What's The Difference between "Ceramic" and "Porcelain"
Floor and Wall Tiles?
By: David Churchman, Ceramic Engineer,
In my line of business, I continually get asked, what
is the difference between "ceramic" and "porcelain" tiles? Over the years I have made it a point
to educate my clients and others on this particular subject matter. Even as porcelain has become more popular versus
its counterpart, it is still apparent the confusion consumers as well as many contractors, retailers, distributors and sales
people have about the significant differences and their meanings. Specifically when dealing with floor and wall tile, the
common misnomer people have is calling floor and wall tile simply ceramic. Basically, "ceramic" is sort of
like saying a cup is a cup. We all know there are many kinds of cups like styrofoam, cardboard, paper, plastic, etc. same
goes for ceramic. A good example of a ceramic is your fine china. Would you compare the fine china your guests eat on
to the floor tile you walk on or merely call them ceramic dishes, I think not! You probably paid good money for your
fine china and for good reason. So let's get down to the intricacies so you can make a well informed decision when selecting
a floor or wall tile that will be suitable for your home and lifestyle.
"ceramic" means a compound that is an inorganic, non-metallic oxide that is formed by heat. The word "ceramic"
is actually a generic term that encompasses things such as porcelain, red and white body tiles, glass (although glass is an
amorphous material meaning there is no crystalline structure), space shuttle tiles, semi-conductors, dishes, toilets, etc.
For instance, when selecting floor or wall tiles you are actually selecting among the vast array of tiles such as: glazed
and unglazed red and white body tiles, glazed porcelain, glazed and unglazed through body porcelain tiles, and glass tiles.
Whew! All of these different types of tiles can really get one confused. All floor and wall tiles go through a similar manufacturing
process with the exception of glass tile, the raw materials are mined from the ground, mixed together at certain ratios and
processed through different manufacturing steps, then the material is pressed, glazed, fired, inspected/sorted, packed and
shipped. So you ask where is this difference?
As described earlier, "ceramic"
is a generic term. So let's rephrase the question for a clearer answer. "What is the difference between porcelain
and non-porcelain tiles?" For floor and wall tile, the real difference we are comparing is the "physical"
properties between porcelain tiles and non-porcelain tiles. Specifically, we are comparing the water absorption
or the porosity of the tile. Porcelain tiles have a water absorption of less than 0.5% and non-porcelain tiles have
a water absorption of greater than 0.5%. Additionally, porcelain is stronger and more durable than red/white bodied
"non-porcelain" because it is almost completely vitreous like glass. These differences are achieved mainly
by its composition.
The predominately known non-porcelain floor tile most
people commonly call ceramic is the red bodied tile. When you look at the underside (no glazed side) of the tile the
color will be apparent. The typical water absorption of the red bodied tile is about 4%. These tiles are manufactured
with materials such as silica and feldspar that in general have not been highly refined. The main component of red body
tiles is ball clay which contains free silica, quartz, alumina-silicates and other minerals that are beneficial to the final
product along with a lot of organic materials. As you may guess, the color of the ball clay is red. Porcelain
tiles contain kaolin (sometimes called china clay), feldspar, silica and aluminum oxide. Sounds like your high school
geology class coming in handy for once. The obvious difference between the two "bodies" is the type of clays
used. Clay is used in the bodies in order to allow the tiles to maintain its shape during the firing process.
All clays vitrify (develop glassy qualities) at extremely high temperatures unless they are mixed
with materials that lower the vitrification threshold. Unlike glass, however, clay is refractory meaning it holds its
shape when heated. Ball clays melt and lose their shape at a much lower temperature than kaolin. This is why you
may often hear that sizes may vary more in that of non-porcelain tiles. The average firing temperature for red bodied tiles
is 2100 degrees F whereas the average firing temperature for porcelain tiles is 2350 degrees F. Although both temperatures
seem really hot, 2100 degrees F is not enough heat to achieve the same amount of vitrification (glassiness) as at 2350 degrees
When shopping around for tile, you may realize that non-porcelain tends
to be less expensive to its porcelain counterpart. But be aware, although non-porcelain tiles may be less expensive
they are also less desirable due to their durability. And glazed surfaces may chip easily exposing the red clay body
which can not only be an eye sore but may also cause other issues requiring attention sooner than porcelain. Non-porcelain
tile is also not recommended for outdoor installation, especially in freezing climates due to its high absorption rate.
The down side to porcelain is that the price tends to be higher than non-porcelain. However,
due to the amount of competition, this price difference has shrunk dramatically in the past few years. Porcelain floor
tiles are a wise investment over non-porcelain tiles. It is a very durable material that comes in many different colors,
textures and sizes. Due to the almost zero porosity, porcelain tiles can be used in a wide variety of applications from
commercial use in high traffic area floors, walls and pans in showers, decorative tiles in pools, and outdoor patio decks,
to elegant floors in century old homes with proper installation (always use a licensed contractor).
So there you have it. Do you have a better understanding about the difference between porcelain and
non-porcelain tiles? I hope so. What about travertine or marble or granite, where do they fit into the scheme
of things? Avid Tile "We are licensed to install what we sell" 951-334-7154
©Avid Tile 2008