Why Do I Have Cracked and Sinking Concrete in my Home?

Concrete can start to crack and sink for a number of reasons, and the most likely causes can vary depending on the nature of the structure and where the concrete is located. Internal and external surfaces are likely to have different issues, for example, but both will suffer if there are defects in the cement.

Defects and Flaws 

Both internal and external surfaces can be damaged by flaws in the process of mixing or laying the concrete. The issues with cement formulation and mixing have already been covered, and while too much water or sand are some of the most common causes of defective concrete, there is another possibility that must be considered. 

Concrete takes a long time to properly set and cure, and there is a point at which it is too dry to be remolded but far too wet to be hardened. There are some contractors who use a process called hard troweling to speed the process of compaction. The problem is that this disrupts the concrete and can lead to the uneven distribution of water in the mix. When this happens, it leaves huge fault lines on a concrete surface. This can cause many issues, obviously, but the most common are cracking and sinking. 

Damage 

Of course, concrete can also become cracked, deformed, or sunken as a result of damage. The most common forms of damage are caused by excessive weight or pressure. For example, a driveway that is supporting more weight than it was designed to or a wall that is starting to bow because of excessive hydrostatic pressure from the soil around it. 

Another common cause of damage to concrete surfaces is a lack of support. For example, if the soil under a property is very loose or weak and it starts to shift during periods of heavy rainfall (a process known as soil washout), this can leave voids underneath the property. When this happens, the structure may crack or sink under its own weight.