Two Pathways, One Outcome

Every granny flat in NSW needs approval before construction. There are two pathways:

1. Complying Development Certificate (CDC) — private certifier, 10-15 business days, $3k-$5k. No neighbour notification, no council assessment, no discretion. Either you meet the SEPP and you're approved, or you don't.

2. Development Application (DA) — council assessment, 40-90 days, $3k-$10k. Neighbour notification mandatory. Council planner exercises judgement.

Buildana (Lic. 487805C) runs roughly 85% of granny flats as CDC. The other 15% go DA because of heritage, flood, bushfire or non-standard design needs.

CDC — When It Works and When It Doesn't

CDC works when ALL of these are true: • Lot ≥ 450 sqm. • Residential zone (R1/R2/R3/RU5). • Not heritage-listed and not in a Heritage Conservation Area. • Not flood-prone (check your council flood map). • BAL-29 or lower (not BAL-40 or Flame Zone). • Not contaminated land. • Internal area ≤ 60 sqm. • Wall height ≤ 3.8m, overall height ≤ 6m. • All setbacks met (0.9m sides, 3m rear, behind principal building line, 3m from main house if detached). • Parking provided (1 space). • Private open space provided (24 sqm).

If ANY of these fail, CDC is unavailable. Most failure cases are heritage and flood — neither can be designed around because they are inherent to the site.

DA — When You Have No Choice

Going DA is more work but unlocks design flexibility CDC doesn't allow:

• Variations to setbacks (especially front-of-building-line variations on irregular blocks). • Wall heights above 3.8m (useful on sloping sites where step-footings would otherwise be required). • Larger 'attached' configurations that exceed the standard envelope. • Heritage-area builds with material conditions. • Flood-resilient designs (raised floor levels, water-resistant materials below FFL).

DA cost: $3k-$10k including the council fee, Statement of Environmental Effects, shadow diagrams, landscape plan, and any specialist reports (heritage assessment, flood study, bushfire assessment).

DA timeline: 40-90 days assuming a complete application. RFI delays add 4-8 weeks each. Two RFIs is common on contested sites.

Documentation Checklist (Both Pathways)

Architectural drawings — site plan, floor plan, elevations, sections, schedule of finishes. BASIX certificate — energy and water efficiency assessment. Structural engineering certification — slab class (AS 2870), framing, footing design. Geotechnical report — soil class, contamination check. Survey plan — boundary, contours, existing services. Stormwater management plan — where rainwater will discharge. Waste management plan — for the construction period.

DA-only additionally: • Statement of Environmental Effects. • Shadow diagrams (overshadowing of neighbours). • Landscape plan. • Council-specific reports (varies by LGA — Fairfield wants specific tree report formats, Liverpool flooding details, Cumberland heritage notes if applicable).

Buildana prepares all documentation as part of the contract. Clients don't chase architects, engineers, or certifiers — we do.

Timeline Reality

CDC pathway typical project timeline: • Site assessment + design: 1-2 weeks. • Drafting + documentation: 3-4 weeks. • CDC lodgement + approval: 10-15 business days. • Total to construction start: 7-9 weeks. • Construction: 14-18 weeks. • Total to occupation certificate: 5-6 months.

DA pathway typical project timeline: • Site assessment + design: 1-2 weeks. • Drafting + documentation: 5-7 weeks (more reports). • DA lodgement: 1 week. • Council assessment: 8-13 weeks (assume one RFI). • Total to construction start: 14-22 weeks. • Construction: 14-18 weeks. • Total to occupation certificate: 8-10 months.

The gap between CDC and DA is roughly 2-4 months. On a $180k granny flat earning $440/week in rent, that delay is $9,500-$19,000 in lost rent. Worth factoring into the project economics.

Contact Buildana for a free site assessment.

Once you know the rules, the next step is matching them to a layout that fits your block. Our full library of compliant granny flat designs sits at /homes/granny-flats/designs — 47 plans ranging from 35m² studios up to 60m² 2-bedroom units, all sized to NSW SEPP requirements.