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Teretek® Resin Injection Underpinning Solution

Discover the modern alternative to traditional underpinning with Teretek® Resin Injection. This innovative solution offers a fast, clean, and cost-effective method for strengthening weak ground beneath subsided foundations.


Unlike traditional underpinning, which involves extensive digging and disruption , Teretek® requires no excavation and most projects are completed in just one day.


Choose Teretek® Resin Injection for a seamless and efficient way to raise, rel-level and re-support your property without the hassle and expense of traditional methods.

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Common causes of a shifting house foundation

Queensland homes are known to experience subsidence due to sandy soils and extreme weather conditions.

This can be evident by signs of sinking and cracked floors or concrete slabs, a crack in the wall, doors, and windows that won’t close. Not attending to these issues could result in a safety hazard, significantly devalue your property or the need to invest additional costs to rectify foundation damage, particularly if left unaddressed. This is where Mainmark helps you choose the most appropriate techniques to rectify the issue. One of the most popular and cost-effective methods is resin injection; a more modern, but proven, method of underpinning and strengthening building foundations.

Queensland is a unique area of Australia with extended periods of rain and drought, sandy soils and other factors that impact coastal and inland ground conditions. In addition to extreme weather events, particularly around the coastal and flood zone prone areas, homes may be affected by the following causes of foundation problems:

Causes of foundation problems:
Leaking pipes

Over time pipes under properties tend to deteriorate, becoming damaged or blocked which then causes cracks, allowing water to seep into the ground, both around and directly underneath the property. Clay pipes and modern thin plastic pipes are known to be the common culprits. Leaky gutters and downpipes or dripping outdoor taps are also frequently identified as the source of water collecting near house foundations.

Inadequate drainage

Excess water within the grounds of a property can cause weakening of ground and the structure to ultimately subside. Hence, moisture management is key for good foundation and footing maintenance.

Poor building work

Where there is evidence of insufficient ground preparation, particularly with newer constructions, structures will often shift causing damage to walls, floors, doors and windows. This is usually when house underpinning is considered, as well as other costly remediation works for fixing cracks in walls, concrete slabs and driveways.

Adjacent development

As developers look to utilise every inch of land during construction, building or renovation works can affect neighbouring property. Stability of the soil is compromised when heavy machinery is used during construction which can have a knock-on effect on the soil on your side of the fence. This is even more problematic when coinciding with periods of heavy rain which soften the ground and may lead to soil erosion and voids. In addition, removal of any trees or vegetation can affect the water table as moisture is no longer drawn out of the soil by a tree’s roots.

Tree roots

Maturity of trees can cause roots to damage pipes resulting in cracks or loose joints. Tree roots will naturally grow towards these areas in search for water. Eventually, aggressive root systems will infiltrate pipes causing blockages which cause water to spill into the ground, impacting the stability of house foundations.

The Mainmark solution

Since 1989 Mainmark has successfully raised and re-levelled thousands of homes and driveways throughout Queensland.

Mainmark offers some of the most advanced non-invasive resin injection technologies to quickly correct foundation ground issues with minimal mess or disruption.

With a sound knowledge of Queensland’s unique local conditions, Mainmark utilises its Teretek® engineered resin injection solution to effectively raise, re-level, and re-support footings under a home. Teretek®is a unique two-in-one solution that provides both ground improvement and re-levels homes, backed by a 50-year product warranty. It increases ground bearing capacity, fills voids, rehabilitates foundation ground which helps raise sinking floors and reduces wall cracking, all at a fraction of the cost of traditional underpinning, and with no detrimental effects on the environment.

Benefits & Features

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.

A cost-effective alternative

Underpinning homes is generally a costly exercise using traditional methods due to the invasive nature of concrete underpinning, which is generally a lengthy and messy process. Teretek® is the modern way to raise, re-level and re-support your home by providing a unique two-in-one solution delivering both ground improvement and re-levelling.

It’s applied like keyhole surgery and most jobs can be done in a day, usually reducing the cost of the works when compared to traditional underpinning. As every home is different, Mainmark finds the best solution to treat the root of the problem. The cost of each job will vary according to:

  • Your location
  • The actual cause of the problem – what other things need to be resolved as part of the works eg. drainage
  • The nature and condition of the foundation soil – including an assessment of the soil type
  • The type and profile of the building footings – are the existing footings damaged or in need of replacement?
  • The surroundings e.g. access to the site, adjacent buildings or retaining walls
  • Unknown or unforeseeable underground conditions – problem solving on site
  • The volume of material that will be required – an estimate will be provided but may need to be re-assessed following more detailed ground investigation
  • The time that the work will take – based on Mainmark’s extensive experience.

Why choose Mainmark?

Queensland’s trusted re-levelling, ground improvement and void filling specialist since 1989.

Calling in experienced ground engineering consultants for an appraisal can help to quickly diagnose the issue and find a solution tailored to your home. Mainmark has raised, re-levelled and re-supported homes and buildings for over 30 years, delivering successful solutions to thousands of homes in Queensland from coastal to inland areas.

Our solutions are cutting edge and the modern answer to the traditional way to underpin. We can underpin, raise and re-level strip footings and raft slabs, plus we can infill slabs and driveways. Mainmark’s proprietary product Teretek® addresses building foundation problems, with minimal intrusion into the property and minimal interruption to the occupants, effectively underpinning by non-invasive expanding resin injection. In most cases, residents are not required to move out or move any furniture during the ‘home lift’ process.

In contrast, traditional concrete can be a slow process; involve excavation which causes mess; can reduce bearing capacity; cause differential movement between the underpinned sections of the structure and the rest of the structure; and be labour intensive.

Queensland by location

Helping to protect your biggest asset.

Queensland is known to have high concentrates of moisture in the soils, causing movement and instability in the ground. This can generally be attributed to the severe weather conditions it experiences from high rain fall and flooding, to extended dry periods.

Property foundations around water – primarily beach, lake and river side homes – seem to be the most affected. The tell-tale signs normally consist of step cracks starting to appear on walls, floors and driveways sinking and/or cracking and jammed doors and windows.

Foundation movement may also be caused by other underlying or site-specific issues which require a professional assessment and working knowledge of the local area.

Far North Queensland / North Queensland

Houses around the coastal area of northern Queensland are often built on sandy or silty soils that can compromise the strength of building foundations. The root cause can be attributed to insufficient ground compaction during construction, where soils shrink and swell due to adverse weather conditions. Sandy soils sometimes need permeation grouting in addition to resin treatment to strengthen the ground before a home is re-levelled. Areas affected by these conditions include Cairns, Port Douglas, Ingham, Cardwell, Innisfail, Magnetic Island and Townsville.

Central Queensland / Mackay, Isaac Region and Whitsunday Coast

Soil in these areas comprise of silty, clay and sandy soils, with properties near the coast most affected by erosion. Significant problems may occur following lengthy periods of extreme weather like droughts and floods. On sloping blocks heavily affected by rains, it may also be important to treat the ground underneath driveways and paths to prevent cracking and trip hazards. New developments are also susceptible to sinking, particularly when the ground may not have been prepared properly, resulting in the house settling. Teretek can improve the grounds bearing capacity prior/after construction. Areas affected by these conditions include Bowen, Airlie Beach, Mackay, Isaac Region, Rockhampton and Gladstone.

Wide Bay Burnett / South East Queensland

These areas contain a lot of larger blocks with single or double-storey homes that utilise concrete, masonry rock and stone foundations. Reactive clay soils are susceptible to expansion and contraction with varying soil moisture content which over time can cause these footings to sink. With new developments, removal of trees and shrubs around a building moisture levels can be affected causing settlement. Vibrations from neighbouring properties which are being developed may also cause ground disturbance and subsidence, aggravating wall cracks. Brisbane, Gold Coast, Sunshine Coast, Gympie, Maryborough and Bundaberg are likely impacted.

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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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.


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

Mainmark Ground Engineering Pty Ltd
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