Step 2 - Porous Bedding

The guideline is 3mm-6mm aggregate with 250 Kg of cement per cubic metre.

The advantages of this rigid laying course are:-

Connected void spaces allow free drainage of any excess water.

The porous laying course fills the top layer of the porous base. This provides a strong join between the layers that resists shear forces and allows the layers to act as one.

There is no requirement for material surcharge of the porous laying course. Once stone elements are laid onto the porous laying course there is no requirement to “compact” the stone elements into the porous laying course. This reduces the risk of the laying course partially filling the joints (this happens with any method that compacts the stone elements into the laying course). This leaves the full height of the joint available for the mortar material.