What is haunching?
Haunching is concrete or mortar placed against the rear face of a kerb or channel to provide lateral support and prevent movement or subsidence.
In paving work, haunching refers to the concrete base or mortar bed applied to the back face of edge kerbs and channels. It sits along the length of the kerb and provides the structural support needed to keep it upright and firmly in place against the forces of traffic, ground settling, and weather exposure.
A well-executed haunching prevents kerbs from tilting, shifting sideways, or sinking unevenly into the surrounding ground. Without it, even properly bedded kerbs can move over time, breaking the straight line of a paving scheme and creating uneven surfaces that trap water or become a trip hazard. Haunching is particularly important in areas with heavy foot or vehicle traffic, or where water drainage is critical.
The material and method vary depending on the kerb type and the substrate beneath. Most haunching uses concrete mixed to a firm consistency, applied in one continuous run along the entire back of the kerb. Some installations use bedding mortar instead, though this is less common for permanent outdoor work. The depth and profile of the haunch must match the kerb dimensions and load conditions to be effective.
Contractors in Cheltenham carrying out block paving, concrete, or natural stone work will include haunching as a standard step in kerb installation to ensure the finished scheme stays level and functional.