Why is my driveway sinking? 7 common causes
If your driveway slabs are dropping or sloping toward your garage, one of these seven culprits is almost always the reason.
1. Soil washout under the slab
Water from gutters, downspouts, and irrigation slowly washes fine soil out from under your concrete, leaving voids the slab eventually drops into.
2. Poor original sub-base compaction
If the gravel and soil weren't properly compacted when the driveway was poured, the slab will settle naturally over years.
3. Freeze-thaw cycles
In Canada, soil expands when frozen and contracts when thawed. Repeat cycles compact the sub-base and cause uneven settlement.
4. Plumbing leaks
Hidden water service or sewer leaks under the driveway saturate and erode the supporting soil — sometimes dramatically.
5. Tree roots
Large nearby trees pull moisture from clay soils and physically push slabs upward, causing heaving and cracking.
6. Heavy load damage
Repeated parking of trucks, RVs, or trailers on a slab not designed for the weight accelerates settlement.
7. Backfilled trenches
Driveways poured over recently backfilled utility trenches almost always settle as the trench fill compacts.
The fix: polyjacking
For all seven causes, the fix is the same: fill the voids and lift the slab back to level. Polyjacking does this in hours using polyurethane foam — no demolition, no replacement.