External 20mm Porcelain Tiles

20 mm porcelain is a structural external paving product rather than a thicker version of an internal tile. The additional depth gives the breaking strength to ISO 10545-4 required for dry laying on pedestals, gravel or grass, which is what makes it the standard solution for podium decks, roof terraces and landscape paving.

Specifying 20mm porcelain

• Laying methods. Adjustable pedestals over waterproofing, on a gravel or grass bed, or fully bonded onto a drained screed. Pedestal systems keep the tile clear of the membrane, allow drainage and services in the void, and permit individual units to be lifted for access.
• Frost and absorption. Confirm frost resistance to ISO 10545-12 and water absorption to ISO 10545-3, with group BIa at 0.5% or less for fully exposed positions.
• Wet slip resistance. External pedestrian surfaces should carry a wet PTV of 36 or above to BS 7976-2, higher on ramps and steps. Grip finishes on 20 mm ranges are produced for exactly this condition.
• Loading. Pedestal-laid paving is rated for pedestrian use. Where vehicle or plant loading is possible, including maintenance access routes, the build-up has to be designed for it rather than assumed.
• Matching internal ranges. Many 20 mm products have an internal-thickness counterpart in the same appearance, which lets a floor line run from an internal space onto a terrace. Confirm the external version has its own test data.

For landscape and terrace applications see garden tiles, and for the full external range see exterior tiles.

Frequently asked questions

Why is 20mm porcelain used outside instead of standard tiles?

Breaking strength. At 20 mm the tile can span between pedestals or bed onto gravel without support across its full face, which standard 8 to 10 mm porcelain cannot do. That enables dry-lay systems and lift-out access over waterproofing.

Can 20mm porcelain be laid on grass or gravel?

Yes. Both are recognised laying methods for 20 mm paving, subject to a compacted, free-draining base and correct edge restraint. A properly prepared sub-base is what prevents settlement and rocking later.

Can 20mm porcelain be driven on?

Not as a pedestrian specification. Vehicle loading requires a designed build-up, normally fully bedded on a suitable base rather than pedestal-laid, and confirmation from the manufacturer for the loading involved.