What Causes Wall Cracking in Adelaide Homes?

Wall cracking is a common issue in Adelaide and Australian homes, affecting both newly built and older properties. While some cracks are minor and develop naturally, others can indicate serious structural problems. This article explores the key causes of wall cracking, including foundation movement, soil reactivity, drought conditions, and external environmental factors.

Causes of Wall Cracking

Foundation Movement

Foundation movement is one of the leading causes of wall cracking in homes. As moisture levels in the soil change, expansion and contraction occur, resulting in shifts in the foundation. Even after a home is built, the soil beneath it continues to settle, sometimes unevenly, causing structural stress and the formation of cracks. In some cases, sandy soils erode over time, further weakening the foundation and leading to instability. Additionally, tree roots growing beneath the footings of a home can disturb the surrounding soil and foundation, exacerbating the risk of cracking.

Effects of Reactive Soil

Reactive clay soils are a major contributor to wall cracking in Australia, particularly in masonry buildings. These soils can extend deep beneath structures, increasing their impact on foundation stability. The key issue with reactive soils is their tendency to shrink when dry and swell when wet, causing foundation movement. This repeated cycle of shrinkage and expansion results in the foundation being lifted and lowered unpredictably, placing strain on the structure and causing cracks to develop over time.

Drought and Moisture Fluctuations

Drought conditions significantly contribute to wall cracking by drying out clay-heavy subsoils, causing them to shrink. When a building is supported on shrinking clay soil, it settles unevenly, creating structural stress. This uneven settlement frequently leads to cracks in brickwork and stonework. Such cracks are commonly found around windows and doors due to the additional stress placed on these areas.

Other External Causes of Cracking

Vibrations from external sources such as heavy traffic or construction, can also cause stress fractures in masonry buildings. Underground movements, including mine subsidence and tunneling, can shift the foundation, leading to cracking. Additionally, water infiltration plays a crucial role in destabilising footings—whether due to stormwater accumulation or broken service pipes.

Conclusion

Wall cracking can result from a variety of factors, including foundation movement, soil reactivity, drought conditions, and environmental stressors. Identifying the cause of cracking is essential to determine whether intervention is needed. Homeowners should monitor cracks over time and seek professional advice if they worsen. Understanding these causes helps in implementing preventive measures to protect homes from long-term damage.