Porcelain Paving Thickness: 16mm vs 20mm vs 30mm

Outdoor porcelain paving in the UK is 20mm thick as standard. That thickness, laid on a full mortar bed over a compacted MOT Type 1 sub-base, covers every normal domestic use: patios, paths, steps, dining areas and pool surrounds. Pave Direct's outdoor ranges — including Kandla Grey — are supplied at 20mm calibrated.

The three thicknesses at a glance

• 16mm — light-duty pedestrian slabs: balconies, weight-sensitive terraces, small patios on a flawless full bed or a rated pedestal system. Lighter and slightly cheaper, but zero tolerance for bedding voids and never for vehicles.
• 20mm — the industry standard: all pedestrian garden applications, and the thickness pedestal/raised-deck systems are designed around.
• 30mm — heavy-duty: driveways, vehicle crossings and commercial loads on an engineered base.

Driveways: the one decision that matters

Two accepted build-ups exist: 30mm porcelain on a substantial compacted sub-base, or 20mm porcelain fully bonded to a reinforced concrete slab that does the structural work. Standard 20mm on a mortar bed alone is a pedestrian specification. Decide the build-up before ordering slabs — see the full thickness guide and driveway options.

Thickness is only half the specification

Porcelain fails in bending over voids, not in compression — so a 20mm slab on a full, primed mortar bed outperforms a thicker slab spot-bonded over hollows. Full bed plus priming slurry is non-negotiable at any thickness (laying method; bonding systems).

Indoor tiles are not thin outdoor tiles

Indoor porcelain floor tiles run 8–11mm and are not rated for frost exposure, ground bedding or outdoor point loads. Any "outdoor" slab under 16mm deserves suspicion.