Blog
Wahroonga — Duplex via CDC/DA
Author
Amy Wong
Published
Oct 20, 2025
Category
Design & Inspiration
Feasibility tuned for leafy Wahroonga—check bush-fire-prone mapping, BAL implications and nearby heritage areas so your duplex/KDR follows the right CDC/DA path before you spend.
Author
Amy Wong
Amy is the coffee-powered creative mind behind this blog. With over a decade of experience in architecture and design, he loves blending innovation with practicality. When not sketching blueprints or writing tips, you’ll find James exploring art galleries or chasing the perfect sunset for inspiration.
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1. Local Controls
Housing reforms & dual occ: NSW enabled dual occupancies across R2 zones in 2024–25; Ku-ring-gai is nominating a local minimum lot size (1015 m²) for dual occ via DA to manage character and tree canopy
Bushfire overlay: Large parts of Ku-ring-gai are bush fire prone with special construction standards and development restrictions; always check Council web map/RFS tool.
Item | Typical LMR non-refusal standard* |
|---|---|
Min lot size / width | 450 m² / 12 m |
Height / FSR | 9.5 m / 0.65:1 |
Parking | 1 space / dwelling |
Subdivision (Torrens) | ≥225 m² & 6 m width per lot |
*LMR Local Housing Area controls apply only in mapped areas; outside those areas you’re assessed under Council LEP/DCP. Source example: Mosman FAQ summarising LMR non-refusal standards
2. Typical Block Profiles in Wahroonga
Wide + gentle fall: side-by-side duplex with shared deep-soil bands for tree retention.
Deep + slope to rear: consider split-level entry, driveways with <1:6 ramp and internal stormwater detention near the rear easement.
Corner lots: best candidates for two crossings + clean strata/Torrens split after DA.
3. Risks & “Gotchas”
BAL ratings (12.5–FZ) ⇒ materials/spec upgrades, defendable space, APZs; early RFS advice saves redraws.
Council minimum lot size process (2025) ⇒ feasibility must check whether your site falls in any minimum-lot-size layer proposed/gazetted.
4. Our Recommendation
Address check (NSW Spatial Viewer + Council bushfire map).
CDC vs DA path: if inside an LMR area & hazard-free ⇒ CDC may be viable; otherwise DA with tree/landscape evidence and bushfire report. planningportal.nsw.gov.au
Concepts in 7 days, cost plan linked to /kdr-cost-calculator/.
Thomas, Carrington Rd Wahroonga
“We were told our BAL rating killed the duplex. AUD staged the build, introduced ember-resistant specs and got a DA through without losing our big turpentines.” — Thomas, Carrington Rd Wahroonga
5. Ready to Move from Idea to Action?
Address-level clarity in days—not months.
Get your 48-hour Feasibility & Budget Card with our KDR Cost Calculator:
👉 https://au-design.org/e_kdr-cost-calculator.htmlHave questions or want a tailored consult? Make an enquiry:
👉 https://audesign-property.com/contact-us
