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Stabilising your home's foundation is simple with Buildfix's advanced subsidence solution.
- Free assessment · 1–2 day repair · 20-year warranty
- Structural Engineers · Licensed Builders · Skilled Technicians
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Stabilising your home's foundation is simple with Buildfix's advanced subsidence solution.
- Free quote · 1–2 day repair · 20-year warranty
- Structural Engineers · Licensed Builders · Skilled Technicians
Solutions
Subsidence repair — raise and stabilise your foundation permanently
Stabilising your home's foundation is simple with Buildfix's advanced subsidence solution.
- Free structural assessment and honest advice
- Non-disruptive — most jobs completed in just one day
- 20-year warranty — if your home’s subsidence returns, so do we
Structural Engineers · Licensed Builders · Skilled Technicians
TrustpilotGoogleIs your home suffering from subsidence?
Subsidence can impact your home dramatically. If you suspect your house is suffering subsidence, it's worth having it looked at sooner than later. We're happy to take a look at your home for FREE.
What are the symptoms of subsidence that I should be looking out for?
Wall Cracks
Sometimes wall cracks are purely cosmetic. Other times, the cracks indicate structural issues brought on by your house sinking. If your wall cracks appear stepped, appear in both the internal and external walls of your house as well as the corners of walls, your house may be sinking.
Ceiling and Cornice Cracks
Just like wall cracks, ceiling cracks can be superficial but can also indicate deeper structural problems due to the sinking of your home. The sinking places pressure upon the entire house starting in the foundations. This travels up walls into your cornices and ceiling, causing them to crack.
Doors & Windows Jamming
If you can’t close or open your doors and windows without them jamming, there’s a likelihood the foundation of your home has sunk, unevenly. What was initially level isn’t anymore. It’s this lack of balance in the structure’s foundation that causes doors to hit the floor when you open them or has walls squeezing windows in so they can’t be opened or shut.
Leaning or Off-level Walls
The source of leaning or off-level walls is the same as jammed windows and doors. As your house sinks, the unevenness of your home’s foundations can cause walls to lean one way or another. Leaning or off-level walls should be checked sooner rather than later — the further a wall leans, the harder it works to hold itself up.
Sloping Floors
If you have sloping floors, the reason is, again, unevenness in the foundations of your home due to sinking. Your floors will slope as one side of the house sinks downwards more than the other. To double check for a sloping floor, just place a ball on the floor and see if it rolls away from you. If it does, it’s likely you’re in a sinking house.
Gaps between Walls & Floors
As the foundation underneath your home sinks, the floors pull away from the base of your interior walls, causing gaps to appear. The sinking of your home may also result in a floor that becomes bouncy as you walk upon it. This is likely caused by the ground pulling away from the upper parts of your home’s structure — a sign your floor’s support system is beginning to sag and weaken.
What causes subsidence?
Subsidence always has a cause. Knowing yours changes everything about the fix.
Reactive Clay Soil
Reactive clay is the single biggest cause of subsidence across Melbourne, Western Sydney, and South East Queensland. It swells when wet, shrinks when dry, and moves your foundation with it. Drought, new trees, or altered drainage can pull even more moisture out of the soil — and the shrinkage accelerates.
Water Erosion
Burst pipes, leaking mains, overflowing stormwater drains, or unconnected downpipes — any of these can saturate the soil beneath your home. The ground softens, loses its bearing capacity, and the foundation sinks into it. That’s subsidence by another name.
Tree Roots and Vegetation
Tree roots draw moisture out of the ground beneath your home. The soil dries, shrinks, the foundation loses support — and subsidence follows. Large trees close to the house are the most common culprit — but even garden beds and hedges with shallow roots can pull enough moisture to cause movement. Sickly vegetation is the thirstiest of all. A struggling tree or shrub puts out far more root to find water than a healthy one, and sucks more out of the soil under your footings doing it. A rule of thumb from the old hands: roots grow out to about twice the spread of the branches. If the canopy reaches your house, the roots are already under it.
Nearby Construction
The neighbour adding a pool. An extension next door. A tunnelling project down the road. Nearby construction disturbs the ground — vibrations loosen the soil, and larger infrastructure projects can alter water tables, drying out the ground and causing it to shift. Your foundation moves with it. It isn’t only building sites. A main road where heavy trucks run all day, a train line with carriages passing at speed, or an airport with planes landing and taking off do the same thing, every day — the ground shakes, aerates and slowly loses the strength that was holding the footings up.
Poor Workmanship
If the ground beneath your home wasn’t properly compacted before the footings were poured, it was never going to stay stable. Poorly compacted fill, missing drainage, or skipped soil testing — the foundation was sitting on borrowed time. Subsidence usually finds it.
Wrong Footing Type
Most footings are designed to Australian Standards — but standards assume the soil has been classified correctly. If the soil is more reactive than the classification assumed, or the footing type doesn’t suit the conditions, the ground moves more than the footing can handle. And subsidence sets in.
Why does it matter?
Subsidence can impact your home dramatically. When a home suffers from subsidence, an immense amount of force is being exerted onto the structure. This force strains the footings, floors, walls, ceiling and even the roof. If subsidence isn't stopped, structural issues like wall cracks can multiply.
Introducing GeoPoly™ — the non-invasive solution to subsidence
Non-Invasive. Precision-Controlled. Guaranteed.
No Digging. No Mess. A Fraction of the Cost.
GeoPoly™ solves subsidence issues without the hassle; it's like keyhole surgery for foundations. Unlike traditional underpinning, GeoPoly™ eliminates the need for disruptive digging and costly construction work. It's injected through small, coin-sized holes in the ground. Once injected, it expands into voids beneath the footings. This process has the potential to close cracks and even level walls. GeoPoly™ can re-support your home's foundation while instantly enhancing its appearance.
Watch: GeoPoly™ transforms a sinking home in minutes! Then read the technical detail on the GeoPoly™ GER60 page.
6 reasons why you should choose Buildfix
FREE structural assessment and honest advice. Buildfix structural engineers or consultants come to your home at no cost. Our assessments are thorough, uncovering your home's issues and the best solutions.
UNLIMITED GeoPoly™ for your job. After we've completed your quote, we don't change it. We don't add extra costs at the end. With us, there are no tricks, no games and zero surprises.
Permanent repair guaranteed. Using our advanced underpinning technology, GeoPoly™, we can lift your foundations and solve your subsidence permanently. Everything we do is guaranteed to last.
Experience — thousands of projects completed. With well over 15,000 projects completed, you'll get the most experienced and committed teams around. Your home is in expert hands with our proven track record.
Best price promise. With our leading techniques and technology, we work more accurately and more efficiently than anyone else. We promise the best price* on advanced underpinning technology, if not we'll beat lower offers by 5%. *Must be like-for-like, covering the same area with unlimited GeoPoly™, or similar material.
We cover locations throughout Australia. Our teams are ready to go where you live. Whether it be in Brisbane, Sydney, Canberra, Melbourne or anywhere else in between**, we'll come out and do the job for you. **Excludes some remote locations.
What to expect
How the subsidence repair process works — from assessment to completion.
Step 1Free Structural Assessment
A Buildfix engineer inspects your home, identifies the root cause of the subsidence, and designs a repair plan on-site. Measurements, photos, and markings are recorded using mobile software — and the price is usually explained there and then.
Step 2Get Your Quote and Book
A complete quote package arrives — detailed drawings, repair method statement, and a fixed-price quote. The price you see is the price you pay. When you’re ready, book through the online portal and suitable dates are organised for the work.
Step 3Drill for Access
Small, coin-sized holes are drilled at precise intervals around the problem areas. These allow the injection pipes to reach the exact depths needed beneath your footings.
Step 4Inject, Lift, and Level
GeoPoly™ resin is injected through the access points. The resin targets and fills voids and weak spots in the soil, then lifts and when conditions allow, relevels your foundations. Laser levelling equipment and digital sensors monitor every millimetre of movement in real time — so the lift is precise and controlled.
Step 5Patch and Clean Up
The drill holes are patched, the site is cleaned, and your home looks exactly as it did before. Except now it’s on solid ground.
Step 6Receive Your Warranty
Your 20-year product and workmanship warranty arrives via email with the Completion Package — a job report covering the work, materials, and images.
See the difference
Actual GeoPoly™ subsidence repairs — before and after.
Press the image for a closer look.Click on the image for a closer look.
Instant results.
Guaranteed to last.
The advantages of our GeoPoly™ solution.
If your foundations are subsiding, GeoPoly™ can give them a lift. Cracks may even close, making your home look better instantly.
Need a subsidence solution? Book a FREE structural assessment today.
Real homes. Real results.
15,000+ homes and structures repaired. Want to see real Buildfix subsidence repairs? Browse a few below.
CommercialBlack Mountain, ACT
CSIRO’s Research Facility Relevelled
When Australia’s national science agency — the country’s foremost authority on foundation subsidence — needed their own buildings fixed, they called Buildfix.
HomeownerStrathfield, NSW
Heritage Home Repaired Twice, Same Team
When new cracks appeared in this 150-year-old Strathfield home, the owner didn’t hesitate — they called Buildfix again. Buildfix had already fixed the front of the house years earlier. This time, the team tackled the rear.
StrataKensington, NSW
1920s Apartment Stabilised After Light Rail
Light Rail construction shook a century-old apartment block to its foundations. GeoPoly™ stabilised six residences at a fraction of underpinning costs — residents never had to leave.
HomeownerSunnybank Hills, QLD
Cracked Brick Veneer Bungalow Stabilised
Years of Queensland drought shrank the clay away from this 1980s slab-on-ground bungalow until the brick veneer step-cracked and a 20mm gap opened at the windows. GeoPoly™ filled the voids and closed the cracks in a day.
HomeownerMorayfield, QLD
Sinking Waffle Slab Home Lifted 15mm
A 15-year-old Morayfield home on a waffle slab was sinking so fast the tenants felt like they were walking up and down hills. GeoPoly™ filled the voids under the slab and lifted the house 15mm in a day.
HomeownerGoulburn, NSW
Heritage Bungalow's Sinking Walls Lifted
A disconnected downpipe soaked the ground under this Goulburn Federation bungalow for years until the walls sank away from the roof and the gable began to twist. Lifted, stabilised and stitched without removing a brick.
HomeownerBlacktown, NSW
Sinking Extension Underpinned in a Day
A rainwater tank's overflow had been draining under this rear extension for 20 years until it sat 100mm below the house. GeoPoly™ filled the washed-out ground and lifted the extension back to level in a day.
CommercialBerwick, VIC
Heritage School Building, Precision-Lifted
A heritage commercial building — in this case a 95-year-old school building in Berwick, VIC — was cracking inside and out. GeoPoly™ stabilised the foundations with a precision-controlled lift set for the building’s age, then HelicalBar™ wall crack repair reinforced the walls.
HomeownerKeilor East, VIC
Underpinning Failed — Resin Fixed It
After traditional concrete underpinning failed and brand-new windows wouldn’t fit, GeoPoly™ resin injection stabilised the foundation in a single day — with millimetre precision.
“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.
