Block paving, patios and surface-water runoff
How sub-bases, falls, joints, thresholds and drainage affect durable paving.
This is general information, not a survey, design, legal or Building Control decision. The correct scope and standard depend on the property, work, date and regulatory route.
A paved area needs a stable, properly compacted sub-base suited to the ground and expected loading. Falls should direct water to an appropriate drainage point without sending runoff onto a neighbour, highway or building; paving levels also need to preserve damp-proof courses and thresholds.
Block paving relies on edge restraint, compatible bedding, jointing material and compaction. Slabs need a suitable full-bed or system specified for their format and substrate, not isolated dabs that create voids. Existing tree roots, clay, made ground and utility covers can change the design.
Where infiltration is proposed, check soil, groundwater, pollution risk and local requirements. A channel drain is not useful if its outlet is unconnected or inaccessible. Confirm the drainage route before covering it.