How Long Does a Knockdown Rebuild Actually Take in Sydney?
Most builders quote you '8 to 10 months on site.' That's the truthful slice. The honest answer is 12 to 18 months from signing the design brief to handing you the keys — and that's when nothing goes sideways.
This is a real Sydney KDR timeline, month by month, based on the projects we've actually delivered across Fairfield, Liverpool, Cumberland and Canterbury-Bankstown. Where I write 'add 4–8 weeks' it's because I've watched it happen. Sentry's got the on-time data — the average slip on a Western Sydney KDR is closer to 11% past the contracted construction date, not the 30%+ horror stories you'll see on builder review sites.
Months 1–2 — Design and Costing
Month 1: Site visit, brief, soil class assumption, preliminary design concepts. This is where you get the layouts, the orientation, the rough form. The biggest mistake here is rushing — a week saved at concept costs you ten weeks at variation later.
Month 2: Working drawings, structural engineer engagement, preliminary fixed-price quote. By the end of month 2 you should have:
• Floor plans signed off by both partners (this is where 70% of delays start) • Elevations agreed • Specification document (door types, window sizes, ceiling heights, insulation grades) • A genuine fixed-price quote — not a 'guide'
If the builder hands you a quote with TBC items still in the spec, push back. TBC is just a variation in disguise.
Months 3–5 — Approvals (CDC or DA)
CDC pathway (if your site qualifies): 4–8 weeks total. BASIX, structural certification, geotech, surveyor, certifier review, issue. Cost $4k–$7k all-in.
DA pathway (Fairfield, parts of Liverpool, heritage areas, flood overlays): 12–22 weeks. Council fees + acoustic, traffic, arborist reports as required. Cost $8k–$18k.
This is the phase where I see clients lose patience. They've already paid the architect and the builder's design deposit, the family is living in a rental, and council emails are slow. Hold the line on quality — don't sign a construction certificate with conditions you don't understand. A bad CC binds you for the whole build.
For the full approval pathway comparison see /insights/cdc-vs-da-approval-fairfield-western-sydney.
Months 6–7 — Demolition and Site Prep
Month 6: Disconnect services (Sydney Water, Ausgrid, Jemena gas), asbestos audit, demolition permit, demolition. A standard 1960s–1980s house with asbestos in the eaves and bathroom tiles costs $22k–$35k to demolish properly in 2026. No asbestos: $14k–$22k.
Month 7: Site clear, soil tests confirmed, set-out, construction certificate issued, site fencing, temporary toilet, water meter relocate. Footings excavation begins.
Watch for: tree protection orders that emerged late in DA, neighbour-notification disputes during demolition, and the always-classic 'we found a buried slab from a previous demolition' add-on. Allow $3k–$8k contingency for site surprises. They almost always show up.
Months 8–12 — Lock-Up and First Fix
Month 8: Slab pour. This is your first real construction milestone. Photograph everything.
Month 9: Frame up (single storey) or first lift (two storey). Brickies start veneer or full brick. A two-storey delays here because of the second-lift scaffold and brick lift.
Month 10: Roof on, fascia, gutters, sarking. House is officially weather-tight. Windows installed. Lock-up reached.
Month 11: First fix electrical, plumbing, HVAC. Insulation. Plasterboard. This is the fastest-feeling month — you walk through and suddenly the rooms are real.
Month 12: Cornice, set, sand, paint prep. Cabinetry templating. Stone benchtops measured. Tiles laid. Driveway form-up.
If you're in month 12 and the kitchen hasn't been templated yet, that's a 4-week delay coming.
Months 13–14 — Fit-Off, Defects, Handover
Month 13: Cabinetry install, stone install, tapware, appliances, painting final coats, floor finishes, electrical fit-off (light fittings, switches, fans), plumbing fit-off (WCs, vanities, sinks). Hard landscaping, fencing, driveway concrete cure.
Month 14: Final clean, certifier final inspection, occupation certificate, defect walk-through with the client, defect punch-list, defect rectification. Handover.
The 28-day defect period after handover is real — use it. Walk every room with a torch. Open every cupboard. Run every tap. Cycle every door. You will not get easier access to the builder than in those four weeks.
For cost details on each phase see /insights/knockdown-rebuild-cost-sydney. For the contract clauses to scrutinise before signing, read /insights/knockdown-rebuild-contract-checklist-sydney. To start a real timeline conversation visit /homes/knockdown-rebuilds or call 0476 300 300.
