Common Causes
Poor Compaction
If the subgrade was not properly compacted, the slab may settle over time.
Drainage Issues
Water running under the slab can wash fines out of the base.
Soil Movement
Expansive or compressible soils shift with moisture and temperature.
Buried Debris
Backfill over voids or organic material eventually collapses.
What Sinking Concrete Looks Like
- One side of a slab lower than the other
- Water pooling on or beside the concrete
- Cracking along the sunken area
- A step formed at a control joint
Options
Repair depends on how far the slab has moved, the surrounding conditions, and whether the base can be reasonably stabilized. Some situations are best resolved by removal, base correction, and a new pour.
Frequently Asked Questions
Why does concrete sink?+
Sinking concrete almost always traces back to the base under the slab: poor compaction, washout from drainage issues, or soil movement.
Is sinking concrete a safety issue?+
It can be. Trip hazards, drainage problems, and structural offset near foundations should be reviewed rather than ignored.
Request a Concrete Estimate
Call Springfield IL Concrete or submit the estimate form to discuss your project.