Abrasion Resistance

Abrasion resistance is a classification that indicates how well glazed floor tiles withstand friction, scratching, wear and tear, etc. when subjected to different levels of traffic.


Absorption
All tiles are given a rating according to their level of water absorption, which also indicates a tile's frost-resistance and its suitability for external use. This varies greatly depending on the material of the tile for example, porcelain tiles have 0.5% absorption rate making them suitable for outdoor use whereas glazed stoneware tiles have 6% making them only suitable for indoor use. A tile's absorption rating is calculated by the ratio of the weight of the water absorbed into the weight of the dry tile, which is then displayed as a percentage.

• Porous bodied glazed: More than 10% for indoor use only.

• Medium water absorption: 6% to 10% for indoor use only.

• Semi-vitrified: 3% to 6% for indoor use only.

• Vitrified: 0.5% to 3%, and suitable for external use, but may require sealing.

• Fully vitrified (porcelain): Less than 0.5%, frost-proof, and suitable for external use.

Acrylic

Acrylic is a synthetic polymer based on resins made by the polymerisation of acrylic monomers, such as ethyl acrylate and methacrylate, and used in the manufacture of baths, shower trays, adhesives, grouts, tanking membranes, and sealants.

Adhesive

Any substance which uses surface attachment to hold materials together. In tiling, typically an organic substance used to bond tiles to a wall, floor or other surface. Rubber solutions, reaction resin-based and rubber emulsions are also sometimes used.

Admixture

A material other than water added to an adhesive or grout before or during mixing as a means of modifying its properties, such as increasing its flexibility.

Antibacterial/Antifungal

The property of a substance to prevent or retard the spread or growth of fungus, typically through the use of specialist ingredients.

Back Buttering
The direct application of adhesive to the back of a tile to improve coverage.


Battens
Straight-edge wooden battens are used to align the tiles horizontally and vertically, and to support their weight while the adhesive dries, when fixing wall tiles.


Bed
The depth of applied adhesive or mortar into which tiles laid.


Bevel Format
The tile has been cut to create angled edges that slope away from the flat top surface.


Biscuit/ Bisque
The name given to the ceramic tile body moulded under high pressure and then fired.


Bonding Agent
A substance applied to a suitable substrate to create a bond between it and a succeeding layer such as render, screed or plaster.


Bookmatching
The practice of matching two stone or marble surfaces, so that two adjoining surfaces mirror each other, giving the impression of an opened book. Bookmatched porcelain tiles, in both marble and other stone-effects, are an increasingly common design feature. End-matched tile installations - a pattern that runs across four tiles – is also growing in popularity.


Border Tile
Any tile, differing in appearance to the field tiles, used to frame a central body of tiles to add an extra design element to a tiling scheme.


Breaking Strength
A tile’s breaking strength, as defined by BS EN ISO 10545-4: 2004, indicating its resistance to cracking or chipping. Typical ceramic floor tiles have a breaking strength of approx. 113kg, which rises to approx. 181kg for porcelain tiles.


Broken Joint
Ceramic tile laying pattern in which each row is offset by half the length of a single tile.


British Standard/ BS 5385
British Standard relating to wall and floor tiling:

• Part 1 is a code of practice for the design and installation of internal ceramic and natural stone wall tiling and mosaics in normal conditions.

• Part 2 is a code of practice for the design and installation of external ceramic and mosaic wall tiling in normal conditions.

• Part 3 is a code of practice for the design and installation of internal and external ceramic floor tiles and mosaics in normal conditions.

• Part 4 is a code of practice for the design and installation of tiling and mosaics in specific conditions.

• Part 5 is a code of practice for the design and installation of terrazzo tile and slab, natural stone and composition block floorings.

British Standard/ BS 12002
British Standard relating to the determination of transverse deformation for cementitious adhesives and grouts.

British Standard/ BS 12004
British Standard providing definitions and specifications for adhesives for tiles.


British Standard/ BS 13888
British Standard providing definitions and specifications for grouts for tiles.


British Standard/ BS 14411
Provides definitions, classification, characteristics and marking of ceramic tiles.


Brushed
The stone's surface is brushed with rotary diamond pads, resulting in a textured finish to the surface and rounded edges.


Calcium Sulphate (or Anhydrite) Screeds
Calcium sulphate dihydrate, also known as gypsum, is used as an alternative to cement/sand mortar screeds, especially over underfloor heating systems.


Ceramic
Produced with red, brown or white clay, these tiles are softer and less dense meaning they are easier to cut, drill and ideal for wall applications. Due to their high water absorption, ceramic tiles are always glazed.


Coefficient of Friction
A number used to describe the slip resistance of a tile: the higher the number, the greater the slip resistance.


Coefficient of Thermal Expansion
An indication of the extent to which a rise in temperature will cause a tile to expand.


Colour Gamut
The complete range of colours reproducible from a printing system on a specific substrate.


Coloured Grout
A commercially prepared cementitious mix used for filling joints between tiles. Colourfast pigments are added to Portland cement, aggregate, plasticisers, and water-dispersing agents. When set, the grout offers an attractive coloured finish to complement, or contrast with, the tiles.


Continuous Compaction
The production of gauged porcelain panels, often referred to as slabs, is results from this innovative compaction technology that allows the manufacture of XXL tiles in a wide size and thickness range. Rather than vertical presses and trays, with a continuous compactor the clay body powder is deposited on a belt, carried inside the press beneath an upper belt, where the combined action of the two belts and two compaction rollers between non-deformable containment buffers, operating at extremely high pressure (around 400 bar/sq. metres) creates the flat green sheets ready for decoration and subsequent firing.


Cushioned/ Pillowed
The straight edges of a tile have been rounded and softened.


Curvature
Curvature describes the extent to which an object, such as a ceramic tile, deviates from being flat. BS EN 14411 details and defines the maximum permitted deviation from surface flatness, such as centre curvature and edge curvature, for each type of ceramic tile.


Digital Decoration
Today majority high proportion of ceramic tile manufacturers in the major European producing countries, Spain and Italy, have already converted to digital inkjet printing. These manufacturers have all cut production costs, reduced waste, work-in-progress and stocks of finished products, and improved responsiveness to design changes and customer demand.

They are also producing higher quality tiles that offer more realistic reproduction of marble and other natural materials. And they are doing so in the short runs that buyers demand – using digital, a single ceramic tile can be produced cost-effectively. Instead of competing on price, these manufacturers can compete on creativity and innovation, and do so in new markets.


Dimensions
Tiles are specified by size, with standard sizes given in millimetres: 150 by 150mm, 300 by 300mm, etc. These equate approximately, but not exactly, to the traditional standard sizes of 6 by 6in, 12 by 12in, etc. Standard dimensions for mosaic tiles are indicated in the same way and can include 25 by 25mm (1 by 1in), 50 by 50mm (2 by 2in), 75 by 75mm (3 by 3in), etc. Work size is the length, width and thickness of the tile, whereas the co-ordinating size also includes the width of the joints between the tiles (work size plus joint width).


Dispersion Adhesives
Pre-mixed adhesives, also known as ready-mix or paste, containing organic binders, mineral fillers and organic additives. These are classified as either D1 or D2. The D1adhesives are not water resistant and may be used for dry internal wall tiling. D2 adhesives are suitable for such wet areas as showers, but not for total immersion conditions. Reduced slip, an optional characteristic, may also be classified and shown with a ‘T’ and an extended open time, i.e. longer than 30 minutes, shown with an ‘E.’


Double Loaded
Term to describe double pressed porcelain tile manufacturing process. A second loading in the porcelain pressing process adds fine coloured powders onto the top of the main body of the tile to give a particular appearance and depth when fired.


Double Pressed
Process by which a porcelain tile goes through a press, is decorated and then pressed again before firing. Aids in the production of impervious and durable tiles.


DoD (Drop-on-Demand)
The type of digital inkjet printheads used in tile production that only produce ink drops when required.


Dry-Pressed Ceramic Tile
A ceramic tile which has been created in a die or mould, using direct pressure onto powdered or granular material. Often called dust pressed.


Elastomeric
Capable of returning to its original state after deformation. An elastomeric adhesive will deform under stress, then return to its starting condition.


Efflorescence
Whitish residue deposited on the surface of bricks, tiles, mortars or grouts caused by the crystallisation of soluble salts.


Epoxy Resin
A polymerised synthetic resin composed of epoxy used in conjunction with a curing agent (hardener) to form a reaction resin, chemical-resistant adhesive, or chemical-resistant grout.


Ettringite
A natural mineral (hydrated calcium aluminium sulphate hydroxide) found in a hydrated Portland cement system as a result of the reaction of calcium aluminate with calcium sulphate, both present in Portland cement. Its expansile nature can lead to tiles de-bonding if not treated/removed prior to tiling.


Expansion Joints
A joint extending through tile, adhesive, and any reinforcing wire from the substrate, typically used in larger tiled floors and walls. Expansion joints are required when a tiled floor may be subject to movement, to prevent cracking of tiles and grout. In such cases, these will always be needed at the floor perimeter. See Movement joint.


Extruded Tile
Tiles formed by forcing a dense clay mixture through a shaped die. This creates a continuous ribbon of formed clay of uniform width, which is then cut to length.


Fast Setting
BS EN 12004: 2007 defines a minimum early tensile adhesion strength development after not more than six hours. As a general rule, if tiles are ready for grouting within two to three hours of fixing, the adhesive used is deemed to be fast setting.


Field Tile
The main base tile used in covering a floor or wall.


Filled
Voids, pits and holes (a natural characteristic of some stone) in a tile have been filled with a resin to create a smooth surface.


Floating Screed
Screed laid over the sub-floor but not bonded to it, typically separated from it by a thermal or acoustic insulating layer.


Frost Resistance
The ability of a ceramic tile to resist frost is tested against the standard EN ISO 10545-12.


Frits
The main component of a ceramic glaze. A glaze is usually made up of one or more frits with the addition of pigments, salts, etc.

Full-Bodied
This refers to tiles whose surface colour is the same all the way through the tile. Also known as 'through-bodied' or 'technical' porcelain, these tiles are made of a single material with no glaze applied making them extremely hard wearing and perfect for any application.


Fully Vitrified
Vitrification (turned to a glass-like state) describes the extent to which a tile’s porosity is reduced by the heat of kiln firing. A fully vitrified material is effectively impervious, completely resistant to water penetration. BS EN 14411 defines a floor and wall tile with a water absorption lower than 0.5% as being fully vitrified (or porcelain).


Geometric Tiling
An arrangement of tile in two or more colours, and often in different sizes and shapes, to form a pattern.


Glaze
Either a ceramic coating, in a glassy state, on a ceramic tile or the material from which such a coating is made. Glazing serves both practical and artistic purposes, providing aesthetic beauty, water repellence, durability, and hygienic properties.


Granite
A natural stone formed from molten lava that never rose above the surface of the earth. Granite is denser than marble and is extremely durable.


Green cutting
The cutting of unfired porcelain tiles from XXL slabs, typically 3,200 by 1,600mm, into sub-multiples (600 by 600mm, 800 by 800mm, 300 by 1,200mm, etc) prior to firing. The main benefit is increased production output.


Grout
A special mix used to fill gaps between tiles to provide a durable, hard wearing, low-shrinkage decorative joint finish, while protecting the underlying layers. Available in both cementitious and chemically-setting, formulations grout is available in a range of colours to complement, or contrast with, the tiles.


Hard Water
Water with a high mineral content, typically comprising calcium (Ca2+) and magnesium (Mg2+) metal cations. May also contain other dissolved compounds such as bicarbonates and sulphates. Where a swimming pool’s water is hard, for example, or can be maintained at a level over 200mg/ litre expressed as CaCO3, cementitious grouts modified with polymers are generally suitable.


Honed
A machine process which results in a smooth, matt surface.


Hygroscopic
Materials that attract water molecules from the surrounding atmosphere.


Ink-Jet
A term that refers to the print or pattern on the tile which has been applied using an ink-jet printer.


Inset Tile
A decorative tile used in isolation within a plane of field tiles to enhance the appearance of a wall or floor.


Isolation Joint
A gap between adjoining parts of a concrete structure, usually a wall or other vertical plane, at a point designed to minimise interference with the structure’s performance but which allows relative movement.


Kaolin
Generally, a mineral (Al2Si2O5(OH)4) used in tile body, also known as china clay, that fires to a white, or nearly white, colour.


Laitance
A weak, non-durable layer or crust commonly present on the top of new concrete, containing cement and fine aggregate particles. It is caused by water bleeding from wet concrete. Its relatively poor adhesion to the mass of the aggregate renders it liable to delaminating under impact or traffic. Laitance can be removed by acid etching, grit blasting, mechanical planning, grinding, or abrading.


Limestone
A hard wearing stone that can come in a variety of colours from shades of white to deep black. It can be used in almost any environment due to the wide selection of finishes that can be applied to it.


Large Format Tile
Traditionally a term used to describe a floor or wall tile larger than 300 by 300mm.


Listello
A decorative border tile, generally for wall applications.


Marble
Formed over millennia from limestone, this crystalline rock is extremely durable making it ideal for floors. Due to the creation process, veins and colour changes can appear in the stone which can look like faults but are actually an inherent characteristic of the stone and are of no concern. Marble can come in a variety of textures and finishes due to its versatile nature. It can be polished to a high gloss finish and other common finishes include honed, split-faced, and acid washed. Onyx, serpentine, travertine, and verde antique are all types of marble, although the term is often used to describe any calcium carbonate stone capable of being polished.


Modular size
Tiles manufactured in a range of sizes that are multiples of the same index dimension, typically 50mm.

Moisture expansion
The increase in dimension or volume of materials, such as porous ceramic tile, due to changes in prevailing moisture conditions.


Mosaic
A design, pattern or image on a wall, floor or other surface created using small pieces of ceramic or porcelain tile (tesserae), natural stone, coloured glass, or other materials, including metals. Mosaic tiles are often premounted on a backing for ease of installation.


Movement Joint
A stress-relieving profile used to compensate for movement of tiles and / or the substrate, by separating a large tiled area into independently moving tile fields to prevent cracking, bulging/ tenting or debonding. Movement joints should be planned so that the maximum tile field should be no more than 10 metres in any direction but, in practice, movement joints may be required at intervals of between five and eight metres, such as where thermal influences exist or when tiling over suspended floors.


Narrow Joint
Any joint between tiles, 3mm or less, requiring grout containing finer fillers.


Non-Contact Printing
A process in which there is no contact between the substrate and whatever applies the ink. In digital inkjet ceramic decoration the distance between the ceramic tile and the printhead is generally 3 to 5 mm. This means that no mechanical pressure is put on the ceramic tile, and that digital inkjet printers can print on 3D surfaces to create edge-to-edge textured tiles.


Non-Vitrified
Tiles with a water absorption of 7% or greater. Usually used as a wall covering and suited for indoor, dry area use only.


Notched Trowel
A trowel of either serrated or toothed design, with square, trapezoidal or round notches available in various sizes, used for the consistent application of a gauged amount of adhesive in ridges of a specific thickness and cross-section. The right tooth size and depth must be used to ensure the specified thickness of adhesive is applied.


Open Time
The length of time after adhesive has been applied to the substrate during which it retains its ability to adhere to and bond a tile. An open time of 20 or 25 minutes is typical for most tile adhesives.


Orange Peel
Pitted tile glazes that resemble the surface of rough orange peel in texture.


Overglaze Decoration
A raised textured decoration applied directly to the surface of a tile and covered with a transparent glaze.


Paver
An unglazed natural clay or porcelain tile for exterior use in such areas as drives and patios.


PEI Rating
Named after the Porcelain Enamel Institute (PEI) in the USA, these abrasion resistance classifications indicate how well a glazed tile will withstand friction, scratching, wear and tear, etc., when subjected to various levels of traffic.

• Class 1 - Walls only

• Class 2 - Light residential

• Class 3 - All residential, light commercial.

• Class 4 - Commercial

• Class 5 - High traffic areas, heavy commercial/industrial

Pendulum Test
The pendulum coefficient of friction test was developed with the intention of providing a ‘portable’ method of assessing slip resistance on flooring. The standardised test, as defined in BS 7976: Parts 1-3, 2002, is used to measure skid resistance of tiles and other flooring, particularly important in testing non-slip surfaces. A swinging imitation heel, with a standardised rubber sole, is swept over a set flooring area in a controlled way, with the slipperiness of the flooring shown as a pendulum test or slip resistance value.


Pitting
Small indentations in the finished surface of an individual tile, typically the result of corrosion, cavitation, or manufacturing defects.


Plasticiser
A material that increases fluidity or plasticity of a mortar, cement paste, or concrete mixture.


Polished
The tile's surface is buffed by a machine, resulting in an even, smooth and highly reflective surface.


Lightly Polished
The tile's surface is polished to a softly reflective sheen.


Polymer Modified
Polymers were first used as additives to cement mortars and concrete during the 1920s, when natural rubber latex was added to road paving materials. There has been considerable subsequent development of commercial products, called admixtures. Polymer-modified Portland cement is widely used in the production of tiling adhesives and grouts to improve application and the performance characteristics, including easier handling, increased tensile and flexural strength, enhanced adhesion, improved water resistance, and greater durability. It also tends to prolong the hydration period, giving increased density and shear strength, extending the working time and, of particular importance with grouts, promoting colour uniformity in the end product.


Porcelain
These tiles are made with white clay and fired at a high temperature making them dense, hardwearing and perfect for floors. They have an extremely low water absorption rate of less than 0.5% making them well suited for bathrooms and wet rooms. Porcelain tiles can be glazed or unglazed.


Pot Life
The period of time during which a material, such as adhesive or grout, maintains its workable properties after it has been mixed.


Primer
A liquid, typically acrylic-based, used for preparing floor and wall backgrounds prior to fixing of ceramic/ mosaic and natural stone tiles. PVA-based primers are not normally recommended for tiling applications, as the water content changes the constituency of the PVA, returning it to a tacky state that prevents the adhesive from penetrating the substrate which could lead to tiles de-bonding.


Quarry Tiles
Extruded tile, typically 13 to 19mm thick and 150mm square (or larger), manufactured from shale or natural clays. Usually unglazed, they are generally available in terracotta, brown and black. They are rarely used on walls, but can occasionally be seen on countertops.


Quartz
A mineral occurring naturally in more than a dozen common types, including amethyst and onyx.


Quartz Tiles
Tiles described as “quartz tiles” are not natural stone, but are manufactured using quartz sand, resin, and mirror flecks. The mixture is heated to an extreme temperature to create the finished articles. The better quality tiles have a high natural quartz content, typically 90% or more.


Ramp Test
One of the standard methods of testing the slip resistance of tiles and other floor coverings (see Pendulum test). This involves the testing of flooring samples with a surface that has been ‘contaminated’ with, for clean water, a soap solution, oil or other substance. An individual walks forwards and backwards on this sample that is set at increasing angles of slope. The average angle of inclination at which the walker slips enables calculation of the coefficient of friction (CoF) for the flooring material. The UK Slip Resistance Group
(UKSRG), in conjunction with the Health & Safety Laboratory (HSL) and the British Standards Institute (BSI), have developed their own version of the ramp test.
Outside the UK, recognised DIN standards offer two versions of the test, which classify slip resistance for each tile material/type: DIN 51097 Barefoot Ramp Test, for wet and barefoot conditions; and DIN 51130 Shoe Shod Ramp Test for safetybooted feet on a lubricated surface. Barefoot testing classes are: A (12° to 18° slope); B (>18° to 24°); and, the highest rating, C (>24°). The shoe shod classes are: R9 (6° to 10° slope); R10 (10° to 19°); R11 (19° to 27°); R12 (27° to 35°); and the top-rated R13 (>35°).


Reaction Resin
Any resin involving two or more components including a synthetic resin and mineral fillers or additives and which requires a chemical reaction to harden. Typical examples would include polyurethane and epoxy resins.


Ready-Mixed
Tiling adhesives are available in two forms: powder and ready-mixed. Powder adhesives, which require the addition of water, are available for both floor and wall use but ready-mixed adhesives are generally only suitable for use on walls. This is due to the essential difference between their characteristics: powders set through a chemical reaction brought about by adding water, while ready-mixes set by losing the water already contained within the mixture. In use, a ready-mixed adhesive takes at least 24 hours to set before grouting, while 16 hours would be normal for a powder, or as little as two hours for a rapid-setting adhesive.


Rectified
Although ceramic tiles exit an extruder or press with virtually identical dimensions, the drying and firing processes cause shrinkage that can vary from tile to tile. In order to assure users that tiles are consistently sized, they can be rectified after firing. This consists of machining each tile, with saws or grinders, to ensure that all tiles within a batch are the same size.


Rectification
This process involves removing the edges of the tile to give a cleaner finish and meet size specifications. Tiles cut in this manner have a uniform size thereby reducing grout joints to a minimum.


Rectified Glazed Porcelain
These are porcelain tiles that have been cut during the manufacturing process to meet the exact sizing requirements. They are much more aesthetically versatile, coming a variety of finishes including matt, glazed, metal effect or stain.


Semi-Vitrified
Tiles with a water absorption greater than 3%, but less than 7%. Suitable for indoor use only.


Non-Rectified
Non rectified tiles have natural, uneven pressed edges that may vary slightly in size and require a wider grout gap.


Sandstone
A natural stone, comprising mainly sand-size grains of rock or mineral and usually composed of quartz, feldspar or a mixture of the two. Its typical resistance to weathering but easy workability makes it a popular material for tiles.


Screed
A layer or strip of material used either for levelling a floor or to give it a smooth finish prior to tiling. Sand-andcement mixtures and concrete are both commonly used. Can also mean flat, level strips of wood or other material at the edges of a screed, used to guide a straight edge in levelling.


Screen Printing
The traditional printing process used to decorate ceramic tiles; a contact printing process in which each colour is applied by a separate roller.


Self-Levelling Compound
Self-levelling (or self-smoothing) compounds are used on both new and existing sand-and-cement or concrete substrates to level off any surface irregularities and provide a smooth finish. It is available in powder form and, mixed with water, finds its own level. It is only suitable for filling small holes, typically to a maximum depth of 5mm.


Setting Time
The time taken for an adhesive to become fully hardened. It is measured from the point of application for ready-mixed adhesives, for which it is typically 24 hours. For powder adhesives, it is measured from the point of mixing and, while it can be as long as 24 hours, it can be as little as two hours for rapid-setting adhesives.


Shear Adhesion Strength
Shear adhesion strength describes an adhesive’s resistance to transverse deformation. Effectively, this means how difficult it is to move a tile sideways after fixing into fresh adhesive.


Silicone Sealant
An elastomeric material used to fill and seal expansion joints to allow movement at the joint while preventing the passage of moisture. It is only suitable when a non-epoxy grout has been used. Typical applications include sealing the joints between sinks, baths or shower trays and surrounding tiling.


Sintered stone
Sintered stone is manufactured using carefully selected minerals and stone particles carefully selected for quality, colour and texture. These particles are then subject to extreme heat and pressure that causes them to be bonded together permanently, without the need for resins or bonding agents. Essentially this is fully-vitrified porcelain tile, distinguished by the careful mix of materials that make up the body of the tile. The resulting slabs or tiles are weatherproof, unaffected by heat or cold, stainproof, scratch-resistant, easy to clean, food safe, hygienic, and nonporous.


Slate
A fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism.


Slip Resistance
The level of slip resistance of floor tiles describes the degree to which tiles resist slipping. It is the coefficient of dynamic friction, In the UK the preferred method of testing is the Pendulum Test, which simulates the action of a slipping foot.


Spacers
Plastic spacers are inserted between tiles as they are placed in position on walls and floors to ensure consistently accurate width of the gaps between the tiles. Widths of 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 8 mm and 10 mm are generally available, as straight spacers and in ‘T,’ ‘Y’ and cross shapes. Plastic wedges are also offered for use when fixing wall tiles above an uneven surface, such as rough concrete. They enable precisely level positioning of a row of tiles and prevent them slipping down the wall while the adhesive dries.


Specification
In the UK, there is a recognised national standard specification service for building construction, produced by National Building Specification (NBS). Its wide range includes the standard M40 Tiling Specification in two formats: architects’ specification and contractors’ specification. For any given job, the information will be consistent between the two, but emphasis and level of detail will differ.
The recommendations within any specification should be aligned with appropriate, recognised industry guidelines and standards, including any relevant BS EN codes of practice. An M40 Tiling Specification will cover much more than merely an overview of the specific tiles to be used, the background, preparation, bedding, adhesives, grouts and joint widths. It will address every possible aspect of the project in fine detail, laying out exactly what is, and is not, to be done.


Structured
Where the face of the tile is changed during the forming process from a flat to a textured surface, ranging from a rough random texture to 3D geometric shapes. Structured faces can provide a degree of slip resistance.


Substrate
The underlying support for a tile installation; the background onto which tiles are to be fixed, such as concrete, plaster, brickwork, backboards, or existing tiles.


Tensile Adhesion Strength
Testing for the tensile adhesion strength of tiling adhesives is defined in the standard BS EN 1348 Adhesives for Tiles - Determination of Tensile Adhesion Strength for Cementitious Adhesives. This measures the force required to de-bond a standard tile from a standard concrete substrate when fixed with the adhesive under test.


Terracotta
A natural tile made from clay, typically used for interior flooring. Such tiles are highly absorbent and should normally be sealed to prevent soiling and staining.


Tessera
Small unit of stone, ceramic, or glass used to create a mosaic.


Thermal Shock Resistance
Thermal shock occurs when tiling cracks or breaks as a result of rapid changes in temperature, which causes differential expansion or contraction.


Through-Bodied

There are two main types of porcelain tile: glazed and through-bodied (or full-bodied). A through-bodied tile comprises a mixture of clay, sand and other natural materials, pressed and fired at a high temperature. The term refers to consistency of composition, with the colour and texture running through a tile’s full dimensional thickness, so that if the surface is worn down the colour or pattern will not change. These tiles are typically suited to high traffic areas.


Travertine
A pale stone with inherent pits and holes which can be filled. It's marble-like qualities make it easy to cut making it suited for internal walls, floors, showers and hearths. It is not recommended for outdoor use as it is susceptible to frost damage.


Tumbled
The surfaces of the stone have been textured, worn and weathered by contact with abrasive materials.


Unbonded Screed
A screed which is not laid directly onto the substrate, but onto a separating layer acting as a damp proof membrane.


Uncoupling Membrane
Impervious sheet material used as a separating layer between substrate and screed.


Unglazed Tile
A hard, dense through-bodied tile which derives its colour from the materials of which it is made. It will normally require sealing before use.


Unfilled
Voids, pits and holes within travertine have not been filled prior to installation. However, they can be grout filled.


Vitrified
Ceramic tiles that have been chemically altered during the firing process to yield high water resistance, typically with water absorption below 3%.


Warpage
Any curvature of a tile, whether concave or convex, which results in the tile surface not being perfectly flat.


Water Absorption
The ability of a material to take up and retain water. Conversely, water resistance is the ability of a material to resistant penetration by water.


X-Ray Diffraction

A test used to identify a material’s crystalline components by comparing the diffraction spectra with those of known materials.