The Concrete Dried Unevenly
When concrete slab foundations are first being installed for newly built homes, the concrete has to be mixed and set properly in order to ensure that the foundation is as strong as possible. After a few hours of drying time, when the concrete is in its plastic state, meaning it is still wet and able to be molded, the foundation may develop cracks due to losing too much water near the surface of the concrete while the concrete further below the surface is more moist. These types of cracks are called plastic shrinkage cracks, and they commonly occur as a result of hot, dry and windy weather conditions. Plastic shrinkage cracks are usually aesthetic and rarely require repairs.
The Concrete Dried Too Quickly
While drying quickly sounds beneficial, it sometimes causes large branching collections of cracks known as crazing cracks. Like plastic shrinkage cracks, these marks are mostly just aesthetic and usually don’t pose any structural threat. However, they are bigger eyesores than most plastic shrinkage cracks since they cover more area and branch out all over the surface. Luckily, they are easily repaired.
Too Much Water in the Concrete Mixture
Drying shrinkage cracks form when concrete with too much water dries. Typically, workers will be able to notice these cracks as they’re occurring during a regular foundation inspection and stop them by decreasing the amount of water and increasing the amount of aggregate in the mix. Drying shrinkage cracks, like plastic shrinkage and crazing cracks, are almost always purely aesthetic issues that are easily repaired.
Pressure After Setting
After a concrete foundation has set, it’s very common for pressure cracks to develop as a result of heavy equipment driving over the concrete or large building materials being placed on the foundation. These cracks are known as pressure cracks. While pressure cracks are more concerning than the previously mentioned cracks, they still usually aren’t dangerous and are fixed easily.
If the land isn’t properly prepared or water has infiltrated the underlying and surrounding area due to heavy rain and melting snow, your foundation is at risk of ice damage. Most concrete slab foundations are mixed with special additives that will prevent cracks from forming due to cold conditions, but poorly mixed concrete or concrete that hasn’t properly set yet will react poorly to intense cold and ice buildup in the soil, causing cracks. Additionally, frost heaves in the soil may push the concrete or create gaps underneath the foundation that will also cause cracks. Severity of ice cracks varies widely depending on weather conditions and location. Some cracks caused by ice are small and aesthetic while others are very large and require professional repairs as soon as possible.
Older houses with trees nearby run a significant risk of developing heaving cracks, which are caused by tree roots pushing on the foundation as they grow. As the roots pull moisture from the soil, they may also pull the foundation down, which will also cause cracking. It takes a long time for heaving cracks to develop, but they can quickly get severe once they start. Cracking caused by tree roots is one of the more complicated slab foundation problems since it requires repairing the foundation, getting the roots away from the home and fixing the soil, but it’s very manageable if caught early.
Foundations are always settling as the ground beneath them changes. Whether it’s due to pockets of air, water or even earthquakes, your foundation will need to adjust. Most foundations have no problem adjusting, but more drastic cases of shifting cause cracks. Settlement cracks are very concerning since they frequently indicate that a weakening foundation is sitting on potentially unstable soil. These cracks need to be seen by a professional as soon as possible.
No matter the cause or if the cracks are aesthetic or potentially hazardous, you can contact Centex Foundation Repair to fix the problem as professionally and quickly as possible. They will provide you with a full estimate on your slab foundation repair costs, give you plenty of options for financing and even offer you a lifetime warranty on the repairs.