Build a Patio or Driveway

A patio or driveway is a sandwich, and the filling matters more than the bread. The surface you see — pavers, slabs or poured concrete — is only the top 50–60 mm (2–2.4 in). Everything beneath it, from the compacted sub-base to the bedding layer to the edge restraint, is what stops the surface settling, rutting and puddling a few years later. Get the base right and almost any surface lasts; get it wrong and nothing does.

This hub puts the whole job in one sequence: plan the area and its fall, excavate to the right depth, total the sub-base in tonnes and the bedding sand in cubic metres, then count pavers with waste and finish the joints. Driveways follow the same steps with heavier numbers — typically more sub-base depth, and a surface rated for vehicle loads rather than foot traffic. If you'd rather pour a slab than lay units, the concrete calculator covers that route too.

The typical figures here — fall rates, bedding depth, sub-base thickness — are common trade practice, not universal rules. Ground conditions and local standards vary, so treat them as starting points and adjust to what the spade tells you.

1. Set out the area and the fall. Fix the size and shape with string lines and check it against the house, boundaries and doors. Water has to go somewhere: a typical fall is 1–2% (a 10–20 mm drop per metre) away from the building toward a drain or a garden edge.
2. Excavate. Dig to the finished level minus the whole build-up — surface, bedding and sub-base — typically around 200–300 mm (8–12 in) down for a patio, more for a driveway. Keep the bottom of the dig firm; over-digging loose soil that then gets backfilled is a classic cause of settling.
3. Lay and compact the sub-base. Crushed stone, compacted in layers. A typical compacted thickness is 100 mm (4 in) under patios and 150 mm (6 in) or more under driveways, but it varies with soil and load — the gravel guide covers the reasoning.
4. Spread the bedding layer. Sharp sand screeded to a typical 25–40 mm (1–1.6 in) for pavers; concrete slabs are more often laid on a full mortar bed. The paver calculator adds compaction allowance to the sand volume.
5. Lay the surface. Pavers in your chosen pattern, slabs on mortar, or a poured slab with its thickness chosen by use. Cuts fall at edges and obstacles — straight patterns typically waste 10%, diagonals and herringbone more.
6. Fill the joints. Kiln-dried sand brushed into paver joints and compacted in; mortar joints for slabs. Jointing is what locks a flexible pavement together — skip it and edges creep.
7. Edge and finish. An edge restraint stops the surface spreading under load; beds and borders around the paving get mulched, which is where the mulch calculator earns its place on a paving page.