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No-dig underpinning that lifts your Brisbane home back towards level — designed for Queensland slabs, stumps and reactive clay soils.
- Free assessment · 1–2 day repair · 20-year warranty
- Structural Engineers · Licensed Builders · Skilled Technicians
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No-dig underpinning that lifts your Brisbane home back towards level — designed for Queensland slabs, stumps and reactive clay soils.
- Free quote · 1–2 day repair · 20-year warranty
- Structural Engineers · Licensed Builders · Skilled Technicians
Underpinning Brisbane
No-dig underpinning that lifts your Brisbane home back towards level — designed for Queensland slabs, stumps and reactive clay soils.
- Done in 1–2 days · coin-sized holes · stay home the entire time
- Save thousands compared to traditional underpinning
- 20-year product and workmanship warranty
Structural Engineers · Licensed Builders · Skilled Technicians
TrustpilotGoogleUnderpinning your Brisbane home — without rebuilding it
Underpinning strengthens the foundations beneath a Brisbane home so the structure above stops moving. Cracked walls. Sloping floors. Doors that won't close. They're all signs the ground beneath the slab or stumps has given way — and the fix has to address the soil, not just the symptoms above.
Traditional mass concrete underpinning works — done well, it's a legitimate engineering solution. But the Brisbane reality is that most homes have a concrete slab (conventional or waffle), strip footings, or suspended timber on stumps — and digging trenches around or under any of those is invasive, slow and expensive. There's a non-invasive alternative.
GeoPoly™ resin injection is Buildfix's underpinning method for Brisbane homes. Coin-sized holes, no digging, the foundation lifted back towards level in 1–2 days. Works across slabs, waffle rafts, strip footings and stumps — the engineer designs the lift around what your home actually sits on.
Why Brisbane homes sink
Reactive clay soils across South East Queensland are the biggest cause. After a wet summer the clay swells and the foundation lifts. After a dry winter the clay shrinks and the foundation drops. Add Brisbane's extreme weather pulses — drought, flood, drought again — and homes built on shallow footings or undersized stumps shift first.
The Brisbane reality also depends on what your home is built on. A 1930s strip-footing cottage in Paddington behaves differently to a 1990s waffle-raft slab in Springfield Lakes. The cause, the timing and the right fix are all different. A free on-site assessment maps the levels and reads the soil before any work is proposed.
The traditional ways of underpinning brisbane a home
Brisbane uses four common foundation types. Each one fails differently — and each needs a different approach.
Conventional Concrete Slab
The most common Brisbane foundation — 150–300mm of poured concrete with steel reinforcement. Versatile, durable, but heavy. On weak or aerated clay soils, conventional slabs sink as a whole or rotate as one corner drops. GeoPoly™ lifts the slab back as a piece, through the slab itself.
Waffle Raft Slab
Common in modern Brisbane subdivisions — a grid of concrete beams over polystyrene void formers, the whole slab floating on the soil. Cheaper to build, but vulnerable to reactive clays. A waffle slab that has rotated or sunk needs the soil beneath it stabilised — GeoPoly™ does that without breaking the slab open.
Strip Footings
Found under older Brisbane homes from the 1930s onwards — usually clay brick or stone bonded with lime mortar, often only 450mm deep. Shallow strip footings are exposed to soil shrinkage, leaking pipes and storm drainage. Traditional underpinning gets risky on brittle old footings — GeoPoly™ stabilises the soil without disturbing the footing itself.
Suspended Timber on Stumps
The classic Queenslander — timber floors supported on concrete, steel or hardwood stumps. Stumps drop when the ground beneath them moves; the bearer above loses contact, the floor bounces, the door jams. Pier jacking with GeoPoly™ lifts each stump back into contact with the bearer — no replacement needed.
How Brisbane homes are built — and where they fail
Our Brisbane underpinning method — GeoPoly™ resin injection
GeoPoly™
Resin Injection Underpinning
GeoPoly™ is Buildfix's proprietary geopolymer resin. Injected beneath the footings through coin-sized holes, it compacts loose soil, fills voids, and lifts the foundation back towards level. No digging. No mass concrete. No weeks of disruption.
The lift is monitored in real time on a laser level — every millimetre of movement is watched as the resin expands beneath the foundation. Most Brisbane homes are stabilised in 1–2 days, and the family stays in the house the entire time.
GeoPoly™ has stabilised more than 15,000 homes and structures. It works across all four common Brisbane foundation types — conventional slabs, waffle rafts, strip footings and suspended timber on stumps — because the resin treats the soil rather than the foundation itself. Same product. Different injection grid. Engineered for what your home is actually built on.
Want to know if GeoPoly™ is the right fix for your Brisbane home? Book a free on-site assessment. A structural engineer comes from our Molendinar office, maps the floor levels with a laser, identifies the cause, and gives you a fixed-price quote on the spot.
What to expect
How underpinning your Brisbane home actually works.
Step 1Free On-Site Assessment
A structural engineer comes to your Brisbane home from our office at 7 Enterprise St, Molendinar. Floor levels are mapped with a laser, the cause of the movement is identified, and the repair plan is designed for your home's foundation type. Takes 30–60 minutes. Free.
Step 2Fixed-Price Quote
After the assessment, you receive a fixed-price quote on the spot. The price you see is the price you pay. No allowances, no per-kilo charges, no surprises mid-job.
Step 3GeoPoly™ Resin Injection
Small coin-sized holes are drilled into the slab or near the footings. GeoPoly™ resin is injected beneath the foundation through the holes. The resin expands under pressure, fills voids, and compacts the soil.
Step 4Real-Time Laser Monitoring
As the resin lifts the foundation, every millimetre is watched on a laser level. The injection is paused, adjusted, and resumed as the readings dictate — until the foundation is back at its target level.
Step 5Verify and Finish
Once the laser readings confirm the lift, the injection holes are patched flush. The resin reaches 95% strength within ten minutes. The slab is back in use the same afternoon.
Step 620-Year Warranty
Every Buildfix underpinning job is backed by a 20-year product and workmanship warranty. If the foundation issue returns, so do we.
See the difference
Brisbane homes before and after GeoPoly™ underpinning.
Press the image for a closer look.Click on the image for a closer look.
Instant results.
Guaranteed to last.
Why Brisbane homeowners choose Buildfix to underpin their home.
Most Brisbane underpinning jobs are completed in one or two working days — whether it's a Queenslander on stumps, a waffle raft, or a conventional slab. No weeks of trenches, no concrete trucks.
Get your Brisbane foundation checked out. Takes 30–60 minutes. It's free.
“All of the Buildfix team have been easy to communicate with. Everyone was punctual and communicated arrival times well ahead of arrival.”
Scott HolmesMelbourne, VIC
“All of the Buildfix team have been easy to communicate with. Everyone was punctual and communicated arrival times well ahead of arrival.”
Scott HolmesMelbourne, VIC
“All of the Buildfix team have been easy to communicate with. Everyone was punctual and communicated arrival times well ahead of arrival.”
Scott HolmesMelbourne, VIC
“All of the Buildfix team have been easy to communicate with. Everyone was punctual and communicated arrival times well ahead of arrival.”
Scott HolmesMelbourne, VIC
Questions?
Our team is here to answer any questions you may have Monday – Friday 8am to 5pm AEST. Give us a call on 1300 854 115.
