Cracked Red Brick Wall

Putting cracks into perspective

Our homes are typically one of the biggest investments we make in our lives. It therefore stands to reason that the last thing we want to see are cracks in the walls, as they can be an indication of structural damage which can lead to financial strain.

However, cracks have a variety of implications, so it is important to know how to gauge the cause and severity of the cracks in your walls to determine the best course of action.

There are cracks in my walls – how serious is this?

No crack within the home is welcome, but there is a difference between minor hairline cracks that can be patched up with little hassle and larger cracks that may indicate serious structural issues. Shorter or thinner hairline cracks are typically superficial, appearing on the surface of walls and unrelated to the structural condition of the house or its foundations. These cracks can be unsightly but don’t usually point to severe damage and any repairs are largely cosmetic. Larger cracks, however, are often the result of ongoing building movement or external issues that have compromised the house’s structural integrity. The cause of large cracks can be costly to repair and create ramifications for a house’s value and the safety of its occupants.

What can cause cracks to occur?

There are a number of reasons why a structure may form cracks. One of the most common causes of significant wall cracks is poorly compacted foundation ground, or weak, unstable ground conditions, known as subsidence, leading to structural movement. For example, the foundation ground underneath your house may consist of loosely compacted soil or reactive clay, which is affected by varying moisture levels in the ground. Excess water in the ground caused by a change in the water table, or weather events such as heavy and persistent rain, can lead to the ground swelling. This same saturated ground will dry out and shrink when extended warm weather or drought conditions arrive, causing foundations to shift and the building to become unlevel over time.

Superficial cracks can also form as a result of seasonal shifts. It is common for houses to experience subtle movement as a result of building materials reacting to age, weather and temperature changes – this is known as the house ‘settling’. Thermal and moisture changes can also affect the paint, causing it to stretch and break, resulting in cosmetic cracks.

What do I do if I have cracks in my walls? What should I look out for?

The most important thing is not to panic. Take the time to understand your situation to help lead you to the best solution.

You can start by printing out Mainmark’s Wall Crack Guage to help you assess the size of the crack. This handy tool will give you an indication of the severity of the crack. Once you have printed your Mainmark Wall Crack Gauge, you can then ask yourself the following questions:

  • Is the crack 5mm or wider on the Wall Crack Gauge?
  • Is the crack jagged or zig-zagged? And do the cracks originate from windows, doorways or other framing?
  • Is the crack outside? Is it stepped in brickwork or following mortar lines?
  • Are doors and windows misaligned or difficult to open and close?
  • Do the floors also slope or appear to be sinking?

If you answer ‘yes’ to any or all of these questions, the cracks may indicate structural damage or issues with the ground or environment on which your house stands. This means you should consult a professional and obtain advice on how to best repair the damage in the future.

It is possible that the cracks are superficial hairline cracks, caused by natural occurrences such as  seasonal shifting and structural settling. It is still advisable to take action to rectify these cracks, such as taping, re-sealing and re-painting, but there is usually little concern for major short-term damage.

Ultimately, greater knowledge of how cracks can form and what the implications are can prevent added stress and unnecessary costs. Of course, if you’re unsure about how to best preserve your home, a structural engineer or a professional ground engineering company such as Mainmark can inspect the property and provide some further, site specific insight.

For more information and advice about cracks in your home, contact Mainmark on 1800 623 312 in Australia, 0800 873 835 in New Zealand or visit

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.