Additional Laying Requirements

Drainage

All types of paver installation need effective drainage for surface water. To achieve a satisfactory run off it is recommended that longitudinal gradients should not be less than 1 : 100, and that cross falls should be approximately 1 : 40.

For large areas of pavements it may be necessary to include drainage provision within the pavement itself. Ketley provide drainage units which are compatible with standard metal gully outlets.

Flexible pavements may allow water to penetrate the surface and therefore consideration should be given to drainage of the underlying formation. Drainage of the bedding course can be achieved by sub-base drains which should be laid at the low points below the level of the sub-base using perforated or open joint pipes. A free draining geotextile should be used to prevent the loss of bedding sand..

Access Cover

The siting of inspection covers is important to preserve the aesthetics of a paved area.Covers must be sited with some care, located within an area of paving and aligned with the pattern. They should not straddle different colours or patterns.

Recessed covers inserted with matching pavers are desirable as they are less intrusive although it is likely that pavers will need to be cut to fit. In rigid paved areas movement joints should be provided around covers.

Gradients

As a general guide, flexible pavements can be laid to a maximum slope of 1 in 10. For steeper gradients rigid paving should be used. Paver laying should always commence at the bottom of the gradient and provision for bedding course drainage should be made at this point. For gradients in excess of 1 : 20 consideration should be given to the use of an acrylicpre polymer to prevent the wash out of jointing sand. It may be necessary to break up flexible paving into shorter lengths, say 10m on slopes with the use of rigid restraints, in order to prevent the creeping action of pavers and sand down the slope.

Steps

Riser height of steps is usually between 100 - 175mm. Each step should feature a fall to the nose - approx. 6mm to clear surface water. Experience suggests that the square edges of standard bricks are vulnerable to damage and that large radius bulinose bricks are not recommended from a safety viewpoint. Therefore the Ketley specials range includes a tight radius nosing as a special feature for steps.

Post Laying Care

In the immediate period following paver laying it is usual for there to be settlement of sand within the joints. The site needs to be monitored and further sand should be brushed in as a "top-up" to the joints. Vacuum road sweepers should not be used during the early life of the pavement as they will remove the jointing sand.

In situations where an excessive amount of grime and dirt has built up, occasional steam cleaning should be carried out. Jointing sand levels should be checked after this operation and replaced as required, Pavements in damp areas such as beneath trees and in permanent shade may develop unwanted weed or moss growth. A proprietary weedkiller should be used which will have no detrimental effect on the pavers.