What is Subsidence and how to fix it?

Subsidence can happen naturally as part of the earth’s constantly shifting crust. It can be exacerbated by issues such as soil compaction, loss of ground moisture, excessive excavation, or erosion. Ground instability causes subsidence and, often, the damage can seem to be reversed as the ground shifts back and forth over time.

Mainmark offers state of the art technology to stabilise the ground beneath your home.

Using resin injection ground stabilisation, we improve ground compaction. We can then raise and re-level sunken buildings, then add support to the ground for soil stabilisation to strengthen the foundation and stop the soil underneath and around the buildings slipping or moving. We have successfully raised, re-levelled, and re-supported thousands of homes around the world.

How much does subsidence repair cost?

Get a FREE house assessment in 3 simple steps:

Step 1:

Submit your enquiry using our online form. Include a brief message about the type of foundation issues you are experiencing.

Step 2:

Our friendly customer service team will be in touch to schedule a site assessment that suits you.

Step 3:

One of the Mainmark experts will visit your home or property, assess the damage, and ascertain the likely cause. They will establish the approach needed, creating a plan specific to the needs of your building and provide you with a detailed quote.


How we get your home back to level in as little as a day.

Unlike many level correction processes, our methods are very resident­-friendly.

We use non-invasive techniques, likened to keyhole-surgery, so we don’t tear up floors and excavate ground (the injection holes can be as small as 6mm).

We are very quick – many jobs are completed in a day.

Residents can usually stay in the home and may not even need to move much furniture.

We help strengthen the future of the house – the methods we use strengthen weak ground, so your home generally becomes level, crack-free and more stable.

We don’t make mess – there’s no concrete dust, water or anything else to clean up.

We don’t cause further damage; in fact cracks generally close up and windows and doors become usable.

We provide peace of mind – our resin injection method is backed by an industry leading 50 year product warranty. We are also a licenced builder that provides Home Warranty Insurance/Builders Warranty Insurance where required.

We're happy to have helped

“S____ who was leading the Mainmark team onsite is a credit to your company. He talked us through the job, kept us informed of progress and spoke about issues along the way that he resolved in conjunction with your engineer. The team of 3 you sent were probably the most trustworthy, friendly and professional of trades we have come across. They were also respectful of the property and mindful of the need to keep the disruption to a minimum.”

Tim, Caulfield South, VIC. July 2021.

“B____ visited our site and was informative, thorough and helpful. On this particular occasion Mainmark was not able to assist with our problem. This was explained to me and I was directed to the appropriate engineering service. Very professional, would recommend.”

Michelle, Bayswater, Auckland, NZ. July 2021.

“The people we dealt with were polite, timely and kept us informed at all times. All questions we posed were answered without any hesitation They presented as true professionals, completed the work efficiently and left our property in a very tidy state.”

Ken, Boondall, QLD. June 2021
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Problems we solve

Icon2_Cracked Walls

Cracked Walls

Solutions for structural damage due to sinking foundations

Icon1_Sinking Floors

Sinking Floors

Solutions for building subsidence

Icon3_Unlevel Buildings

Unlevel Buildings

Solutions for weak ground and subsidence

Icon4_Ground Instability


Solutions for shifting ground and ground instability


Holes and Voids

Solutions for cracks, crevices and large voids


Earthquake Damage

Solutions for liquefaction mitigation and ground strengthening

computer screen with Typical signs of subsidence

Want to learn more about the signs of subsidence?

Explore our interactive house and view typical subsidence problems around your home

Sinking floors, paths and driveway slabs, cracked walls, jamming doors and windows can all be indicators of structural damage due to subsidence and voids under the ground. Typical causes are unstable or weak ground, a broken pipe causing soil erosion, moisture changes in clay soil, nearby building and excavation works, and seismic activity or liquefaction. Our solutions are cutting edge and the modern answer to the traditional way to underpin; they are like keyhole surgery compared to concrete underpinning. Our alternatives to underpinning are not just for concrete slab floors. We can underpin, raise and re-level strip footings and raft slabs, plus we can infill under slabs and driveways.

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Teretek® Strengthens Foundation, Raises and Re-levels a Family Home

The homeowner stated that, “the Mainmark team was very friendly and hard working. They have also given us the assurance that the house is now stable. I’m very happy with the work that they did.”

Mainmark’s engineered resin injection solution, Teretek®, was applied beneath the external walls at the back of the home in a U-shape formation, to strengthen the ground beneath the foundations, and re-level and re-support the home.

This successful project was completed in a single day and the fast completion time minimised disruption to the occupants. The solution has also provided the family with peace of mind knowing that their home is now stable and liveable into the future.

JOG Computer-Controlled Grouting and Teretek® Resin Injection Combined to Save House from Demolition

My dealings with Mainmark were nothing but professional. They ensured all aspects of the work, including any queries I had, were thoroughly explained so all parties were aware of the process and that the outcome would be achievable prior to the project commencing. This gave the owner the reassurance and confidence that the home could be stabilised and that there would be no surprise costs or variations to the work.

Mainmark successfully re-levelled the entire length of the three affected side walls, lifting the slab to within +/- 10mm of its target RL without needing soil removal. Mainmark is uniquely positioned to deliver projects of this size and scope utilising two complimentary, proprietary non-invasive solutions. The project took Mainmark a total of only 14 days to complete and was delivered within budget to the client’s complete satisfaction.