Difference Between Glazed and Unglazed Porcelain Tile
The number of different “types” of ceramic tile used today appears almost equal to or between the number of “styles” of tile
We had gone a long way since the 1970s, when the majority of bathroom wall tiles were Johnsons “chicken” tiles that were 6″ square and available in a dozen various colors, with Japanese floor tiles that were made of glazed mosaics
We now have vitrified porcelain, both full-bodied and double-loaded, as well as a plethora of glazed porcelain tiles, available with a matte glaze, a gloss glaze, a “lappato” or semi-polished finish, plus a variety of textured, slip-resistant tiles, in addition to the bicottura and monocottura types that dominated the residential market until the late 1990s
Similarly, totally vitrified, unglazed porcelain tiles are available in a range of finishes
Even if it’s not always simple to tell what kind of tile anything is just by looking at it, understanding the differences is essential if you want to pick the best tile for the job at hand and stay safe
We have compiled a useful overview of the most popular tile kinds, their performance characteristics, where to use them, and how to maintain them to help you navigate this difficult terminology maze
In addition, we dispel several falsehoods and misinformation about glazed and unglazed tiles
Ceramic tile: Depending on the type of tile, ceramic tile is made of clay combined with sand, felspar, quartz, and water
The mixture is then compressed firmly and burned at temperatures between 1000 and 1300 degrees Celsius
Either the MONOCOTTURA or BICOTTURA method can be used to make ceramic tiles
Tiles made with the monocottura process, which is Italian for “single-fired,” are typically used on floors
However, they can also be used on walls
When firing monocottura tiles, both the body and the glaze are burned quickly and simultaneously at a high temperature
The vast majority of all home floor tiles were produced using this technique up until the late 1990s
The bicottura process is used to create wall tiles, which offer a wider choice of colors and beautiful surfaces
The number of glaze layers used may affect how many times these tiles are actually burned, contrary to what the translation suggests
Bicottura tiles are fired at a lower temperature than monocottura tiles since hardness is not a necessary outcome
In general, tougher tiles result from greater temperatures
Ceramic tiles absorb over 4% of water
They should not be viewed as having a flaw or a limitation because full vitrification is an unnecessary step in their production
Porcelain tile is technically a member of the ceramic family but has unique qualities because of the kinds and combinations of clays used in its creation as well as those processes
Ceramic is a much weaker counterpart of porcelain
Both are produced from clay and heated in a kiln
The primary distinction is that porcelain tiles are entirely vitrified, which makes them extremely hard and suited for heavy traffic floors, including industrial settings, with a water absorption rate of less than 0
5%
Porcelain tiles can be utilized in almost any scenario, including factory floors, swimming pools, and light traffic bathroom floors (and walls) as well as in and around them (as mosaics)
The tremendous pressure used to press the clay—up to 100,000 lbs per square inch—the volcanic temperature—approximately 1250 degrees Celsius—and the combination of clays and minerals employed—are the three key contributors to this porosity rate
The variation in the clay mix, which includes kaolin, felspar, quartziferous sand, and metallic oxides, drives all the other variables since it allows for intense pressing and burning
(White china clay, known as kaolin, is essential for helping the tile hold its shape during the fire
)
The clay dust particles are squeezed very closely together, and the amount of air and moisture between the particles is decreased by injecting the pigmented dry dust clay into molds and pressing at such amazing pressure
A denser, less porous body results from this
Because of the characteristics of porcelain clay, dust particles melt and fuse together to form vitrification when fired at a temperature of about 1250 degrees Celsius
The process of vitrification
It is the process of turning melted clay into a ” glass-like ” material with a porosity of only 0
5%
The harder the tile and the less porous, the less likely it is to absorb liquids and become stained
Additionally, the less likely it is to scratch or chip, the greater the vitrification
Of course, the less likely moisture is to penetrate a tile’s surface, the more likely it is to sit on the surface, which may raise the risk of slipping depending on the texture of the surface
Vitrified tiles come in four varieties: full body, double loaded, glazed, and soluble salt
This last type won’t be taken into account in this article for a number of reasons
Unglazed Porcelain Tile
Unglazed Porcelain: Full-bodied porcelain is a sort of vitrified tile in which a single color extends continuously from the tile’s surface to its base
The technical characteristics, such as water absorption, frost resistance, and acid resistance, are also constant throughout, in addition to the color
Before burning, two layers of clay—typically of different colors—are compressed together to create double-loaded tiles
The two layers fuse to create a perfectly uniform product because the clay is entirely made of porcelain
When the top layer’s color is created using very expensive pigments, such as cobalt, this is typically done
It keeps the costs in check by limiting the color to the top 3–4mm rather than the entire 9–10mm
Traditional encaustic tiles have recessed areas created when the decorative pattern is stamped into the top surface of the base tile
These recessed areas are then filled with contrasting colored “slip” (liquid clay), which is then fired to create a homogeneous porcelain tile with the same characteristics as a full-bodied porcelain product
Polished porcelain that is not coated with a gloss finish is shiny but unglazed
It is an unglazed tile that has been mechanically polished in the same way that polished marble or granite tiles are polished to make them shiny
Polished porcelain requires sealing in the same way that polished marble or granite tiles do to keep them from becoming stained
Polishing porcelain changes the material’s technical properties, particularly how much it absorbs
Standard, or “matte,” porcelain does not collect dirt and stains because of its finely textured surface, although it might show soiling that is limited to the tile’s surface and is easily washable
The use of a penetrating sealer is required because mechanical polishing by the factory results in a smoother surface that is much less prone to catch and hold dirt from shoes, etc
, but damages the tiny porcelain dust beads and opens up the tile’s microscopic pores
The porcelain tile becomes slick when wet as a result of polishing, which smooths the surface to a bright, mirror sheen
(Despite the fact that they are more slippery—and hence dangerous—when wet—polished porcelain tiles are typically used for public thoroughfares in shopping malls because they are easier and less expensive to maintain
) The polished, or lappato, unglazed porcelain tiles must be cleaned with a specially developed pH-neutral cleanser after a penetrating sealer has been put to their surface
Standard floor cleaners have a high pH level that degrades the sealer, diminishing its effectiveness and limiting its life
It is advised to use polished porcelain on walls or floors where there is little to no danger of their getting wet because applying a quality penetrating sealer will only address the staining problem and not the slipperiness issue
Although matte-finished tiles are slip-resistant, it is always advisable to check the manufacturer’s slip rating
Varied colors may produce a different slip rating even with matte-finished, unglazed porcelain
A lappato, or honed, finish on unglazed porcelain will have a slip rating that falls midway between polished and matte
Only utilize textured surfaces outside due to their difficulty in cleaning and extremely high non-slip rating
Porcelain that has been “glazed”: Most people think the word “glazed” means “shiny” or “glossy
” However, the term is used to describe the colored or patterned coating that is applied to a tile’s surface in the tile industry
For example, one can have marble with a “glossy” surface or unglazed porcelain that is “glossy,” but neither product is “glazed
” The glaze is a material, not a description of a textural finish
Like how you can have matte paint for your walls and gloss paint for your doors and skirting, think of glaze as paint
The paint for your tiles is glaze
The majority of floor tiles and almost all wall tiles are glazed
Before the tile enters the kiln, the glaze is applied; during the firing process, it fuses to the porcelain body’s surface
Glazed porcelain tiles have the same four basic glaze finishes as unglazed porcelain tiles: gloss, matte, lappato, and textured, of which there are several variations
Lappato-glazed tiles shine more than matte tiles but have a softer touch than gloss tiles
The term “honed”—a term used frequently in the stone business to describe marble with a satin finish rather than a highly polished, shining one—comes from the Italian meaning “semi-polished” or “honed
” Inkjet Printing: Thanks to recent developments in glazing technology, porcelain tiles may now be printed with any digital image you can think of
With up to 1000 nozzles and a resolution of up to 1000 dpi, inkjet printers can use up to six different colors
The most noteworthy quality of this printing method is its incredible versatility, which includes the ability to print all the way to the edge of the tile and reproduce natural stone, wood, terrazzo, concrete, or any other pictorial image with excellent accuracy and without the use of screens, which created a pixelated effect
This explains why glazed porcelain tiles are frequently used in bathrooms for both the walls and the floors, with gloss or lappato glazed tiles being more popular for the walls
The ability to print on non-flat surfaces, including curved or textured ones, is another distinctive quality of this technique
This broadens the range of image types that can be generated and the applications for the tiles
Only with an inkjet printer is it possible to decorate over frit grains since there is no physical contact with the surface
Frit: Frit is a type of ceramic glass that has been pre-mixed from raw, finely ground minerals, melted, and then finely pulverized
The type and grade of frit will influence the glaze’s endurance as well as its level of hardness, color, and gloss
Porcelain tiles with glaze do not need to be sealed because it is the glaze’s intended use
Consider them to be like your ceramic tableware; while your plates don’t require sealing to prevent stains, they do require washing
Damage to the glaze is one of the characteristics of glazed porcelain that is frequently recognized as an issue or a potential problem
What are the effects of a damaged glazed surface on a tile, both practically and aesthetically? The answer to this query has less to do with glazed porcelain tiles specifically and more to do with the type of glazed porcelain tile being used and where
If the tile is of great quality, it is quite unlikely that something will fall on it and scratch or chip the glaze
Keep in mind that these tiles were created to be installed on the floor and walked on
Should damage to the surface occur, some glazed porcelain tiles feature a porcelain body that is colored to match or nearly resemble the color of the glaze
It is suggested to avoid using such a tile in a high usage location because there will be visible wear if there is a large difference between the glaze and body colors
