Raising an existing home and building underneath is one of the most cost-effective ways to double your living space — particularly for timber homes on stumps. It’s also one of the most distinctly Queensland things you can do to a house. The rest of Australia doesn’t really have this option at scale, because the rest of Australia built mostly on concrete slabs. We built on stumps, and that creates an opportunity that’s genuinely unique to Queensland.
The Queenslander — timber-framed, elevated on hardwood or concrete stumps, with high ceilings and wide verandahs — was designed for the subtropical climate before air conditioning existed. Elevation created cross-ventilation under the floor, kept the living areas above ground moisture and pests, and made flood events survivable. From the 1880s through to the 1970s, this was how Queensland built.
The result, 50–100 years later, is a large stock of elevated timber homes sitting on stumps with a functional ground level that’s being used for parking and storage. That underfloor space is an extraordinary opportunity. You already own the land. You already own the structure above. Building underneath means you’re doubling your floor area without buying more land and without the full cost of building a new house from scratch.
On the Gold Coast specifically, this matters because land values have increased dramatically. A block in Southport, Labrador, or Varsity Lakes that sold for $200,000 in 2010 might now be worth $800,000+. The land is the expensive part. The raise and build under approach leverages the land you already own.
You physically lift the existing home higher on its stumps — or onto a temporary support system — then construct a new living level underneath. The upper level remains your original house. The lower level is brand new construction: footings, concrete slab, framing, cladding, windows, and full fit-out. At the end, you have a two-level home where previously you had a single-storey elevated home with storage underneath.
Good candidates: Timber-framed homes on stumps, post-war Queenslander-style homes, 1960s–80s timber homes with sound framing and bearers/joists in reasonable condition. The test is structural integrity — the frame needs to be sound enough to be lifted without racking or distortion. See our guide on heritage and character home renovations for design considerations with older homes.
Not suitable: Brick veneer homes (too heavy and the brick skin can’t be lifted as a unit), concrete slab construction (can’t separate from the ground), homes with significant structural damage to bearers or joists, and some heritage-listed properties where raising would alter the heritage character beyond what council will permit.
The first step for any raise and build under project is a structural engineer’s assessment of the existing home. This tells you the stump condition, bearer and joist sizing and adequacy, and whether the frame can tolerate being raised. Budget $1,500–$4,000 for this assessment. It’s money well spent before you commit to anything.
This is where my dual background as a licensed builder and building designer genuinely matters. I can read a structural report and understand what it means for the construction programme — not just the design outcome.
A structural engineer assessing a raise and build under candidate will look at:
I’m going to say this clearly because I’ve seen it catch clients by surprise mid-project: if your home was built before 1990, assume there is asbestos-containing material (ACM) somewhere in it until a licensed asbestos assessor tells you otherwise.
Common locations in Queensland homes built pre-1990: fibrous cement sheeting (wall linings, eaves, fascias, soffit linings), floor underlays, pipe lagging, and some textured ceiling coatings. Asbestos itself isn’t dangerous when it’s intact and undisturbed. It becomes a serious problem when you start cutting, drilling, or demolishing — which is exactly what happens during a raise and build under project.
Before any raise and build under project on a pre-1990 home, commission an asbestos assessment report from a licensed asbestos assessor. Cost: $500–$1,500. If ACM is found, removal by a licensed asbestos removalist is required before construction work begins. Asbestos removal costs vary significantly depending on the quantity and location: budget $3,000–$15,000 for typical residential quantities. Factor this into your project budget early — it’s not optional and it’s not negotiable under Queensland law.
Raise and build under projects on the Gold Coast require Building Approval as a minimum, and may require Development Approval depending on the site and the extent of works.
Building Approval (BA): Required for all raise and build under projects. The certifier will need structural engineering documentation for both the raising methodology and the new lower level construction. The completed building must comply with current NCC requirements for the new works, even though the original upper level has existing use rights.
Development Approval (DA) triggers:
The flood overlay is particularly relevant for raise and build under on the Gold Coast. Many of the properties best suited for raising — older timber homes in established suburbs close to waterways — are also in flood overlay areas. Paradoxically, the raise and build under approach is often specifically beneficial in these locations: by raising the habitable floor level, you can bring the upper level above the defined flood level, which improves flood resilience and may reduce insurance costs. But the lower level construction needs to comply with flood overlay requirements — typically requiring resilient construction, flood-compatible materials, and in some cases a flood-resistant lower level design. See our guide to building in flood overlay areas.
| Component | Typical Range |
|---|---|
| Structural assessment | $1,500-$4,000 |
| Asbestos assessment and removal (pre-1990 homes) | $3,500-$16,500 |
| Design and documentation | $8,000-$15,000 |
| Engineering | $4,000-$8,000 |
| Council/certifier fees | $3,000-$8,000 |
| Restumping (if required) | $15,000-$40,000 |
| 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 | $293,000-$636,500 |
Typical budget: $350,000–$500,000 for 80–120sqm new lower level. The wide range reflects the variation in existing home condition (restumping adds $15,000–$40,000 if needed), asbestos situation, and lower level fit-out specification. For design fee details, see our guide on building designer costs.
The cost per square metre of new floor area — once you account for the full project cost — typically works out at $2,500–$5,000/sqm for a raise and build under, compared to $3,500–$6,000+/sqm for a second storey addition and $4,000–$7,000+/sqm for a knockdown rebuild. It’s not always the cheapest option per sqm, but on the right site with a sound existing structure, it delivers excellent value for the amount of space gained.
Scenario 1 — The Southport Queenslander: 1950s timber home on a 600sqm block. 120sqm of living upstairs, underfloor parking for 2 cars and storage. After raise and build under: 120sqm upper level (original home, minimally touched), 100sqm new lower level with 2 bedrooms, bathroom, and rumpus room. Total living area nearly doubled. Cost: approximately $380,000. Comparable new 220sqm home on equivalent land: $900,000+.
Scenario 2 — The Labrador flood overlay block: 1970s timber home in a flood overlay area. Currently set at 500mm above ground — technically above the defined flood level but only just, and the insurance costs reflect it. After raise and build under: upper level raised to 2.4m above ground (well clear of any realistic flood level), new lower level constructed with flood-resilient materials (concrete, masonry, ceramic tiles — nothing that water can’t touch). Insurance premiums reduce. The home is substantially more marketable. Cost: approximately $450,000 including flood-compliant lower level construction.
Scenario 3 — The growing family in Mudgeeraba: 3-bedroom single-storey raised home, good structural condition, 650sqm block, stumps in good condition, no asbestos. Family has outgrown the home but loves the location and doesn’t want to move. After raise and build under: original 3 bedrooms upstairs become parents’ retreat plus 2 kids’ rooms. New lower level has open-plan living/dining/kitchen, laundry, and double garage. Effectively a fully functional home on two levels where previously they had a cramped 3-bedroom. Cost: approximately $420,000.
| 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 when the existing structure is sound. For help deciding between approaches, see our guide on renovation vs knockdown rebuild.
Cost effective: You’re building one new level, not an entire house. The existing upper level is largely retained with only integration works required.
Preserves character: The original upper level — often a genuine Queenslander with high ceilings, VJ walls, and wide verandahs — is maintained. This character is genuinely valued and increasingly hard to replicate.
Flood resilience: Higher floor level for the habitable areas — particularly relevant for properties in flood overlay areas.
Better views: An elevated outlook in an established suburb is hard to put a price on. Raising adds typically 1.5–2.5m of height.
Minimal demolition: You’re not knocking anything down. The existing home is retained, reducing both waste and the cost of full demolition.
No need to move permanently: Most families relocate temporarily during construction (4–6 months) rather than having to find permanent accommodation during an 18-month knockdown rebuild.
The completed building must comply with the zone height limit — typically 9m for residential zones in the Gold Coast City Plan. The practical limit is determined by the existing home’s height plus the amount you raise it. Most raises are 2–3m, which creates adequate lower level ceiling height (2.4–2.7m) without pushing the total building height to the zone limit. A structural engineer and your building designer will work through the numbers for your specific home. See our guide on Gold Coast building codes and regulations.
Yes — during the actual raising (1–2 weeks), the home is not habitable. Services are disconnected, the home is jacked up, and the structure is in a transitional state. Most families relocate for the full construction period (4–6 months) rather than moving in and out multiple times. Plan for 4–6 months of temporary accommodation in your project budget.
Potentially, with a structural assessment. Homes that have already been raised once may be at or near the practical height limit for the zone, and the structure may have been modified in ways that complicate a second raise. Needs a structural engineer’s opinion specific to the building.
The physical lift — jacking the home up — takes 3–5 days for a typical home. The full 1–2 weeks of the raising phase includes service disconnection before the lift and service reconnection and temporary propping after. The home raising specialist manages this process with input from your plumber, electrician, and the structural engineer.
Many older Gold Coast homes are overdue for restumping regardless of a raise project. Timber stumps typically have a service life of 40–60 years. If the existing stumps are deteriorated, the raise project is actually an ideal time to restump — the house is being lifted anyway, so restumping adds relatively little additional cost compared to doing it as a standalone exercise. Budget $15,000–$40,000 for restumping a standard home, depending on the number of stumps and accessibility.
$350,000–$500,000 for 80–120sqm of new lower level floor area. Best value for adding significant space to Gold Coast timber homes without buying more land or knocking down a character home. Preserves the existing upper level, improves flood resilience, gains views, and leverages land you already own. The process takes 4–6 months of construction and requires a structural engineer’s assessment, building approval, and — for pre-1990 homes — an asbestos assessment. Start with a consultation and structural assessment before committing to anything.
Raise and build under is one of several dual living options available on the Gold Coast — alongside attached dual living, detached secondary dwellings, and internal conversions. See Design Science’s complete guide to dual living and multi-generational home design on the Gold Coast for a full comparison of all configurations, costs, and council requirements.
Related: Knockdown rebuild Gold Coast | Renovation design | Dual living and multi-generational design
Design Science has experience with raise and build under projects on the Gold Coast. Request a 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.
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