Streetworks

Kerbs - Purpose
Kerbs are used in heavily trafficked areas to provide extra strength to the edge of the carriageway. They also:

Prevent vegetation encroaching onto the road
Act as a debarkation line between the road and footway
Deter traffic from mounting the footway
Provide a wall to divert water run off into the gullies
Prevent the surfacing materials on the road from spreading under load

Reinstatement
Kerbs or footway edge restraints removed, displaced or damaged during excavation works or otherwise must be replaced at the time of permanent or interim repair. This is required to maintain the structural integrity of the road and adjoining surfaces.

During excavation work care must be taken to prevent unnecessary removal or disturbance of the kerbs. Any concrete bed that is undercut during excavation will be difficult to reinstate and remedial work should be carried out, this may require the removal of any undercut bedding and kerbs.

Care needs to be taken where natural stone kerbs have been used as replacements are expensive and not easily sourced. Damaged natural stone kerbs may be sourced from the local authority if stocks are held for such an eventuality.

Kerbs and edge restraints must be replaced as existing to maintain the appearance of the surface.

Concrete used as bedding or backing must conform to Clause 1602 (Class E). This can be mixed on-site using a 1:3:6 mix ratio.

There are two methods of laying or re-laying kerbs and edge restraints.

Method One - Wet Bed
This method is more suitable for reinstatement purposes. A bed of concrete is laid so that it is 20 - 40mm proud and the kerbs knocked down level with the adjacent line of kerbs. This bed of concrete should be laid on the sub-base. A backing, as existing, is then placed using the same quality concrete as the bed, where paving is to be laid care should be taken to prevent the concrete backing being too high and encroach on the laying of the paving. Once the concrete has set any adjacent works may commence.

Method Two - Dry Bed
A bed of concrete is laid that will allow the kerbs to be laid on a bed of mortar about 15mm thick once the concrete has set. In some situations an epoxy resin may be used in place of mortar. Backing is then laid in the same way as the wet bed method.

The tolerances permitted are + or - 6mm between adjacent kerbs, but in high amenity areas this may be unacceptable. Where ever possible the kerbs should be flush along the top and face of the kerb line.

Any gaps between the kerbs are filled with fine concrete or a mortar mix.

Edge restraint are laid in the same way as kerbs.

Any reinstatement within 250mm of adjacent kerbs of edge restraint must be removed and included within the resurfacing of the pavement.

Any channel blocks or other special feature must be replaced at the time of reinstatement.

The interface between kerbs must be treated with joint sealant prior to resurfacing to prevent the ingress of water.

Highway Ironwork
Any fixed feature such as ironwork must must be reset if disturbed during excavation work or otherwise. If the ironwork has been damaged it should be replaced with a similar type and design. Any ironwork that is disturbed or damaged should be notified to the owners.

Where any reinstatement is within 250mm of any ironwork the area between should be trimmed back to include it at the time of resurfacing.

Care must be taken not to allow any compaction equipment to come into contact with any ironwork during reinstatement as it could dislodge it and break the mortar bed or underlying block work.

The tolerances given on ironwork are + or - 6mm to the adjacent surface, gullies may be up to -15mm. Where the ironwork is within a footway there should be no significant trip that would put pedestrians at risk.