Types of Ceramic Tiles
Ceramic tiles are thin slabs generally used to cover walls and floors. They are made from clay and other inorganic raw materials that are ground and/or mixed and then moulded before drying and firing at sufficiently high temperatures to acquire the necessary stable properties.
Ceramic tiles may be unglazed (UGL) or glazed (GL). Unglazed tiles are fired only once, whilst glazed tiles receive a vitrifiable coating between the first and second firing (in the case of double fired tiles) or before the sole firing (in the case of single fired tiles).
The following names and descriptions are based on objective criteria relating to the tiles’ use, technical properties, customs classifications etc., as well as the most commonly used commercial terminology. However, there are no commonly accepted names or definitions for the various types of ceramic tiles, and it may therefore be necessary to provide additional comments, especially in the cases mentioned specifically.
The following pages provide descriptions of the various types of ceramic tiles, including details of their characteristics, most common uses, production, appearance and classification in accordance with standards etc.
Wall tile is the name given to a dry-pressed, glazed ceramic tile with a high water absorption rate. These tiles can be single or double fired. Thanks to their technical characteristics, they are particularly suited as coverings on indoor walls in residential or commercial premises.
This is the most commonly name given to highly porous ceramic tiles that are dry pressed, glazed, and single or double fired. Their characteristics make them mainly suitable as indoor wall coverings in residential or commercial premises. The tile body, made of majolica (fine earthenware), can be white or colored, ranging from bronze to yellowish brown or reddish, without the color affecting the tiles’ properties in any way. The tile body has a fine, uniform texture, with no grain, inclusions or pores that are easily visible to the naked eye. The surfaces and edges are even and well finished. The top surface is covered in a vitrified glaze in a wide choice of colours. It may also be decorated.
Most tiles are square or rectangular in shape. They are produced in many sizes, with the most common ranging from 10x10cm to 35x70cm. The most typical complementary tiles are listels or strips, mouldings and border tiles. These tiles fall into group BIII, GL, in accordance with standards ISO 13006 and EN-UNE 14111, Appendix L (glazed dry-pressed ceramic tiles with a water absorption rate of E>10%).
Stoneware Floor Tile
This is the most common name for ceramic tiles with a low or medium-to-low water absorption rate, also known as “ceramic floor tiles”. This type of tile is ideal for indoor floors in residential or commercial premises. Some models are particularly resistant to frost and ice and abrasion, and so they can also be used as cladding on façades and for outdoor floors.
A stoneware floor tile is the name most commonly used for dry-pressed glazed ceramic tiles with a low or medium–to-low water absorption rate that are generally single fired. This kind of tile is also known as a vitrified floor tile, glazed ceramic floor tile or simply as ceramic flooring.
These tiles are suitable for indoor floors in residential or commercial premises. When they unite the necessary characteristics, particularly resistance to frost and ice or a high resistance to abrasion, they can be used as cladding on façades and on outdoor floors.
They have a stoneware tile body (with a low water absorption rate) or vitrified one (with a medium-to-low water absorption rate). This can be white, pale or somewhere between ochre and dark brown, without the colour affecting the tiles’ other characteristics. The tile body has a fine, homogenous texture, with no grain, inclusions or pores easily visible to the naked eye. The surfaces and edges are even and well finished. The glaze on the top surface, ranging from matt to high gloss, can be white or single coloured. It can also be decorated with different patterns.
Most tiles are square in shape, ranging from 10cmx10cm to 60cmx60cm, with some models with one or more chamfered corners, although rectangular tiles can also be found. The most common special tiles are insets, listels, skirting tiles, step tiles and step skirting tiles.
Stoneware tiles fall into groups BIb, GL (dry-pressed glazed ceramic tiles with a low water absorption rate E<3%) and BIIa, GL (dry-pressed glazed ceramic tiles with a medium-to-low water absorption rate 3%≤E<6%) in accordance with standards ISO 13006 and EN-UNE 14111, Appendixes H and J.
On occasions this name is used for extruded tiles, with a water absorption rate of about 3%. It is therefore advisable to check the exact nature of the tiles.
Porcelain stoneware is the name given to single-fired, dry-pressed, generally unglazed ceramic tiles with a very low water absorption rate.
A name widely used for unglazed ceramic tiles with a very low water absorption rate. Body stains are added to the tile body to colour them. These tiles can be used just as they are after firing or else the top surface can be polished to give it a smooth, shiny finish. The top surface can also feature embossed patterns for decorative purposes or non-slip protection.
Porcelain stoneware is the most recent type of ceramic tile to become available on the market available on the market. Spain manufactures a wide variety of such tiles and the demand for them is growing. There are two basic types:
- Unglazed porcelain stoneware, for which the name through-body porcelain tiles has become widely used, with an extremely low water absorption rate (less than 0.1%). The top surface is the upper part of the actual tile body and it can be plain coloured or decorated. The tile body can be fired only, (natural porcelain stoneware) or polished to a greater or lesser degree to make it smooth and shiny (polished and satin porcelain stoneware). The top surface can have an embossed pattern for decorative purposes or embossed diamond-shaped dots, grooves or angles to provide non-slip protection when used on outdoor floors or in industrial premises.
- Glazed porcelain stoneware, with a very low water absorption rate (threshold 0.5%). The top surface is covered in a vitreous coat that can be single coloured or decorated. The colour of the tile body varies, depending on the type of product, and it has a very fine, uniform texture, with no heterogeneous elements visible to the naked eye (unless added intentionally).
The surfaces and edges are even and well finished, except in the case of dry-pressed tiles with an intentional rustic look or extruded tiles.
Most tiles are square or rectangular in shape. The usual formats tend to vary from 15x15cm to 60x120cm. Complementary tiles used with them comprise listels, insets, step tiles and skirting tiles.
Dry-pressed porcelain stoneware tiles fall into group BIa (dry-pressed ceramic tiles with a water absorption rate of E<0.5%) in accordance with standards ISO 13006 and EN-UNE 14411, Appendixes G and A. Spain has proposed the creation and inclusion in the standard of a group called group AIa (extruded ceramic tiles with a water absorption rate of E<0.5%).
This is the name usually given to extruded ceramic tiles that are generally unglazed with a low or medium-to-high water absorption rate. Thanks to their special characteristics, they are particularly apt for a range of different uses: as cladding on façades; on outdoor floors, even in public spaces; on the floors of public or industrial premises etc. Their finish, with a slightly uneven surface, edges and colour, ensures special decorative potential.
Rustic stoneware is the name used for extruded ceramic tiles that are generally unglazed with a low to medium-to-low water absorption rate. They should not be confused with glazed stoneware with an intentional rustic look. Thanks to their special characteristics, they are particularly suitable as cladding on façades; on outdoor floors, even in public spaces; on the floors of public or industrial premises etc. Their uneven colour, surface and edges ensure special decorative potential.
A wide variety of types can be found, including:
› ’Quarry tiles’, whose name comes from their similarity with British quarry tiles. After being extruded and cut, they are moulded at a low pressure and, at this point, a mark can be made on the edges.
› Split tiles, known by the German name “Spaltplatten”. Two tiles are simultaneously moulded by extrusion, joined by the grooves on the back. They are split apart once fired by giving them a quick tap. This leaves the grooves with a roughly broken look. The long sides have a recessed edge to protect them when they are fired.
› Salt glazed tiles. These are covered in an uneven, shiny bronzish film, generated by dropping common salt on the tile surface during the firing process. These tiles are used on walls, including outdoor ones, because they lose their surface film if laid on floors, even if subject to light traffic.
The tile body ranges from ochre to dark brown. It has a heterogeneous texture, with grains, inclusions, pores and other irregularities visible to the naked eye. The surfaces and edges can be uneven, and this is accepted as being inherent in these tiles or even intentional.
Most tiles are square or rectangular in shape, ranging from 11x11cm to 45x45cm, with widely varying thicknesses, depending on the type of tile and format.
Rustic stoneware mainly falls into groups AI, UGL (unglazed extruded ceramic tiles with a water absorption rate of E<3%) or AIIa (unglazed extruded ceramic tiles with a water absorption rate of 3%≤E<6%) in accordance with standards ISO 13006 and EN-UNE 14411, Appendixes A, B and C. On occasions, this name is used for tiles moulded by dry pressing them. It is therefore advisable to check the exact nature of the tiles.
This is the name generally used for small square tiles measuring up to 7x7cm, although normally they measure between 2x2cm and 5x5cm.
The name mosaic tile only refers to the measurements of the tiles and not to the type of material. To make it easier to lay them, they usually come surface-mounted on perforated paper sheets or back-mounted on textile, paper or plastic mesh. They come in a 30x30cm or 30x60cm mesh-mounted format, made up of identical chips or matching sizes and shapes of one or more colours, even forming designs (borders, checkerboard patterns etc). The paper on surface-mounted tiles is removed after they have been laid, while the mesh on back-mounted ones is left in contact with the bonding material.
The following types are currently produced in Spain, in stable, limited numbers:
› Stoneware mosaic tiles with a low or medium-to-low water absorption rate, with a white tile body or coloured one through the addition of body stains. Used in kitchens and private toilets and bathrooms, and also now in wet areas for public use (swimming pools, showers, and similar).
› Glazed mosaic tiles, with a high-to-medium or high water absorption rate, and a pale-coloured tile body. Available in varying formats, even non-rectangular ones, they are used as coverings in private toilets and bathrooms, and swimming pools, and to cover curved surfaces or ones with convex or concave sections.
› Glass mosaic tiles. Even though they are not made of ceramic material, they are mentioned here, given their similarity to the above. They are practically non porous, can come in a wide variety of plain or speckled colours, and are suitable for covering walls in wet areas or swimming pools.
› ’Trencadís’ tiles can also be considered mosaic tiles. That is, tiles broken into irregular pieces of different colours, used for decorative purposes.