Raising an existing home and building underneath is one of the most cost-effective ways to double living space — particularly for timber homes on stumps.
Physically lift your existing home higher, then construct a new living level underneath. Upper level = original house. Lower level = brand new construction.
Good: Timber-framed on stumps, post-war Queenslander-style, 1960s-80s timber homes with sound framing. See our guide on heritage and character home renovations for design considerations with older homes.
Not suitable: Brick homes (too heavy), concrete slab (can’t separate), significant structural damage, some heritage-listed.
| Component | Typical Range |
|---|---|
| Design and documentation | $8,000-$15,000 |
| Engineering | $4,000-$8,000 |
| Council/certifier | $3,000-$8,000 |
| House raising | $20,000-$60,000 |
| Lower level construction (80-120sqm) | $200,000-$400,000 |
| Staircase | $8,000-$20,000 |
| External cladding integration | $15,000-$40,000 |
| Services upgrades | $10,000-$25,000 |
| Total | $283,000-$621,000 |
Typical budget: $350,000-$500,000 for 80-120sqm new lower level. For design fee details, see our guide on building designer costs.
| Option | Cost | New Area | Disruption |
|---|---|---|---|
| Raise and build under | $350K-$500K | 80-120sqm | 4-6 months |
| Rear extension | $100K-$250K | 30-60sqm | 3-5 months |
| Second storey (on top) | $400K-$700K | 80-150sqm | 4-8 months |
| Knockdown rebuild | $500K-$900K | Full new home | 12-18 months |
Best value per sqm of new space. For help deciding between approaches, see our guide on renovation vs knockdown rebuild.
Cost effective: Building one new level, not entire house.
Preserves character: Original upper level maintained.
Flood resilience: Higher floor level — particularly relevant for properties in flood overlay areas.
Better views: Elevated outlook.
Minimal disturbance: No demolition.
Completed building must comply with zone height limits (typically 9m residential). Practical limit determined by council restrictions and visual impact.
Yes, during raising (1-2 weeks). Most relocate for full project (4-6 months).
Potentially, with structural assessment. May have reached practical limit.
3-5 days for the physical lift. 1-2 weeks including service disconnection and reconnection.
$350,000-$500,000 for 80-120sqm new lower level. Best value for adding space to Gold Coast timber homes. Preserves character, improves flood resilience, gains views. Start with structural assessment and design consultation.
Design Science has experience with raise and build under projects on the Gold Coast. Book a $280 consultation to assess your home’s raising potential with our renovation design team.
David Steadman
Licensed Builder & Building Designer
David Steadman is the founder of Design Science, a Gold Coast building design practice backed by over 30 years of hands-on construction experience. One of few Australians holding both a QBCC Builder's Licence and Building Designer licence, David brings a rare combination of design thinking and practical building knowledge to every project.
