Time efficient solutions for lifting large concrete slabs in industrial environments


Large concrete slabs play an important role in warehousing and logistics environments, where hardstands for loading and unloading heavy road freight trucks and haulage vehicles, and vast storage facilities are essential to core business operations.

If these heavy concrete slabs are compromised in any way, due to underlying issues below ground, it can significantly disrupt business operations, impact equipment performance and load tolerance, affecting the safety of operators and drivers, and raising serious concerns for operations managers.

To avoid service disruptions or, in the worst case, workplace accidents in an environment where heavy vehicles and machinery are common, effective and proactive health and safety management is crucial, including looking out for less obvious hazards as well as the obvious ones.

For example, early signs of sloping or sinking transport yard pavements and driveways, or a sudden increase in concrete cracks, may indicate unstable ground due to voids beneath the surface.

Subsidence can occur when the soil beneath the slab compresses under pressure, or swells and contracts due to changes in the ground’s moisture level as a result of heavy rainfall, leaking pipes or tidal flow in wetland areas.

Other common indicators of issues beneath the slab are misaligned joints between slab panels, and soil being pumped out between joints as vehicles travel across the slab. Soil pumping at a joint is evidence of voiding beneath the joint and if not addressed leads to the slab cracking, while misaligned joints can cause jolting of forklift loads as they cross the joint.

Slab subsidence occurred at a Queensland wharf logistics business located close to the Port of Brisbane. Due to its close proximity to the river, a large concrete hardstand was built on reclaimed marshland, with the substrate consisting of soft marine mud.

South East Queensland Hauliers’ (SEQH) hardstand is the central transport hub where large shipping containers, up to 40ft long and weighing 30 tonnes, are loaded and unloaded from heavy haulage trucks by 40 tonne forklifts. It is operational 24/7.

Daily tidal flows affecting the soft ground beneath the hardstand, combined with failing joint seals in the concrete slabs, resulted in settlement. Over time, the outer edges of the hardstand sat higher than the midline (known as dishing), which caused water to pool in the centre further compounding the problem, affecting 3500m2 of the 12000m2 hardstand.

This is a common issue affecting external slabs and pavements when water seeps into the foundation ground. As heavy traffic loads pump the saturated foundation ground, it leads to even more damage and increased subsidence. The biggest concern for business owners is not if, but how and when to address the issue without impacting daily operations.

Using innovative ground engineering technologies and solutions, it is possible to not only stabilise and re-level large transport yards and hardstand areas by improving the ground beneath the concrete slab; you can also achieve this without interrupting access for heavy vehicles, or risking the safety of people or property.

One such solution is JOG Computer-Controlled Grouting (or JOG), a computer-controlled injection technology that uses fast setting grout and is ideal for remediating large areas and heavy structures, gradually and gently lifting them back to level. A total of 400 injection points were installed in carefully selected points along the SEQH hardstand, allowing technicians to control the lift in increments less than 0.5mm across sections of up to 700m2 at a time.

JOG also proved ideal for re-levelling a large factory and warehouse in Sheffield, England which was situated on a previous coal mining site. The building had subsequently suffered significant differential settlement due to voids and subsidence, which resulted in severe cracking and sloping floors.

Another solution that is ideal for remediating concrete slabs at factories and truck depots is our Teretek® engineered resin injection solution. A transport yard at one of New Zealand’s largest companies, Fonterra, had settled due to unstable soils and voids under the 150mm-thick concrete slab. A build-up of water underneath resulted in the slab moving every time a vehicle drove over it. The challenge was identifying a solution that would raise and re-level the slab without impacting up to 500 vehicle movements daily, including milk tankers, trucks and light vehicle traffic.

Teretek filled the voids, lifted the slab, and ‘stitched’ sections of the slab back together, in a single day without disruption to business operations. The unique engineered resin increases ground bearing capacity and delivers re-levelling solutions at a fraction of the cost of traditional underpinning. The injection process is likened to keyhole surgery, with the resin delivered through small tubes, typically 16mm diameter, and is controlled with constant monitoring by laser level. The process is extremely quick and non-invasive: as this time lapse video demonstrates, with most slab lifting completed in less than a day.

For more information about Mainmark’s innovative ground engineering solutions that are suitable for factory, warehousing and logistics environments, contact Mainmark on 1800 623 312 in Australia, 0800 873 835 in NZ, or visit www.mainmark.com.

By James O’Grady

James O’Grady is a Sales and Business Development Manager at Mainmark. He is a civil engineer with 25 years’ experience in structural engineering, construction materials and ground treatment.

Inside Mainmark: developing a career in ground engineering

Mainmark staff discussion

For most young undergraduate engineers, ground engineering is not a top-of-mind focus when deciding on career path. However, the opportunity to learn about new ground improvement technologies and methodologies has made the journey incredibly worthwhile for three young engineers in the Mainmark team.

When Theo Hnat (BE (Hons), MEngNZ) was a first-year student completing a Bachelor of Engineering and a Mechanical Engineering degree at the University of Canterbury, a 6.3 magnitude earthquake struck Christchurch. The devastating impact of the 2011 seismic event led him to pursue a career in earthquake engineering.

Theo joined Mainmark nearly six years ago while completing his studies and has been instrumental in developing and validating the use of resin injection as a ground improvement solution for buildings and critical infrastructure in seismic regions. He played a pivotal role in Mainmark’s research trials that took place in the Christchurch Red Zone which led to the launch of Terefirm™ Resin Injection, Mainmark’s liquefaction mitigation solution.

“Being heavily involved in the Red Zone trials was certainly a career highlight for me as it was exciting to be able to prove a theory,” said Theo, in his current role as Business Development Manager (NZ).

Through the success of the Red Zone ground improvement trials, engineers and asset owners now have a proven and commercially viable solution for improving soil density beneath structures affected by, or at-risk of, liquefaction.

Mainmark is pioneering the use of resin injection for liquefaction mitigation, and Theo travels the world on behalf of the organisation, sharing key learnings of the methodology with the broader engineering community.

Dolan Nilson’s (BEng (Petroleum), BComm) career took a different direction, after starting in petroleum engineering and gaining oil and gas industry experience in Scotland, Texas, Indonesia and Malaysia.

“As a young student it’s hard to know exactly what you want to do. There are so many opportunities that are open to young engineers,” said Dolan, who was working in macro-economics and futures trading before returning to engineering joining Mainmark in 2017 as Technical Sales Manager.

“It was an opportunity I jumped on and I’m glad I did; Mainmark has a number of innovative technologies and solutions to problems that others cannot solve.”

JOG Computer-Controlled Grouting is just one approach that has been very well received by customers according to Dolan. With the unique ability to be applied beneath large structures with utmost precision, JOG ensures minimal stress is placed on the building during the re-levelling process.

Dolan has assisted on a range of ground improvement projects throughout Australia, including decommissioning an underground water main in suburban Perth; a tricky project due to its location directly beneath a new overpass bridge construction.

“It was a complex project but rewarding because we were able to overcome a number of challenges that would otherwise have caused enormous disruption to traffic in the local area. The crew put in a huge effort to meet extremely tight timelines; it was great to be a part of that,” said Dolan.

A keen interest in problem solving and civil structures led Mainmark Technical Manager (VIC/TAS) Max Kudrenko (BSc (Civil), MEng (Civil), MIEAust) to study engineering at the University of Melbourne. He joined Mainmark nearly 4 years ago, initially focusing on the ground remediation of residential buildings, however, this soon evolved.

“I moved into a role where I was able to work on the structural monitoring of larger and more complex structures, such as high rise buildings and bridges,” said Max.

As the exclusive partner of STRAAM (Structural Risk Assessment And Management) in Australia and New Zealand, Mainmark uses the technology for one-off applications and ongoing asset monitoring, helping to keep structures safer by identifying weakness or issues.

Working with STRAAM, Max has contributed to a range of projects, both locally and abroad. “I have been fortunate to have the opportunity to travel overseas with Mainmark, including Japan where I was working on several monitoring projects involving seismic affected structures in Tokyo, Sapporo and Kumamoto,” said Max.

Max was also project manager when STRAAM was used to validate the structural viability of a rooftop renovation at the Guardian Early Learning Centre in Sydney to ensure it didn’t adversely impact the building, was compliant with Australian Standards, and most importantly, remained safe for children. The project was referenced in a winning AIB Award submission at the 2018 National Professional Excellence in Building Awards.

Max advocates the advantages of the structural monitoring platform, which he has presented at the International Conference on Bridge Maintenance, Safety and Management (IABMAS) and more recently, the Bridge Asset Management and Renewal Conference.

“The idea that work I do can directly have a positive impact on thousands of people through the remediation of infrastructure is a big drawcard for personal fulfilment,” said Max.

Despite their different specialties, Max, Theo and Dolan all agree that a career in ground engineering at Mainmark is diverse and rewarding.

“One week I may be working on a project proposal, then next week I could be in any corner of the country performing a technical assessment of a project. No two days are the same and there are always brand-new challenges presenting themselves,” said Max, who encourages other young engineers to gain hands-on experience as early as possible.

“Don’t be afraid to get out in the field and get your hands dirty, a good mix of theory and practical experience can provide a more rounded understanding. The industry is booming at the moment, so there is plenty of opportunity.”

By Claire Hartley

Claire is a strategic senior marketing and communications professional who joined Mainmark in 2015. She has extensive experience gained in a range of organisations across the APAC region and the UK; from large multinationals and start-ups to industrial B2B, IT and online businesses.

How innovative monitoring and engineering solutions can help renew bridge networks

STRAAM equipment

As bridges gradually age and absorb increasing traffic volumes, regular inspections and maintenance are crucial, to ensure structural integrity, stability and safety well into the future.

There are an estimated 53,000 public road bridges in Australia covering various distances to provide access across rivers, inaccessible terrain, elevated surfaces and city infrastructure.

For the asset managers responsible for maintaining this infrastructure, identifying and remediating structural issues is an immense undertaking.

Innovative monitoring and engineering technologies can help determine the current and long-term safety of bridges, and to remediate the issues that arise as a result of ground subsidence, or the effects of structural degradation and fatigue over time.

Ground engineering techniques and tools to assist asset managers maintain the structural health, and safety, of bridge networks was on the agenda at the recent Bridge Asset Management & Renewal Conference held in Sydney.

This includes one of the world’s most advanced monitoring platforms, STRAAM (Structural Risk Assessment And Management) which measures the ambient vibrations that occur in response to environmental factors, and identifies abnormal responses that may indicate structural damage or weakness.

Monolithic structures such as bridges have constant ambient movement (natural excitation) which STRAAM is able to capture, to create a baseline dynamic signature.

As the exclusive partner of STRAAM in Australia and New Zealand, Mainmark uses the technology for one-off applications and ongoing asset monitoring. STRAAM can record baseline data within a day, utilising the normal traffic conditions and wind loads on the structure to measure its frequency response, and accurately assess its strength.  Continuous monitoring may then be used to identify if the dynamic response is changing over time, particularly if there is nearby construction work underway, severe weather, seismic events or an increased traffic load, which can have a serious impact on the structure.

The capability to measure almost-imperceptible movements has far-reaching benefits that include making bridges safer, understanding the risks and causes of damage and helping asset owners to make more informed decisions about maintenance needs.

In one example, STRAAM was used prior to the commencement of an infrastructure remediation project in Boronia, Victoria, capturing ‘snapshot’ baseline measurements to provide commentary on how the structure was performing. More recently, STRAAM helped to assess the condition of an ageing, 3 arch stone rail bridge in Lithgow, NSW, to validate speed restriction currently in place on the bridge, while also capturing the baseline data for future monitoring.

Mainmark’s Teretek® resin injection is a ground improvement solution has been used to improve structural integrity of traffic bridges and overpasses. Teretek can be precisely, discretely and efficiently applied beneath existing structures. In a process likened to keyhole surgery, the engineered resin is injected into the ground and immediately expands, increasing ground bearing capacity and filling voids.

Teretek helped to rectify underlying ground settlement that had cause a bridge pier in Queensland to become unlevel, ensuring the bridge could continue to safely bear the weight of constant traffic, including heavy vehicles.

For more information and advice contact Mainmark on 1800 623 312 in Australia, on 0800 873 835 in NZ, or visit www.mainmark.com.

By Max Kudrenko – Technical Manager

Max Kudrenko is the Technical Manager Vic/Tas for Mainmark Australia. Since joining Mainmark in 2016, Max has led Australian and international projects focused on structural monitoring of larger and more complex structures, such as high rise buildings and bridges. Max was Project Manager for the Guardian Early Learning Centre STRAAM project which won the AIB Award at the National Professional Excellence in Building Awards for 2018.

Silvia rides again! Paul Hickman’s 2019 Peking to Paris

silvia rides again! paul hickman's 2019 peking to paris

Mainmark Chief Executive Officer and car enthusiast, Paul Hickman, has again taken part in the famous Peking to Paris rally, behind the wheel of his lovingly restored 1953 Bristol 403, “Silvia”.

Paul was joined by friend and co-pilot Sebastian (Bas) Gross, a recognised Bristol car restorer, who has dedicated many hours to preparing Silvia for the Peking to Paris.

The Bristol 403 is a limited-edition luxury car manufactured between 1953 and 1955, featuring a BMW-style radiator grille and two extra headlights at the side, which is unusual in cars of that era.

The annual event is a re-enactment of the famous 1907 Peking to Paris automobile race organised by the Endurance Rally Association, and is only open to cars produced before 1976. It is the longest and toughest driving challenge for vintage and classic cars.

The 2019 rally got underway in Beijing (formerly Peking), travelling through an impressive 12 countries and covering 13,695 kilometres over 36 days before concluding in Paris, France.

As is tradition, the 2019 event brought participants to the Great Wall of China for the official start on Sunday 2 June. Paul, Sebastian and Silvia joined 119 other teams, reconnecting with old friends and rally enthusiasts, and meeting a few newcomers.

Team Silvia achieved their goal to drive an average 450 kilometres per day, with the longest haul being 664 kilometres into St Petersburg.

The epic journey once again brought many new friends and millions of adventure stories. Paul recalled travelling up a very steep gravelly mountain in Mongolia, when it started raining, then sleeting, then snowing.

“Several attempts were needed to get enough traction on the gravel to ascend, but at least we didn’t need towing like several other participants. The biggest delight was to come across a Mkll Jag, pulled along the side of the road, with good ol’ Brit participants stopped for their scheduled Sunday sandwiches,” said Paul.

There were also plenty of “bar” stories from the journey, usually about how quickly they ran out of alcohol. On one occasion an enterprising well-heeled gent solved the situation when he came back with all of his many inside and outside pockets crammed with little bottles of whisky, vodka etc – like the biblical loaves and fishes story!

Paul and Bas maintained an impressive 9th position overall in Classic Cars (72 cars) and were awarded 2nd in Class D (31 cars), receiving a trophy at the prize giving gala dinner on Sunday 7 July. They also received one of 20 gold medals for cars which completed every stage of the rally in specified time, and successfully undertook all the many daily “race tests”.

”I’m very lucky to have the opportunity to partake in something as remarkable as the Peking to Paris – there’s a thrill in life that is worth taking. You walk away with a bag of new stories and some great people who will be friends forever.”

By Claire Hartley

Claire is a strategic senior marketing and communications professional who joined Mainmark in 2015. She has extensive experience gained in a range of organisations across the APAC region and the UK; from large multinationals and start-ups to industrial B2B, IT and online businesses.

The tape tells a story when treating the causes of wall cracks

Brick cracks with tape

Not all cracks are the same; the type, size and location of cracking is important to consider when identifying the cause of the issue, as well as the best steps to resolve the problem.

In the same way, measuring the success of a remediation project draws on a combination of tools.

Different types of wall cracks

The most common types of wall cracks that generally appear in buildings are:

  • Interior cracks affecting plasterboard, gyprock or brickwork
  • Exterior wall cracks in brickwork or cement rendering of external walls

If wall cracks suddenly appear in your home, they may be a symptom of a deeper, structural  issue. An earlier article highlighted the types of wall cracks that homeowners should act on, with location, direction and extensiveness of the crack likely to indicate the seriousness of the underlying problem.

Smaller hairline cracks are fairly common in walls and not usually cause for concern. Larger cracks that start at windows, doorways or corners of buildings may suggest the property foundations have sunk, subsided or lost strength, causing all or part of the building to sink.

Pay attention to whether the crack is jagged, horizontal or vertical, zig-zagged, stepped in brickwork, or follows mortar lines. If the crack is 5mm or wider, or you notice a complete separation in the mortar or cement between bricks, professional advice is recommended. Depending on the underlying cause, you may need a plumber to address leaking pipes, or deeper investigations by a geotechnical engineer or structural engineer to determine the reason for structural issues before speaking with ground engineering experts about remediation solutions.

The process of remediation

Once the underlying issue has been identified as subsidence or reduced bearing capacity, there are several solutions to consider. These include traditional methods like concrete underpinning, or non-invasive resin injection, which is comparatively much faster and usually more cost effective.

Teretek® resin injection is designed to be applied once the exact areas of subsidence and weakness beneath the structure have been pinpointed. Using a process likened to keyhole surgery, the engineered product both increases ground bearing capacity and re-levels the building with a high degree of accuracy. While the objective is always to improve the ground and return the structure to as close to level as possible, whether wall cracks fully close or not will depend on the direction of the crack and the soil beneath your home.

Why tape is applied over cracks

In many case, homes can be re-levelled within a day using resin injection, and the application process is tightly-controlled with constant monitoring using laser levels to ensure accuracy.

Mainmark applies a special indicator tape on to significant wall cracks before re-levelling works commence. This visual indicator is one of many measurement techniques that technicians use to carefully monitor change throughout the controlled remediation process. To answer a common question, the tape does not close wall cracks, but plays an important part all the same. For the trained eye, it may be possible to spot visible movement of the tape even before incremental change is picked up using the highly accurate laser level. The tape can also show how the structure is moving in response to foundation ground remediation, including the direction and degree of lift. In some cases, technicians may adjust the location of injection points accordingly.

Although the tape can be left in place for the homeowner to continue to monitor changes in the weeks following treatment, it is not necessary to do so. Once re-levelling works are complete, above ground structural repairs can take place with the help of a professional builder to patch and repaint walls as needed. For the best long term results following remediation works, the Foundation Maintenance and Footing Performance guide from Australia’s CSIRO provides expert advice for homeowners to help ensure both the building and property are well managed, with ongoing moisture ingress kept under control.

For more information and advice contact Mainmark on 1800 623 312 in Australia, on 0800 873 835 in NZ, or visit www.mainmark.com.

By James O’Grady

James O’Grady is the Sales and Business Development Manager at Mainmark. He is a civil engineer with 25 years’ experience in structural engineering, construction materials and ground treatment.

How leaking water pipes can wreak havoc on a home’s foundations

Flooding from a hurricane flooding from a hurricane or tropical storm

Cracked pipes, blocked gutters and broken sewer lines are a surprisingly common cause of the foundation issues that can affect properties.

Put simply, when the ground becomes oversaturated and waterlogged, the soil is weakened and loses strength, which can result in structural issues.

For homeowners, the best way to avoid the costs of repairing foundation issues is to regularly check the ground around your home for damp, waterlogged or subsided areas and act immediately if there is a suspected leaking pipe or drainage issue. It’s also recommended that you look out for the warning signs of foundation issues, such as internal and external wall cracks, uneven floors and misaligned doors or windows.

Different types and locations of pipes

When it comes to maintenance of water, stormwater and sewer pipes, there are some things to be aware of.  Mains water supply, stormwater and sewerage networks are all separate systems, with each designed to meet different needs. Sewer pipes are usually smaller in diameter than stormwater pipes, but can be the same size.

Typically, homeowners are responsible for all of their own property’s pipework within the boundary, subject to the form of title of their property, as well as the pipes leading up to and including the water meter connection. Local councils are typically responsible for the stormwater network that extends beyond the boundary, and the various utility authorities are responsible for the water meter, water mains and sewer pipes that lead to or away from the property. That means the onus is on homeowners to not only fix a leaking or blocked pipe on their property, but also to pay for any excess water wasted as a result.

Signs of water leakage

A hidden or concealed leak can be difficult to spot, as water slowly seeps into the ground, sometimes over a long period of time, before there are any signs of structural issues. This was the case when widespread wall cracks appeared in a heritage-listed Sydney home. The four-bedroom property was built on highly reactive clay soil which became oversaturated due to moisture from the broken sewer and stormwater under the home.  It was suspected that the leaking water had been ongoing for as long as a decade.

Before the home could be re-levelled, the foundation ground first needed to be improved  to prevent further settlement and damage. Using Teretek® resin injection, Mainmark was able to strengthen the clay ground and achieve the necessary amount of lift to bring the home back into alignment.

Another example of structural issues caused by sodden ground occurred at a Sydney home where a modified rainwater downpipe outside the patio area occasionally flooded, washing away underlying soil. Over the course of 18 months, the owners noticed the patio floor was sinking and cracks were starting to appear on the walls.

The poor drainage system needed to be replaced before the patio slab could be returned to its original position, rectifying the alignment and functionality of doors and windows. Teretek® was injected through a series of small keyholes, instantly filling the voids that had formed under the patio and returning the structure back to level without impacting the repaired stormwater drain pipe and a sewer main located underneath the slab.

Common causes for leaking pipes

There are a number of other external reasons that can cause pipes to crack and leak, such as invasive tree roots, overflowing stormwater during heavy or prolonged rain, or the presence of older, clay pipes.

  • Invasive treet roots

Tree roots can enter pipes through tiny fractures or small gaps in search of water, especially during dry spells. Once inside the pipes, they continue to grow, damaging pipes and causing blockages. Tip: understand the tree root system and the projected mature height of the tree and plant at an appropriate distance from foundations, driveways, patios, footpaths. Your local arborist, geotech and structural engineers can best assist to guide you on tree planting guidelines.

  • Broken clay pipes

While PVC or plastic pipes have been used in Australia for more than 40 years, many older homes still have clay or terracotta pipes in place which are liable to leakage at segment joints, and other wear and tear over time due to ground movement, creating holes, cracks, and eventually breaks in the pipes. Clay pipes are also particularly weak against root intrusion. Tip: consult a licenced plumber to check the current health of pipes on your property.

  • Stormwater overflow

In wet weather, rainwater can overwhelm the stormwater network and spill over into the sewer system, which may cause sewage to be overloaded, back up and potentially overflow into the ground. Overloaded stormwater drainage systems can also result in over land flow and ponding in low lying locations, that may concentrate water to foundation soils and cause structural issues. Tip: make sure stormwater pipes do not drain rainwater from your roof gutters into the sewerage system and that your stormwater disposal system is regularly maintained and cleaned to avoid being overloaded and over flowing.

Preventing structural issues

For homeowners, it is important to watch for signs of leaking pipes or drainage issues before ground subsidence begins to impact your home’s foundations. Pay attention to slow-draining sinks, toilets or showers, ensure rainwater is not directed into stormwater pipes and check your water bill for unusually high levels of consumption.  In extreme situations sink holes can appear at the surface where the subsurface foundation soils are being washed away by leaking services.

If a leak is detected, the first priority is to have it fixed by a licensed plumber as quickly as possible to avoid losing excessive amounts of water or having uncontrolled stormwater or sewer disposal, and before it can impact the home’s foundations.

For advice on the best way to remediate structural issues that may occur as a result of underground water leaks, contact Mainmark on 1800 623 312 in Australia, on 0800 873 835 in NZ, or visit www.mainmark.com.

Laurie Andrews MainmarkBy Laurie Andrews

Laurie Andrews is Mainmark’s Business Development Manager for NSW & ACT. Laurie is a qualified civil and structural engineer with nearly 30 years experience working in the construction and engineering industry.

Global markets continue to embrace Mainmark’s innovative ground engineering solutions

Mainmark has been providing specialist ground engineering and asset preservation solutions since 1983.

Originally founded in Australia, our local operation has grown into a global enterprise with offices in New Zealand, Japan and the UK.

Mainmark’s global standing received a boost after it won a major Ground Engineering Award in 2016 for its work in re-levelling the Christchurch Art Gallery following the 2011 earthquake events. This was testament to the exceptional level of engineering expertise and geotechnical innovation that Mainmark continues to uphold across its global business operations.

The business has a history of innovation and doing what others can’t.  It continues to invest significant resources into developing new ways to address a variety of unique ground engineering problems such as Terefirm™ Resin Injection, a proven, non-invasive soil densification and liquefaction mitigation technique that can be easily applied beneath existing structures. This initiative was undertaken as part of the Christchurch Red Zone research trials, in partnership with New Zealand’s Earthquake Commission (EQC) and the Ministry of Business Innovation and Employment (MBIE), and the outcomes are now included in the MBIE Module 5: Ground Improvement of Soils Prone to Liquefaction.

With a reputation for unwavering commitment to research, development, testing and innovation, Mainmark has also aligned with world-renowned experts such as Dr Alan Jeary, an industry pioneer who co-created STRAAM monitoring technology, to complement its business offering.  STRAAM was used to help preserve the White Rabbit, a valuable heritage-listed building in central Auckland, by monitoring the structure for building movement prior to and during construction.

In the growing UK market, Mainmark has completed a number of impressive projects that solve a range of issues relating to poor soils. The commercial sector represents a large proportion of re-levelling projects in this region, including a large factory and warehouse located in Sheffield which had suffered severe differential settlement.  The building was built on a former coal mining site with highly reactive compacted fill soil that was susceptible to voids and subsidence, and was subsequently suffering from severe cracking and sloping floors, that were out of alignment by up to 156mm.  Mainmark remediated the structure in stages using a bespoke engineered solution including use of our proprietary JOG Computer-Controlled Grouting.  A robotic survey station was also set up to provide real-time lift data to monitor the grout injection process, which required injection rods to be inserted at 112 locations to a depth of 6m.  This highly complex project was completed in 42 days without impacting the business, which continued to operate while the works were carried out.

More recently, the UK team remediated the Traders Coffee site in South London.  The commercial business unit had been built on poorly compacted ground and the weakening soil had compromised the building’s structural integrity, which had worsened after the addition of a mezzanine floor.  Ground subsidence had been progressively worsening due to poor drainage and an overflowing gutter.  Previous owners had attempted to solve the issue by pouring additional layers of concrete over the affected floor area, which had dropped by approximately 120mm. This measure did not, however, address the underlying ground subsidence.  Mainmark’s UK team was able to solve the issue by strengthening the underlying soil using Teretek® resin injection and JOG Computer-Controlled Grouting, which effectively re-levelled the building.

In Asia, Mainmark solutions and technologies are applied and adapted for the varied local conditions. A large number of commercial projects have been completed throughout the years, including several airport sites.  At Nagoya Airport in Japan, for example, Mainmark re-levelled a drainage channel on one of the airport’s taxiways. Whilst at Gimpo International Airport in South Korea, Mainmark remediated a runway that was affected by subsidence.  In Thailand, the Mainmark team re-levelled and re-supported a factory canteen floor that had suffered severe subsidence due to weak sub-base soil and had become a dangerous trip hazard. The floor was successfully remediated in seven days using resin injection technology.

For more information about Mainmark’s innovative ground engineering solutions and other global projects visit www.mainmark.com.

By Claire Hartley

Claire is a strategic senior marketing and communications professional who joined Mainmark in 2015. She has extensive experience gained in a range of organisations across the APAC region and the UK; from large multinationals and start-ups to industrial B2B, IT and online businesses.

A commitment to excellence: remembering Mainmark founder Philip Mack

Phil Mack legacy

On 9 April 2019, Mainmark staff bid a sad farewell to our company’s founder and chairman, Philip Mack.

Philip originally established the Mainmark group back in 1983, building the business from the ground up. The name came from an Aboriginal word ‘manymak’, which translated to ‘good’ or ‘excellent’, a word that strongly resonated with Philip and reflected his work ethic.

“We started with the name. From there, I’d like to think that I fostered a culture of excellence by setting a good example, although too often I have been tarred with the stigma of being a perfectionist, which is seen by many as impractical,” he once said.

Philip’s ethos set a successful course for Mainmark, one that was built on hard work and determination. In 1989, following the disastrous earthquake that affected Newcastle, Mainmark quickly established itself as a local industry leader in earthquake repair and remediation, with a focus on reinforcing stonework in heritage buildings and churches.

Russell Deller, who joined Philip as a member of Mainmark’s team in the early days and continues to this day, said: “Philip often thought back to where we began during the Newcastle earthquake repair days, fondly remembering the challenges and how we were always inventing and innovating.”

“He saw success as a by-product of doing something as best you can and genuinely seeking to solve a problem for someone else. He always asked, “Is there anything else we can do?” before leaving a person’s home, often resulting in us putting out wheelie bins!”

When the work in Newcastle concluded, the company ventured into new territory. One of company’s earliest projects involved reinforcing the iconic brickwork arches of the Paddy’s Markets’ façade in Sydney using specialist grouting techniques, while raising and re-levelling the floor with pressure cement grouting. The project proved to be a catalyst for the future of Mainmark.

During a quiet period for the business, Philip researched global innovations in ground engineering. A picture of Uretek resin injection from the United Kingdom struck a chord, leading Philip to design and build the first Uretek rig to suit Australian conditions. Philip gradually added one rig a year over the next five years.

In the early days, Philip was not only the business owner, but also a salesman, supervisor, accountant and even tea lady. As the organisation grew, he maintained a hands-on approach, which included travelling from Australia to oversee the first project in Japan, and then pumping the entire job by hand when the pump broke down. 

When the global financial crisis struck in 2008, Philip was forced to reassess the Japanese business operation which was still in its infancy. Despite the economic challenges, he forged ahead, not wanting to let anyone down. It proved to be the right decision and, thanks to the combination of a strong product and good people, Philip’s determination paid off.

Under Philip’s guidance and commitment, Mainmark continued to diversify and expand globally, growing from a team of two to well over 300 employees with 15 offices across the globe, including eight offices, seven rigs and 70 staff in Japan. 

Over the years, Philip instilled a strong work ethic, and culture of trust and loyalty in those that worked with him. It was simply a reflection of who he was and what he believed.  

Philip’s commitment to excellence and family values never changed, and it was these qualities that drove Mainmark’s growth. He believed in getting the job right the first time, with careful planning to ensure the structure was correctly understood and remediated. This same ethos continues today.

Above all else, Philip valued people. He was phenomenally proud of his three sons Robert, David and Ian, and his wife Meaw.

Son David was equally proud of his dad, saying: “Philip took Mainmark from the front room of our house, to a dingy office above a dry cleaner, to a global enterprise employing hundreds. He saw Mainmark as an extension of his family. In truth, I never really thought he’d ever retire. A builder by trade, he wasn’t ever going to stop until the job was done.”

Outside of work, success to Philip was about helping others and enjoying the company of the people in his life. He was adventurous and extremely well travelled, completing the Kokoda track with son Ian, as well as reaching the South Pole, coming within 10 degrees of the North Pole, and exploring just about everywhere in between. He loved to laugh and made friends wherever he went. Typically, those friends also became business partners and colleagues.

Philip maintained a watchful eye over key projects, especially the Christchurch Art Gallery remediation. The Art Gallery suffered significant damage to its foundations during the 2010 and 2011 earthquakes, causing the 33,000-tonne building to sink.

Mainmark worked closely with the remediation project’s engineering team to successfully re-support and re-level the 6,500 square metre foundations in just 52 days. Philip was immensely proud of the outcome, for which Mainmark received the International Project of the Year Award at the 2016 Ground Engineering Awards.

The best way to understand the true connection Philip Mack had with the company he built, is perhaps through his own words: “I have loved every moment at Mainmark and have been incredibly lucky to find my niche. Even more so to find others of the same ilk to share the experience with me.”

On behalf of the Mack family, including Philip’s wife Meaw Mack, and all Mainmark staff, we look forward to honouring and building on this tremendous legacy.

By Paul Hickman

Paul Hickman is Mainmark’s Chief Executive Officer. He joined the business in 2005 and has more than 30 years’ experience in the construction industry. In his spare time, he’s a car enthusiast, music lover and supporter of women’s and human rights initiatives.


The sinkhole phenomenon – what causes them and how are they remediated?

The road repair and caution with blocked barrier over concrete digging

When it comes to ground issues, sinkholes can appear suddenly, often with dramatic and serious consequences. 

While the ground may seem to unexpectedly collapse, the reality is that sinkholes generally develop over a period of time until the ground above simply loses support and gives way, leaving a gaping hole.

Understanding what causes sinkholes

Sinkholes have been known to open up in all manner of locations – beaches and oceans, residential gardens, motorways, even shopping centre carparks.  While sinkholes are a rare occurrence, there are a few common natural and man-made causes that can lead to the formation of a sinkhole, and these are usually exacerbated by flowing water. Nearby construction or excavation, leaking pipes, reclaimed landfill sites, as well as historical mining or tunnelling activity can also impact the stability or compaction of the surrounding layers of earth, leading to voids and potential sinkholes.

Groundwater – when water creates natural currents underground, the ground below the surface layer may slowly erode or wash away, causing voids to form. Over time, the underground void grows, causing the surface layer of the ground to gradually become thinner and span further, eventually caving in. In areas where the rock below the ground is made up of limestone, which dissolves easily, sinkholes are more common.

Heavy rainfall, floods, or leaking or burst drainage pipes can cause excess water to  travel through the ground, washing out fines and causing cavities, and potentially triggering a sinkhole.

Earlier this year, a burst water main was thought to be the cause of a sinkhole that formed in the middle of a suburban road in Melbourne, partially swallowing a car.

Likewise, excess water was responsible for a sinkhole that formed in a landscaped courtyard located within a residential complex in Sydney’s Lane Cove. Ground engineering specialists identified the formation of a ‘void zone’ between the perimeter wall and the adjacent natural rock supporting wall. Over time heavy rainfall soaked into the courtyard lawn and slowly migrated through the ground towards the void, washing away the soil beneath the courtyard, causing it to erode and form a sinkhole.

The warning signs

Despite the surface layer of the ground remaining intact, as an underground cavity forms and increases in size, there are likely to be signs that indicate the presence of a void or emerging sinkhole.

Recognising these signs and acting quickly, may help to put preventative measures in place, thereby avoiding significant damage to homes, business facilities and roads, while also minimising the risk to human safety.

Pay attention to these potential warning signs:

  • Cracks forming in the ground outside
  • Unexplained depressions or dips in the ground
  • Trees or fence posts that tilt or fall
  • Rapid appearance of a hole in the ground

Comprehensive and affordable remediation solutions

When remediating the Lane Cove residential complex, Mainmark’s versatile Terefil® was an ideal solution, rapidly filling the void without placing undue pressure on existing drainage or perimeter walls. View this time lapse video to see Terefil in action, filling the underground void in Lane Cove.  

Terefil is a lightweight cementitious fill used for a variety of complex geotechnical applications, which includes filling and sealing large underground voids and sinkholes. The comprehensive solution is exceptionally lightweight, while also providing superior load bearing capacity to the ground above.

It is also highly flowable meaning it can be pumped across long distances so that it can be applied at sites even when access is limited. This makes the application of Terefil quick and efficient, causing minimal disruption to home and business owners. When used to fill voids that have formed beneath roads or highways, there is little or no effect on traffic.

Always seek expert guidance

If signs of underground voids or sinkholes appear, consult structural and geotechnical engineers or ground engineering experts. 

For more information and advice about ground issues and remediation solutions, contact Mainmark on 1800 623 312 in Australia, on 0800 873 835 in NZ, or visit mainmark.com.

By James O’Grady

James O’Grady is the Sales and Business Development Manager at Mainmark. He is a civil engineer with 30 years’ experience in structural engineering, construction materials and ground treatment.

The value of ground strengthening for redevelopments in seismic prone areas

Uploaded ToThe value of ground strengthening for redevelopments in seismic prone areas

The devastation caused by seismic events in New Zealand, including the significant 2010 and 2011 Canterbury earthquake sequence, has seen growing awareness about the interaction between building structures and soil during an earthquake.

The challenge for home owners and developers undertaking earthquake strengthening works is to consider both ground strength and building behaviour so that the most cost effective and long-lasting solution can be identified to protect buildings and their occupants.

Liquefaction-induced settlements have affected countless building foundations, and is a major contributor to seismic risk, or the risk of earthquake damage, in urban areas.

The effect of liquefaction on structures and buildings can be extremely damaging. Buildings with foundations that are directly on sand which liquefies, commonly experience a sudden loss of support. This often results in drastic and irregular settlement of the building which causes structural damage to the foundations, cracking of the walls and in the worst cases, leaving the structure completely unserviceable.

New Zealand’s Building (Earthquake-prone Buildings) Amendment Act 2016 (EPBA) which categorises seismic risk under the New Building Standard (NBS) is changing the way earthquake-prone buildings are managed.

The New Building Standard (NBS) is a national approach which considers a number of factors relating to seismic performance and risk including public safety, remediation cost and heritage preservation.  It takes a statistical, balanced approach to the practicalities of strengthening or replacing buildings.

When property developer KCRB Ltd purchased the Kamahi Apartments in Christchurch, the goal was to renovate the landmark eight-storey residential apartment building in keeping with the city’s overall rejuvenation, and to then sell the individual apartments and penthouses. The developer wanted to achieve 100% NBS and assure future owners that the building was well prepared for earthquake resilience.

Geotechnical investigations identified that there was adequate ground stability to proceed with re-levelling the building, which suffered differential settlement due to the earthquakes.  In addition to re-levelling, seismic strengthening works were undertaken, which involved widening and strengthening the building foundations.

With extensive experience improving ground affected by seismic liquefaction beneath hundreds of structures of all sizes, including Christchurch Art Gallery, KCRB Ltd chose to work with Mainmark on the ground remediation.

JOG Computer-Controlled Grouting (JOG) was identified as the most suitable solution for re-levelling the Kamahi Apartments. JOG is an advanced and precise method for returning foundations to level, providing precise, incremental amounts of lift. It works by improving the soil beneath the foundations and delivering accurate, computer-controlled re-levelling, regardless of building size or complexity.

Mainmark’s ongoing commitment to developing ground improvement solutions for seismic prone areas has also lead to a new technique to improve soil density beneath structures affected or at-risk of liquefaction.

Following extensive testing and field trials, Mainmark has been able to introduce Terefirm™ Resin Injection, the first commercially viable, non-invasive ground improvement and liquefaction mitigation technique that can be applied beneath existing structures.

Terefirm™ Resin Injection is fully engineered and validated by geotechnical testing and can help protect structures at risk from soil liquefaction.

For more information and advice about earthquake resilience, ground issues and remediation solutions, contact Mainmark New Zealand on 0800 873 835 or complete our enquiry form.

By Theo Hnat

Theo Hnat is a R&D and Technical Manager at Mainmark. Based in New Zealand, Theo’s responsibilities include research in new technologies in ground improvement and liquefaction mitigation, structural risk assessment of existing structures, design, and analysis.

How extreme weather can affect your home’s foundations


Extreme weather events, natural disasters and extended dry spells have a significant impact on the ground and subsequently, on building foundations.

Summer 2018/19 was the third-warmest ever recorded in Australia, and the hot weather pattern has continued, with January one of the hottest on record across both Australia and New Zealand.  While many of us have sweltered through record high temperatures, others have experienced ongoing drought conditions and a series of natural disasters, including floods, fires, monsoonal rain and cyclones, which have had a sudden and devastating impact on many homes and the wider community. After months of very little rain, numerous suburbs in South East Queensland have experienced dry ground conditions, and a reported increase in cracks and crumbling walls in homes.

How weather conditions affect the ground

The most common soil types in our region have different characteristics and responses to weather conditions and can seriously impact a building’s structural foundations. Houses built on loosely packed soils, sand and reactive clays can be particularly affected by seasonal or extreme rain, floods and drought.

  • Reactive clay expands and contracts during wetting and drying, resulting in cracking during prolonged dry periods and swelling under moisture.
  • Sand and silt is prone to settlement due to water flow which can wash away finer grains in the soil leaving larger grains to settle.
  • Fill often consists of soil as well as other materials such as aggregate, rock or crushed construction waste. When a significant volume of water works its way through fill and washes away finer particles, it can lead to settlement. This may initially present as a depression on the ground’s surface, and can be exacerbated by poor compaction and the general composition of the surrounding soil.

When the ground changes and can no longer support the building’s foundations, they  gradually move downwards, causing the home to sink in one area or across the entire footprint. This is known as ground subsidence.

The ground’s moisture level is a key consideration.  For instance, clay soils in temperate areas tend to be moist, making it susceptible to shrinkage during prolonged dry weather, leading to ground subsidence.  During a flood, fast flowing water can wash soil away creating erosion and sinkholes.  Both scenarios can cause serious foundation damage to homes, buildings and surrounding roads

The escalating impact of extreme weather is worldwide. After a record-breaking summer in the UK last year, heatwave conditions affected many building foundations as sustained warm weather caused water from subsoils to dry out, resulting in shrinkage. This has resulted in a subsidence surge with insurers receiving an unusually high number of related claims.

How to address subsidence

Thankfully, there are methods available to quickly, efficiently and cost-effectively treat foundations impacted by subsidence, using advanced solutions that offer an alternative to the traditional invasive and time-consuming method of concrete underpinning.

Mainmark’s proprietary resin injection solution, Teretek®, requires no excavation, creates minimal mess, and homeowners can often continue living in the property while the work is carried out.

Remember, when the signs of subsidence appear, seek expert advice from structural and geotechnical engineers or ground engineers to ensure you have all the information and facts needed to determine the right solution.

For more information and advice about ground issues and remediation solutions, contact Mainmark on 1800 623 312 in Australia, 0800 873 835 in NZ or visit mainmark.com.

By James O’Grady

James O’Grady is the Sales and Business Development Manager at Mainmark. He is a civil engineer with 25 years’ experience in structural engineering, construction materials and ground treatment.

What to do if your home is subsiding

What to do if your home is subsiding

Foundations are a structurally significant part of any building.

While solid, stable foundations help ensure your home has the support it needs for years to come, buildings can and will move. A fundamental reason for this movement is often due to changes in the ground under your home’s footings.

Many homes experience foundation movement due to changing ground conditions; this is known as subsidence. Regardless of where they live, homeowners share a common goal – to protect their biggest asset. That’s why it is important to identify the signs of subsidence early and act without delay.

The signs to look for

When the ground can no longer support the building, the foundations gradually move downwards, causing the home to sink in one area or across the entire foundation footprint. Every home is different and the signs may not be immediately obvious, so it’s important to know what to look for.

Pay attention to sinking or sloping floors, cracks in walls, paths and driveways as these may be the first signs of structural issues caused by subsidence. Windows and doors becoming jammed or misaligned, skirting boards separating from the wall or the formation of puddles around the perimeter of your home may also indicate foundation ground issues.

When to worry about cracks in walls

While smaller hairline cracks in walls are fairly common and not usually cause for concern, large cracks may appear because the property’s foundation has shrunk or lost its strength, causing all or a part of a building to sink.

Problematic wall cracks typically start at windows, doorways or corners of buildings, and are often zig-zag/stepped cracks in brickwork which usually follow the mortar lines. They are usually wider than 5mm (or half a centimetre) or big enough for you to insert your little finger in them.

Be aware of conditions beneath your foundations

Understanding what’s happening in the ground beneath your home, including the type of soil your house is built on, may be the key to identifying the cause of subsidence and possible solutions.

This is especially important for homeowners in areas where soil is known to be unstable. Houses built on loosely packed soils, old landfill sites, sand and reactive clays can be particularly affected by seasonal or extreme weather conditions, drought and floods. Historical mining activity can also impact properties in certain areas, like this home in New South Wales.

Structural problems often result from varying moisture levels in reactive clay soil which can shrink, or crack and shift during hot weather, and then expand during wetter seasons. Other problems can arise due to tree roots removing moisture from the soil or penetrating pipes to create underground leaks. Poor drainage beneath a concrete slab was the issue identified as the likely cause of the subsidence of a sunroom patio in a brick veneer home. The homeowner worried that the entire building would need to be replaced. Fortunately, after addressing the underlying drainage issues, the home was re-levelled within a few hours, at a fraction of the cost of replacement or other solutions.

Seismic activity such as earthquakes can cause soil to temporarily lose stability, known as liquefaction, which may then lead to subsidence. After a major earthquake in New Zealand, the owner of a large family home near Wellington noticed cracks appearing around door frames and along the ceiling joint as well as plaster detaching. Using a precise application method, the ground under the slab was treated via tiny injection points, to strengthen the ground. The cracks have since closed and the doors and windows have come back into alignment.

Subsidence can also occur when nearby excavation, tunnelling or drilling activity causes vibration and ground movement, impacting foundation stability. Whether it’s a neighbour adding an inground pool, new developments in the area or major infrastructure projects underway, it’s important to understand the cause of subsidence to treat the problem effectively. Remediation solutions can usually be applied with minimal impact, to protect the integrity of even the most fragile structures, like a heritage church in central Sydney where the foundations were impacted by deep excavation during a nearby infrastructure development project.

Simple and affordable remediation solutions

Today, there are innovative solutions available to help address structural issues which are non-invasive, fast and cost effective when compared to traditional underpinning methods. Homes can usually be re-levelled within just a few hours without the need for occupants to vacate the property or move furniture.

Ask an expert

If signs of subsidence have appeared, consult structural and geotechnical engineers or ground engineering experts. Mainmark has treated more than 30,000 sites throughout Australasia, from single-storey homes to large commercial buildings. The Teretek® engineered resin injection solution uses a “key-hole” approach, has been extensively tested for local conditions and comes with a 50-year product warranty, providing long-term peace of mind.

For more information and advice about ground issues and remediation solutions, contact Mainmark on 1800 623 312 in Australia, 0800 873 835 in NZ or visit mainmark.com.

By James O’Grady

James O’Grady is the Sales and Business Development Manager at Mainmark. He is a civil engineer with 25 years’ experience in structural engineering, construction materials and ground treatment.