How do I lay patio tiles and paving blocks on soil?

Patio tiles must not be laid directly on natural ground or made-up ground. Path slabs must not be laid directly on natural ground or made-up ground. Paving blocks must not be laid directly on natural ground or made-up ground. Patio tiles, path slabs and paving blocks all require a laying course.

Topsoil does not provide sufficient bearing capacity. Cohesive soil is susceptible to frost heave, and tiles laid on it can settle or be lifted unevenly. Paving blocks laid on it can also settle or be lifted unevenly. This applies to both natural ground and made-up ground.

Remove the topsoil, trim the substrate to formation level and compact it. Any fill must be placed and compacted in layers. The required thickness of the sub-base depends on the intended use, soil type and frost exposure at the site. A garden path carries less load than a driveway, and the sub-base is made thicker on clay soil than on sandy soil. For protection against frost, the total construction depth from the surface to formation level is decisive.

Rubber tiles are not normally laid on loose sand, chippings or gravel. They are generally laid on a supporting layer of plastic honeycomb grids, sold as gravel grids, grass grids or gravel honeycombs. Gravel grids should be filled with chippings to their top edge and levelled off.

Where the ground has sufficient bearing capacity and loads are low, the gravel honeycombs can be laid on a carefully prepared formation with a smooth, level laying course of chippings 2 to 5 cm thick. The same applies where the ground is not susceptible to frost and loads are low. On unfavourable ground or where loads are high, a crushed stone sub-base is added beneath the laying course and compacted in layers.

Paving blocks with interlocking connectors require edge restraint, as do rubber tiles with interlocking connectors.