A sunken driveway track, low patio corner, or rocking walkway paver is easy to see. The cause is often below or beside the visible surface. Resetting pavers without understanding that cause can leave the same area vulnerable to movement.
The pavers are only the finish layer
Interlock performance depends on the soil, compacted granular base, bedding layer, edge restraint, jointing material, surface slope, and water path. When one layer loses support, the pavers follow it.
Common reasons interlock settles
Insufficient or poorly compacted base
A base that is too thin for the expected load or compacted in overly deep lifts can continue compressing after installation. Vehicle wheel paths often reveal this weakness first.
Water entering the base
Runoff from downspouts, neighbouring grades, melting snow, or poorly drained surfaces can move fine material or keep the base saturated. Freeze-thaw cycles can amplify the movement.
Failed edge restraint
When edges spread, paver joints can open and the field can migrate. This is common near unsupported driveway borders, garden edges, or areas repeatedly crossed by vehicles.
Disturbed soil and utility trenches
Backfilled trenches and recently disturbed areas may settle differently than undisturbed ground. A repair should consider whether the failure follows a known trench, service line, or excavation.
What a repair assessment should review
- The size and pattern of settlement
- Surface drainage and nearby downspouts
- Edge condition and paver movement
- Expected vehicle or pedestrian loads
- Cracked, stained, or reusable pavers
- Transitions to garages, steps, walls, and drains
Suitable repairs may involve lifting reusable pavers, excavating the failed area, rebuilding and compacting support, correcting edges or elevations, and reinstalling the field. Widespread base failure or a desired layout change may make replacement more practical.
Do not hide a drainage problem under new sand
Joint sand is part of a paver system, but it cannot rebuild a failed base. If a low area collects water or repeatedly sinks, investigate the water source and outlet as part of the repair plan.
A lasting interlock repair should respond to the reason the surface moved, not only the shape of the depression.