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