Ceramic tile (non -porcelain/vitrified tiles): Ceramic tiles are generally made from red/white clay fired in a kiln. Ceramic tiles finished with a durable glaze which carries the color and pattern. These tiles are used in both wall tiles and floor tiles applications, softer and easier to cut than porcelain/vitrified tiles and usually carry a PEI 0 to 3 of rating. These types of ceramic tiles are usually suitable for very light to moderate traffic and generally have a relatively high-water absorption rates that make them less frost resistant and they are more prone to wear and chipping than porcelain tiles.

Porcelain/Vitrified tiles: These tiles are generally made by the dust pressed method from clay which results in the tiles that are dense, impervious, fine grained and smooth, with a sharply formed face. Porcelain/Vitrified tiles normally have a much lower water absorption rate (less than 0.5%) than ceramic tiles which makes them frost resistant or frost-proof. Different types of porcelain/vitrified tiles are:

• Nano polished vitrified tiles:If you apply a layer of liquid silica on vitrified tiles then it fills the micro (nano) pores on the tiles surface and makes it smooth. These tiles are called nano polished vitrified tiles.
• Double Charge vitrified tiles: are fed through a press that prints pattern with a double layer of pigment; they are 3 to 4 mm thicker than compared to other tiles. This process does not permit complex patterns but results in a long-wearing tile surface, suitable for heavy traffic and vast commercial projects.
• Full body vitrified tiles: have pigment in entire body (thickness) of the tiles. This makes chips and scratches less visible and gives an ideal choice for high traffic zones, but the process considerably increases the cost.
• Matt Porcelain Glazed Tiles / Glazed Vitrified Tiles(GVT) are glazed surfaced tiles. They offer a vast variety of design, art work and surface textures like wood grain, bamboo, slate or stone. This tile is now printed through digital printing technology.
• Polished Porcelain Glazed Tiles / Polished Glazed Vitrified Tiles(PGVT) are similarly the GVT tiles in glossy form.

For end user the physical appearance of tile is most important however it is not correct that every good looking tile is having good quality. There are various parameters on which the quality of tiles depends.. So the important parameters are explained below:-

• Breaking Strength – It is a force applied to an unsupported portion of the tile specimen until it breaks. Breaking strength is important for floor tiles. When you step/drop something on a tile, you don’t want it to break. The European standard requires minimum of 1300 N breaking strength. The higher the breaking strength, the better is the quality of tile.
• Resistance to surface abrasion (PEI class) – The PEI categorization primarily defines the hardness and durability of the various ceramic / porcelain products that are tested. It should be noted that the PEI rating involves testing of only the surface wear layer of a tile’s enamel glazing; it does not measure the fracture strength of the entire tile, nor does it offer any rating of the slip-resistance of the tile.

Group 1 – Suitable only for residential / commercial walls. Not suitable and/or recommended for foot traffic.

Group 2 – Suitable for general light residential traffic.

Group 3 – Suitable for all residential and light commercial areas.

Group 4 – Suitable for residential, medium commercial and light institutional applications.

Group 5 + – Suitable for heavy traffic in both residential and heavy commercial applications.

• Water absorption – Water absorption measures how much moisture a specific type of tile is likely to absorb on an ongoing basis. The European standard requires water absorption <0.5%. The lower is the water absorption, the better is the quality of tile.

Porcelain/vitrified tiles material are perfectly suitable to be used with underfloor heating provided the correct substrate preparation and a suitable flexible cement based tile adhesive and grouts are used.