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About Ceramic Tile
The definition of ceramic tile:

Ceramic tile is simply a mixture of clays which have been shaped and fired at high temperatures, resulting in a hard body. This hard body may then be left untreated or it may receive a glazed wearlayer. In its most basic form, ceramic tile is clay with colored glass coating packaged in a box.

Make up of ceramic tile:

All of the raw materials that go into making ceramics come from the earth, including the clays and the minerals used to produce the glaze colors. Man has been successful in finding ways to improve most products by substituting natural materials with synthetics, such as we've seen with carpet. But man has not been able to improve on the quality of the raw materials found in ceramics. These materials have basically remained unchanged for thousands of years! This is a real testimonial to the quality of ceramic tile.

Facts About the Glaze:

The glaze is a glass that has been sprayed, poured, dropped and/or silk screened onto the surface of the tile. It is then fused and hardened by means of tremendous heat (kiln fired).

The colors of the glaze are made from a mixture of minerals such as gold, silver, zinc, copper, mercury, cobalt and many others.

The following factors may effect the hardness and/or wear rating on ceramic products:

   1. Temperature - In most cases, the higher the kiln temperature, the harder the glaze.
   2. Color - Dark color glazes such as blacks, reds, yellows and blues are usually slightly softer than light     colored glazes and generally show foot wear much easier due to the darkness of the color and/or the     lighting.
   3. Gloss Levels - Shiny (high gloss) glazes usually show foot wear faster than matte and/or satin finished     glazes. This is because light is reflected differently from rough textured surfaces than from flat shiny     surfaces.


Glazed ceramic tile varies in gloss levels depending on the look the manufacturer wants to achieve. It can range from matte, to satin, to high gloss.

Generally speaking, foot wear will usually appear faster the higher the gloss level that is applied. Areas of the home that don't receive heavy wear, such as bathrooms, use a higher gloss level than those in high and concentrated traffic areas.



To avoid choosing the wrong product, consult the following P.E.I. guide (used by most manufacturers) to rate the durability of each tile.

Group I     Tiles suitable only for residential / commercial walls.
                  Not suitable and/or recommended for foot traffic
Group II    Tiles suited to general light residential traffic, except kitchens, entrance halls, and other areas                   subjected to continuous foot traffic.
Group III  Tiles suited for all residential and light commercial areas such as offices, reception areas and                   boutiques.
Group IV   Tiles suited for residential, medium commercial and light institutional applications such as                        restaurants, hotels, hospital lobbies and corridors.
Group V    Tiles suitable for heavy traffic both residential and heavy commercial applications such                            airports, malls and subways.

N0TE - the letters P.E.I. stand for Porcelain Enamel Institute.

    * The P.E.I. ratings are derived from a combination of tests that not only address the physical wear of the        glaze surface itself, but also include a visual wear of the glaze surface appearance after the test.
    * The wear ratings are listed on all of our loose tile labels, literature & sample boards. This takes all of the        guesswork out of selecting the right tile for the right application.

IMPORTANT: The P.E.I. wear rating of tile does not include the slip resistance, body moisture absorption and/or the breaking strength of the product. In other words, the P.E.I. rating does not necessarily determine the over all quality or price, only the glaze durability. Some of the most expensive and luxurious tiles in the world rate only P.E.I. I or II

Facts About the Clay Body:

The clay body, called bisque, is made up of various types of clay and other minerals. Combined, these raw materials give the bisque its strength and stability.

Its density also determines the strength of the bisque as it relates to the water absorption level. The strongest bisques (those suited for heavy commercial installations) have the smallest and fewest number of air pockets which, in turn, will affect the over all water absorption, breaking strength, and impact resistance of the finished product. The density of the clay also determines if the tile is or is not suitable for outdoor use.

Tile density is measured by the amount of water it absorbs.

   1. Non -vitreous Tiles - absorb 7% or more of its body weight in water. They are suited for indoor use only        and considered to be non-frost resistant.
   2. Semi -vitreous Tiles - absorb between 3% to 7% of its body weight in water. They are suited for indoor        use only and considered to be non-frost resistant.
   3. Vitreous Tiles - absorb between 0.5% to 3% of its body weight in water. They are suited for both interior        and exterior applications (covered and/or non-heated rooms not exposed to standing water) and                  considered to be frost resistant.
   4. Impervious Tiles - are the strongest. They absorb between 0 and 0.5% of their weight in water.

Suited for both interior and exterior use and considered to be frost resistant. (NOT FREEZE PROOF). However, be aware of the C.O.F. (stands for coefficient of friction and means the slip resistance factor) when deciding on the use of these types of products in exterior applications.


Illustrating How Air Pockets Determine Density

The absorption percentage is based upon the amount of mosture absorbed as compared to the body weight.     

Swiff-Train Company rates tiles for you with an easy system of 1-4 stars to help you understand the quality of the products. The system is based on the clay body density levels (mentioned above), with one (1) star indicating good products (non-vitreous tiles), and four (4) stars indicating exceptional products (impervious tiles).    

Glaze process:

A step and/or method during manufacturing in which the glaze is worked with (brushed) and/ or applied. Counting the glaze processes helps to show the complexity of design and justifies the cost.

Glaze passes:

A step and/or method during manufacturing in which the glaze (or a portion of the glaze design) is applied to the body. Counting the glaze passes helps to show the complexity of design and justifies the cost, as multiple glaze applications are used to create different textures, colors and/or patterens. 


A punch is the stamp that forms the tile and creates the design, depth and overall texture of the tile body. The number of punches actually refers to the number of different punch designs used for each product line (series). When more unique punches are used, it increases the cost of production, yet adds to the depth and complexity of the finished product. It also affects the glaze applications because glaze adheres differently from punch to punch. The end result is a product line with multiple textures and shades.


The Mohs test determines the scratch resistance (hardness) of tile glaze, and uses the following procedure:

    1.      Using certain minerals of defined hardness (see list below), draw over the surface of the ceramic tile in              four cycles.  Moving up the mineral scale, use a fresh edge of the mineral on each cycle until scratches              are visible to the naked eye.
    2.      A minimum of three test tiles must be used.
    3.      For each tile note the mineral of highest Mohs hardness that produces no more than one scratch.
    4.      In the case of tiles having variable scratch hardness, note the lowest Mohs hardness.

Test Minerals  
Mohs Hardness
 Talc   1


A. Wall Tile:

Any ceramic tile is suitable for walls, but the very thin, high glossed and decorative tiles are most commonly used. The most popular size for wall tile is still 4 1ž4” x 4 1ž4 ” & 6” x 6” but it appears that there is a trend taking place for larger, more luxurious tiles. Wall tiles have a very soft glaze and porous body and therefore should never be used on floors or for outdoor applications.

B. Floor Tiles:

    *These tiles (glazed or unglazed) have the sufficient strength, impact and abrasion resistance to            withstand foot traffic and static weight.
  •     *They are usually thicker, denser and heavier than wall tiles.
  •     *If the substrate is strong enough to support the weight, floor tiles may also be used on walls and       counter tops.


  • The two most common methods of tile production are as follows:

  • A. Monocottura - Monocottura is an Italian word meaning single -fired and is the most common method used to produce tile. This process allows the tile to be shaped, glazed and fired in one step.

  • The development of the Monocottura technology totally changed the industry for the better. To put it into the proper prospective, it was as revolutionary to the ceramic industry as the tufting machine was to carpet. Its advantages are as follows:

  •     1. It dramatically speeds up production, resulting in cost saving that is passed through to     consumers. Prior to the development of the Monocottura method, some tiles were fired (baked) in     the kiln (oven) for days. Today, these tiles can be produced in less than one hour.

  •     2. Monocottura tiles are not only quicker to make, but they also have a denser body and harder glaze     as compared to the previous methods of production.

  •     3.Single fired products are produced with a flat back, which makes installation much easier than the     old fashion button, or lug backed tiles.

B. Bicottura - This is an Italian word meaning double -fired. The clay body is baked on the first pass to remove the excess water within the body, then the glaze is applied prior to the second pass through the kiln. Actually, Bicoturra tiles may go through the kiln as many as four times. The pros and cons of Bicottura tile are as follows:

  •     *This double -fired method of production has been replaced by the Monocottura method for making     floor tiles due to the additional cost associated with the Bicottura method.

  •     *Bicottura floor tiles are produced with lugs on the back to allow the heat to circulate during the     firing process, making installation more difficult.

  •     *Bicottura floor tiles have a softer body and a weaker glaze than a Monocottura tile and are not     recommended for outdoor use or heavy traffic areas.

The Bicottura method is still considered by many to be the best method to use when producing decorative wall tiles.


This refers to the color of the clay body used when producing glazed tile. Many distributors and consumers believe that one color is superior to the other, but this is not necessarily true.

The quality of the tile has more to do with the quality of the manufacturer, denisty of the clay, and breaking strength rather than the color of the clay. Porcelain is simply a finer grade of clay and makes a more dense, harder tile body.

If the glaze was to chip from the white body, once the floor is mopped and water penatrates the body, you will be left with a brown spot. A red bodied tile would also brown after mopping, which makes any argument over the tiles pointless.


A. Shading:

Many tiles are deliberately produced with a wide shade variation to capture the natural beauty of the product. However, a certain degree of shade variation is inherent in all ceramic tiles.

The manufacturers limit the amount of shade variation within a carton by sorting the tile as it comes off the production line. The shade and run numbers are marked on each carton. To minimize any noticeable shade variations, the installers must work out of several cartons at the same time. By doing this, they are able to blend the tiles together.

It is very important for the consumer to understand the need for blending tiles before an installation is begun, or an unnecessary situation may be the result. Manufacturers will not accept complaints on tiles after they have been installed, since they are almost always visual defects, which could have been detected before installation.

If the glazed ceramic tiles were visually problematic after the conclusion of the job, they were almost certainly a problem before, and should have been noticed at the time they were handled and placed.

The shade rating system called the STV (Shade Tone Variance or for short the “V” rating) is now being used as a way to singify how much shade variance you should expect from one tile to another, within the same item / color:

shade & tone index guide:

B. Sizing:

  •    *Tile sizes will vary slightly. This is due to the manufacturing process and kiln firing.
  •     *Most manufacturers will keep sizing to an acceptable level by sorting the tile by size prior to                 packing.
  •     *Grout joints will conceal slight size variations.

  • NOTE: If either the sizing or shading is too great, the installer should not set the tile.


  • Although most tile is advertised and sold by nominal sizes such as 12" x 12" the actual size will be more like 11 7/8” x 11 7/8”. Nominal sizing is a legal and ethically accepted practice since many tiles are manufactured in countries where the units of measurement are metric, and the carton information has been converted to standard U.S. units.


  • All ceramic tiles share unique and exceptional qualities that can be found in no other type of decorative building products.

Abrasion resistance:

How will a tile's glaze or surface hold up under continuous wear? This is a very important consideration when choosing any glazed floor tile. Commercial areas, as well as areas of the home such as kitchens or foyers subjected to heavy use, demand a good abrasive resistant glaze. If the right product is chosen and it is maintained properly, kept free of sand and grit, it could easily last the lifetime of the home. Be sure you refer to the P.E.I. ratings given on each of the products being considered to select the product appropriate for its intended application.

Water absorption:

A good quality glaze on ceramic tile is non -porous at time of manufacturing. Therefore water absorption pertains only to the tile's body. The water absorption rate is important information in selecting the right product for outdoor use. If the tile absorbs more than 3% moisture, it is not suitable for outdoor use in colder climates where tile may freeze and crack.

Frost resistance:

Frost resistance goes hand in hand with water absorption. The less water the tile absorbs, the greater its frost resistance. Most labels, literature and sample boards will clearly identify those tiles which are frost resistant.

Stain resistance:

Glazed ceramic tile material, in general, is the most stain resistant building product in the world. At the time of manufacturing, a good quality glazed ceramic tile will resist practically any compound that could cause staining as compared to other types of flooring products.

Slip resistance:

The slip resistance of ceramic tile, in ordinary applications, is comparable to that of most hard surface flooring materials and it is significantly better than some. Unglazed tiles have greater slip resistance than glazed tiles and are recommended for areas subjected to high water spillage. Many glazed and unglazed tiles also feature abrasive grit on their surface, which substantially increases their slip resistance. These tiles are particularly suited to public areas with direct access to the outdoors.

Color permanence:

While most colored materials will be altered by long exposure to light, colors in glazed ceramic tiles are unaffected and will not change or fade from exposure.

Dirt resistance:

Good quality glazed ceramic tiles do not retain dust or residues. Plain water or a damp cloth is generally all that is required to keep the tile clean. No polishing or buffing is necessary to maintain the finish. You may need to use a non-detergent (non foaming) cleaner for sanitary purposes.

Fire resistance:

Ceramic tiles are completely fire -proof at any temperature. They will not burn or feed a fire. Their surface will not alter, nor will they give off any toxic gases, smoke or fumes during a fire. The glaze color, however, could be affected at extreme heat.

In addition to being fire-proof, tiles have been found to provide some degree of protection for structural surfaces during fires.


The face of good quality glazed ceramic tiles will not retain liquids or absorb fumes, odors, or smoke, thus allowing for good hygiene. Tiles are suited for any environment where hygiene is essential.


A.     There are two basic types of tile: Glazed and Unglazed.

B.      There are two distinct advantages of glazed tiles: unlimited color range and superior stain resistance.

C.     The two advantages of unglazed tiles are: wear resistance and added slip resistance as compared to glazed ceramic tile.

D.     A good quality glaze is a non-porous, protective glass coating (at time of manufacturing).

E.       The overall strength of a tile is determined by: The hardness of the glaze and the density of the clay body. Porcelain tile bodies contain a finer grade of clay.

F.      The P. E. I. wear rating chart was developed as a guide to help customers select a tile strong enough to withstand the abuse to which it is going to be subjected.

G.     Ceramic tiles’ features and benefits have no equal, they will not:

         ·         Fade or stain from sunlight (good quality glazed ceramic tile).

         ·         Be adversely affected by moisture.

         ·         Have their glaze penetrated by soil, fumes, smoke and (unless chipped or worn away).

         ·         Emit any odor or gasses.

Ceramic tile combines beauty with outstanding durability and has been praised for its versatility of use. Therefore, while carpet and vinyl are produced mainly for floors, the area of usage for ceramic tile is limitless.

- Article Courtesy of Swiff-Train Company, Copyright© 2003, All Rights Reserved.


Excellent customer service is all about “going the extra mile.” K&S lives this philosophy. They are prompt, polite and professional. I know this sounds cliché, but if you want it done right the first time, this is the guy to call. Plain and simple – he knows what he’s talking about and he’s ethical and forthright, too. So if you’re looking for a remodeling contractor who shows up at the scheduled time, does the job in a timely manner, and is very thorough, give K&S Remodeling a call. We’re certainly glad we did!

-Muriel Timmermann
K & S Remodeling, LLC | P.O. Box 270851 | Vadnais Heights, MN 55127 | P: 612.518.3804 F: 651.426.2725 | Email:

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