What is a laying course?
A laying course is a compacted sand layer placed over a sub-base to receive and bed paving blocks, flags, or setts, allowing them to be levelled and seated properly.
The laying course sits directly beneath your paving blocks or flags, forming a critical interface between the structural sub-base and the finished surface. It is typically a 30-50mm layer of coarse sand or sharp sand, compacted to provide a stable, level foundation for bedding individual units.
This layer matters because it allows paving contractors to achieve accurate surface levels and true planes across large areas. Without it, blocks and flags would sit unevenly on compacted hardcore, creating trip hazards and poor drainage. The sand also absorbs minor variations in the sub-base and acts as a levelling medium, so each unit can be properly seated and tapped down to match its neighbours.
Proper laying course installation requires the sand to be spread evenly, screeded flat, and left loose (not compacted). Contractors then bed each block or flag into it, using a tamper or rubber mallet to press units home to the correct level. Once the surface is complete, polymeric sand or traditional jointing sand is brushed into joints to lock the units together and prevent movement.
Poor laying course work is a common cause of settling, lippage (uneven surfaces), and drainage problems in block and flagged pavements. For paving contractors in Cheltenham, getting this layer right is fundamental to a durable, safe finish.