Choose slab thickness by use. Around 6 mm suits walls, furniture and overlays; 9 mm is the most common Morbi thickness for floors and walls; 12 mm and 15 mm suit worktops and heavier loads.
Thicker is not always better. A thicker slab is stronger but heavier, harder to fit and costs more to ship. The right choice is the thinnest slab that meets the job and the installer's method.
What each thickness is used for
- 6 mm slabs are light and easy to bend slightly during fitting. They suit walls, shower panels, doors, furniture and laying over existing tiles. Many 6 mm slabs carry a mesh or fibre backing for strength.
- 9 mm slabs are the everyday thickness from many Morbi slab lines. They suit interior floors and walls in homes and light commercial spaces.
- 12 mm slabs are a common choice for kitchen worktops, vanity tops and table tops, where the slab spans small gaps.
- 15 mm slabs give more strength for worktops with overhangs, heavier commercial floors and some outdoor uses. Some plants also offer 18 or 20 mm.
What Morbi plants offer
As of October 2026, Morbi listings most often show 9 mm, with 6, 12 and 15 mm offered by some plants. Not every size is made in every thickness, so ask for the matrix of sizes and thicknesses each plant makes on its own lines.
How standards treat thin slabs
In the US, ANSI A137.3 covers gauged porcelain tiles and panels or slabs. It defines two thickness classes: 3.5 to 4.9 mm for walls only, and 5.0 to 6.5 mm for floors and walls. It also sets minimum properties and thickness accuracy for those products.
Slabs thicker than that are generally assessed as porcelain tile under ANSI A137.1 in the US and EN 14411 in Europe. The key tests are the same: water absorption, breaking strength and flatness. Our guide on what makes a tile vitrified explains the absorption limit.
Thickness and strength
Breaking strength, measured to ISO 10545-4, rises sharply with thickness. That is why worktops use thicker slabs. The material's bending strength per unit thickness stays similar, but a thicker panel carries far more load before it breaks.
For worktops, the fabrication plan matters as much as thickness. Overhangs, sink cut-outs and joints all need support. Our guide on porcelain slab kitchen worktops covers this.
Thickness and weight
Porcelain weighs roughly 2.3 to 2.5 kg per square metre for each millimetre of thickness. A 9 mm slab is therefore around 21 to 22 kg per square metre, and a 15 mm slab around 35 to 37 kg.
That weight decides how many slabs fit in a container, how many people the fitter needs, and whether a wall can carry the load. Ask the factory for the actual weight per slab and per crate, because body mix and backing differ.
What to put in your order
- State the nominal thickness and the allowed tolerance in millimetres.
- State whether the slab has a mesh or fibre backing.
- Ask for a test report for the exact thickness you are buying, not a thicker product in the same design.
- Ask for the weight per slab and per crate for the loading plan.
Next step
We check thickness on samples and again at loading, and make sure test reports match the product you buy. To choose thicknesses for your range, book a free sourcing review.