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Cracks in walls

When should you worry about cracks in walls?

Disregarding cracks in walls may mean you’re missing the warning signs of serious and ongoing structural damage caused by subsidence.

Cracks are a mechanism for releasing stresses built up within a structure, and they will naturally exploit inherent weaknesses in your home’s design.

While cracks in walls are common in buildings, and some are nothing to worry about, others can indicate subsidence and a sinking or damaged foundation.

Some characteristics of larger cracks that are cause for concern include:
When two sides of a wall are at differing heights
When doors and windows have gaps around their frames
When the cracks are wider than 5mm or you can insert your little finger into them

Zig-zag or stepped cracks in brickwork that usually follow the mortar lines may also be indicators of structural defects and weaknesses in the building’s foundation. As the subsidence continues, the cracks will get wider.

Contact us if you would like an expert assessment.

Fast, cost-effective and non-invasive solutions to treat subsidence and remediate cracked walls


Mainmark technologies for cracked walls and subsidence remediation

Teretek® – Subsidence remediation through resin injection

With over 25 years of experience, Mainmark is a world leader in resin injection solutions. Teretek® uses an injection delivery method that raises, re-levels and re-supports buildings and other above-ground structures and deals with the root cause of subsidence and cracks in walls.

Teretek® resin injection technology

Subsidence remediation with JOG Computer-Controlled Grouting

JOG Computer-Controlled Grouting is an award-winning technology for strengthening weak ground beneath larger residential buildings and other structures, using a cement grout injected under computer control. It is an extremely precise method for the remediation of foundation subsidence, improving and consolidating weak ground and lifting foundations to deliver specific, engineered outcomes, regardless of complexity.

JOG Computer-Controlled Grouting

Before and after treatment

Mainmark solutions to minimise wall cracks and treat subsidence

Mainmark’s subsidence and ground improvement treatment methods are effective for fixing cracks in walls in homes and buildings of any size.

One of Mainmark’s experts will visit the site to conduct a survey, assess the damage and ascertain the cause. Our experienced engineers and technicians are skilled at establishing the most appropriate methods and creating treatment plans specific to the needs of each building.

Houses and buildings that develop cracks in walls, which can occur internally and externally, often need to be re-levelled. These structures require their foundations to be lifted. As the building is re-levelled, wall cracks generally close, leaving only a little cosmetic crack repair, such as patching and painting, to deal with. Most importantly, structural damage is resolved, to the relief of the building owner.

Individual houses, terraced houses, apartment buildings and commercial structures can all suffer from settlement. Settlement of a floor slab or foundations supporting the walls or structure of the building often causes cracking in the brickwork walls.

Mainmark’s non-invasive underpinning solutions can lift foundations and re-level buildings By injecting our structural resin or cementitious grout mix into the ground under the building’s footings, we can stabilise the ground under the foundations and lift the structure back to level. In most cases, this closes any cracks in the walls that may have formed.

As opposed to more traditional methods of underpinning buildings, our Teretek® resin injection solution is quicker and, in most cases, done from the outside using 16mm diameter tubes. If interior injection is required, only a 6mm tube is used. The size of the tubes means that there is minimal intrusion into the property.

Another of our non-invasive crack repair methods is JOG Computer-Controlled Grouting, which allows our team to inject cement grout under a property at as many as 128 points to create a simultaneous, precise re-levelling process.


Mainmark technology benefits

Benefits of Mainmark’s subsidence and cracked wall treatments


Our subsidence remediation methods have fast curing times. Treated areas can be used quickly without the delays associated with traditional repair methods.

Environmentally Inert

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


Our solutions are surgical in nature compared to traditional methods.


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

Guide to wall crack types

Need help with a project? Contact us today.

What causes cracks to form in walls?

Cracks in walls are often caused by subsidence. There are many different causes of subsidence and various contributing factors. All involve some kind of change in the ground, which, in turn, generates movement of the soil.

In addition, different types of ground are more affected by various conditions.

When the ground has been affected, building subsidence is common. Foundations or footings are no longer fully supported and sink 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 particles 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 they soak up moisture from the ground.

Footing systems

Poor foundation design or inadequate soil compaction during construction may result 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, causing footings to subside.

Extreme or seasonal weather

Natural disasters such as flooding, drought and earthquakes affect soil moisture levels, particularly 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.

Start measuring wall cracks

If you notice wall cracks around your home that are:

Large, starting at windows, doorways or corners of buildings

Wider than 5mm

Jagged, horizontal or vertical, zig-zagged, stepped in brickwork or follow a mortar line

These characteristics may indicate weakness in your property’s foundation.

We’ve developed a handy tool to help you discover if the cracks in walls around your home could be due to subsidence. Download our FREE crack gauge and start measuring and monitoring the wall cracks around your home now!

Get a quote

Arrange a site assessment in three 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 Mainmark’s experts will visit your home or property, assess the damage and determine the likely cause. They will establish the approach needed, create a plan specific to the needs of your building and provide you with a detailed quote.

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