Glazed Porcelain Tile

What a glaze is on porcelain

A glaze is a thin layer of glass fused onto the body in the kiln, and it is what makes a printed marble possible at all: the figure is applied to the tile and then a clear cover glaze is fired over it, so the pattern ends up sealed inside glass instead of sitting on a surface that feet can wear away.

On an unpolished glazed tile that glass skin is continuous, and water has nothing to go into. That is the ordinary case, and it is where the reputation of glazed porcelain for being impervious comes from.

Polished and what it costs

Almost everything in this selection is polished, and the polish is a mechanical operation: the fired glaze is ground and buffed until it reflects. That deepens the color, sharpens the veining and throws light back into a room, and it is the finish that makes a printed marble convincing at a distance.

It also opens the surface. A fired glaze is densest in its outermost skin, and grinding takes that skin off and leaves the slightly more porous glass beneath it exposed, still glaze but no longer sealed. That is why polished tiles are commonly supplied with a factory anti-stain treatment where a matte tile of the same series is not, and it is a real difference between the two finishes.

The second trade is visibility. A reflective surface keeps a record of what touches it, so footprints, water spots and fine scuffs read on a polish and are hard to see on a matte. Between them, those two are why the same series is usually offered both ways.

The marble effect and the print list

Marble effect covers the majority here, with travertine, zellige, concrete and stone effects behind it in small numbers. The series names are production lines: Sande, Eden, Aria, Kaya, Regallo, Brighton, Pietra, Exotika, Bernini.

The number of faces a series was printed with matters here more than on most tile. A short print list means the same stone appears again within a few square yards, and a reflective floor gives the eye a continuous surface across which to notice it.

Large format leads

24x48 is the biggest single group here, with 12x24 behind it and 24x24 after that. Above all of them sit a handful of panels at 31.5 by 94.5 and 31.5 by 71 inches, which are close to slab size and are used the way a slab is used, on a wall or a counter, not as field tile.

Large format and polish work together. A polished surface reads as continuous, and fewer joints across it is what sells the illusion; a polished mosaic breaks the same light into a grid.

White leads the color list

White is well over half of this range, then gray and beige, with a smaller black group and a handful of blues. That is the marble palette, which follows from what the prints are copying.

On a polished white the thing to look at is the ground tone underneath the veining. A wet-looking surface pushes both warmth and coolness further, so two whites that agree with each other matte will separate once both are shining. That is a reason to compare samples in the finish you are actually buying.

Trim in the same face

Moldings and bases are a real part of this range at 3x24, 3x18 and 4x24, and that matters more on polished tile than on matte. A polished field with a matte base beside it is a visible mismatch, because the two surfaces return light differently even in the same color.

The trim range sets out which profile answers which edge.

Thickness across the range

These run from about 0.32 up to 0.40 of an inch. The two commonest figures, 3/8 and 25/64, are 0.375 and 0.391, so most of the range sits in the upper part of that band and the thinner pieces are nearer 5/16. The whole spread is under a tenth of an inch and it matters in one place, at a doorway where a new floor meets an old one.

The panels sit outside that band. They are thin for their size, which is what makes a piece that large possible to lift and cut at all.

Rectified edges and the joint

Most of the large formats here are rectified, which is a separate operation from the polish: the fired piece is ground to an exact dimension on every edge. That allows a narrow joint, and on a reflective surface the joint is what the eye uses to count the tiles.

It matters more on a reflective face than on a matte one of the same size, because the eye follows an unbroken surface until something interrupts it. The joint width therefore does as much for a large polished floor as the format does, and it is settled at setting out rather than at ordering.

Where a polished porcelain belongs

A formal room, a hallway, a bathroom wall and a commercial lobby are where most of this goes, and the common factor is that they are looked at more than they are worked in. A kitchen sits between the two: a polished floor there is an ordinary choice and it is also the room that produces the most footprints.

The porcelain tile range is where the matte and honed finishes sit, and marble look porcelain approaches the same tiles by their effect.