Ceramic Tiles
Ceramics are inorganic, non-metallic materials that have been subjected to heat treatment. Materials used are mixtures of clays, sand, and other natural substances.
They are prepared and are then molded into the required shapes. They are then fired at high temperatures between 1000º and 1250º C, depending on the types of tile.
There is a vast range of wall and floor tiles to choose from, which is perhaps as great as that for fabrics and clothes.
Glazed or unglazed
Tiles have a surface that is covered by a colored layer of glaze. This gives them important design characteristics (such as color, shininess, decoration, shades of color, etc.) and technical characteristics (such as hardness, impermeability, etc.). All these characteristics, both technical and aesthetic, depend on the type of glaze and may vary greatly. Unglazed tiles, on the other hand, are perfectly uniform both in surface and in thickness, and normally have no decorations or patterns.
with a compact or “porous” body
The body may be compact or, to use the current term in the tile industry, “impervious”. Otherwise, it may contain “pores” that are linked to one another in various ways. An extremely powerful microscope would be required to “see” this characteristic of the body. In order to measure porosity, the quantity of water that is absorbed in given conditions is measured. In other words, water absorption is measured. The higher the water absorption, the more porous the body.
Pressed or extruded
Ceramic tiles can be formed either by pressing or extrusion. Pressed tiles are obtained from a clay paste that is compacted and formed by a high pressure press. Extruded tiles are formed by passing the raw materials in the form of a paste through a special tube.
Red or clear (or white) paste
Depending on the raw materials used, the body of the tiles can be colored (any color shade from yellow to reddish brown) or else they can be whitish (sometimes white). In glazed tiles, the colour of the body is relatively unimportant. For certain unglazed tiles, different colors can be obtained by adding coloring pigments.
Different shapes and dimensions
The most common shapes are square and rectangular, but there are also others, of varying complexity (e.g. hexagonal, octagonal, Proven, Moorish, etc.). The dimensions range from “mosaic” tiles with a side of 2.5″ of length to plates of 24″ side and more. The thickness varies from 1/3″ to over 2/3″.
Table 1 shows some properties of ceramic tiles that attributes to its wide usage in bathrooms.
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Ceramic Tiles
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| Colour Permanence While most colouring materials will be altered by long exposure to light, colours in ceramic tiles are unaffected and will not change or fade from exposure. |
| Dirt Resistance Ceramic tiles do not retain dust or residues as these particles will not adhere to their surface. Routine maintenance, usually no more than wiping tiles with a damp sponge is all that is necessary to maintain their lustre. |
| Fire Resistance Ceramic tiles rank highest in studies comparing the resistance of building materials under fire. Ceramic tiles are completely fire-proof at any temperature. They will not burn or feed a fire; their surface will not give off any toxic gasses or fumes during a fire. These are important considerations in selecting any building material for the home.In addition to being fire-proof, tiles have been found to provide excellent protection for structural surfaces during fire. |
| Hygiene The face of ceramic tiles will not retain liquids or absorb fumes, odours or smoke. Tiles are suitable for any environment where hygiene is essential. |
| Electrical Conductivity Ceramic material is electrically insulating. However, it does not substantially accumulate electrostatic charges, Consequently ‘shocks’ from electrostatic build-up are rarely experienced from a ceramic floor.In areas where electrostatic charges can threaten personal safety or the proper functioning of delicate electronic instruments (such as hospital operating rooms or computer rooms), specially produced electro-conductive, antistatic tiles are used. |
| Thermal Conductivity Ceramic tiles have a negligible thermal conductivity coefficient (0.35-0.65 Btu/h ft. degrees F or in metric 0.5-.09 Kcal/m.h. degrees C) making them excellent insulators and passive solar energy collectors. |
| Thermal Expansion The coefficient of linear thermal expansion for ceramic tiles is between 4×10-6 and 10×10-6 degrees C-1. The linear moisture expansion has a maximum allowable of 0.6 mm/m. |
| Mechanical Strength Usually measured by flexural breaking load, ceramic tiles generally demonstrate a breaking strength of greater than the practical requirements for most floor applications. (not a necessary measurement for wall tiles.) |
| Weight Weight varies as a function of type of material used. Weights range from 10-15 kg/m2 for wall tiles and19-24 kg/m2 for floor tiles |
References
[1] M. Y. L. Chew, Construction Technology for Tall Buildings, 6th Edition, World Scientific, 2024.
[2] M. Y. L. Chew, Maintainability of Facilities – Sustainable FM for Building Professionals, 3rd Edition, World Scientific, 2024