Is my house suffering from subsidence & sinking deeper into the ground?

If a structural engineer tells you your home is suffering from subsidence, what they’re really telling you is your home is sinking. Subsidence exerts an immense amount of force on your home. The force created by the sinking strains your home’s foundations, the floor, the walls, the ceiling and even the roof.


If subsidence isn’t stopped, the force exerted on your home can quickly multiply foundational and structural issues. This can also multiply the cost of repairs, hurting your wallet over the long-run.


If you suspect your home may be suffering from subsidence you’re in the right place. Read on to learn about the symptoms and causes of subsidence.

What are the symptoms of subsidence?

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 and 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 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 are horribly dangerous if left unchecked and unfixed. They have the potential to fall over and cause injury or worse.

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 and 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. This is dangerous because this indicates your floor’s support system is beginning to sag and weaken.
Brick wall displaying severe vertical and horizontal cracks indicating foundation subsidence damage.

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.
Foundation repair for ceiling-to-wall crack with visible subsidence damage and molding separation.

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.
Technician in white gloves addresses wall cracks during foundation repair.

Doors and 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.
Painted concrete column at building corner showcasing subsidence foundation repair solution.

Leaning 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 are horribly dangerous if left unchecked and unfixed. They have the potential to fall over and cause injury or worse.
Sunken floor and wall

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.
Sunken floor in a residential home

Gaps between Walls and 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. This is dangerous because this indicates your floor’s support system is beginning to sag and weaken.

What causes subsidence?

Reactive Clay Soil

Reactive clay soil is a dense material that expands or contracts under different weather conditions. When it’s wet and cool, reactive clay soil absorbs moisture and expands but when it’s hot and dry, it shrinks. It’s the contraction of the soil that can cause the subsidence of your home.

Subsidence can also come from the introduction of new plants and trees as well as new drainage systems or altered ones. They draw more water out of the ground than usual to dramatically impact the stability of your home’s foundations.

Water Erosion

Water erosion is often a cause of subsidence. When water pools into a specific spot in the ground too much, the soil becomes saturated and weak. If this water happens to pool into the soil under your home, your home will no longer be sitting on stable ground.

Burst, cracked and leaking pipes near or around your home can pool water. Overflowing stormwater drains, mains inlet pipes and unconnected downpipes also cause subsidence.

Tree Roots and Vegetation

Thirsty tree roots and vegetation draw water out of the ground under your home. The soil becomes aerated and unstable and as a result subsidence occurs.

Sickly vegetation is especially thirsty. They have a lot of roots that suck more water out of the soil than healthy plants do.

Ground Vibrations

Subsidence can occur due to dramatic vibrations in the ground. Vibrations from a nearby construction site, a main road where heavy vehicles travel all day or nearby train lines with heavy train carriages running at high speed aerate and destabilise the ground.

A nearby airport with planes taking off and landing all day can also cause subsidence.

Poor Workmanship

A major cause of subsidence is poor workmanship. If contractors and builders haven’t poured trenches or compacted the ground under your home, it won’t be stable for long. Poor workmanship and negligence can result in weak, aerated and voided soil, ready to subside. The installation of poor or faulty drainage can cause water erosion which also leads to subsidence.

Wrong Footing Type

Although most footing designs follow Australian Standards, some are used in locations where a more unique design is required. Building a footing that isn’t suitable for the ground below, might cause subsidence.
Reactive clay

Reactive Clay Soil

Reactive clay soil is a dense material that expands or contracts under different weather conditions. When it’s wet and cool, reactive clay soil absorbs moisture and expands but when it’s hot and dry, it shrinks. It’s the contraction of the soil that can cause the subsidence of your home.

Subsidence can also come from the introduction of new plants and trees as well as new drainage systems or altered ones. They draw more water out of the ground than usual to dramatically impact the stability of your home’s foundations.
Water erosion

Water Erosion

Water erosion is often a cause of subsidence. When water pools into a specific spot in the ground too much, the soil becomes saturated and weak. If this water happens to pool into the soil under your home, your home will no longer be sitting on stable ground.

Burst, cracked and leaking pipes near or around your home can pool water. Overflowing stormwater drains, mains inlet pipes and unconnected downpipes also cause subsidence.
Tree roots and nearby vegetation

Tree Roots and Vegetation

Thirsty tree roots and vegetation draw water out of the ground under your home. The soil becomes aerated and unstable and as a result subsidence occurs.

Sickly vegetation is especially thirsty. They have a lot of roots that suck more water out of the soil than healthy plants do.
Vibrations

Ground Vibrations

Subsidence can occur due to dramatic vibrations in the ground. Vibrations from a nearby construction site, a main road where heavy vehicles travel all day or nearby train lines with heavy train carriages running at high speed aerate and destabilise the ground.

A nearby airport with planes taking off and landing all day can also cause subsidence.
Sunken floor and wall

Poor Workmanship

A major cause of subsidence is poor workmanship. If contractors and builders haven’t poured trenches or compacted the ground under your home, it won’t be stable for long. Poor workmanship and negligence can result in weak, aerated and voided soil, ready to subside. The installation of poor or faulty drainage can cause water erosion which also leads to subsidence.
Sunken floor in a residential home

Wrong Footing Type

Although most footing designs follow Australian Standards, some are used in locations where a more unique design is required. Building a footing that isn’t suitable for the ground below, might cause subsidence.

Need a solution for subsidence?

Buildfix technician applies GeoPoly injection for subsidence and foundation repair.
If your your home is subsiding, our solution can save you time, money and hassle.
Buildfix technician injecting GeoPoly insulation to address foundation subsidence and wall cracks.
If your your home is subsiding, our solution can save you time, money and hassle.

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.