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A sign of subsidence
What is Subsidence and how to fix it?
Subsidence can happen naturally as part of the earth’s constantly shifting crust. It can be exacerbated by issues such as soil compaction, loss of ground moisture, excessive excavation, or erosion. Ground instability causes subsidence and, often, the damage can seem to be reversed as the ground shifts back and forth over time.
Using resin injection ground stabilisation, we improve ground compaction. We can then raise and re-level sunken buildings, then add support to the ground for soil stabilisation to strengthen the foundation and stop the soil underneath and around the buildings slipping or moving. We have successfully raised, re-levelled, and re-supported thousands of homes around the world.
Video
Re-levelling In Action
This remarkable solution is the key to raising, re-leveling, and re-supporting properties affected by subsidence. Our skilled team of engineers and technicians will guide you through the process, demonstrating how we restore structural integrity and eliminate those troublesome wall cracks.
Trust Mainmark for excellence for re-levelling
Identifying subsidence
Subsidence is not without warning signs. Some of the most common include:
Internal cracked walls
Wall cracks are common in homes and are often the first sign of foundation subsidence. Inside the house, they appear like steps in the brickwork/blocks or tiles and typically follow mortar or grout lines. The mortar and masonry deteriorates over time due to the movement of the affected wall.
Sinking floors
A concrete floor slab within a home can sink due to weak ground or subsidence. A building can sink at various localised points or can be spread across the entire footprint of the house foundation.
Jammed doors
Doors that don’t open smoothly, have uneven gaps or rub against frames are often a first indication of foundation damage
Exterior cracked walls
Step wall cracks are common in homes and are often the first sign of foundation subsidence. The mortar and masonry deteriorate over time due to the movement of the affected wall. Wall cracks are usually of concern when one side of the wall is higher than the other or cracks are wider than about 5mm.
Sinking & uneven concrete slabs
Sinking and uneven concrete driveways or path slabs can be an indication of unstable ground due to voids beneath the surface. If there is noticeable soil building up around slab joints, the concrete slab can start to crack around the edges as weight is exerted where there is no ground support.
Articulation joints
Usually visible in building extensions where two walls join and in modern buildings at the sides of large window and door openings. The gap is often wider at the top of the joint, exposing the lining.
What causes subsidence?
There are many different causes of subsidence and various contributing factors.
All involve some change in the ground, which, in turn, generates movement of the soil.
As well, different types of ground are more affected by different conditions.
When ground has been affected, building subsidence is common. Foundations or footings are no longer fully supported, sinking due to weak ground.
Soil Types
Moisture levels in the soil affect reactive clays as they expand and contract.
Oversaturated clays lose their strength resulting in footing subsidence. In loosely packed soils, such as sand and silt, the fine particales in the soil can wash away causing the footing to settle.
Tree Roots
Neighbouring trees and shrubs absorb water using their roots causing movement in the soil as it soaks up moisture in the ground.
Footing Systems
Poor foundation design or inadequate compaction of soil during construction results in movement of the structure as it settles.
Excess Water
Burst or cracked water pipes including blocked sewage and rain gutters can oversaturate clay soils or wash fine particles from sand and silt soils and cause footings to subside.
Extreme or Seasonal Weather
Natural disasters such as flooding, drought and earthquakes affect soil moisture levels in particular clay resulting in excessive foundation movement.
Renovation or Construction
Vibration caused by nearby construction activity such as drilling or piling, or heavy road traffic causes soil particles to shift and settle, resulting in ground subsidence.
Residential Subsidence Repair
Before & After Treatment
Houses that need to be re-levelled often develop cracks in walls, sinking floors, sticking windows or jammed doors.
Our innovative solutions are designed to address sinking foundations and cracked walls, ensuring long-lasting stability for your home. Whether it’s a sinking foundation or a cracked wall repair, sinking concrete floor or re-levelling a driveway, we provide tailored services to every job.
We offer a range of underpinning options, including resin injection underpinning and concrete underpinning, to help raise and relevel sunken structures. The cost of underpinning varies depending on factors like the extent of damage and the type of foundation. Our expert team specialises in underpinning footings and crack wall repair, ensuring your home is safe and secure for the future.
*Results may vary depending on site conditions, ground behaviour and specific requirements of each project.
How we get your home back to level in as little as a day.
Features & Benefits
Mainmark’s Level Correction Methods For Subsidence
Fast, Surgical & Accurate
The process is accurate within a few milimteres and completed within hours compared to traditional methods.
Environmentally Inert
No effect to the surrounding soils
Non-Invasive
Repairs are performed without the need for excavation, extensive road closures or traffic disruption.
Cost-Effective
Compared to traditional methods, our solutions are more cost-effective.
Sinking floors & concrete
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Subsidence Repair FAQs for New Zealand Homeowners
How do I know if my house has subsidence?
Your house may have subsidence if you notice cracked walls, sinking floors, uneven concrete slabs, jammed doors, sticking windows, gaps around skirting boards or visible movement around the foundations. One sign alone may not confirm subsidence, but several symptoms appearing together can indicate ground movement or loss of foundation support.
What causes house subsidence in New Zealand?
House subsidence is usually caused by changes in the ground beneath the property. Common causes include weak soils, soil compaction, erosion, poor drainage, leaking pipes, tree roots, seasonal weather, drought, flooding, nearby construction vibration or seismic activity. When the ground loses strength, the foundations can settle or move unevenly.
Can subsidence be repaired without traditional underpinning?
In many cases, yes. Mainmark uses resin injection ground stabilisation to improve weak ground, fill voids and help re-support or re-level sunken buildings. This can often reduce the need for traditional excavation-based underpinning, depending on the cause of the subsidence and the condition of the foundations.
What is the difference between subsidence repair and foundation repair?
Subsidence repair focuses on treating the ground movement or loss of support causing the building to sink. Foundation repair focuses on the affected footings, slabs or structure above that ground. In many homes, both are connected, and a site assessment is needed to identify the right repair approach.
Can Mainmark re-level a house affected by subsidence?
Yes. Mainmark can assess homes affected by subsidence, foundation settlement or sinking floors and recommend a suitable re-levelling or foundation re-support solution. Using resin injection ground improvement, Mainmark can help raise and re-level affected areas while improving support beneath the home.
How much does subsidence repair cost in New Zealand?
The cost of subsidence repair depends on the size of the affected area, how much the home has moved, ground conditions, site access and the repair method required. Because every property is different, a site assessment is the best way to understand the cause and receive a tailored quote.
Should I fix wall cracks before repairing subsidence?
If cracks are caused by foundation subsidence, cosmetic repairs may not last until the underlying ground movement is addressed. Patching, painting or repairing plaster and brickwork first may lead to cracks returning. It is usually better to assess and repair the cause before completing cosmetic repairs.
How long does house subsidence repair take?
Timing depends on the size of the affected area, the amount of movement, access and the repair method required. Resin injection repairs can often be completed faster than traditional methods because the process is targeted, accurate and non-invasive. Mainmark can provide clearer timing after inspecting the property.
Who provides subsidence repair near me in New Zealand?
Mainmark provides house subsidence repair, foundation repair, foundation re-levelling and ground stabilisation solutions across New Zealand, including Auckland, Wellington, Christchurch and surrounding regions. If you are searching for subsidence repair near you, Mainmark can inspect the property and recommend a practical repair approach.
Why choose Mainmark for subsidence repair?
Mainmark is a specialist ground engineering company with extensive experience in subsidence repair, foundation re-levelling, resin injection and ground stabilisation. Homeowners choose Mainmark for practical assessments, non-invasive repair options and solutions focused on treating the cause of ground movement, not just the visible damage.
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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