What are edge restraints (edging kerbs)?
Edge restraints are fixed kerbs or channels installed around the perimeter of block paved areas to contain the blocks and prevent outward movement.
When block paving is laid, the individual blocks naturally want to move and shift outward under load and seasonal changes. Edge restraints stop this spreading by creating a fixed boundary around the perimeter of the paved surface.
These are typically L-shaped or channel-profile kerbs set into a concrete foundation. The restraint sits flush with or slightly proud of the paving, anchoring the outer row of blocks and transferring lateral pressure down into the sub-base rather than allowing the blocks to migrate outward.
Common materials include concrete kerbs, which are durable and cost-effective for most applications, and concrete channels designed to grip the edges of blocks. Some installations use timber or metal edging for aesthetic effect, though concrete remains the standard in Cheltenham driveways and patios.
Proper edge restraint installation is essential for long-term performance. Without it, the paved surface develops an unstable perimeter where blocks tilt, settle unevenly, or cup. Water seeps into gaps, accelerating damage. Over time, an unrestrained edge can compromise the entire paved area. Block paving contractors specify edge restraints as part of their structural specification, not an optional extra.
The depth and strength of the restraint should match the anticipated traffic and usage. A domestic driveway requires different edging to a commercial forecourt or public plaza.