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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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Causes of a shifting house foundation in Victoria

Homes in many parts of Melbourne may experience ground subsidence that leads to sunken building foundations.

Sinking floors, a visibly widening crack in the wall, an uneven concrete driveway, and doors and windows that won’t close properly can all be warning signs of ground weakness under a structure. If a building becomes un-level due to subsidence, the effects are not just cosmetic.

If left unaddressed, these symptoms can result in significant and expensive damage to the home and may also lead to safety issues for the occupants.

When cracks and other structural changes present themselves, homeowners may look for solutions, including underpinning services and contractors, to effectively ‘underpin’ their home.

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 Victoria.

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 Melbourne’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?

Melbourne’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 Melbourne 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.

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 commercial 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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Melbourne by location

Helping to protect your biggest asset.

Melbourne has a variety of soil types including black sands, reactive clays and silty soils which shrink and swell according to moisture levels. While seasonal changes occur, a mixture of high drought and heavy rainfall may cause ground subsidence, resulting in significant and visible slab shifts.

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

Eastern Suburbs & City of Knox

Many homes in Melbourne’s east are built on reactive, deep clay soils where movement is typically caused by changes in the moisture of the ground, including periods of drought, established trees drying out the soil, or old earthenware pipes cracking and leaking excessive moisture into the ground. These factors can all contribute to subsidence issues. Drain repair and drainage solutions may also form part of the soil improvement recommendations, before re-levelling the home. Areas affected by these conditions include Bayswater, Knoxfield, Boronia, Scoresby, Wantirna, Ferntree Gully, Rowville and Lysterfield.

Southeastern Suburbs & Mornington Peninsula

With homes often more than 80 years old in this part of Melbourne, it’s not uncommon to see symptoms such as cracking in brickwork and gaps starting to appear in between brickwork and the frames of windows and doors. These are indicators that the property may require resin injection underpinning, to effectively raise the foundation, re-level the home and stabilise the ground beneath the building. Areas commonly affected by these conditions include Hawthorn, Hawthorn East, Mont Albert, Balwyn, Surry Hills, Brighton, Flinders, Mount Eliza, Mornington, Malvern, Glen Iris, Camberwell, Canterbury, Caulfield, Carnegie and Kew.

South Eastern Coastal Towns

Built on marshy, sandy, silty soils on beachfronts or manmade rivers, this area is affected by weak soils that are prone to high settlement. Excess water from plumbing leaks can also contribute to soils washing out beneath the footings, potentially leading to house movement causing cracks. Additional Mainmark solutions are available to address sandy soil stabilisation before lifting the home using Teretek. Areas affected by these conditions include Carrum, Carrum Downs, Patterson Lakes, Seaford, Frankston.

Far Eastern Suburbs

With homes often built on highly reactive clays, homeowners will see evidence of seasonal movement. Significant problems may occur following lengthy periods of extreme weather like droughts and floods. Many large native trees in these areas, with wide-spreading roots, can impact the water content of foundation soil, causing footings to shift. This is when re-levelling may be required, which can simultaneously treat the effects of subsidence, including brick wall crack repair. Suburbs affected include Croydon, Ringwood, Mooroolbark, Mitcham, Vermont.

City of Yarra

Fixing cracks in walls may not be the only issue affecting these inner-city dwellings. Older brick and stone foundation materials, such as bluestone, typically need special attention as they may become brittle and are therefore considered less suitable for treatment with traditional, invasive house underpinning and ‘slab jacking’ methods. Generally built before engineering codes were commonly used, these homes will experience footing movement and failure more easily. Large tree plantings alongside footpaths can also impact this densely populated area. Mainmark has completed hundreds of jobs in locations including Richmond, Collingwood, Abbotsford, Fitzroy and Carlton North.

City of Port Phillip & City of Brimbank

This area includes traditional blocks with many older single or double-storey homes, featuring old brick and stone foundations. With buildings constructed on silty clay soils overlying natural clay, further impacted by some sites being located on reclaimed land, footings can experience noticeable movement when soils react to tidal canal water and flood events. Often traditional concrete underpinning would be too invasive a process for remediation. Larger blocks may also be affected by moisture drawn from the mature plane trees in the surrounding area, which can have a significant impact on foundation soil stability. Areas to watch include Elwood, Middle Park, St Kilda, Albert Park, South Melbourne, Williamstown / Newport, Spotswood, Yarraville and Footscray and the wider Brimbank region.

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.

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