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Sinking or Uneven Concrete Driveway
in Nashville, TN
Concrete driveways sink when the ground underneath them stops supporting them. Nashville's clay-heavy soil shrinks during dry summers and swells after rain, and that movement works the soil out from under slabs over time. A sunken slab near your garage or foundation is also a drainage problem — it channels water straight toward your house.
Quick Answer
Concrete driveway slabs sink when the soil underneath them washes away or compresses. In Nashville, heavy rains wash clay and fill soil out from under slabs, and older driveways poured on uncompacted fill just slowly sink. The fix is either mudjacking — pumping material under the slab to lift it — or replacing the slab entirely if it's cracked through. Sunken slabs near your house direct water toward your foundation, so it's worth fixing sooner.
Telltale Signs
Warning Signs to Watch For
- One or more driveway sections sitting lower than the ones next to them
- A lip or edge you can stub your toe on between two sections
- Water pooling on the driveway surface instead of running off to the side
- Cracks running across or through individual driveway sections
- A hollow sound when you walk on a section — like it's not touching the ground below
- Soil or sand washing out from under the slab edge after heavy rain
Root Causes
What Causes Sinking or Uneven Concrete Driveway?
Soil Washout Under Slab
Nashville gets heavy rain events throughout the year, and water finds its way under concrete slabs through cracks and edges. It carries fine soil particles with it as it drains away. Over several years, a void forms under the slab and the concrete drops into it.
The Fix
Mudjacking or Slab Lifting
Mudjacking means drilling small holes in the slab and pumping a cement-and-soil slurry underneath to fill the void and push the slab back up. It's less disruptive than tearing out and repaving.
Poor Compaction at Original Pour
Many driveways in Nashville subdivisions built in the 1990s and early 2000s were poured over fill dirt that was never properly packed down. That fill slowly compresses under the weight of the concrete and vehicles over time. The slab sinks gradually and evenly at first, then unevenly as weak spots collapse.
The Fix
Slab Removal and Base Replacement
The old slab is broken out, the base is excavated and replaced with properly compacted gravel, and new concrete is poured. This fixes the root cause rather than just lifting what's already there.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Soil Washout Under Slab | Poor Compaction at Original Pour |
|---|---|---|
| Hollow sound when you tap or walk on the slab | ||
| Multiple sections sinking at different rates | ||
| Soil visibly washing out from under the slab edge after rain | ||
| Slab settled evenly in one large section, not cracked through | ||
| Water pooling near the garage door or house foundation |
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