
Duplex Builder Spit Junction — CDC-Ready Designs, 15-Day Approval
Spit Junction 2088 duplex specialists. Compliant design means CDC approval in ~15 business days, construction complete in 10–14 months. Feasibility within 48 hours.
Dual Occupancy Developments in Spit Junction
A duplex in Spit Junction is the exception, because this is a mixed-use hub, not a detached-house suburb. It sits at the Military Road and Spit Road intersection around Mosman Square, with B4 along the spine and R3 medium-density on the side streets. Lots run a tight 350 to 700m2 against a 650m2 Mosman duplex minimum, so many fall short and the realistic redevelopment on the R3 land is a townhouse or unit scheme.
Where a rare 650m2-plus side-street block outside a Heritage Conservation Area exists, a dual-occupancy can be modelled. The stock is Federation cottages, inter-war flats and post-war, so heritage covers several streets and I check it first. The ground is sandstone on the ridge, moderately reactive, reaching Class H to E on the harbour fall, engineered to suit.
What I would check first on your Spit Junction block: the zoning and the area against 650m2, because both usually favour medium density over a duplex.
We build these fixed-price, licence HBL 487805C. Send me the block and I will tell you honestly what it can carry.
Buildana manages the full duplex development process in Spit Junction — from feasibility assessment and architectural design through to DA or CDC approval, and fixed-price construction to dual handover. One builder, one contract, two homes.
Read our Complete Duplex Building Guide or explore duplex developments across Sydney.
- Dual occupancy in Spit Junction from $750K
- Mosman Council DA and CDC approvals managed
- R2 and R3 zones — established dual occ. provisions
- Minimum lot size 650m² in Spit Junction
- M — engineered dual-slab design included
- Strata or Torrens title subdivision available
- 6-year structural warranty per dwelling
- Free feasibility check — near North Sydney (5 km) station

Reviewed by Oliver Alameri
Licensed Builder (NSW 487805C) · Master of Property Development · PhD Student · Building across Western Sydney since 2010
Mixed-use hub, tight lots
Spit Junction runs B4 along the spine and R3 on the side streets around Mosman Square.
Lots run 350 to 700m2 against a 650m2 minimum, so many fall short of a straight duplex.
Heritage and harbour fall
Heritage Conservation Areas cover several side streets, checked before any design.
Sandstone ridge ground reaching Class H to E on the harbour fall means footings and slab engineered to suit.
Duplex builder in Spit Junction — key facts
- Suburb
- Spit Junction, NSW 2088
- Council / LGA
- Mosman Council (Mosman)
- Primary zoning
- R3
- Typical lot size
- 350–700m²
- Soil class
- M
- Median house price
- $3.5M–$5.5M
- Home era
- 1900s–1960s + apartments
- Typical price range
- $750,000 – $1,500,000+
- Typical timeline
- 14–22 months design to handover
- Approval pathway
- CDC for compliant dual-occupancy, else DA
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Last updated: 1 July 2025
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