Ceramic tile
Ceramic tiles are ceramic plates that are used as wall cladding as well as coverings for the floor , work surfaces, window sills and other surfaces, both indoors and outdoors. The term "tile" is also used for natural stone , glass , carpet , etc. to classify components of a similar shape and use. In Switzerland one speaks of "Plättli", while in the written language mostly "Platten" or "Platchen" is used. The term tile is more common in southern Germany and Austria ( see also: stove tile ). Art historical research and description always uses tiles .
history
Ceramic comes from the Greek word for clay, "Keramos". Clay minerals arise from the predominantly finest-grained weathering products of feldspars , which have been deposited with various admixtures. The composition of the clay, the preparation and the firing determine the color of the unglazed body . The word tile comes from the Middle High German kachele ("earthen pot").
The first objects made of baked clay were made by humans around 30,000 years ago, while the first ceramic vessels were made around 11,000 years ago in the Nile Delta . The first European ceramic industries were to be found in the Roman Empire: red, glazed utility ceramics ( terra sigillata ) were widespread throughout the Roman Empire. The typical red roof tiles have also been produced in large quantities. Floor tiles were also used in the lower middle class. The Roman underfloor heating was based on ceramic and therefore heat-resistant materials. The red color was created by the controlled ventilation of the kiln . Black ceramic was fired in the absence of air and was relatively expensive, as it was very time-consuming to seal the kiln.
Ceramic tiles as wall coverings were used in ancient times in Egypt , Mesopotamia and Persia and were later adopted by Islamic-Arabic architecture . With the Moors , colored glazed mosaic tiles came to Spain and Portugal , where they are known as azulejos .
The first non-Roman ceramic floor coverings in Germany can be found in the year 1000 . The trade routes of the Dutch, Spanish and Italians spread the ceramics throughout Europe. However, the production was very complex and expensive, as the technical knowledge of the Romans for industrial production had been lost.
In Western and Central Europe, tiles were mainly used as floor coverings and to surround chimneys in the Middle Ages . These clay tiles , also known as clay tiles , often had relief decorations or different colored clay was inserted so that a two-tone pattern was created.
Faience tiles from Italy , Spain and France are mainly mentioned for the 15th and 16th centuries . From there the faience reached Antwerp , which developed into a center of tile production between 1520 and 1570. After the Treaty of Antwerp in 1609, tile production began in the Netherlands . Although the products are mostly called Delft tiles , Delft lost its importance as a tile producer from 1650 and was replaced by factories in Rotterdam , Utrecht , Haarlem and Makkum . The blue-and-white Dutch tile tableaus and individual tiles became so important that they were even exported back to Portugal or there encouraged the production of " Azulejos in Dutch fashion". Also, northern Germany and Denmark imported Delft tiles, which often whole offices ( Pesel were embellished). Accordingly, the range of images ranged from Bible tiles to seafaring and hunting .
With the industrial revolution in the 19th century, the spread of ceramic floor coverings increased sharply. Initially produced as extra income from the brickworks , an independent industry emerged . Since the late 20th century, tiles have been produced almost exclusively in highly automated factories. But there are still small craft businesses that produce individual ceramics in very small series.
Manufacturing
Processing of raw materials
The raw materials used have changed little since the beginning of ceramic production. The basis is clay as the main ingredient of the soil type . Mixtures from different clay pits are used, depending on the application. In addition to clay, other mineral raw materials are part of the recipe for a ceramic. The most important additives are quartz , kaolin and feldspar . Depending on the application, calcite , dolomite , fluorspar or chamotte are also added. The art of processing is to be able to control, among other things, the prevention of segregation prior to shaping and the shrinkage behavior in the event of fire. These factors largely depend not only on the grain size, but above all on the grain shape. The rounder the grains, the lower the strength, and the lower the shrinkage.
Shaping
Hand-formed ceramic tiles are usually only made with cotto or special applications. The extrusion process and powder pressing (also called dry pressing) are used in modern ceramic production. During extrusion, an endless band is made from a plastic ceramic mass by extrusion as single or double tiles (split clinker) and then cut into tile size. In the dry pressing process, specially prepared ceramic powder is pressed into molds at high pressure and then fired.
All tiles have special patterns on the underside of the tile that create a better mortar bond. During extrusion, there are always longitudinal grooves due to the process, which can also be deepened in a dovetail shape; during pressing, only simple patterns can be pressed in.
A relatively new process is the use of roller presses for large-format porcelain stoneware panels (1 to more than 300 cm). The ceramic base material is pressed between two axially moving rollers. A pure powder press with plate sizes of more than two square meters would not be economical.
Colours
The color of unglazed ceramic tiles is usually caused by coloring oxides . These oxides are either natural components of the raw materials (for example iron oxide , manganese dioxide , titanium dioxide ) or they are specifically added to the body.
With glazed ceramic, the surface is colored by a glaze applied to the body . In the Monoporosa process, the glaze is applied before firing. In the biporosa process, the body is first fired, cooled and then fired again with the glaze raw material.
Types of ceramics for walls and floors
| product | Product standard | Areas of application |
|---|---|---|
| Earthenware tiles |
EN 14411 group BIII |
Wall coverings in residential and non-residential construction |
| Stoneware tiles |
EN 14411 group Blb; BIIa; BIIb |
Interior wall coverings in residential and non- residential construction Floor coverings according to the required wear class (interior and exterior coverings ) Tank construction (drinking water tanks , swimming pools) |
| Fine stoneware |
EN 14411 group BIa |
Preferably (wall and) floor coverings in residential and non-residential construction |
Earthenware
Earthenware (DIN EN 14411, group BIII, appendix K) is ceramics whose “shards” show a water absorption of more than 10 percent after firing at 950–1150 ° C. The advantage is that they can be easily machined and decorated. Due to its high porosity, earthenware is not frost-resistant and is restricted to indoor applications. The main application here is as a glazed wall tile. A distinction is made between two processes in the manufacture of earthenware: In the single- firing process (monoporosa) , liquid glaze is applied to the tile immediately after it has been shaped . The tile is then printed with a desired pattern; In the two-fire process (biporosa) , the body is burned first. Then the tile is glazed and printed and then fired again.
Stoneware
Stoneware is defined as ceramic with a water absorption of less than 3 percent. Due to its low porosity, the material is frost-resistant. Compared to the more porous earthenware, stoneware has a higher density and better mechanical strength. Almost all tiles for heavily used areas of application, for example in industry, trade or for public areas, are made of unglazed stoneware. The slip resistance is adjusted by the surface structure. Stoneware tiles with glazes are the classic floor ceramic. The technical properties of the glaze determine its abrasion resistance and slip resistance.
In contrast to the earthenware, the body is fired at 1150–1300 ° C. By adding fluorspar and other fluxes, the porosity can be reduced.
Porcelain stoneware
Fine stoneware (FSZ) is characterized by a very low water absorption of less than 0.5%. It represents a further development of the stoneware tiles, the water absorption of which is below 3%. Porcelain stoneware is produced by dry pressing of finely prepared ceramic raw materials with larger proportions of quartz , feldspars and other fluxes under high pressure. The body is then burned in a roller kiln at high temperatures (1200–1300 ° C).
Due to its high breaking strength and good wear properties, FSZ is preferred in public and heavily used areas. The slip resistance of R 9 - R13, V4 can be adjusted by means of appropriate surface structures.
First of all, unglazed tiles were produced, which have a high-density sintered burning skin that is almost as resistant to the formation of stains as glazed surfaces.
This firing skin and also specially glazed surfaces can be refined to a so-called "lapped" surface using fine diamond polishing discs. If this surface is structured or designed in a relief-like manner, the higher projecting area appears rather shiny, the lower area rather matt.
Polished FSZ does not have a closed surface. The pore spaces of the body are opened during polishing by removing the so-called burning skin, which makes certain impurities that occur after laying, more difficult to remove. The porosity varies greatly depending on the manufacturing process.
The surface of unglazed FSZ can be influenced by applying colored ceramic powders or soluble salts. However, the options are limited due to the translucent body. Glazed and printed FSZ is increasingly being manufactured with a wide variety of decors. For example, stones, woods, fabrics, cork, leather, etc. can be imitated.
Glazes on stoneware and porcelain stoneware usually do not achieve the abrasion resistance of the carrier material.
terracotta
The basic material for this type of tile, also known colloquially as cotto , is a marl of lime , which is also known as Tuscan slate and contains impurities from quartz crumbs . The material obtained in the open-cast mine is mixed with water, kneaded, rotated by a shredding system ("Wolf") and extruded or dry-pressed, or pressed into wooden molds and dried in the air. Traditionally, reliefs or patterns were also pressed into the moist mass. After the drying process, the surface structure is partially adapted by working with steel brushes. The fire takes place over 36–48 hours at a temperature of 950 to 1050 ° C. Oxidation of the blue-gray tone creates the typical reddish colored cotto. Terracotta products are made with a greater material thickness than modern ceramic products, since the coarse and calcareous raw material often does not have great strength.
Clinker and split clinker
The classic clinker bricks belong to the heavy clay products . Consisting of chamotte , feldspars and white or red-burning clays (ie the color is only created by the fire), they are mixed like cotto as a dough and shaped in an extrusion process. When a residual moisture of around three percent has been reached during drying, the hard brick is glazed or unglazed and fired at 1200 ° C. In order to minimize deformations during firing due to differently structured upper and lower sides, such panels are often formed as split clinker in duplicate (back to back, connected with bars), fired together and only separated or split after completion.
High edge sharpness and resistance to water and frost are the prerequisites that clinker is an ideal floor and wall covering for indoor and outdoor areas, also as a facing that is glued in front of a masonry with a clinker mortar. The popular name as "clinker wall" for each facing wall shell is incorrect. For this, softer stones, also harder burnt perforated brick, are used, but only rarely (and improperly) full clinker stones, as such walls easily crack due to insufficient mortar bond.
Solid clinker is mainly used as a pavement surface. These are unglazed clinker bricks. These are sure-footed, water-repellent, frost-resistant and durable. They also change their color very little in use and hardly get dirty, they just get a patina.
Criteria for the properties of use
Tiles are essentially classified according to their water absorption capacity, their frost resistance, their slip-resistant properties and the resistance of their surface to abrasion .
Ceramic tiles are divided into two qualities: first and second choice. Both visual and qualitative requirements are placed on the glaze, surface, dimensional accuracy and water absorption. Tiles with gross defects are often offered as a third choice or are rejected.
Water absorption capacity
| group | Mass% water absorption capacity |
|---|---|
| Yes | at most 0.5% |
| Ib | at most 3% |
| IIa | 3% to 6% |
| IIb | 6% to 10% |
| III | more than 10% |
The European standard DIN EN 14411 divides ceramic tiles into five groups according to their water absorption capacity. The test is carried out in accordance with DIN EN ISO 10545.
Only tiles from groups Ia and Ib are frost-resistant and therefore suitable for outdoor use. This also applies to tiles on roofed surfaces such as balconies , as these can also be damaged by frost after they have become damp. Since ordinary grout is permeable to water, care must be taken to use frost-resistant materials and correct processing when gluing and substructure.
Because of the dense body, porcelain stoneware tiles are generally frost-resistant.
Abrasion resistance
The abrasion resistance of the glaze of stoneware tiles (resistance to surface wear ) is tested by a standardized test method with a testing machine with rotating steel brushes from the American Porcelain and Enamel Institute (PEI) or by sandblasting and according to DIN EN ISO 10545-7 in classes 0 to 5 (see table).
Abrasion (surface wear) occurs on floor coverings as a result of abrasive, rubbing stress and can become visible in glazed tiles through a change in the gloss of the surface. Glazed stoneware tiles are divided into groups according to their resistance to abrasion and can thus be assigned to areas of application. The abrasion resistance (wear group) is the resistance of glazed tiles and slabs determined by grinding and sandblasting tests. It is specified by the manufacturer.
| Abrasion class |
Test revolutions | Areas of application |
|---|---|---|
| 1 | 150 | for wall material as well as surfaces walked on barefoot or with slippers |
| 2 | 600 | for light use in less used rooms in private households |
| 3 | 750/1500 | for medium and scratchy wear with normal shoes; in private hallways, hallways and balconies, as well as in hotel rooms and bathrooms |
| 4th | 2100/6000/12000 | for heavy use due to frequent walking with normal shoes in public entrance areas, terraces, kitchens, as well as in commercial and sales rooms, hospitals, office buildings, hotels and schools |
| 5 | > 12000 | Areas of application with very high levels of public traffic, such as traffic facilities, restaurants, sales, assembly and sports facilities, as well as where traffic is stressed, such as in garages |
Artificial abrasion is determined by adding water and defined abrasives. The result is a value that indicates the number of revolutions at which a visible change occurs. These values are then used for a classification.
In the case of unglazed ceramic tiles, the depth of wear is determined in accordance with DIN EN ISO 10545-6. The "resulting abrasion" is measured with fused corundum and a special grinding wheel. The lower the value, the more wear-resistant the ceramic is.
Slip resistance
| group | Coefficient of friction | Inclination angle |
|---|---|---|
| R9 | minimum | from 6 to 10 ° |
| R10 | elevated | from 10 to 19 ° |
| R11 | increased2 | from 19 to 27 ° |
| R12 | big | from 27 to 35 ° |
| R13 | very large | over 35 ° |
| group | Minimum volume (cm³ / dm²) |
|---|---|
| V4 | 4th |
| V6 | 6th |
| V8 | 8th |
| V10 | 10 |
The anti-slip test according to DIN 51130 results in the classification in R values. The higher the number behind the "R", the more slip-resistant and difficult to clean the flooring is. As can be seen from the table, there are evaluation groups from R9 to R13. However, the BGR 181 of the employers' liability insurance association does not apply to floors in work rooms, work areas and company traffic routes where no slip-promoting agents are to be expected. Umbrellas transport water, so BGR 181 should always be taken into account. If there is a deviation from BGR 181, the employers' liability insurance association and the trade supervisory authority should always be asked about the respective building object, as it is possible that both institutions may have different opinions. In areas where greasy, pasty or fibrous-viscous substances get on the floor, tiles may also have to have a "displacement space". This displacement space is the hollow space below the walking level that is open towards the walking level and is assessed according to four V-classes. The V-value indicates how many cm³ of liquid the soil can at least absorb on one dm².
Ceramics for wet barefoot areas are a specialty . These surfaces are tested according to DIN 51097 and divided into evaluation groups according to GUV 26.17 A, B and C.
There are no guidelines for the private sector. Polished or glazed ceramics can be used there. However, a private swimming pool or sauna should be designed in accordance with the rules of GUV 26.17 anti-slip protection for wet barefoot areas.
If floor coverings are planned or installed with a lower minimum slip resistance (according to BGR 181 / GUV 26.17), there is a risk of claims for damages or recourse in the event of an accident.
Acid resistance
The acid resistance is determined according to DIN EN ISO 10545-13.
Stain sensitivity
Stain sensitivity is classified according to DIN EN ISO 10545-14.
Ecological aspects
As a result of the fire, ceramic tiles do not contain any gases that pollute the room. When laying with a lime or cement mortar, the room air is no longer polluted when the mixing water has evaporated.
Fine stoneware as well as glazed stoneware and earthenware have a very dense surface. Molds generally only find a suitable substrate in the joints.
When laying with reactive resins, which are acid-resistant, there is not only a risk of evaporation but also a higher risk of microbiological colonization compared to alkaline adhesive and grouting mortars.
The radiation exposure depends on the raw materials used. Sodium diuranate (uranium glass) and cobalt glazes used to be the main hazard . (See Radon Exposure .)
Formats
Until the 1970s, the 15 × 15 cm format dominated the wall tiles. Since then, a large number of new formats have been offered with the tendency towards larger and larger tiles that are now room-high.
The most common formats in 2008 were between 25 × 33 and 30 × 90 cm for wall tiles made of earthenware and 30 × 30 and 45 × 90 cm for floor tiles made of (fine) stoneware. In the new millennium, 30 × 60 (porcelain stoneware and earthenware) and 60 × 60 cm (porcelain stoneware) were the standard formats and were accordingly inexpensive.
In 2020, formats around 60 × 120 cm and 90 × 90 cm will be offered in the medium price segment and will achieve double-digit market shares, while XXL formats from 240 × 100 to 320 × 160 cm, often only 3–7 mm thick, can still be found in the upscale segment are and are increasingly being used for shower areas with few joints and surfaces of tables and kitchen worktops . Due to the more complex manufacturing process and investments in new production facilities, larger formats are usually more expensive than the most widespread or already discontinued formats.
Mosaic tiles in sizes from 1 × 1 cm to 10 × 10 cm are also increasingly used.
There are also shaped pieces for plinths, borders , steps, corners etc. as well as special rails for connection to other floor coverings, corners etc.
Dimensions
A distinction must be made between the nominal size, the factory size, the coordination size, the modular size and the actual size.
The nominal size (e.g. 15 × 15 cm) describes the nominal tile size in cm under which the tiles are traded. The actual size describes the actual dimensions that can vary from tile to tile within the tolerance range.
The work dimension "W" is the manufacturing dimension provided by the manufacturer and is added with the joint to form the coordination dimension "C" (in mm). For example, a tile with a work dimension of 247 × 197 × 5 mm has a coordination dimension of 250 × 200 mm and a joint width of 3 mm. The nominal size is 25 × 20 cm.
The modular dimension is based on a grid of M = 100 mm and is the same as the coordination dimension. This means that it contains the specification for the joint thickness in connection with the work size.
calibration and rectification
Due to the firing process, traditionally manufactured tiles have slightly rounded edges and certain dimensional deviations and are intended for laying with joint widths of around 5 mm (or in the range of 3 to 8 mm).
In order to achieve narrower joint widths without visually noticeable deviations in dimensions, tiles are pre-sorted in the factory (according to "caliber"). Assorted tiles usually have dimensional deviations of less than ± 0.7 mm and are marked on the packaging with the information “calibrated” or “cal.” As well as the exact dimension or a code number. Tiles with the same code number should be used when laying with a narrow joint width.
Porcelain stoneware tiles are also offered as "rectified". Rectified tiles were cut to size after the fire so that they had sharp and precisely right-angled edges. With precisely defined external dimensions, the joint width can be reduced to 1.5 to 2 mm. The sharp-cut edges are, however, clearly noticeable optically and when walking on floor surfaces if there are height differences between the panels. Special care is therefore required when laying.
Ceramic tile surfaces and cleaning
Dirt adhesion and cleaning effort are primarily dependent on the surface roughness. While wall tiles and many floor tiles have an easy-care, smooth surface, a non-slip surface is required in commercial kitchens and swimming pools, which can be achieved by structuring and increasing the roughness of the tile surface.
impregnation
Impregnating agents such as silanes reduce the stain sensitivity of open-pored surfaces. Color-changing substances can also move into capillary absorbent ceramics such as terracotta or earthenware .
In the case of glazed ceramics, unpolished porcelain stoneware and unglazed, but surface-treated coverings by the manufacturer ("ceramic sealing"), impregnation cannot penetrate the surface and would leave an undesirable layer on the surface. Even with open-pored materials, residues of the impregnating agent that are not absorbed by the surface can lead to the adhesion of impurities, especially soot contained in rubber .
When polishing porcelain stoneware, the sintered surface is removed so that the fine pore spaces are exposed. Although porcelain stoneware is hardly absorbent by capillary action, manufacturers often recommend impregnation to make cleaning easier.
Brick floors made of unglazed stoneware ( terracotta ) or (split) clinker bricks were traditionally impregnated with clinker oil or other pore-filling agents if it seemed necessary to protect them from grease, red wine and other stains. Some manufacturers recommend impregnating before grouting.
Special impregnating agents are available to seal the joints. It is often recommended to clean the joints beforehand with an acidic cleaning agent (e.g. anti-limescale).
Factory remuneration
Subsequent protective treatments using impregnation agents differ from factory-made mineral surface finishes such as glazes or engobes . These are melted onto the surface in the course of a second firing process and form a smooth, liquid and dirt-repellent coating.
cleaning
Especially after grouting unglazed tiles, the grout should be washed off thoroughly so that the binder does not stick to the surface and harden there. If the surface does discolour, cement film remover can be used to loosen and remove the gray cement covering. This acidic special cleaner also attacks the joints. They should therefore be moistened to make it more difficult for the cleaner to penetrate the joint. After washing off the cleaner, the surface can be neutralized with an alkaline (cleaning) agent.
Tiles with a closed surface are easy to care for and can be cleaned with any household cleaner. Alkaline cleaning agents are recommended to remove greasy contamination.
Cleaning agents containing care products that leave behind a film of grease , wax or polymer can change the appearance of the tile surface and, in the long run, accumulate in an unsightly and, in the worst case, sticky layer. If these agents are used in the professional sector to influence the properties of the tile surface, the layers that remain are usually removed again during an intensive annual thorough cleaning.
In the case of stubborn soiling and non-slip tiles with a rough surface structure, it may be necessary to let the cleaning agent take effect and use microfiber covers, brushes or cleaning pads. Brushes and pads should not contain any abrasive grain additive that would dull or wear off the surface.
Mold and black mold stains are removed with chlorine-based cleaning agents or a special mold remover.
Tile mirror
A tile mirror is a wall covering halfway up that does not reach the floor. Tile mirrors are used as splash protection behind sinks , washbasins and other sanitary items and as the back walls of kitchen units.
See also
literature
- Anne Berendsen u. a .: Tiles - A history of wall and floor tiles. Keysersche Verlagbuchhandlung, Munich 1964.
- Wilfried Hansmann, Wilhelm Joliet: A lot of fun with falcons and herons - the Rotterdam tiles and tile panels in Falkenlust Castle in Brühl. Administration of Schloss Brühl, Brühl 2004.
- Rational cleaning magazine , edition 11/2009.
- Leaflet ZDNW 1.10 (terminology, cleaning).
Web links
- BGR 181: Floors in work rooms and work areas with risk of slipping, from October 1993, updated version October 2003. In: bgbau-medien.de. Retrieved November 13, 2015 .
- Wilhelm Joliet: ## The history of the tile
- Cleaning instructions for mineral floor coverings (PDF file; 3.7 MB)
Individual evidence
- ↑ cf. in the Art and Architecture Thesaurus : tiles (object genre) and Tile in the German translation; also in the common authority file : Tile
- ↑ In the St. Nicolaikirche in Grünhain hangs a Sunday celebration picture officially known as a clay tile painting from the year 1914 from a Marburg pottery.
- ↑ «What is the difference between wall and floor tiles? »Hansa-fliesen-depot.de. In: hansa-fliesen-depot.de. Retrieved April 11, 2018 .
- ↑ https://www.fliesenverband.de/wissen/fliesen-glossar-az/ https://www.fliesenverband.de/wissen/fliesen-glossar-az/ Fliesen-Glossarr AZ - The A to Z of the ceramic tile, In: Fliesenverband.de; accessed in July 2019
- ↑ also 33 x 33 cm
- ↑ Explanation of the tile label , Hornbach.de
- ↑ Tiles calibrated or rectified? What's the difference? , Blog FliesenAktuell.de
- ↑ How to> What are calibrated tiles? , Fliesen-Kemmler.de
- ↑ Baunetz Knowledge Tiles and Panels : Calibration , BauNetzWissen.de
- ↑ What do rectified and calibrated tiles mean? Edge processing for tiles , Jonastone.de
- ↑ "seal joints" Franke-Raumwert.de. In: www.franke-raumwert.de. Retrieved November 30, 2017 .
- ↑ a b c d Cleaning and care instructions for ceramic tiles , Federal Association of Ceramic Tiles
- ↑ «Cleaning tile joints» Franke-Raumwert.de. In: www.franke-raumwert.de. Retrieved March 15, 2016 .