Glossary of Industry Terms





A ceramic mineral or mixture fired to less than fusion for use as a constituent in a ceramic composition. (ASTM C 242).


A deflection that is intentionally built into a structural element or form to improve appearance or to nullify the deflection of the element under the effects of loads, shrinkage and creep.


See Bullnose.

Cassiterite (Sri 02)

An inorganic mineral of the tetragonal form used as a source of tin and tin oxide. (ASTM C 21)


Forming ceramic ware by introducing a body slip into a porous mold which absorbs sufficient water from the slip to produce a semirigid article. (ASTM C 242).

Casting, drain (hollow casting)

Forming ceramic ware by introducing a body slip into an open porous mold, and then draining off the remaining slip when the cast has reached the desired thickness. (ASTM C 242).


Mortar or concrete which is deposited in the place where it is required to harden as part of the structure, as opposed to precast concrete.

Casting plaster

A fast-setting gypsum plaster that is used to anchor marble to walls, set spots, or mix temporary “hot mud.”

Casting solid

Forming ceramic ware by introducing a body slip into a porous mold which usually consists of two major sections, one section forming the contour of the inside of the ware and allowing a solid cast to form between the two mold faces. (ASTM C 242).

Caulking compound

A soft, plastic material consisting of pigment and vehicle, used for sealing joints in buildings and other structures where normal structural movement may occur. Caulking compound retains its plasticity for an extended period after application. It is available in forms suitable for application by gun and knife and in extruded preformed shapes.

Ceiling mortar

Extra-rich wall mortar.


Usually refers to portland cement which when mixed with sand, gravel, and water forms concrete. Generally, cement is an adhesive; specifically, it is that type of adhesive which sets by virtue of a chemical reaction.

Cement-body tiles

Tiles with the body made from a mixture of sand and portland cement. The surface may be finished with portland cement, spheroids of marble or other materials.

Cement grout

A cementitious mixture of portland cement, sand or other ingredients and water which produces a water resistant, uniformly colored material used to fill joints between tile units.

Cement, masonry

A hydraulic cement for use in mortars for masonry construction, containing one or more of the following materials: portland cement, portland blast-furnace slag cement, portland-pozzolan cement, natural cement, slag cement or hydraulic lime; and in addition usually containing one or more materials such as hydrated lime, limestone, chalk, calcareous shell, talc, slag, or clay, as prepared for this purpose.

Cement mortar

A cementitious mixture of portland cement, sand or other ingredients and water which is used for bonding tile to back-up material.

Cement portland

A hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates, and usually containing one or more of the forms of calcium sulfate as an interground addition. Cement, white. Portland cement which hydrates to a white paste; made from raw materials of low iron content, the clinker for which is fired by a reducing flame.


A scale of temperature which features 0° and 100° as the freezing and boiling point of water respectively. To convert centigrade to Fahrenheit multiply by 1.8 and add 32, e.g., (100°x1.8)-‘ 32=212°F.

Ceramic article

An article having a glazed or unglazed body of crystalline or partly crystalline structure, or of glass, which body is produced from essentially inorganic, nonmetallic substances and either is formed from a molten mass which solidifies on cooling or is formed and simultaneously or subsequently matured by the action of the heat. (ASTM C 242).

Ceramic mosaic tile

An unglazed tile formed by either the dust-pressed or plastic method, usually 1/a to 3/s in. (6.4 to 9.5 mm) thick, and having a facial area of less than 6 in. 2 and which is usually mounted on sheets approximately 2 by 1 ft. (0.3 by 0.6 m) to facilitate setting. Ceramic mosaic tile may be of either porcelain or natural clay composition and may be either plain or with an abrasive mixture throughout. (ASTM C 242).

Ceramic paste

A French term synonymous with “ceramic body.” (ASTM C 242).

Ceramic process

The production of articles or coatings from essentially inorganic, nonmetallic materials, the article or coating being made permanent and suitable for utilitarian and decorative purposes by the action of heat at temperatures sufficient to cause sintering, solid-state reactions, bonding, or conversion partially or wholly to the glassy state. (ASTM C 242).

Ceramic tile

A ceramic surfacing unit, usually relatively thin in relation to facial area, made from clay or a mixture of clay; and other ceramic material, called the body of the tile, having either a “glazed” or “unglazed” face, and fired above red heat in the course of manufacture to a temperature sufficiently high to produce specific physical properties and characteristics.

Ceramic whiteware

A fired ware consisting of a glazed or unglazed ceramic body which is commonly white and of fine texture. This term designates such products as china, porcelain, semivitreous ware and earthenware. (ASTM C 242).


A general term applied to the art or technique of producing articles by a ceramic process, or to the articles so producing. (ASTM C 242).


See Bar support.

Chalk line

Usually cotton cord coated with chalk. The cord is snapped to mark a straight line. The chalk line is used to align spots or screeds.


Short shallow cracks on the surface. Chemical porcelain. Vitreous ceramic whitewares used for containing, transporting, or reacting of chemicals. (ASTM C 242).


A glazed or unglazed vitreous ceramic whiteware used for nontechnical purposes. This term designates such products as dinnerware, sanitary ware, and art ware when they are vitreous. (See also Bone china.) (ASTM C 242).

China process

The method of producing glazed ware by which the ceramic body is fired to maturity, following which the glaze is applied and matured by firing at a lower temperature. (ASTM C 242).

China sanitary ware (sanitary plumbing fixtures)

Glazed, vitrified whiteware fixtures having a sanitary service function. (ASTM C 242).


The scaling or breaking off at the edges of fragments from the surface of a tile, as might result from rough handling.


Caused from the same reasons as given under “pitted” or by rough handling and confined to the corners and edges of the tile.

Chipping hammer

The chipping hammer is a lightweight hammer that comes in a variety of sizes. The head and back can be capped with tungsten carbide for durability. It is used by the tilesetter to chip excess material from the backs and edges of wall and quarry tiles, thus reducing the amount of grinding work necessary to smooth a cut.


A natural mineral aggregate, consisting essentially of hydrous aluminum silicates; it is plastic when sufficiently wetted, rigid when dried en masse, and vitrified when fired to a sufficiently high temperature. (ASTM C 242).

Clear glaze

A colorless or colored transparent ceramic glaze. (ASTM C 242).

Cleavage membrane

A layer of 15 lb. roofing felt, or an equivalent type of construction paper or polyethylene sheeting, used to isolate a wire reinforced mortar bed for tile from the concrete substrate. (CTI)

Cold joint

Any point in a tile installation where tile and setting bed have terminated and the surface has lost its plasticity before work is continued.
Cold joint lines. Visible lines on the surfaces of formed concrete indicating the presence of joints where one layer of concrete had hardened before subsequent concrete was placed. (See also Cold joint).


The aspect of the appearance of an object dependent upon the spectral composition of the incident light, the spectral reflectance of transmittance of the object, and the spectral response of the observer. Hue – The attribute by which a perceived color is distinguished as red, yellow, green, blue, purple or a combination of these. White, gray and black colors possess no hue. Lightness – The attribute by which a perceived color is judged to be equivalent to a member of the continuous series of grays ranging from black to white. Saturation – The attribute by which a perceived color is judged to depart from gray of equal lightness toward a pure hue.

Colored grout

Commercially prepared grout consisting of carefully graded aggregate, portland cement, water dispersing agents, plasticizers and color fast pigments. (CTI).


A member used primarily to support axial compression loads and with a height of at least three times its least lateral dimension.


The process whereby the volume of freshly placed mortar or concrete is reduced to the minimum practical space usually by vibration, centrifugation, tamping, or some combination of these; to mold it within forms or molds and around embedded parts and reinforcement, and to eliminate voids other than entrained air.

Composition tile

A hard tile surfacing unit made from a mixture of chemicals. The finished surface can be the mixture of chemicals or can be marble chips to create a terrazzo finish. The unit is made hard by the set of the chemicals and the product is not fired as in the manufacture of ceramic tile. (CTI)

Compressive strength

The measured maximum resistance of a concrete or mortar specimen to axial loading; expressed as force per unit cross-sectional area; or the specified resistance used in design calculations, in the U.S. customary units of measure expressed in pounds per square inch (psi).


A composite material which consists essentially of a binding medium within which are embedded particles or fragments of aggregate; in portland cement concrete, the binder is a mixture of portland cement and water.
Concrete, fibrous. Concrete containing, dispersed, randomly oriented fibers.
Concrete, field. Concrete delivered or mixed, placed, and cured on the job site.

Concrete, foamed

Concrete made very light and cellular by the addition of a prepared foam or by generation of gas within the unhardened mixture.

Concrete, green

Concrete which has set but not appreciably hardened.

Concrete, precast

See Precast concrete.

Concrete pump

An apparatus which forces concrete to the placing position through a pipeline or hose.

Concrete, prestressed.

See Prestressed concrete

Concrete, pumped.

See Pumped concrete

Concrete, refractory.

See Refractory concrete.

Concrete, terrazzo

Marble-aggregate concrete that is cast-in-place precast and ground smooth for decorative surfacing purposes on floors and walls.


Usually refers to liquid drops which form when a vapor is chilled below its boiling point. Also refers to water droplets that deposit on surfaces whose temperature is below the dewpoint.

Conductive (adj.)

Having the quality or power of conducting or transmitting heat, electricity, or static electricity.

Conductive mortar

A tile mortar to which specific electrical conductivity is imparted through the use of conductive additives. (TCA)

Conductive tile

Tile made from special body compositions or by methods that result in specific properties of electrical conductivity while retaining other normal physical properties of ceramic tile. (SS-T-308b)


Stained tile as a result of carton and tile being saturated by moisture, oils, solvents or other materials.

Contraction joint

Formed, sawed, or tooled groove in a concrete structure to create a weakened plane and regulate the location or cracking resulting from the dimensional change of different parts of the structure. (See also Isolation joint.)

Control joints

See Expansion joints.

Conventional installation

The method of installing ceramic tile with portland cement mortar.


The material or units used to form a cap or finish on top of a wall, pier, pilaster, or chimney.


A projection from the face of a beam, girder, column, or wall used as a beam seat or a decoration.

Cordierite porcelain

A vitreous ceramic whiteware for technical application in which cordierite (2 MgO 2A1203 ‘ 5Si02) is the essential crystalline phase. (ASTM C 242).

Cordierite whiteware

Any ceramic whiteware in which cordierite (2MgO – 2A1203 – 5Si02) is the essential crystalline phase. (ASTM C 242).


The eating and wearing away by chemical action (pitting, rusting).


A trim tile unit having one edge with a concave radius. A cove is used to form a junction between the bottom wall course and the floor or to form an inside corner. (TCA)

Cove base (sanitary)

A trim tile having a concave radius on one edge and a convex radius with a flat landing on the opposite edge. This base often is used as the only course of tile above the floor tile.


A measure of the amount of material required to cover a given surface.
Covering power. The ability of a glaze to uniformly and completely cover the surface of the fired water. (ASTM C 242).


Hair-line fissures.

Crack-control reinforcement

Reinforcement in concrete construction designed to prevent opening of cracks, often effective in limiting them to uniformly distributed small cracks.


Tiles that have actually been cracked in one or more pieces usually during the beating in process of installation. These will show up as hairline cracks.


A parting and contraction of the glaze on the surface of ceramic ware during drying or firing, resulting in unglazed areas bordered by coalesced glaze. (ASTM C 242-58T)


The cracking which occurs in fired glazes or other ceramic coatings due to critical tensile stresses. (ASTM C 242).


Time-dependent deformation due to sustained load.

Crooked edges

A curvature of the sides, either convex or concave, measured along the sides. The degree of crook is the departure from the straight line between two corners, expressed in percentage of the tile length. Crow hop. a slang term used to describe tile joints that are out of alignment.

Crystalline glaze

Glazed tile with an extra heavy glaze produced for use on counter tops and light duty floor surfaces where abrasion or impact is not excessive. (CTI)


Maintenance of humidity and temperature of freshly placed concrete during some definite period following placing, casting, or finishing to assure satisfactory hydration of the cementitious materials and proper hardening of the concrete.

Curing, electrical

A system in which a favorable temperature is maintained in freshly-placed concrete by supplying heat generated by electrical resistance.

Curing, steam

See Steam curing.

Curing blanket

A built-tip covering of sacks, matting, hessian, straw, waterproof paper, or other suitable material placed over freshly finished concrete. (See also Burlap.)

Curing compound

A liquid that can be applied as a coating to the surface of newly placed concrete to retard the loss of water or, in the case of pigmented compounds, also to reflect heat so as to provide an opportunity for the concrete to develop its properties in a favorable temperature and moisture environment. (See also Curing.)


The distortion of an originally essentially linear or planar member into a curved shape such as the warping of a slab due to creep or to differences in temperature or moisture content in the zones adjacent to its opposite faces.

Cushion-edged tile

Tile on which the facial edges have a distinct curvature that results in a slightly recessed joint.