Small crack showing on bathroom wall

Cracks in Wall, Should I Be Worried?

24 March 2021

If you have recently bought a new home or been in living in the property for a long period of time, then you might start to see cracks on the walls of the building. So, what does this mean? Should you be worried that the building’s structural integrity is vulnerable or is it that your home just needs time to “settle”?

In this guide we hope we can answer this question and alleviate some stress for you but also if the issue is problematic, we hope to provide guidance on what to do next.

What Causes Cracks in Walls?

Small Cracks

There are a number of reasons why cracks can occur in buildings and it is more than likely that every property will face some sort of crack in its walls at some point or other. The most common form of cracking, which we mentioned earlier, is what tends to happen to all new houses called “settlement”.

When a new house is built, the foundations underneath tend to move and will cause small cracks on the walls. If your property is beside a busy road for example this can cause cracks to your property due to vibrations from road traffic. If there new double glazing is installed, without the support of lintels, then this could lead to your property suffering from having cracks around the windows.

Older housing can also be vulnerable to problems with wall cracks this could be due to no control in temperature and humidity levels. If these are not controlled, then the structure of the building can swell and sink over a period of time.

Although small hairline cracks are only minor issues and don’t look pleasing to the eye, at the same time they should not be ignored. These small cracks could lead to further problems down the line so you should keep an eye on the issues highlighted above and if the cracks expand contact a structural engineer for further advice.

Larger Cracks

While the types of cracks we have just highlighted can be a simple fix, there are larger types of cracks that can cause serious problems to the building’s structural integrity. Larger cracks within your building could potentially be caused by dampness penetrating its way through into the property.

If there are drainage problems or there are leaks in the basement then this can lead to large cracks appearing. When there are periods of heavy rainfall this can be a cause in itself and be made even worse when there is flooding involved.

Whilst a majority of severe structural problems occur from dampness, it can also lead to problems relating to cavity wall tie failure. Wall ties can corrode and expand over a period of time which will lead to the mortar joints separating apart leading to cracks appearing in the outer walls.Horizontal Mortar Joint Cracking

There have also been cases in the past, where there have been long periods of dry weather that can also lead to cracks in walls as well.

How to Identify the Types of Cracks on External Walls?

There are two types of cracks that can appear on the walls of your building – these are classed as either vertical or stepped.

Vertical Cracks

When there is a lack of support from the foundation below the building then this when vertical cracks can occur. The reason vertical cracks appear is that the earth underneath the building is not properly compacted or compressed.

Stepped Cracks

Most commonly found in the corners of the buildings and mortar joints, stepped cracks are caused by the foundations of the property moving or as a result of leaks.

How to Know Which Types of Cracks in My Building Are a Cause for Concern?

Now you know why cracks appear at a property, we can now explain which types of cracks in a property are a cause for concern. Cracks in walls can vary in length and width. When you are having problems with larger cracks then it is always best to contact a fully qualified structural engineer to provide a full inspection at the property.

There are categories used by the BRE Group that describe the size and severity of the structural damage which are listed below:

  • Hairline and fine cracks are below 1mm and require little or no action. Any hairline and fine cracks can be easily treated by any form of redecorating.
  • Cracks that are between 1 to 5mm may not be clearly visible but may require some repointing to ensure there is no further damage.
  • If the cracks are between 5 to 15 mm this will require some professional work with some mason repair and the external repointing of brickwork.
  • When the cracks are between 15 to 25 mm in width these could be signs of structural damage and should require a qualified structural engineer to replace the sections of the walls that are supporting the doors and windows above.
  • If the wall cracks are above 25mm then there is severe structural damage to the building and it will require major repairs. This could involve partial or complete rebuilding.

No matter whether the cracks in the walls are small or large it is always best to seek professional help from a fully qualified structural engineer. The earlier the structural problem is found and action is taken, the less damage will be caused and the less the cost will be to repair the problem.

Contacting One of Our Surveyors

We hope this article has given you an insight into the reason why cracks occur, the types of cracks and which are a cause for concern. If you are looking to understand how wall cracks can be repaired then check out our how to repair cracks in walls page. If would like to contact one of our highly experienced surveyors at Timberwise instead then simply call us on 0800 288 8660 or contact us online.