Jointing and compacting a block driveway

Why is kiln dried sand used for jointing?

It is dry and finely graded, so it falls straight down into 2-3mm joints instead of bridging them. Damp building sand clumps at the surface and leaves joints half empty, which is where movement and weed growth start.

How many times is the surface compacted?

At least twice. The first pass beds the blocks and drops the sand, then more sand is swept in and a second pass fills what settled. The drive is left with a light covering of sand that traffic and rain work in over the following weeks.

• Plate compactor used with a rubber mat to protect faces
• Surface swept clean of debris before each pass
• Joints topped up until they stop taking sand

Should block paving be sealed?

It is optional. Sealing stabilises joint sand and makes oil marks easier to lift, but it needs redoing every few years. An unsealed drive jointed properly performs perfectly well and is simpler to repair.