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House Underpinning Repair

The Modern Alternative To Underpinning

Teretek® Resin Injection

Traditional underpinning involves digging deep holes adjacent to the footings, disturbing gardens and pavements; often taking weeks. Underpinning transfers the footing loads deeper into the ground.

When only underpinning part of the building footing in reactive clay, the resultant differential movement between the underpinned footings and the rest of the footings can cause cracks greater than the original damage the underpins were used to fix.

Teretek® Resin Injection improves the ground and strengthens weak ground beneath subsided footings. The Teretek® ground compaction does not require gardens to be dug up and most jobs are completed in one day. The Teretek® resin injection improves the ground beneath the cracked walls, and does not create the differential movement about the building that is caused by partial underpinning in reactive clay soil.

Resin Injection – the modern alternative to traditional underpinning

House Underpinning

The traditional method

Excavation – Heavy machinery is required to dig large holes to depths often up to 3 metres.
Soil removal – large quantities of dirt and rock are loaded onto dump trucks and transported away from the site
Pouring Concrete– filling the holes or “piers” with concrete can be complex and logistically challenging depending on the site.
Curing time – concrete can take several days to get to strength.

House Resin Injection

The modern alternative

Tiny holes– Teretek is applied through keyholes, typically 6mm to 16mm in diameter.
Clean and quiet – The process is clean and quiet, has minimal impact on residents.
Resin injection – The resin injects into the ground and expands in the ground within minutes.
Curing time – 30 minutes. You can even use the building during the process.

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

Features & Benefits

Mainmark’s Solutions & Technologies


Our technologies have fast curing times and treated areas can be used immediately or without the delays compared to traditional repair methods.

Environmentally Inert

Our technologies use an inert material that is non-toxic and does not leach into the environment or affect the treated area.


Our solutions are of surgical nature compared to traditional methods.


Compared to traditional methods, our solutions are more cost-effective, with minimal disruption to the area.

Underpinning Frequently Asked Questions
What is underpinning?

Underpinning is the process of extending the foundation of a building to a deeper layer of soil. This is traditionally done by digging deep holes under the footing and filling the hole with concrete.

What are the alternatives to underpinning a house?

The main alternatives to traditional underpinning are resin injection and screw piles.

Resin injection strengthens the soil beneath the footing by compacting the ground. Screw piles extend the footings to a deeper layer of soil.

What is the cheapest method of underpinning a foundation?

The cost to underpin a footing can vary significantly, and depends on the method adopted, soil condition, accessibility to the failed footing and proximity of other buildings and pavements to the work area.

Traditional underpinning is labour intensive and involves large excavations, so its price does depend on how busy the contractor is. Resin Injection and screw piling have more stable prices.

How much does the underpinning cost?

Traditional underpins vary from $1000 to $4500 per underpin for shallow underpins.

Deeper underpins are more expensive as each excavation requires shoring to make the hole safe.

How much does resin injection underpinning cost?

Resin injection typically costs in the range of $1100 to $1400 per linear meter of the footing to be supported.

How long does it take to underpin a house?

Traditional underpinning required digging holes next to the footing and then filling them with concrete.

The excavation of the holes can take some time and will impact gardens and paths as they will be removed.

Traditional underpinning could take a few days for a single underpin to several weeks.

How long does underpinning last?

Concrete underpins if well-constructed using sound concrete should last more than 50 years.

Is resin injection as good as underpinning?

Resin injection is different to underpinning.

Resin injection involves strengthening the ground beneath the footing, whereas underpinning involves extending the footing to a deeper layer of soil.

What are the dangers of underpinning?

There are several pitfalls when using concrete underpins.

In reactive clay soils, if only part of the footing is underpinned then there will be differential seasonal movement between the underpinned sections of the footing and the rest of the footings.

This difference in seasonal movement will result in large cracks forming in the walls adjacent to the areas that have been underpinned.

Another problem that arises with traditional underpinning is poorly compacted soil adjacent to the underpin acts as a water path to the underside of the underpin and can undermine the underpin.

Get a quote

Arrange a site 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.

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© 2024 The Mainmark group of companies. ‘Mainmark®’, ‘Terefil®’, ‘Terefirm®’ and ‘Teretek®’ are trademarks of the Mainmark group of companies.

Mainmark Ground Engineering Pty Ltd
ABN: 51 606 182 503

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