Why Does Concrete Sink?

sidewalk of concrete tiles that are starting to sink and have created a depression

Concrete sinking, also known as slab settlement, is a common issue that occurs when the soil beneath a concrete surface compresses or shifts, causing the concrete to settle unevenly. Several factors contribute to concrete sinking, making driveways, sidewalks, steps and other concrete surfaces unsafe. The following are some of the factors that cause sinking concrete and solutions for correcting this common problem.

Soil Consolidation and Compaction

Over time, the soil beneath concrete can compact due to various reasons like changes in moisture content, soil erosion or natural settlement. This consolidation leads to voids or gaps forming beneath the concrete, causing it to sink into these spaces. Also, improperly compacted soil during the initial installation of the concrete can create weak spots beneath the surface. As the soil settles or shifts, these weak areas can cause the concrete to sink.

Water Erosion

Excessive water from heavy rainfall, improper drainage, or plumbing leaks can erode the soil beneath concrete surfaces. As soil washes away, it creates voids, undermining the support for the concrete, leading to sinking or settling.

Underground Utilities or Excavation

Underground utilities installation or excavation work near concrete surfaces can disrupt the soil, causing settling as the disturbed soil compacts or shifts. Landscaping changes, hardscape installations and changes in underground pipes can all contribute to sinking concrete.

Concrete sinking can result in uneven surfaces, tripping hazards, poor drainage and structural issues. To rectify this problem, concrete leveling techniques are employed. One such method, deep foam injection, is what we use at Advance Concrete Lifting and Leveling due to its effectiveness in restoring level concrete surfaces.

Concrete Leveling with Deep Foam Injections

Deep foam injection, also known as polyurethane foam lifting or foam jacking, involves injecting expanding polyurethane foam into voids or gaps beneath the sunken concrete. This method offers several advantages over traditional techniques:

  • Lightweight and Strong Support: Polyurethane foam is lightweight but incredibly strong. Once injected, it expands to fill voids, compacting loose soil and creating a solid, supportive base for the concrete.
  • Minimal Disruption: Deep foam injection requires small, strategically placed holes drilled into the concrete surface, minimizing disruption to the area. Traditional methods often involve more invasive procedures like mudjacking, which requires larger access holes and more extensive surface disruption.
  • Quick and Efficient: The process of injecting foam and allowing it to expand and cure is relatively fast compared to other methods. The concrete can often be used shortly after the procedure, reducing downtime.
  • Long-lasting Results: The polyurethane foam used in deep foam injection is resistant to moisture and won’t degrade over time. This provides a long-term solution, preventing future sinking or settling issues.

Overall, deep foam injection offers a reliable and efficient solution for addressing concrete sinking and restoring stability, level surfaces, and structural integrity to affected areas with minimal disruption and long-term effectiveness. If you have sinking concrete on your property in the Alpharetta, GA, area, contact our team at Advance Concrete Lifting and Leveling to learn more about deep foam injection.

Posted on Behalf of Advance Concrete Lifting and Leveling