When extending wins
- You love the block, the schools, and the neighbours
- The gap between your current house and your dream house is 1-2 rooms
- Your suburb is appreciating faster than the metro average
- Selling costs (stamp duty on the new place + agent fees) would exceed 70% of the extension cost
When selling wins
- The problem is the block itself (slope, aspect, size, noise)
- The extension would cost more than 40% of the current property value
- You cannot see yourself in this suburb in 10 years
- The kids need a completely different school catchment
Real 2026 Adelaide numbers
- Extension cost (30sqm rear): $180k – $340k
- Second-storey extension: $380k – $720k
- Selling costs on a $900k property: $65k – $88k (stamp duty on new + agent + conveyancing + moving)