Adjustment depth
Rebuilding beyond 75 mm typically adds £80–£180 for each additional 100 mm of depth.
Replacement ironwork
A new compliant frame and cover generally adds £350–£800 depending on loading class, size and specification.
Traffic management
Dedicated lane closures, permits and temporary controls can add £750–£2,500 per visit or increase the unit rate by 20–60%.
Rapid-set materials
Proprietary bedding and reinstatement systems typically add £50–£120 each but reduce closure time and return visits.
Working hours
Night, weekend or restricted-hour operations commonly increase labour and plant allowances by 25–50%.
Small quantities
Isolated adjustments can attract a 15–35% premium because mobilisation, cutting equipment and supervision are spread across fewer items.