Sinking or shifting pavers are almost always caused by improper base preparation or poor drainage. Inadequate excavation or a thin base allows water to penetrate and the sub-grade soil to shift, causing pavers to become uneven.
Interlock repair, often called a "lift and relay," is the professional solution. This involves carefully lifting the uneven stones, re-excavating and rebuilding the unstable base layers, re-installing and leveling the pavers, and sweeping in new polymeric sand to lock everything into place. It's a cost-effective way to restore your surface without full replacement.
