Granny Flat Builder Hornsby — From $150K Fixed Price
Fixed-price granny flat construction in Hornsby 2077. 1-bed from $150K, 2-bed from $185K. CDC approval, Hornsby Shire Council compliant. No hidden extras.
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A granny flat in Hornsby 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, Hornsby Shire Council approval and fixed-price construction.
Hornsby Granny Flat Construction — Fixed Price
Hornsby in Hornsby Shire has excellent granny flat potential with typical lots of 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) — most qualifying under NSW Housing SEPP for fast-tracked CDC approval. 1900s–1940s Federation heritage (Beecroft/Cheltenham/Pennant Hills/Wahroonga boundary) + 1960s–1990s brick (Cherrybrook/Asquith/Mount Colah/Mount Kuring-gai) + 2010s+ R3/R4 redevelopment around Hornsby/Asquith/Waitara stations-era homes on established blocks make ideal candidates for a granny flat addition, with rental returns in Hornsby reaching $520–$720/week (Hornsby Hospital + Hornsby TAFE + Macquarie University proximity). Hornsby Shire Council manages development in the area, and Buildana has deep experience with granny flat builds across Hornsby Shire.
For a secondary dwelling in Hornsby, the economics are the framing question. Median price $1.8M–$2.6M Hornsby/Asquith/Mount Colah; $2.4M–$3.6M Cherrybrook/Beecroft/Pennant Hills; $3.0M–$8.0M+ Galston/Arcadia acreage; build cost on 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) blocks scales by site conditions and specification. Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA) ground (moderately to highly reactive clay) keeps foundations honest — $24,000–$42,000 band — and blowouts on that line are the single most common reason fixed-price contracts elsewhere don't stay fixed. Buildana itemises the slab, structural engineering, and geotech work upfront so you see the actual cost in the contract. R3 zoning in pockets of Hornsby opens up dual occupancy potential — worth exploring even if you're not initially considering it.
Buildana manages the full granny flat process in Hornsby — 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 Hornsby from $150K
- CDC fast-track approval (10–15 business days)
- 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) blocks — most qualify for 60m² granny flat
- Hornsby zoned R2 / R3 / R4 mixed (Hornsby CBD)
- Fixed-price contract — design to handover
- Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA) soil — engineered slab included
- Rental yield $520–$720/week (Hornsby Hospital + Hornsby TAFE + Macquarie University proximity) in Hornsby
- Free site assessment — near Hornsby station
Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
Why Build a Granny Flat in Hornsby?
Hornsby is the LGA's CBD and rail interchange — Westfield Hornsby, Hornsby Hospital and the Hornsby CBD high-rise zone front the station. R3/R4 redevelopment around the CBD with surrounding 1960s–1990s brick veneer residential streets on 600–900m² R2 blocks. Hawkesbury Sandstone bedrock with rock excavation typical.
Hornsby sits in the Hornsby Shire local government area with 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) residential blocks and R2 / R3 / R4 mixed (Hornsby CBD) zoning. Building costs are around the Sydney metro average, balancing construction value with lifestyle and growth. Hornsby station gives Hornsby direct rail access — a strong draw for residents and tenants. Secondary dwellings on 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) blocks deliver rental returns of $520–$720/week (Hornsby Hospital + Hornsby TAFE + Macquarie University proximity) per week. CDC approval through a private certifier typically takes 10–15 business days. Ground conditions (Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA)) across Hornsby are well understood by local builders — Buildana's engineering accounts for moderately to highly reactive soil movement.
Granny flat builder in Hornsby — key facts
- Suburb
- Hornsby, NSW 2077
- Council / LGA
- Hornsby Shire Council (Hornsby Shire)
- Primary zoning
- R2 / R3 / R4 mixed (Hornsby CBD)
- Typical lot size
- 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe)
- Soil class
- Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA)
- Median house price
- $1.8M–$2.6M Hornsby/Asquith/Mount Colah; $2.4M–$3.6M Cherrybrook/Beecroft/Pennant Hills; $3.0M–$8.0M+ Galston/Arcadia acreage
- Home era
- 1900s–1940s Federation heritage (Beecroft/Cheltenham/Pennant Hills/Wahroonga boundary) + 1960s–1990s brick (Cherrybrook/Asquith/Mount Colah/Mount Kuring-gai) + 2010s+ R3/R4 redevelopment around Hornsby/Asquith/Waitara stations
- 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)
Building in Hornsby — Local Context
Foundations & Slab Design for Hornsby
Hornsby's ground is moderately to highly reactive clay (Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA)). On a 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) block, that translates to engineered slab work in the $24,000–$42,000 bracket for a secondary dwelling. Double-check any quote that doesn't itemise the slab — 'slab as per engineering' usually means the builder will hit you with a variation once the soil report comes back. We commission the geotech upfront, before pricing, so the cost in your contract reflects what your block actually needs. If your neighbour's home shows movement cracks above architraves or below window sills, that's a signal worth knowing before you finalise design — Buildana's site assessment looks at adjacent stock too.
Planning Controls in Hornsby
Hornsby is zoned R2 / R3 / R4 mixed (Hornsby CBD) with R3 Medium Density pockets. Hornsby Shire Council controls FSR, height limits (typically 8.5–9m), site coverage, landscaped area minimums, and setbacks. For a secondary dwelling, the binding constraints on most 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) blocks here are: front setback (around 4.5–6m), side setbacks (1.0–1.5m articulated), rear (3–6m depending on lot depth), and landscaped area (usually 35–40%). Buildana's design team works to those numbers from the first sketch — no late re-design when council comes back with comments.
Hornsby Build Economics
Hornsby sits in the $1.8M–$2.6M Hornsby/Asquith/Mount Colah; $2.4M–$3.6M Cherrybrook/Beecroft/Pennant Hills; $3.0M–$8.0M+ Galston/Arcadia acreage price band, which is the framing for any granny flat decision. On a 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) block here, the build-versus-buy maths usually favours a granny flat for rental yield or family accommodation, with payback inside 8–11 years on $520–$720/week (Hornsby Hospital + Hornsby TAFE + Macquarie University proximity) rental. Free Buildana feasibility runs the numbers against your actual block before any commitment.
Designing for the Hornsby Streetscape
Hornsby's housing stock is predominantly from the 1900s–1940s Federation heritage (Beecroft/Cheltenham/Pennant Hills/Wahroonga boundary) + 1960s–1990s brick (Cherrybrook/Asquith/Mount Colah/Mount Kuring-gai) + 2010s+ R3/R4 redevelopment around Hornsby/Asquith/Waitara stations.. The local anchor is Westfield Hornsby + Hornsby Hospital + Florence Street. For a granny flat, the streetscape question matters more than most builders admit — a brand-new double-storey on a street of single-storey 1900s–1940s Federation heritage (Beecroft/Cheltenham/Pennant Hills/Wahroonga boundary) + 1960s–1990s brick (Cherrybrook/Asquith/Mount Colah/Mount Kuring-gai) + 2010s+ R3/R4 redevelopment around Hornsby/Asquith/Waitara stations weatherboards will draw council attention on bulk and scale, even if technically compliant. Buildana designs the front elevation to read appropriately for the street while modernising the floor plan and structure behind it. Materials palette, roof pitch, fenestration rhythm — all chosen to settle into the existing rhythm rather than fight it.
What Recent Approvals Show
Hornsby Shire Council's recent decisions for Secondary dwellings in Hornsby reveal a clear pattern — clean CDC submissions with correct setback dimensions on plan, BASIX matching the actual specification, and clear separation from the parent dwelling are clearing in 10-12 business days consistently. Sloppy lodgement adds 4-8 weeks of round-trip; clean lodgement doesn't.
Builder's Take on Hornsby
The single most important design decision on a granny flat is natural light. 60m² feels tiny when it's dark. Good north-facing window placement, a skylight in the bathroom, and a glazed laundry door — these turn a 55m² build into something that feels 20% larger.
CDC is the right path for most Hornsby granny flats. Lodgement to approval in 10–15 business days vs 8–12 weeks for DA through Hornsby Shire Council. The only catch: your design has to comply with the Codes SEPP — height, setbacks, landscape area. We check that upfront so there's no wasted design time.
Hornsby vs Nearby Suburbs
Hornsby vs nearby suburbs — key metrics for building a granny flat.
| Suburb | Median Price | Typical Lot | Soil Class | GF Rental | Station |
|---|---|---|---|---|---|
| Hornsby2077this suburb | $1.8M–$2.6M Hornsby/Asquith/Mount Colah; $2.4M–$3.6M Cherrybrook/Beecroft/Pennant Hills; $3.0M–$8.0M+ Galston/Arcadia acreage | 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) | Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA) | $520–$720/week (Hornsby Hospital + Hornsby TAFE + Macquarie University proximity) | Hornsby |
| Asquith2077 | $1.8M–$2.6M Hornsby/Asquith/Mount Colah; $2.4M–$3.6M Cherrybrook/Beecroft/Pennant Hills; $3.0M–$8.0M+ Galston/Arcadia acreage | 700–1,200m² typical (Hornsby/Asquith/Pennant Hills/Beecroft/Wahroonga boundary/Cherrybrook); 1–5ha acreage (Galston/Berrilee/Arcadia/Forest Glen/Glenorie/Berowra Heights bushland fringe) | Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA) | $520–$720/week (Hornsby Hospital + Hornsby TAFE + Macquarie University proximity) | Asquith |
| Wahroonga2076 | $3.0M–$4.6M | 800–1,500m² | Class M | $650–$850/week | Wahroonga |
| Mount Colah2079 | $1.8M–$2.6M Hornsby/Asquith/Mount Colah; $2.4M–$3.6M Cherrybrook/Beecroft/Pennant Hills; $3.0M–$8.0M+ Galston/Arcadia acreage | 700–1,000m² | Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA) | $520–$720/week (Hornsby Hospital + Hornsby TAFE + Macquarie University proximity) | Mount Colah |
Median price, soil class, and lot size shape build feasibility and final cost. Buildana assesses every site against these and other constraints during the free feasibility stage.
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Cost Guide
| Item | Estimated Range |
|---|---|
| Attached granny flat | $160,000 – $220,000 |
| Detached granny flat | $190,000 – $260,000 |
| Above-garage granny flat | $230,000 – $300,000 |
| Premium detached (upgraded finishes) | $260,000 – $320,000 |
Prices are indicative for Western Sydney (2025). Actual costs depend on site, specifications, and approvals.
How It Works
From First Call to Final Key
Assessment is the most important hour you'll spend on the project. Get the position, orientation, and access right and the build runs clean. Get them wrong and you're chasing certifier RFIs for months. Buildana checks every constraint before recommending a position.
⏱We design your granny flat to maximise the 60m² allowance within Hornsby Shire Council's setback and POS requirements. Floor plan, elevations, and 3D render provided. Studio, 1-bed, or 2-bed configurations available.
⏱CDC pathway exists specifically for compliant granny flats — use it. No neighbour notification, no Hornsby Shire Council planner queue, no committee politics. Certifier checks the design against the code; if it complies, it approves. 10–15 business days, every time.
⏱Fixed-price build: slab (Class Hawkesbury Sandstone bedrock predominant (saw-cutting, rock-anchoring $30K–$120K above standard substructure) / Class M Wianamatta Shale on Cherrybrook/Beecroft ridges / bushfire-prone land BAL-12.5 to BAL-FZ on virtually all bushland-fringe (most of the LGA) engineered), frame, roof, fit-out, connections. 10–16 weeks depending on size. Minimal disruption to your existing home.
⏱Walk through your finished granny flat, collect keys. Occupation Certificate, 6-year structural warranty, and maintenance guide provided. List for rent immediately — typical demand in Hornsby fills vacancies fast.
⏱Our Team
Oliver Alameri
Founder / Director / Builder · MPropDev · PhD Student
Ahmad Alameri
Accounts Manager
Claire Wendell
Project Manager
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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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Last updated: 1 July 2025
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