WHAT ARE TILES?
A tile is a manufactured piece of hard-wearing material such as ceramic, stone, metal, or even glass. Tiles are generally used for covering roofs, floors, walls, showers, or other objects such as tabletops. Alternatively, tile can sometimes refer to similar units made from lightweight materials such as perlite, wood, and mineral wool, typically used for wall and ceiling applications. In another sense, a tile is a construction tile or similar object, such as rectangular counters used in playing games (see tile-based game). The word is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of fired clay. Tiles are often used to form wall and floor coverings, and can range from simple square tiles to complex mosaics. Tiles are most often made from porcelain, fired clay or ceramic with a hard glaze, but other materials are also commonly used, such as glass, metal, cork, and stone. Tiling stone is typically marble, onyx, granite or slate. Thinner tiles can be used on walls than on floors, which require thicker, more durable surfaces.
Ceramics for tiles include earthenware, stoneware, or porcelain stoneware. Stoneware is harder and more durable than earthenware, and so more suitable for floors. Earthenware is often used for roof tiles. Floor and wall tiles are commonly made of ceramic or stone, although recent technological advances have resulted in rubber or glass tiles for floors as well. Ceramic tiles may be painted and glazed while small mosaic tiles may be laid in various patterns. The spaces between the tiles are nowadays filled with sanded or un-sanded floor grout, but traditionally mortar was used.
Natural stone tiles can be beautiful but as a natural product they are less uniform in color and pattern, and require more planning for use and installation. Mass-produced stone tiles are uniform in width and length. Granite or marble tiles are sawn on both sides and then polished or finished on the facing up side, so that they have a uniform thickness. Other natural stone tiles such as slate are typically "riven" (split) on the facing up side so that the thickness of the tile varies slightly from one spot on the tile to another and from one tile to another. Variations in tile thickness can be handled by adjusting the amount of mortar under each part of the tile, by using wide grout lines that "ramp" between different thicknesses, or by using a cold chisel to knock off high spots.
Some stone tiles such as polished granite, marble, and travertine are very slippery when wet. Stone tiles with a riven (split) surface such as slate or with a sawn and then sandblasted or honed surface will be more slip resistant. Ceramic tiles for use in wet areas can be made more slip resistant either by using very small tiles so that the grout lines act as grooves or by imprinting a contour pattern onto the face of the tile.
The hardness of natural stone tiles varies such that some of the softer stone (e.g. limestone) tiles are not suitable for very traffic-heavy floor areas. On the other hand, ceramic tiles typically have a glazed upper surface and when that becomes scratched or pitted the floor looks worn, whereas the same amount of wear on natural stone tiles will not show, or will be less noticeable.
Natural stone tiles can be stained by spilled liquids; they must be sealed and periodically resealed with a sealant in contrast to ceramic tiles which only need their grout lines sealed. However, because of the complex, non-repeating patterns in natural stone, small amounts of dirt on many natural stone floor tiles do not show.
Most vendors of stone tiles emphasize that there will be variation in color and pattern from one batch of tiles to another of the same description and variation within the same batch. Stone floor tiles tend to be heavier than ceramic tiles and somewhat more prone to breakage during shipment.
Rubber floor tiles have a variety of uses, both in residential and commercial settings. They are especially useful in situations where it is desired to have high-traction floors or protection for an easily breakable floor. Some common uses include flooring of garage, workshops, patios, swimming pool decks, sport courts, gyms, and dance floors.
Plastic floor tiles including interlocking floor tiles that can be installed without adhesive or glue are a recent innovation and are suitable for areas subject to traffic-heavy areas, wet areas and floors that are subject to movement, dampness or contamination from oil, grease or other substances that may prevent adhesion to the substrate. Common uses include old factory floors, garages, gyms and sports complexes, schools and shops.
Ceramic tile is manufactured from clay materials that are quarried, prepared, and then formed into a mould. Common forming methods for ceramic tile include dry press, extruded, and slush mould. The dry press forming method involves a mixture of dry material being pressed into a mould under extreme pressure. Extruded ceramic tile is formed when a mixture of slightly wet material is extruded into a mould. Slush mould is a forming method in which a mixture of very wet material is poured into a mould and then hardened in a kiln at an extremely high temperature.
Porcelain & Non-Porcelain
Ceramic tile can best be characterized as either porcelain or non-porcelain. Traditional ceramic tile is non-porcelain and is made from white, red, and/or brown clay and other minerals. Porcelain ceramic tile is made from clay and minerals as well, but it also contains 50% of a white dust or sand called feldspar. Feldspar is a type of crystal found in rock that acts as a "flux" during the kiln-drying process, melting into a glass-like material and bonding all of the moulded ingredients together. Minor modifications to the ingredients of ceramic tile or the kiln-drying process (i.e., to the temperature and type of kiln) create enormous variety in the appearance and characteristics of manufactured ceramic tile flooring products.
Porcelain and non-porcelain ceramic tile can be either unglazed or glazed. Glazed tile has a matte, semi-gloss, or high-gloss finish applied to the surface during the manufacturing process. In the past, glazed tile was kiln-fired twice, once to harden the tile mould and a second time to harden the glaze. Today, in addition to double-fired ceramic tiles, an automated single-fired manufacturing process called Monocuttura hardens a glazed mould in one step. Glazed tiles have increased stain resistance, scratch resistance, and traction, as well as decreased water absorption, in comparison to an unglazed tile.
Non-porcelain, ceramic tile is among the most economical types of tile flooring. Porcelain ceramic flooring is more expensive than non-porcelain and can be harder to work with. However, it offers greater durability, natural stain resistance, minimal water absorption, and through-bodied color. Many types of tile are manufactured in a similar fashion to ceramic tile, but they are less common. These include brick, cement, glass, encaustic, saltillo, and terra cotta tile. The varying materials and manufacturing processes create distinctive product characteristics.
Natural stone tiles:
Natural stone tile is produced from natural materials that are quarried, slabbed, finished, and cut to size. Common types of stone used as flooring tile include granite, marble, limestone (including travertine), and slate. Among these types of natural stone are thousands of varieties with characteristics that depend on where and when the stone was quarried.
Granite is a type of igneous rock that is very dense and hard. Its distinctive appearance is due to speckled minerals found within the rock, its unique veining, and the thousands of available colors. Granite is nearly impervious and, once it is polished, resists scratching. It is an excellent choice for flooring in kitchens and high-traffic areas.
Marble is a type of metamorphic rock that has rich veining and is available in a variety of colors. Marble is more porous than granite and is not recommended for kitchen flooring unless honed and then sealed on a regular basis.
Limestone is a type of sedimentary rock that offers an earthy appearance in both light and dark shades. The surface can be textured or polished smooth. Limestone is less dense than granite and marble. It can be easily stained and is also prone to scratching. It is not recommended for kitchen or high-traffic flooring applications.
Travertine is a type of limestone that offers an unusual crystallized appearance with an earthy tone. Travertine is a soft, porous stone with a natural surface that has pitting or divots. A honed or polished surface can be achieved after filling the surface voids. Travertine is not recommended for kitchen floors, as it can be easily scratched and stained. Special care and surface sealing is required to maintain travertine.
Slate is a type of metamorphic rock that is extremely dense and very durable. Slate is available in darker earthy tones. The surface of slate is naturally textured unless a smooth, honed finish is achieved. Slate is an excellent choice for kitchen and high-traffic area flooring.
Natural Stone Tile Surface Finishes
The face of stone tile flooring typically has one of three types of finishes applied:
The finishing process of natural stone begins once the stone is quarried and cut into a rough slab. The rough slab face is polished with abrasive pads with extremely coarse abrasive pads being used first, then less coarse pads used until the final buffing.
The tiles are then cut to size by a stone fabricator readied for a surface application. The surface finish you apply will depend on where you intend to use the stone tile and the desired appearance. Natural surfaces are unfinished and have an earthy, dull appearance. Texture and pitting are visible characteristics of natural stone tile.
Honed surfaces are achieved by terminating the finish process prior to buffing. The smooth, matte appearance is excellent for high-traffic and wet areas to prevent slipping and wear. Polished surfaces are highly reflective with a mirror-like finish. The process of achieving a polished finish is a benefit to the porosity of stone tile, creating an almost impervious surface. However, it also creates a more slippery surface. In addition to these common types of finishes, other types are available that offer distinctive appearances and present their own advantages and disadvantages. Depending on the type of stone tile you choose and its intended application, you might opt for one of the other surface finish types. It is best to consult with a stone fabricator to determine the best surface finish for your project.
Similar to mosaics or other patterned tiles, pebble tiles are tiles made up of small pebbles attached to a backing. The tile is generally designed in an interlocking pattern so that final installations of multiple tiling square fit together well and have a seamless appearance.
A relatively new tile design, pebble tiles were originally developed in Indonesia using pebbles found in various locations in the country. Today, pebble tiles feature all types of stones and pebbles from around the world, but are still generally associated with pebbles found in exotic locations.
Ceiling tiles are lightweight tiles used in the interior of buildings. They are placed in an aluminium grid and they provide little thermal insulation but are generally designed to improve the acoustics of a room.
- Mineral fibre tiles are fabricated from a range of products;
- Wet felt tiles can be manufactured from perlite, mineral wool, and fibers from recycled paper.
- Stone-wool tiles are created by combining molten stone and binders which is then spun to create the tile, or gypsum tiles which are based on the soft mineral and then finished with vinyl, paper or a decorative face.
Ceiling tiles very often have patterns on the front face; these are there in most circumstances to aid with the tiles ability to improve acoustics.
Ceiling tiles, especially in old Mediterranean houses were made of terracotta and were placed on top of the wooden ceiling beams and upon those were placed the roof tiles. They were then plastered or painted, but nowadays are usually left bare for decorative purposes.
Printing techniques and digital manipulation of art and photography are used in what is known as "custom tile printing". Dye sublimation printers, inkjet printers and ceramic inks and toners permit printing on a variety of tile types yielding photographic-quality reproduction. Using digital image capture via scanning or digital cameras, bitmap/raster images can be prepared in photo editing software programs.
Specialized custom-tile printing techniques permit transfer under heat and pressure or the use of high temperature kilns to fuse the picture to the tile substrate. This has become an increasingly popular method of producing custom tile murals for kitchens, showers, and commercial decoration in restaurants, hotels, and corporate lobbies.
Diamond etched tiles
A new method for custom tile printing involving a diamond-tipped drill controlled by a special type of computer has been implemented. Compared to laser engraving techniques diamond etching has become a preferred method and is in almost every circumstance more permanent thus the optimal choice.
Decorative tilework and coloured brick
Decorative tile work should be distinguished from mosaic, where forms are made of great numbers of tiny irregularly positioned tesserae in a single colour, usually of glass or ceramic based tiles.
HISTORY OF TILES & TILE WORK
The earliest evidence of tiles is the discovery of glazed bricks in the Elamite Temple at Chogha Zanbil, dated to the 13th century BCE. Glazed and coloured bricks were used to make low reliefs in Ancient Mesopotamia, most famously the Ishtar Gate of Babylon (ca. 575 BCE), now partly reconstructed in Berlin, with sections elsewhere. Mesopotamian craftsmen were imported for the palaces of the Persian Empire such as Persepolis. Tiling was widespread in the time of the Sinhalese kings of ancient Sri Lanka, using smoothed and polished stone laid on floors and in swimming pools. Historians consider the techniques and tools for tiling as well advanced, evidenced by the fine workmanship and close fit of the tiles. Tiling from this period can be seen in Ruwanwelisaya and Kuttam Pokuna in the city of Anuradhapura.
Early Islamic mosaics in Persia consist mainly of geometric decorations in mosques and mausoleums, made of glazed brick. Typical turquoise tiling becomes popular in 10th-11th century and is used mostly for Kufic inscriptions on mosque walls. The Seyed Mosque in Isfahan (1122 AD), The Dome of Maraqeh (1147 AD) and the Jame Mosque of Gonabad (1212 AD) are among the finest examples. The dome of Jame' Atiq, Mosque of Qazvin, is also dated to this period.
The golden age of Persian tilework began during the reign the Timurid Empire. Single color tiles were cut into small pieces and assembled by pouring liquid plaster between them. After hardening, these panels were assembled on the walls of buildings. But the mosaic was not limited to flat areas. Jame Mosque in Yazd (1324-1365 AD) and Goharshad Mosque (1418 AD) are prominent examples of brick and tile mosaics of interiors and external surfaces of domes. Islamic buildings in Bukhara (16th-17th century) also exhibit very sophisticated floral ornaments.
Mihrabs, being focus points of mosques, were usually the places where most sophisticated tilework was placed. The 14th century mihrab at Madrasa Imami in Isfahan is an outstanding example of aesthetic union between the Islamic calligrapher's art and abstract ornament. The pointed arch, framing the mihrab's niche, bears an inscription in Kufic script used in 9th-century Qur'an.
One of the best known architectural masterpieces of Iran is the Shah Mosque, situated in Isfahan, from the 17th century. Its dome is a prime example of mosaic type tiling and its winter praying hall houses one of the finest ensembles of cuerda seca tiles in the world. A wide variety of tiles had to be manufactured in order to cover complex forms of the hall with consistent mosaic patterns. The result was a technological triumph as well as a dazzling display of abstract ornamentation.
During the Safavid period mosaic ornaments were often replaced by a haft rang (seven colors) technique. Where pictures / images were painted on plain rectangular tiles, glazed and fired afterwards. Besides economic reasons, the seven colors method gave more freedom to artists and was less time-consuming. It was popular until Qajar period when the palette of colors was extended by yellow and orange.
The Persianate tradition continued and spread to many parts of the Islamic world, notably the İznik pottery of Turkey under the Ottoman Empire in the 16th and 17th centuries. Palaces, public buildings, mosques and mausoleums were heavily decorated with large brightly coloured patterns, typically with floral motifs, and friezes of astonishing complexity, including floral motifs and calligraphy as well as geometric patterns.
The zellige tradition of Arabic North Africa uses small coloured tiles of various shapes to make very complex geometric patterns. It is halfway to mosaic, but as the different shapes must be fitted precisely together, falls under tiling.
Medieval Europe made considerable use of painted tiles, sometimes producing very elaborate schemes, of which few have survived. Religious and secular stories were depicted. The imaginary tiles with Old testament scenes shown on the floor in Jan van Eyck's 1434 Annunciation in Washington are an example. The 14th century "Tring tiles" in the British Museum show childhood scenes from the Life of Christ, possibly for a wall rather than a floor, while 13th century "Chertsey Tiles", though from an abbey, show scenes of Richard the Lionheart battling with Saladin in very high-quality work. Medieval letter tiles were used to create Christian inscriptions on church floors.
Transmitted via Islamic Spain, a new tradition of ‘azulejos’ developed in Spain and as well as Portugal, which by the Baroque period produced extremely large painted scenes on tiles, usually in blue and white, for walls rather than floors. Delftware wall tiles, typically with a painted design covering only one (rather small) blue and white tile, were ubiquitous in Holland and widely exported over Northern Europe from the 16th century on, replacing many local industries. Several 18th century royal palaces had porcelain rooms with the walls entirely covered in porcelain in tiles or panels. Surviving examples include ones at Capodimonte, Naples, the Royal Palace of Madrid and the nearby Royal Palace of Aranjuez.
There are several other types of traditional tiles that remain in manufacture, for example the small, almost mosaic, brightly coloured zellige tiles of Morocco and the surrounding countries. With exceptions, notably the Porcelain Tower of Nanjing, decorated tiles or glazed bricks do not feature largely in East Asian ceramics.
The Victorian period saw a great revival in tile work, largely as part of the Gothic Revival, but also the Arts and Crafts Movement. Patterned tiles, or tiles making up patterns, were now mass-produced by machine and reliably level for floors and cheap to produce, especially for churches, schools and public buildings, but also for domestic hallways and bathrooms. For many uses the tougher encaustic tile was used. Wall tiles in various styles also revived; the rise of the bathroom contributing greatly to this, as well as greater appreciation of the benefit of hygiene in kitchens. William De Morgan was the leading English designer working in tiles, strongly influenced by Islamic designs.
Since the Victorian period tiles have remained standard for kitchens and bathrooms, and many types of public area. Portugal and São Luís continue their tradition of azulejo tilework today. Notable among American tile manufacturers of the 1920s and 1930s were Ernest A. Batchelder and Pewabic Pottery.