The causes of building cracks and how to fix it

If a system is unable to accommodate this movement, cracking is possible. The presence of distortions and cracks can be visually unappealing and upsetting to inhabitants, and they can affect the structure's integrity, protection, and stability if left untreated. Understanding the causes of building cracks is the first step toward effective care. And then a building repair plan be put in place.

Causes of cracks

The most common causes of cracking are:

• Ground movement (beneath foundations) caused by clay shrinkage, landslip, vibration, subsidence, settlement, heave, sway, and so on.

• Foundation failure due to the decay of soft clay brick, concrete erosion due to chemical contaminants, and so on.

• The decay of the building fabric, due to woodworm, rust, and so on.

• Moisture movement that causes materials to expand or contract, perhaps due to the presence of vegetation or faulty or damaged drains.

• The thermal movement that causes materials to expand or contract as temperature increases or decreases.

• Inherent defects, particularly in historic structures.

• Faulty or damaged drains.

• Suspended structures such as floors that deform under load.

• Tree root growth.

• Absence of foundations in older buildings.

Cracks' shapes

• Hairline cracks are common in many buildings, particularly plaster, which is prone to shrinking and is sensitive to movement.

• Stepped cracks in buildings appear to follow the lines of horizontal and vertical joints, such as mortar beds between bricks or blocks, and can signify structural movement.

• Vertical cracks may signify the failure of structural components such as bricks or blocks, as well as significant stresses inside the building structure.

• Cracks that are wider at the top or bottom may indicate foundation movement, with the direction of the widening suggesting the movement's likely course.

• Horizontal cracks may mean that a structural feature, such as a wall, is failing, posing a safety risk.