By Blue Horizon Projects · · 6 min read
A rear extension is the most common way Central Coast families buy themselves another decade in a home they like. Done well it's transformative; done without a program it's a long year.
Typical cost bands
| Scope | Typical range |
|---|---|
| Single-room addition (approx. 25m²) | $180k – $260k |
| Living, dining and kitchen extension | $280k – $450k |
| Large extension with master suite and alfresco | $450k – $650k+ |
Stage by stage timeline
| Stage | Typical duration |
|---|---|
| Concept and feasibility | 3 – 5 weeks |
| Design documentation and engineering | 6 – 12 weeks |
| Approval (CDC or DA) | 3 – 20 weeks |
| Construction | 16 – 30 weeks |
Where programs slip
- Late client selections on tiles, tapware and joinery
- Variations introduced after framing
- Approval conditions requiring redesign
- Extended wet weather during roof-off stages
Selections locked before construction starts are the single biggest predictor of a build finishing on time.
Living through it
Most extension clients stay in the home. We set up a temporary kitchen, seal the work zone with dust screens and confirm the disruptive weeks well in advance so you can plan around them.
Frequently asked
- Can we keep using our kitchen during the build?
- Usually for the early stages. Expect four to eight weeks on a temporary kitchen when the new one is being installed.
- Do extensions need a DA?
- Many qualify as Complying Development. Heritage, flood, bushfire and foreshore constraints commonly push a project to a DA.
