Porcelain Tiles — Specification, Types and Supply
Porcelain is not a look, it is a measurement: a tile fired from a dense clay body until its water absorption falls below 0.5 per cent. Everything people associate with porcelain — the strength, the frost resistance, the ability to use the same tile indoors and out — follows from that one number.
- Water absorption below 0.5% — the defining threshold
- Frost resistant, so the same tile works indoors and outdoors
- Produced as full body, double charged, GVT and PGVT
Porcelain against ordinary ceramic
Both start as clay and both are fired, but the recipe and the temperature differ. Porcelain uses a finer, denser clay with a higher feldspar content and is fired hotter and longer. The result is a body that has largely vitrified — the particles have fused into something closer to glass than to fired earth.
A standard wall-grade ceramic tile absorbs somewhere between 3 and 10 per cent of its weight in water. Porcelain absorbs less than 0.5 per cent. That gap explains almost every practical difference between the two. Water cannot get far enough into a porcelain tile to freeze and split it, so porcelain can be laid outdoors in climates where ceramic would fail in the first cold season. Stains cannot soak in. The density also makes the tile far harder, which is what allows it to be used on floors carrying real traffic rather than only on walls.
The cost of that density is workability. Porcelain is harder to cut and drill, needs a diamond blade rather than a scoring wheel, and is heavier per square metre. For a wall in a dry room, a good ceramic tile is cheaper, lighter and easier to fit, and there is no benefit in specifying porcelain. For any floor, any wet area and anything outdoors, porcelain is the correct specification.
Porcelain and ceramic compared
| Property | Porcelain | Ceramic |
|---|---|---|
| Water absorption | Under 0.5% | 3-10% |
| Firing temperature | 1200-1300 degrees C | 1000-1150 degrees C |
| Frost resistant | Yes | No |
| Suitable outdoors | Yes | No |
| Floor traffic | Light to very heavy | Light domestic only |
| Cutting | Diamond blade required | Score and snap |
| Relative cost | Higher | Lower |
The four porcelain types we manufacture
All four have the same dense body. What separates them is how the visible surface is created — and that determines both the price and how much traffic the tile will take.
Full Body Porcelain
Heaviest duty
Pigment blended through the entire body. Nothing to wear through, edges can be ground on site, and chips stay invisible. Solid and speckled colours.
Full Body Porcelain ›Double Charged
Heavy duty, better value
A 3-4 mm decorative layer pressed onto the base in the same press stroke. Far deeper than a glaze, and considerably cheaper than full body.
Double Charged ›GVT — Glazed Vitrified
Design-led, matt
Digital print under a matt or textured glaze. The full marble, wood and stone design range, with usable slip resistance.
GVT — Glazed Vitrified ›PGVT — Polished Glazed
Design-led, gloss
The same printed body, polished to a high gloss. Brightest finish available; not for wet or external floors.
PGVT — Polished Glazed ›Reading a porcelain tile specification
- Water absorption — below 0.5 per cent is the porcelain threshold. If a supplier will not quote this figure, the tile is probably not porcelain.
- Breaking strength — quoted in newtons; above 1300 N is normal for a floor-grade porcelain and is what matters over an imperfectly flat screed.
- PEI rating — surface abrasion resistance from I to V. PEI III suits domestic floors, PEI IV and V commercial.
- R rating — wet slip resistance. R9 is an interior dry floor, R10 a kitchen or bathroom, R11 external steps and wet areas.
- Rectified — the tile has been ground to an exact size after firing, allowing grout joints of 2 mm or less.
- Shade and calibre — the batch codes printed on the carton. Tiles from different batches vary; always order a whole job in one shade and calibre.
Frequently asked questions
What makes a tile porcelain rather than ceramic?
Water absorption below 0.5 per cent, achieved by firing a denser clay body at a higher temperature. That single property is what gives porcelain its frost resistance, stain resistance and floor-grade hardness.
Is vitrified the same as porcelain?
In practice, yes. Vitrified is the term used across India, the Middle East and much of Africa for a tile with a dense, glass-like fired body — which is the same thing the European market calls porcelain. Full body, double charged, GVT and PGVT are all vitrified porcelain types.
Can porcelain tiles be used on walls?
Yes, and large-format porcelain on a wall looks excellent. Bear in mind the weight: a large porcelain tile on a wall needs a suitable adhesive and a sound substrate, and on plasterboard the fixing has to be designed for it.
Do porcelain tiles need sealing?
Glazed and unpolished porcelain does not — the body is too dense to absorb anything. Polished porcelain is the exception: polishing opens fine surface pores, and a sealer is worth applying before grouting to keep pigment out of them.
Which porcelain type is best value for a domestic house?
GVT for most rooms. The design range is far wider, the price is lower, and domestic traffic will never wear the surface. Keep full body for the staircase and any external terrace.
Talk to a porcelain tile manufacturer directly
We press and fire in Morbi, so there is no trading layer between you and the kiln. Send your specification and we will quote against it.
Browse the full range
Buying Guides
- Tile Buying Guide
- Full Body vs GVT Tiles
- Step & Riser Tiles Guide
- GVT vs PGVT
- Tile Size Guide
- Laminate Guide
- Porcelain vs Ceramic Tiles
- What Are Vitrified Tiles
- Types of Tiles
- Tile Thickness Guide
- Glossy vs Matte Tiles
- How to Clean Tile Floors
- How to Remove Tile Stains
- How to Fix Cracked Tiles
- How to Clean Marble Floors
- Bathroom Size Guide
- Powder Room Guide