Cause one: inadequate sub-base
If the sub-base was too shallow, poorly graded or compacted in one deep lift rather than layers, it settles under repeated vehicle loading. That shows as dips along the wheel tracks and a low spot where the car sits.
This is the most common cause and the only real fix is to lift the affected area, correct the base and relay. The original blocks are almost always reusable.
Cause two: failed edge restraints
Block paving works by interlock. If the perimeter edging is not properly haunched in concrete, the whole field of blocks slowly creeps outwards, joints widen, and the surface drops.
You can spot it early: widening joints at the edges and blocks that feel loose underfoot near the boundary. Resetting the edging before the field spreads is far cheaper than a full relay.
- Dips in the wheel tracks: sub-base settlement
- Widening joints near edges: edge restraint failure
- Localised hole or hollow: washed-out bedding sand
- Sinking beside a gully or downpipe: water washing the base
Cause three: water washing out the bedding
Where a downpipe discharges onto the paving, or a gully leaks below ground, water travels through the laying course and carries the sand away. A localised hollow appears, sometimes quite suddenly.
Relaying without fixing the water source just recreates the hollow. We always trace the water first.
What the repair involves
Blocks are lifted carefully and set aside, the failed base is excavated and rebuilt with compacted stone, the laying course is re-screeded and the original blocks are relaid, jointed and vibrated.
Because the same blocks go back, the repair blends invisibly — the advantage block paving has over almost every other surface.
Frequently asked questions
Can just the sunken area be fixed?+
Usually yes, provided the rest of the driveway is stable. We assess the whole surface before quoting a localised repair.
Will the repair be visible?+
Rarely. The original blocks are relaid, so colour and weathering match.
How long does a relay take?+
A localised area is often a day or two. A full driveway relay takes longer but is still much quicker than a new installation.
Is it cheaper than a new driveway?+
Significantly, in most cases — which is why we always check whether a relay will do before quoting a replacement.
Got a dip in your driveway?
We will tell you whether it needs a localised relay or something more substantial.