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We’ve developed cutting-edge technologies to resolve your home’s structural issues.

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Underpinning

Stabilising your home’s foundation is simple with Buildfix’s advanced underpinning solution.
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Detecting Subsidence in Your Home

What is underpinning?

Underpinning is a process that strengthens the foundations beneath a house to allow for additional loads and correct subsidence.

Most of the time, the underpinning of a home is a massive undertaking for everyone involved, which can be quite costly for homeowners. Because of this, it’s particularly important to understand what’s causing your home to subside, as well as the various underpinning methods available and the advantages and disadvantages they can bring.

Why is underpinning essential for a sinking home?

When a home suffers from subsidence, an immense amount of force is being exerted onto the structure. This force strains the foundations, floor, walls, ceiling and even the roof.

If sinking isn’t stopped, foundational and structural issues like wall cracks will multiply. This escalates repair costs, putting a massive hole in your budget. Underpinning is essential in stopping this, preventing your home from sinking, avoiding further damage and saving you money.

The traditional ways of underpinning a home

Mass concrete underpinning

Mass concrete underpinning, also known as traditional underpinning, is one of the most common types of underpinning around. It involves excavating multiple holes underneath a home to construct box shaped piers that lend support to the structure. Although being commonly used, concrete underpinning is also well-known for its high cost and inconvenience, making it a less than ideal solution for most homeowners.

Steel pile underpinning

Steel pile underpinning is an option for subsiding homes built on a hillside. It involves driving steel piles into the ground with specialist hydraulic machines. These pipes are then fixed with brackets that are attached to structural walls and footings. This method is effective in certain situations and should be considered in areas prone to landslips. However, it requires heavy machinery, which presents challenges to access in residential areas.

Cement grout underpinning

Cement grout underpinning is a form of preventative maintenance for buildings and structures at risk of subsiding. This type of underpinning is performed by pumping a special concrete mix, or non-shrink cement grout, underneath the structure, filling in any large holes and voids. While effective in theory, this method depends on easy access to the voids beneath homes. This is often a significant barrier to use for homeowners, making it a generally impractical option.

Mass concrete underpinning

Mass concrete underpinning, also known as traditional underpinning, is one of the most common types of underpinning around. It involves excavating multiple holes underneath a home to construct box shaped piers that lend support to the structure. Although being commonly used, concrete underpinning is also well-known for its high cost and inconvenience, making it a less than ideal solution for most homeowners.

Read more

Steel pile underpinning

Read more

Steel pile underpinning is an option for subsiding homes built on a hillside. It involves driving steel piles into the ground with specialist hydraulic machines. These pipes are then fixed with brackets that are attached to structural walls and footings. This method is effective in certain situations and should be considered in areas prone to landslips. However, it requires heavy machinery, which presents challenges to access in residential areas.

Read more

Cement grout underpinning

Read more

Cement grout underpinning is a form of preventative maintenance for buildings and structures at risk of subsiding. This type of underpinning is performed by pumping a special concrete mix, or non-shrink cement grout, underneath the structure, filling in any large holes and voids. While effective in theory, this method depends on easy access to the voids beneath homes. This is often a significant barrier to use for homeowners, making it a generally impractical option.

Read more

Our advanced underpinning solution – GeoPoly™

GeoPoly™ is a game-changer for homeowners, offering a progressive, non-invasive approach to subsidence—it’s like keyhole surgery for your home’s foundations.

Unlike traditional underpinning, which requires disruptive and costly construction, GeoPoly™ works by being injected through coin-sized holes directly into the ground beneath your home.

GeoPoly™ meticulously lifts and stabilises your foundations, effectively solving deep-rooted subsidence issues, ensuring a long-lasting, cost-effective solution with minimal disruption.

Learn More
Learn More

Our advanced underpinning solution – GeoPoly™

GeoPoly™ is a game-changer for homeowners, offering a progressive, non-invasive approach to subsidence—it’s like keyhole surgery for your home’s foundations.

Unlike traditional underpinning, which requires disruptive and costly construction, GeoPoly™ works by being injected through coin-sized holes directly into the ground beneath your home.

GeoPoly™ meticulously lifts and stabilises your foundations, effectively solving deep-rooted subsidence issues, ensuring a long-lasting, cost-effective solution with minimal disruption.

Technical Info
Technical Info

The advantages of our underpinning solution

Lifts foundations

If your foundations are sinking, GeoPoly™ can lift them back. Cracks may even close, making your home look better instantly.

Minimal Disruption

GeoPoly™ is non-invasive and is injected through small holes from the surface. No excavations, and zero mess.

Immediate Results

GeoPoly™ gets to work fast, meaning subsidence can be fixed in no time. Most jobs are completed in just one day.

20-Year Warranty

You’ll get complete peace of mind. We guarantee your subsidence won’t return, or we return at no cost to you.

Need an underpinning solution? Book a FREE structural assessment today

Need an underpinning solution?
Book a FREE structural assessment today

Book now

Watch: GeoPoly™ fixes a sunken home in minutes!

Real feedback from real homeowners

Don’t just take our work for it! Hear what our customers say.

Read genuine reviews on Google and Trustpilot to learn about the real experiences others have had with our services.
Google Reviews
Trustpilot Reviews
Five white stars highlight top-rated foundation repair for subsidence issues Five-star rating representing excellence in repairing cracked walls with HelicalBar Premium rating stars indicating successful rising damp treatment and structural drying Top customer satisfaction for GeoPoly resin injection slab stabilisation services High five-star rating showcasing quality underpinning for sinking foundations.

The Buildfix process was professional…

“The Buildfix process was professional from beginning to end. Their website provides useful information, and it is easy to book an assessment. The inspection is thorough and timely. The technicians are experienced, friendly and happy to answer all questions. The process is amazingly easy compared to traditional underpinning and can be completed in a day with minimal disruption. So far the works looks good.”

Zee J,

14 December
Five white stars highlight top-rated foundation repair for subsidence issues Five-star rating representing excellence in repairing cracked walls with HelicalBar Premium rating stars indicating successful rising damp treatment and structural drying Top customer satisfaction for GeoPoly resin injection slab stabilisation services High five-star rating showcasing quality underpinning for sinking foundations.

GREAT SERVICE

Thankyou to George and Michael for structural helical bar work , stage 2 of work on our home. We were well informed of the works to be carried out, the workman were very proficient and tidy . Very happy with the results .Quality company , well mannered workers highly recommend Buildfix.
Regards
Enzo & Sabien of Saratoga / Davistown NSW

Enzo,

22 September
Five white stars highlight top-rated foundation repair for subsidence issues Five-star rating representing excellence in repairing cracked walls with HelicalBar Premium rating stars indicating successful rising damp treatment and structural drying Top customer satisfaction for GeoPoly resin injection slab stabilisation services High five-star rating showcasing quality underpinning for sinking foundations.

Buildfix and my sinking Brick wall

Buildfix were great from day one! Substantial subsidence was assessed by Dale with short notice fit in with my busy schedule. I was provided with a comprehensive quote, accepted online and given a date and time not long after. On the day Jordan and Jack arrived on time, set up, got on with the job with great results, providing me with updates and were super informative throughout the whole process. They left the site clean. Fantastic, will use these guys again.

John Q,

11 December
Five white stars highlight top-rated foundation repair for subsidence issues Five-star rating representing excellence in repairing cracked walls with HelicalBar Premium rating stars indicating successful rising damp treatment and structural drying Top customer satisfaction for GeoPoly resin injection slab stabilisation services High five-star rating showcasing quality underpinning for sinking foundations.

Excellent service from start to finish

From our first phone call to today when our underpinning was done we couldn’t speak more highly of the service and the work. Learning that your house needs underpinning is extremely daunting but from the moment Joe from Buildfix turned up and was able to take us through what would be done including the fixed cost, we stopped worrying. Everything happened exactly as he said and we are more than happy to recommend Buildfix.

Consumer,

4 September
Five white stars highlight top-rated foundation repair for subsidence issues Five-star rating representing excellence in repairing cracked walls with HelicalBar Premium rating stars indicating successful rising damp treatment and structural drying Top customer satisfaction for GeoPoly resin injection slab stabilisation services High five-star rating showcasing quality underpinning for sinking foundations.

Zee J,

14 December

The Buildfix process was professional…

“The Buildfix process was professional from beginning to end. Their website provides useful information, and it is easy to book an assessment. The inspection is thorough and timely. The technicians are experienced, friendly and happy to answer all questions. The process is amazingly easy compared to traditional underpinning and can be completed in a day with minimal disruption. So far the works looks good.”
Read more

karen bryant,

15 November
Really happy with Buildfix and all the staff members. Bruno took the time to explain everything that was to happen on the of the repair. Andy and Pedro were a pleasure to deal will as they were both very professional and friendly. Again, they took time to explain the procedure. Ryan was also very professional and friendly and talked me through the process. I highly recommended this company.👍
Read more
Five white stars highlight top-rated foundation repair for subsidence issues Five-star rating representing excellence in repairing cracked walls with HelicalBar Premium rating stars indicating successful rising damp treatment and structural drying Top customer satisfaction for GeoPoly resin injection slab stabilisation services High five-star rating showcasing quality underpinning for sinking foundations.

John Q,

11 December

Buildfix and my sinking Brick wall

Buildfix were great from day one! Substantial subsidence was assessed by Dale with short notice fit in with my busy schedule. I was provided with a comprehensive quote, accepted online and given a date and time not long after. On the day Jordan and Jack arrived on time, set up, got on with the job with great results, providing me with updates and were super informative throughout the whole process. They left the site clean. Fantastic, will use these guys again.

Read more

Suzanne Jennings,

24 January
Very happy with how Jared explained the whole process before any work began and kept me updated on all progress. Both Jared and Kurt were courteous, on time hard-working and highly professional. We were overly happy with the result.
Read more

Read more reviews left by genuine Buildfix customers

800+ reviews on
Trustpilot green star rating beside reviews for foundation repair and wall cracks.
502+ reviews on
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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 15000 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, Perth or anywhere else in between**, we’ll come out and do the job for you.

**Excludes some remote locations.

FREE structural assessment and honest advice

One of our structural engineers or consultants come to your home at no cost. Our assessments are thorough, you'll learn about your homes issues, and 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 15000 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*, if not we'll beat it by 5%.

*Must be like-for-like, covering the same area with unlimited GeoPoly™️, or similar material.

We cover many locations throughout Australia

Our teams are ready to go where you live. Whether it be in Brisbane, Sydney, Canberra, Melbourne, Perth or anywhere else in between**, we’ll come out and do the job for you.

**Excludes some remote locations.

#1 Underpinning
Top-Rated in Australia!

Five-star customer rating for Buildfix structural repair and rising damp solutions.

502+ Reviews

ongoogle logoas of Nov 2025
Five white stars highlight top-rated foundation repair for subsidence issues Five-star rating representing excellence in repairing cracked walls with HelicalBar Premium rating stars indicating successful rising damp treatment and structural drying Top customer satisfaction for GeoPoly resin injection slab stabilisation services High five-star rating showcasing quality underpinning for sinking foundations.

Rated 4.9/5

800+ reviews on
Trustpilot green star rating beside reviews for foundation repair and wall cracks.

Frequently Asked Questions

Can underpinning repair wall cracks?

GeoPoly™ effectively stabilises the soil under your foundation, preventing further subsidence. It can even lift the foundations of your home, enabling cracks to close and restoring the functionality of doors and windows. However, it’s important to note that underpinning alone might not address all structural issues in your home. To complement this, we also provide specialised solutions for wall crack repair and undertake cosmetic repairs, such as plastering and brick pointing, to ensure a comprehensive approach to your home’s structural issues.

Mostly, yes. The majority of our underpinning projects are completed within a day. However, the duration varies depending on the complexity of the repair, the foundation size and the ground conditions.
Definitely not. Buildfix primarily works externally, allowing you to continue daily life inside your home without disruption. Occasionally we might require indoor access based on the project’s needs, but we’ll always work around you.
Buildfix has successfully assessed and completed tens of thousands of projects across Australia over the past decade. This mostly includes residential projects but covers commercial and strata buildings as well.
Minimal disruption is one of our aims. We inject our GeoPoly™ resin through small holes in the ground, akin to ‘keyhole surgery,’ minimising excavation and mess. You can continue with your regular home life while the work is being carried out.
Underpinning is the process of strengthening the foundation of an existing building or structure. It is typically necessary when the original foundation is no longer able to support the building due to soil issues or other changes in the ground conditions.
Signs that your property might require underpinning include cracks in walls, especially around doors and windows, doors or windows that stick or won’t close properly, and uneven floors.

Absolutely. We proudly offer an industry-leading, transferable 20-year warranty on workmanship, as well as a 50-year product warranty. This extensive coverage ensures your peace of mind for years to come and adds value to your property, even if you decide to sell it in the future.

GeoPoly™ is a closed-cell geopolymer resin, and belongs to the polyurethane family.

100%. GeoPoly™ is exclusively made by our in-house chemical engineers, at our dedicated manufacturing facility, adhering to our proprietary formulation. This commitment guarantees that you receive the highest-grade material, proudly Australian-made and unrivaled in the market.
Yes, our GeoPoly™ resin is environmentally safe and poses no harm to the surroundings. It is classed as non-hazardous.
When it comes to performing work on the day, our skilled technicians will handle the repairs on your property, directed by our team of structural engineers and builders. All Buildfix technicians, engineers and builders are full-time employees, not subcontractors, ensuring you always receive highly experienced and committed experts
Yes, underpinning is designed to be a long-term solution to foundation problems. The GeoPoly™ method, for instance, is engineered to create a stable base for the structure, addressing the underlying issues causing foundation failure.
Underpinning, especially with techniques like GeoPoly™, is designed to be minimally invasive, reducing the risk of damage to the property’s landscape or structure. However, the extent of any potential impact depends on the specific circumstances and should be discussed with the service provider.
Traditional underpinning often involves extensive excavation and concrete reinforcement. GeoPoly™ is an advanced, non-invasive technique that stabilises foundations by injecting a geopolymer resin into the ground, which then expands and hardens to support the structure.
Buildfix technician drilling with GeoPoly GER60 for foundation repair and wall cracks.
Buildfix technician using GeoPoly GER60 tool for precise foundation repair.

#1 Underpinning
Top-Rated in Australia!

We’re happy to take a look at your home for FREE.
Book your FREE assessment
Construction worker uses GeoPoly GER60 for foundation repair on brick home.

#1 Underpinning
Top-Rated in Australia!

We’re happy to take a look at your home for FREE.
Book your FREE assessment

More Questions...

Look for signs like wall cracks, sloping floors, or sticking doors. If you’re concerned, we offer free structural assessments to identify the cause. We’ll provide honest advice and, if needed, a detailed repair plan with a fixed-price quote.

Our full-time technicians and trades professionals handle your project, overseen by our in-house licensed builders and structural engineers. We never outsource or subcontract, ensuring top-quality work from start to finish.

Our 20-year warranty covers materials and workmanship, plus unforeseen issues like flooding, soil erosion, or tree root damage—even if unrelated to our repairs. If problems arise at the repaired location, we’ll fix it at no cost.

Yes. GeoPoly™ is our proprietary product, developed and manufactured exclusively by Buildfix in Australia. We’re the only foundation repair company with rights to this formulation.

No need. We handle everything, including drainage inspections and blockage repairs. Our in-house plumbers ensure your underground services are protected, making the process seamless and hassle-free.

No. You only pay once the job is completed.

Not always. Fixing the foundation is crucial, but additional repairs may be needed for wall cracks or other issues. We offer over 30 specialised methods to fully restore your home.

We provide various structural repairs like wall crack repairs, concrete slab revelling, floor pier and stump repairs, and solutions for rising damp. We also offer cosmetic services like mortar repointing, plastering, and rendering.

We serve most major metropolitan areas and some regional locations across Australia, with hubs in Sydney, Melbourne, Brisbane, and Perth. Unsure if we cover your area? Call us at 1300 854 115.

More Questions...

Look for signs like wall cracks, sloping floors, or sticking doors. If you’re concerned, we offer free structural assessments to identify the cause. We’ll provide honest advice and, if needed, a detailed repair plan with a fixed-price quote.

Our full-time technicians and trades professionals handle your project, overseen by our in-house licensed builders and structural engineers. We never outsource or subcontract, ensuring top-quality work from start to finish.

Our 20-year warranty covers materials and workmanship, plus unforeseen issues like flooding, soil erosion, or tree root damage—even if unrelated to our repairs. If problems arise at the repaired location, we’ll fix it at no cost.

Yes. GeoPoly™ is our proprietary product, developed and manufactured exclusively by Buildfix in Australia. We’re the only foundation repair company with rights to this formulation.

No need. We handle everything, including drainage inspections and blockage repairs. Our in-house plumbers ensure your underground services are protected, making the process seamless and hassle-free.

No. You only pay once the job is completed.

Not always. Fixing the foundation is crucial, but additional repairs may be needed for wall cracks or other issues. We offer over 30 specialised methods to fully restore your home.

We provide various structural repairs like wall crack repairs, concrete slab revelling, floor pier and stump repairs, and solutions for rising damp. We also offer cosmetic services like mortar repointing, plastering, and rendering.

We serve most major metropolitan areas and some regional locations across Australia, with hubs in Sydney, Melbourne, Brisbane, and Perth. Unsure if we cover your area? Call us at 1300 854 115.

More Questions...

Look for signs like sagging or uneven floors, creaking boards, and difficulty opening doors. If you’re concerned, we offer free structural assessments to identify the cause. We’ll provide honest advice and, if needed, a detailed repair plan with a fixed-price quote.

Our full-time technicians and trades professionals handle your project, overseen by our in-house licensed builders and structural engineers. We never outsource or subcontract, ensuring top-quality work from start to finish.

Our 20-year warranty covers materials and workmanship, plus unforeseen issues like flooding, soil erosion, or tree root damage—even if unrelated to our repairs. If problems arise at the repaired location, we’ll fix it at no cost.

Yes. GeoPoly™ is our proprietary product, developed and manufactured exclusively by Buildfix in Australia. We’re the only foundation repair company with rights to this formulation.

No need. We handle everything, including drainage inspections and blockage repairs. Our in-house plumbers ensure your underground services are protected, making the process seamless and hassle-free.

No, you only pay once the job is completed.

Not always. Fixing sinking piers and stumps is crucial, but additional repairs may be needed for wall cracks or other issues. We offer over 30 specialised methods to fully restore your home.

We provide various structural repairs like wall crack repairs, slab re-levelling, subsidence repairs, and solutions for rising damp. We also offer cosmetic services like mortar repointing, plastering, and rendering.

We serve most major metropolitan areas and some regional locations across Australia, with hubs in Sydney, Melbourne, Brisbane, and Perth. Unsure if we cover your area? Call us at 1300 854 115.

More Questions...

How long will it take for my walls to dry after damp proof treatment?
We employ our damp proofing solution, DampBlock™, to counteract the effects of rising damp in your walls by blocking capillaries, reducing the walls ability to draw moisture upwards. After this process, the existing damp in your walls will generally take 6-12 months to dry out.
After the damp proofing process, your walls will start to dry. However, this can result in natural salt crystallisation and residual dampness on the surface. To prevent the surface plaster from deteriorating and the appearance of damp, an application of a salt-blocking solution is recommended, which we are happy to assist with and discuss during your assessment.
Certainly not. DampBlock™ is non-hazardous and completely odourless, allowing you and your family to stay at home while we work.
Buildfix has successfully completed well over 10,000 projects across Australia over the past decade. This includes mostly residential projects, as well as some commercial and strata buildings.
Absolutely. We proudly offer an industry-leading, transferable 20-year warranty on our products and workmanship, which ensures your peace of mind for years to come and adds value to your property, even if you decide to sell it in the future.
Yes, our DampBlock™ is environmentally safe and poses no harm to the surroundings.
Yes, effective damp proofing can enhance the structural integrity of your property, prevent health hazards due to mould and ultimately improve the property’s market value and appeal to potential buyers.

More Questions...

How do I know if my home needs wall crack repairs?
If you’re noticing cracks in your walls, particularly near doors and windows, or if they’re growing over time, it’s likely you have a structural issue. Contact us for a free assessment and we’ll diagnose the problem.
No, not at all! Unlike traditional methods, our approach is non-invasive. We use HelicalBars™ and other advanced technologies to fix the cracks without any wall demolition.
The cost of repairing wall cracks depends on the severity of the damage. Most residential repairs range from $5k to $20k. We offer a free assessment and provide a fixed quote with no hidden fees.
In addition to wall crack repair, we provide subsidence repair, slab jacking, rising damp solutions, and more. We ensure your home is not only structurally sound but looks great too.
Absolutely! We back all of our wall crack repairs with a 20-year warranty.