Porcelain and ceramic tiles: what actually separates the tile types

The question "porcelain or ceramic?" contains a mistake at its root, and that is why the answers found online seem to contradict one another. Porcelain is ceramic. It is not an alternative material but one of the types that make up the ceramic family — the one with the highest technical performance, yet closely related to all the others.

The right question is a different one: within the ceramic family, which types actually exist, what sets them apart, and at what point do those differences start to matter for a real project? That is what this article answers. Not with a list of pros and cons, but through the technical criterion that orders the entire family — water absorption — and through the concrete thresholds beyond which the choice stops being a preference.

What the word "ceramic" actually covers

When a showroom contrasts "ceramic tiles" with porcelain tiles, it is using a shorthand. Technically, ceramic is the name of the family: every material produced by firing clay-based bodies. Within that family sit types made by different processes, with performance levels far apart from one another. Knowing them explains what you are looking at when two tiles appear identical and one costs twice as much.

Glazed wall tiles (porous body)

The most porous type in the range. A pale clay body fired at relatively low temperatures, always glazed. Water absorption typically sits between 10% and 20%. That porosity is not a flaw but a design decision: it keeps the tile light, easy to cut and drill on site, and dimensionally very stable, which allows generous wall formats without flatness problems. This is the standard solution for interior wall tiling — and it never belongs on a floor or outdoors.

Terracotta

The oldest type. A red clay body fired at low temperatures, unglazed in its traditional form. The warm colour comes from the iron content of the clay. It absorbs a great deal of water and needs periodic sealing to resist staining. It remains a choice with character for rustic settings and heritage restoration, but technically it sits at the opposite end of the family from porcelain.

Glazed ceramic floor tiles (dense body)

A denser body than the wall types, fired at higher temperatures, with water absorption generally between 1% and 3%. This makes it suitable for floors as well as walls, and for decades it was the standard tile in European homes. In most cases this is the "ceramic" people have in mind when they set it against porcelain.

Extruded tiles and klinker

Formed by extrusion rather than pressing, fired at high temperatures, with low absorption and good frost resistance. Historically used for stairs, outdoor areas and technical spaces, often unglazed. Technically close to porcelain, but with a far narrower aesthetic range and limited use in housing today.

Porcelain

A body of selected clays, feldspars and quartz sands, finely milled, pressed under high pressure and fired above 1,200 °C. At those temperatures vitrification takes place: the particles compact into a continuous, crystalline body with minimal residual porosity. Porcelain is the only type in the family that drops below 0.5% water absorption, and the reason the industry term porcelain stoneware exists at all. For a full overview of characteristics, effects and selection criteria, see the complete guide to porcelain tiles.

Water absorption orders the whole family

Every practical difference between these types traces back to a single measurable value: how much water the body can absorb, expressed as a percentage of its weight. This is not a data-sheet detail. It is the parameter that governs frost resistance, stain resistance, mechanical strength and durability. EN ISO 10545-3 sets out how it is measured, and EN 14411 sorts tiles into groups based on the result.

The code printed on the packaging reads as follows: the first letter indicates the forming method (B for dry pressing, A for extrusion), the Roman numeral the water absorption group, the final letter the sub-class. BIa is the porcelain group, and it is the only marking that tells you with certainty what you are buying, regardless of the commercial name of the range. A tile marked BIII will never belong on a floor, however attractive and well finished it may be.

Why the porous types never disappeared

One question is almost always left unanswered in comparison guides: if porcelain outperforms the alternatives on every technical parameter, why do the other types still exist? The answer is not aesthetic but industrial — and it concerns the porous wall types above all.

A porous body is lighter, and on a vertical wall weight matters: bonding a dense material at height calls for adhesives and precautions that a porous tile does without. A less compact body is also far easier to cut and drill, which shortens installation time around sockets, pipework and sanitary fittings. And firing at lower temperatures reduces energy use and allows a wider colour palette in the glazes, because many pigments do not survive the 1,200 °C used for porcelain.

These are real advantages, and they explain why porous wall tiles remain the default on many sites. They are also advantages that technology has steadily eroded, which is why the balance has shifted.

What a chipped tile reveals

As long as tiles are intact, the difference between the types is almost invisible. It becomes obvious at the worst possible moment: when something heavy lands on an edge and takes a chip out of it. The body is exposed, and it tells you what the material is. On any glazed tile, the colour and pattern live in a film a fraction of a millimetre thick, beneath which the natural shade of the body appears — pale or reddish, unrelated to the surface.

The genuinely revealing detail, though, is the grain of the break. On a porous type it looks matt and slightly sandy, because the body contains microscopic voids. On porcelain it is dense and almost glassy: the visible result of vitrification, and still the most direct way to recognise with the naked eye what you are holding.

Where traditional ceramic is still a reasonable choice

There is exactly one context in which the porous types remain technically acceptable: wall tiling in dry interior rooms. A wall carries no foot traffic, faces no frost and takes no repeated impacts, and none of the thresholds that make porcelain necessary is crossed.

It should be said with equal candour that the trend runs the other way, and not for reasons of fashion. Large formats have changed the rules of wall tiling: a 60x120 cm tile on a wall cuts the number of grout lines sharply, and at those dimensions it takes the dimensional stability only a vitrified body provides. Digital printing has erased the decorative advantage the porous types once held. And anyone tiling a bathroom today almost always wants visual continuity between floor and wall, which is achieved by using the same range in different sizes — and therefore only with a single material.

The result is that porcelain has taken over from porous ceramic on walls too, where ten years ago it would have made little sense. Not because glazed wall tiles stopped working, but because the reason to prefer them fell away.

The threshold beyond which porcelain is required

Rather than reasoning room by room, it is more useful to reason in thresholds. There are three, and once one of them is crossed the choice stops being a preference and becomes a technical requirement.

Standing water

Not occasional steam, but water that lingers: the shower area, the surround of a bath, the floor of a utility room. A body that absorbs even 1 to 3% works under those conditions over the years, and the consequences show up in the grout and the bond before they show up in the tile itself. Below 0.5% the issue does not arise.

Foot traffic

Any horizontal surface that is walked on rules out group BIII with no room for discussion. Above that minimum threshold, the difference between dense glazed ceramic and porcelain is measured in surface wear over time: the glaze on a less compact tile dulls where people walk most, and in hallways, entrances and kitchens the wear pattern becomes visible sooner.

Frost exposure

This is the sharpest threshold, because it admits no gradations. Water absorbed by the body expands as it freezes and breaks the tile from within. No installation method and no adhesive can compensate: if the material takes on water and the temperature drops below zero, the damage is a matter of winters. That is why terraces, balconies, paths and pool edges are the exclusive territory of porcelain — where stone-effect tiles are the most requested look, precisely because they deliver the appearance of natural stone without its technical limitations.

How to decide in practice

The criterion is not to look for the best material in the abstract, but to identify which threshold the project crosses. For a dry interior wall, porous ceramic is a technically sound and often more affordable choice. As soon as water, foot traffic or frost enter the picture, porcelain is not a question of product tier: it is the only type that meets the requirements. And since it now covers both scenarios with the same aesthetic freedom, the real question is no longer which material to choose, but whether there is still a reason to use two.

Frequently asked questions

Is porcelain a type of ceramic?

Yes. Ceramic is the family that covers every material produced by firing clay-based bodies. Porcelain is its densest and highest-performing type, with water absorption below 0.5%. Setting "porcelain" against "ceramic" is a commercial shorthand rather than a technically accurate distinction.

What is the difference between porcelain and glazed ceramic tiles?

Density of the body, above all. Glazed wall tiles are porous, absorb between 10% and 20% water and are intended for interior walls only. Porcelain stays below 0.5%, which makes it suitable for floors, wet rooms and outdoor use. Both are ceramic, but they are not interchangeable.

How can I tell which type of tile I am buying?

The classification code on the packaging or technical data sheet is the most reliable reference. BIa indicates porcelain, BIb dense glazed floor tiles, BIII the porous wall types. The commercial name of the range does not carry this information.

Can traditional ceramic tiles be used outdoors?

No, if that means glazed wall tiles or untreated terracotta. Water absorbed by the body freezes at low temperatures and causes flaking or cracking. Outdoor use calls for a material with water absorption below 0.5%.