We Raised Our Queenslander 11 Feet and Built Underneath

The day they raised the house, I stood on the footpath and watched it go up about thirty centimetres an hour.

The raiser had jacks positioned at around thirty points under the floor — steel and hydraulics disappearing up into the guts of a hundred-year-old house — and the whole thing came up together, slowly, with a long groan of old timber each time he cycled the system. The neighbours came out. A couple of people stopped their cars. By mid-afternoon, the bottom of the floor joists were level with the top of my head. By the end of the day, I could walk underneath without ducking.

We raised it to 3.35 metres under floor level. That’s just over eleven feet.

Most Queenslander build-unders aim for 2.4 to 2.7 metres — enough for a liveable room, a standard-height ceiling, code compliance. We went higher. This is why, and what it meant for everything that came after.

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The decision to go to 11 feet

The house sits on a block with a slight fall from front to back. When we first had the structural engineer out, he modelled a few scenarios. At 2.4m under floor level, the slab would need significant cut-and-fill at the rear to keep the level consistent — and we’d still end up with rooms that felt slightly tight. At 2.7m, it was comfortable but unremarkable.

At 3.35m — eleven feet — something changed. The ground floor would feel like a ground floor, not a converted subfloor. Standard door heights, decent ceiling fans with clearance, natural light coming in at the right angle. And critically: the rear of the block would work without major excavation.

The engineer’s advice was that going to 3.35m was achievable with the existing structure, but it would change what he needed to specify. Higher = more moment at the connection points between old bearers and new subfloor framing. The temporary works (the jacking system) would need to account for the additional travel. And we’d need longer stumps, which meant different stump sizes, which added cost.

We ran the numbers. The premium for going from 2.7m to 3.35m was around $8,000 across the raise, structural engineering, and the subfloor. For a permanent gain in liveability and ceiling height, it wasn’t a hard call.

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What the structural engineer had to specify differently

Going to 3.35m isn’t just “same raise, higher” — the engineering changes.

The primary concern at increased height is lateral stability during the temporary works phase. When the house is suspended at eleven feet on a steel crib system, the centre of gravity is higher relative to the base than it would be at 2.7m. Wind becomes more of a factor. The engineer specified temporary diagonal bracing between the crib stacks that wouldn’t have been required at a lower height.

The permanent subfloor also changed. The new steel columns (RSJs) that form the permanent support at the perimeter were specified at a heavier section than they would have been for a lower raise. The bearer connections to those columns were bolted, not just nailed — engineered timber connectors specced to handle the increased moment.

None of this is particularly alarming — the engineer was confident in the design, and it’s the kind of thing that gets resolved in the documentation before anything moves. But it’s worth knowing that height has structural implications beyond just the cost of a longer stump.

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Raise day

The raiser arrived at 6:30 in the morning with a truck that looked too small for the job and a crew of three. By 7am they had the jack positions marked and were sliding the hydraulic equipment into place.

The sequence was this: jack positions identified and set, a test lift of about 50mm to check everything was bearing correctly, then a slow rise in increments of around 100mm at a time, cycling through all the jacks on each pass. Each cycle took about fifteen minutes. The house rose, the timber groaned, the operator walked around checking each point before the next cycle.

A few things worth knowing about raise day:

It is slower than you expect. We knew it would take all day, but knowing that and watching it are different things. The incremental nature of it — the waiting between cycles — tests your patience. Don’t plan to be elsewhere.

Something will crack. About halfway up, there was a sharp crack from inside the house — like a gunshot. The raiser barely looked up. An old plaster cornice had separated from a wall. This is completely normal. Old Queenslanders are flexible; they were built to move. The raiser had seen it hundreds of times. What you’re watching for is anything structural — a bearer splitting, a jack position sinking — and there was none of that.

Access to the house stops. Once the house is off its stumps and rising, nobody goes inside. This is obvious in retrospect but worth planning for: get everything you need out beforehand.

By 4pm, the house was at height. By 5pm, the temporary crib system was in place and the jacks were out. We walked underneath for the first time.

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Standing under 11 feet of floor

There’s a moment, after the dust settles on raise day, when you walk underneath the house and look up.

You’re standing on bare earth — the original ground level, now exposed — and above you is the underside of a hundred-year-old timber floor: the joists, the bearers, the old subfloor boards, some of which date to the original construction. There’s a musty smell of old timber and disturbed soil. It’s dim. The space feels enormous.

At 3.35m, there’s no ducking, no crouching. You can stand anywhere and look up at full arm’s reach and still not touch the joists. The scale of it — the house you’ve been living in, suspended up there — is strange and impressive.

What you’re also looking at is the potential of the space. The ground floor, when built, will have those 3.35m ceilings not as a design statement but as the practical result of the structural decision. When we bring the slab up to finished floor level and account for the ceiling and services void, the finished internal height will be around 2.9m. That’s a quality space.

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Building underneath

The build-under began in earnest about three weeks after the house was lowered onto its permanent subfloor.

A few things that 11 feet of height changed about the build:

The slab. At a lower raise height, the finished slab level might end up only slightly below natural ground level, and you can sometimes avoid significant bulk fill. At 3.35m, we had around 700mm of air between the bottom of the permanent bearers and natural ground — enough room to work, but the slab still needed to be brought up to a sensible finished floor level, which meant compacted fill and engineering sign-off on the bearing capacity.

External walls. The external framing runs from slab to the underside of the old floor — at 3.35m UFL, that’s a lot of wall. Standard stud walls needed head plates at the right height, and the connection between the new external framing and the raised house perimeter required careful detailing at the top.

Window proportions. With taller external walls, you can use taller windows. This sounds cosmetic but it’s actually significant: the light quality in the ground floor is directly related to window head height, and at 3.35m we had room to spec windows with 2.1m head heights. The rooms are genuinely light.

Cost. More wall means more framing, more plasterboard, more paint. The additional height contributed to external cladding and internal wall costs being higher than they would have been at a standard build-under height. We’ve estimated the ground floor build cost was roughly 10–12% higher than an equivalent project at 2.7m, attributable to the additional wall height.

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Would we do it again

Yes, without hesitation.

The additional cost — roughly $8,000 in structural premium and 10–12% more in the ground floor build — bought us a ground floor that doesn’t feel like an afterthought. The 2.9m internal height is the first thing people comment on when they walk in. The proportions are right. The light is right.

There’s also something less quantifiable: the feeling that the decision was made for the right reasons, not the cheapest ones. We went to eleven feet because the engineer confirmed it was achievable, because it solved a site problem without earth-moving, and because it gave us a better outcome. The cost was real. The result is better.

If your block allows it and your engineer supports it, I’d encourage anyone planning a build-under to at least model what 3m or higher gets them — before defaulting to the minimum.

Before After