Why Concrete Settles and Sinks?

• Inconsistency of moisture in the soil:

One of the main reasons why concrete settles and sinks is soil expansion and contraction. Soil expands and contracts as the levels of moisture change during the dry and wet seasons causing soil to settle and lose strength over time. This loss of strength allows slabs to sink.

• Frost Heaving:

When melting snow penetrates the soil under a slab and the temperature drops below freezing, the ground expands. When the earth dries out, the soil contracts. Frost heaving can leave sections of a slab unsupported and susceptible to sinking.

• Poor Drainage:

Another reason why concrete settles and sinks is poor drainage. Improper drainage can result in saturated soil allowing concrete to settle.  Something as simple as a misplaced down spout can result in serious consequences.

• Soil Washout:

Plumbing leaks, floods and heavy rainfall can add a large amount of water to the soil in a short amount of time. As the water moves through the earth, the soil supporting a slab can be diminished, causing it to sink.

• Poor Soil Compaction:

Many homes are built on backfilled areas.  If the backfilled soil is not compacted properly prior to building, the area will slowly and unevenly compact over time resulting in concrete settling.

As a result, the sunken concrete creates an uneven surface and dangerous tripping hazard. If you notice any uneven concrete on your sidewalk, driveway, or patio, it’s likely that the soil beneath has become weak and can no longer support its weight.