactive ground. The older stock can carry fibro, so a licensed asbestos strip-out leads where any demolition is involved.
We build fixed-price, licence HBL 487805C. Zoning, contamination and soil scoped first.
Buildana manages the full granny flat process in St Marys — 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 St Marys from $150K
- CDC fast-track approval (10–15 business days)
- 450–750m² typical (Cranebrook/Werrington/Cambridge Park/Kingswood/St Marys); 250–450m² master-planned (Jordan Springs/Caddens/Glenmore Park new release) blocks — most qualify for 60m² granny flat
- St Marys zoned R2 / R3 / R4 mixed (St Marys CBD)
- Fixed-price contract — design to handover
- M — engineered slab included
- Rental yield $420–$580/week (Western Sydney University + Nepean Hospital staff demand) in St Marys
- Free site assessment — near St Marys station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
A yield play getting stronger
St Marys' 450 to 750m² blocks mostly clear the 450m² Housing SEPP threshold, and land is affordable, so a studio can let for a healthy yield.
The upcoming Western Sydney Airport rail link will lift tenant demand further.
Zoning, contamination and shale
The R3/R4 around the station is geared to apartments, so the granny flat suits the settled side streets, and the eastern-edge legacy precincts carry contamination overlays to manage.
The Wianamatta Shale grading M means a stiffened-raft slab off a geotech, and older stock can carry fibro.
Granny flat builder in St Marys — key facts
- Suburb
- St Marys, NSW 2760
- Council / LGA
- Penrith City Council (City of Penrith)
- Primary zoning
- R2
- Typical lot size
- 450–750m² typical (Cranebrook/Werrington/Cambridge Park/Kingswood/St Marys); 250–450m² master-planned (Jordan Springs/Caddens/Glenmore Park new release)
- Soil class
- M
- Median house price
- $850K–$1.3M typical; $1.0M–$1.6M Glenmore Park/Jordan Springs premium master-planned; $1.6M–$3.0M+ Mulgoa/Wallacia/Castlereagh acreage
- Home era
- 1950s–1980s + 2010s+ R4 apartments
- 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.
Quality Promise
We build St Marys granny flats that hit the NSW 60m² maximum cleanly. Engineered slab, separate meter, rental-ready at handover.
How It Works
From First Call to Final Key
Granny flats get underestimated. A lot of builders treat them as a kit-home product. We don't. Your St Marys block has a main dwelling, a driveway, service connections, trees, and neighbours — the secondary dwelling gets designed around those realities.
⏱The 60m² SEPP cap is not a suggestion. Every millimetre gets used — kitchen, bathroom, laundry, living, bedroom, storage — with the envelope tuned for St Marys's sun and prevailing breeze. Real rooms, not compromise spaces.
⏱CDC gets lodged through a private certifier the week design locks in. 10–15 business days later, slab starts. The trades sequence tight because the footprint is small — one plumber, one sparkie, one tiler, one programme.
⏱Handover gives you a genuinely rentable second home. Separate meter, independent hot water, standalone bathroom, full kitchen. Ready to lease on handover day, not a 'studio' that needs another $20K of finishing.
⏱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
Explore Related Topics
Build a Granny Flat in St Marys
Free site assessment for St Marys 2760. We'll check your block, recommend the best design, and provide a fixed-price quote.
Start Your ProjectMore in St Marys
Other Buildana services in St Marys
Costs, approval pathway and fixed-price contract detail for every other build type we deliver in St Marys 2760. Penrith City Council regulations and local controls are covered on each page.