When is an edge restraint needed for paving or paths?
An edge restraint is needed to prevent lateral movement at the free edges of an area laid on an unbound sub-base.
An edging kerb, also known as a kerbstone or edging stone, provides this restraint. It is particularly relevant for block paving, paving slabs and rubber paving tiles with interlocking connectors. Existing firm boundaries can also provide lateral restraint.
The edge restraint forms the lateral abutment for the surfacing. It absorbs horizontal forces arising from use and movements caused by temperature changes. This keeps the outer blocks or tiles in their intended position, stabilises the joint pattern and prevents movement at the edges.
No additional edge restraint is required where the surfacing is already permanently bounded by an adjoining concrete area, a wall or a fixed building edge.
Independently of its structural function, an edging kerb can provide a clean separation between paths or surfaced areas and grass, garden beds or sand areas. Typical applications include garden-bed edging and the perimeter of beach volleyball courts.
The edging kerb is installed upright on a concrete bed and secured laterally with a concrete haunch. Approximately 65% of its height is below finished ground level. A load-bearing, adequately drained substrate that is not susceptible to frost is required for a permanently stable edge.
Flexible edging kerbs are suitable for both straight and curved edges.