BuildersUpdated March 2026 · 2 min read

How to Quote a Granny Flat Build in Australia

Comprehensive guide to quoting granny flat construction. Covers council requirements, slab, frame, roofing, fit-out, and per-sqm pricing for Australian builders.

Granny Flat Quote Breakdown

A granny flat quote should be broken into stages: site works and slab, frame and roof, lock-up (windows, doors, cladding), rough-in (plumbing, electrical, HVAC), internal lining (plasterboard, insulation), fit-out (kitchen, bathroom, flooring, paint), and external works (landscaping, driveway, fencing). Present each stage with its own subtotal.

Granny Flat Costs in 2026

Basic 1-bedroom granny flat (40sqm): $100,000–$150,000. Standard 2-bedroom (60sqm): $150,000–$220,000. Premium finish (60sqm): $200,000–$300,000. Per-square-metre cost: $2,500–$4,500/sqm depending on finishes. These prices include all trades, approvals, and site connections but exclude land value.

Council Approvals (CDC vs DA)

In NSW, granny flats up to 60sqm can be approved via a Complying Development Certificate (CDC) if they meet specific criteria (lot size, setbacks, floor space ratio). CDCs are faster (10–20 business days) and cheaper ($2,000–$5,000). If CDC criteria aren't met, a Development Application (DA) is required — $5,000–$15,000 and 3–6 months. Include approval costs in your quote.

Managing the Build Process

Granny flat builds involve multiple trades and inspections over 12–20 weeks. Structure your quote with progress payments aligned to milestones: deposit (10%), slab completion (15%), frame and roof (20%), lock-up (20%), rough-in (10%), and practical completion (25%). This protects both you and the client.

Common Granny Flat Quoting Mistakes

1. Not including service connections (sewer, water, electrical) which can cost $5,000–$20,000. 2. Underestimating site preparation costs. 3. Forgetting council and certification fees. 4. Not including landscaping and external works. 5. Quoting without a proper site assessment (slope, access, services).