Image showing cracks in an exterior wall

Cracks in walls

Cracks in walls are more common than you’d think, but not all of them are structurally significant. They tend to be identified in surveys when a property is bought and sold.

What causes cracks in walls?

Cracks are the result of excessive stress in the building material, arising from factors like vertical movement between parts of a building, the effects of heat and cold, poor detailing, deterioration of materials and accidental causes – like a leaking drain. Subsidence (movement caused by changes in the soils below the foundation) is also a common cause. 

Who do I talk to first?

Your insurer. They may ask you to contact a structural engineer to inspect the cracks or they may appoint an engineer to visit and make an assessment.

What sort of work might be required to deal with cracks?

It can be possible to determine the cause and specify remedial work straight away, but often there will need to be a monitoring period to determine if the movement causing the cracks is continuing.

If the movement has stopped and the cause is removed (e.g. a leaking drain is mended), it may be appropriate just to mend the damage.

If the movement is progressing, further investigation may be required and underpinning may have to take place to ensure the building loads are applied on stable sub-soil.

Why is a structural engineer necessary?

Cracks take many forms, but any defect which is cracking bricks (not just the mortar joints) is a cause for concern. If you ignore cracks you risk greater damage.

For instance, a cracked masonry wall will allow water to enter the wall and potentially the building. Once saturated, the masonry may be subjected to cold weather, which could cause the water to freeze, expand, and cause more damage.

Assessing physical stress in materials is a key element of what structural engineers do. A structural engineer can look at the pattern of cracking, the rate at which cracks are widening (or closing) and factors like weather conditions to diagnose the cause and suggest solutions.

What can I expect the structural engineer to provide and/or guarantee?

Following an inspection, the structural engineer should provide a written report setting out clearly their observations, possible causes behind the cracking, and a clear action plan.

The engineer’s initial fee proposal for the survey and report is unlikely to completely resolve the issue, but it should provide a clear way forward and clarity about the severity of the issue.

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