Screening rules
Ten rules, evaluated in order — the first match wins. If none fire, the verdict is Yes — likely suitable (CV) (annotated with constraints when a heritage, bushfire or flood overlay is flagged). All metres and areas are computed in EPSG:3308 (NSW Lambert) true metres.
Trigger: Strata / unit / villa / townhouse / letter-suffix, or a lot shared by multiple addresses.
Verdict: No — strata/unit title or subdivided/secondary address.
Trigger: Primary zone not in R1, R2, R3, R4, R5, RU1, RU2, RU4, RU5, C4.
Verdict: No — zone not eligible.
Trigger: Lot area below 450 m² (or the LEP minimum, whichever is higher).
Verdict: No — lot too small.
Trigger: 3+ existing buildings (CV count), unless a rural lot ≥ 1500 m² with < 15 % coverage.
Verdict: No — multiple existing buildings (CV).
Trigger: 2+ buildings and combined coverage > 35 % (not the big-lot exception).
Verdict: No — multiple dwellings on lot (CV).
Trigger: Shows pre- AND post-build coverage; the cap applies to post-build (existing + 60 m² OHOME).
Verdict: PASS ≤ 50 % · MANUAL REVIEW 50–55 % · FAIL > 55 %.
Trigger: Shows pre- AND post-build landscape; threshold applies to post-build.
Verdict: PASS ≥ 30 % post-build, otherwise MANUAL REVIEW.
Trigger: Frontage < 12 m and not a battle-axe lot.
Verdict: Manual Review — borderline, or No — frontage too narrow.
Trigger: Very steep (≥ 25 %) and lot < 1500 m² (big lots are exempt).
Verdict: Manual Review — borderline (slope).
Trigger: No 6 × 10 m OHOME position holds ≥ 3 m from every existing building (search cascades 3→2→1 m; only 3 m stays Yes).
Verdict: Manual Review — placement tight (CV).
Verdict colours
- Green — Yes, likely suitable.
- Amber — Yes with constraints, or Manual Review (borderline / placement tight).
- Blue — Manual Review, needs CV verification.
- Red — No (any reason).
Indicative pre-screening only — not formal planning or building advice. Outputs should be confirmed by a qualified professional.