What Causes Cracking in Buildings?

Thermal Movement

• One of the biggest causes of cracks in buildings is temperature changes. All materials shrink and contract with the temperature fluctuations. Inner walls have fewer temperature changes and thus less damage. Daily heating and cooling affects the properties of materials used. Over time, vertical expansion will overpower horizontal expansion breaking the material apart. Eventually all buildings will start to show cracks on exterior wall materials such as concrete, plaster and mortar.

Poor Structural Design

• Buildings are heavy, and ground moves. Accounting for foundation construction, as well as materials and load-bearing stresses, are part of designing a building. The building must be designed to withstand all these factors. All buildings settle into the ground over the years. If the foundation is not solid for its weight, twisting occurs, causing cracks. If the designer fails to take into account load-bearing beams or environmental conditions, the building will crack.

Gases, Liquids and Solids

• Carbon dioxide seeps into the pores of cement, causing shrinkage over time. If the cement was not mixed with the correct percentage of water, it will be more porous. Add in a mixture of soluble sulphates that are in various materials as well as soil, and the concrete will start to deteriorate causing it to crack. The type of cement used needs to be able to withstand these elements.

Reinforcement Issues

• Steel is used in larger buildings to add strength to the structure. The physical and chemical bond between the steel and concrete can break down eventually. Moisture and chemicals penetrate the concrete, causing the steel to rust. This breaks the bond between the concrete and steel. As the building vibrates and moves because of environmental forces, the concrete becomes stressed and cracks.