Every porcelain tile is a ceramic tile. The reverse is not true, and the difference is a measured property rather than a marketing word.
The definition is a number
Under the industry standard, a tile is porcelain when it absorbs 0.5% or less of its weight in water. Anything above that is non-porcelain ceramic.
That single figure drives everything else. Less absorption means a denser, harder-fired body, which means it survives freeze-thaw outdoors, tolerates standing water, and chips less. It is also why porcelain is harder to cut and costs slightly more to install.
The two ratings that matter on a floor
PEI — surface wear. A one-to-five scale for how much traffic the glaze will take.
| PEI | Where it belongs |
|---|---|
| 1 | Walls only. Never a floor. |
| 2 | Light residential — a bathroom you walk on barefoot |
| 3 | All normal residential floors. This is the household standard |
| 4 | Residential plus light commercial |
| 5 | Heavy commercial traffic |
PEI 3 is the right answer for almost every room in a house. Paying up to PEI 5 for a bedroom buys nothing.
Slip resistance. The current measure is wet dynamic coefficient of friction, and the benchmark for a level interior floor that will be walked on wet is 0.42 or higher. Bathrooms, entries, kitchens and laundry rooms should all clear it. A polished tile that looks beautiful in a showroom can fall well under it, and a wet polished floor at the top of stairs is a genuine hazard, not a preference.
Glazed, through-body and rectified
Glazed tile has its color in a surface layer. A deep chip shows the pale body underneath.
Through-body or color-body porcelain carries the color all the way through, so chips and worn edges stay close to the surface color. Worth the difference in an entry, a mudroom, or anywhere something heavy gets dropped.
Rectified tile has been mechanically trimmed after firing so every piece is the same size to a fine tolerance. That is what allows the very tight grout joints in modern large-format work. Unrectified tile needs a wider joint to absorb the size variation, and forcing a narrow joint on it produces a wandering, uneven grout line.
The floor under the tile decides whether it lasts
Tile does not flex. Whatever it is bonded to must not flex either.
- The framing needs to be stiff enough that the floor deflects no more than 1/360th of its span under load for ceramic and porcelain. Natural stone is twice as strict at 1/720, because stone cracks where porcelain will not.
- Large tiles need a flatter substrate than small ones. The bigger the tile, the less a hump or dip can be absorbed by the mortar bed, and the more likely you get lippage, one edge standing proud of its neighbour.
- A crack isolation membrane over a slab lets a hairline crack in the concrete move without telegraphing straight up through the tile.
This is why a tile quote moves more on subfloor preparation than on the tile itself, and why an honest estimate itemises it.
Grout is the thing you will maintain
The tile is effectively permanent. The grout is not.
- Sanded grout for joints of about 1/8 inch and wider, unsanded for narrower ones, because sand cannot pack into a joint too fine to hold it.
- Epoxy grout resists staining and does not need sealing, but it costs more and sets fast enough that it is unforgiving to install.
- Cement grout in a shower or an entry should be sealed, and resealed. That is the routine job people forget, and discolored grout is usually what makes an otherwise sound tile floor look old.
Natural stone is a different material with a different job
Marble, travertine, slate and granite are sold alongside tile and behave nothing like it. Stone is porous, so it needs sealing from the day it goes down. Acid — lemon juice, wine, some cleaners — etches marble and travertine permanently regardless of sealer. Stone rewards you with a surface no manufactured tile matches, and asks for real maintenance in return.
What it costs
Tile and stone run $7 to $14 per square foot installed. The spread is mostly labour: a small format in a straight lay is quick, while large format, a diagonal or herringbone pattern, or a floor that needs levelling first all add hours.
Where tile beats everything else
Bathrooms, entries, laundry rooms, mudrooms, and any room with a floor drain. It is the only common flooring that does not care about standing water at all, and with underfloor heating beneath it, its one real drawback mostly disappears. Cold and hard underfoot stops being true.