Tiles are not just tiles. There are glazed and unglazed tiles, which are predominantly manufactured from non-vitreous or vitreous ceramics.
Non-vitreous tiles are dry-pressed and, at 10%, the water absorption is relatively high. The top surface of the tiles must therefore always be glazed. Because they are not resistant to frost, non-vitreous tiles are typically used as wall tiles for indoor spaces. They can only be used as floor tiles if the manufacturer guarantees suitability.
Special advantages: High dimensional accuracy and therefore thin grout lines, exceptional décor possibilities, filigree and elegant appearance.
Vitreous tiles are dry-pressed and sealed by firing. Water absorption is therefore low (0.5 to 3%). They are frost-resistant, can be used indoors or outdoors and are typically used as floor tiles – although they can theoretically also be used as wall tiles.
Special advantages: High dimensional accuracy and therefore thin grout lines, wide range of colours, designs and surface finishes, glazed or non-glazed, colour extends throughout the thickness and vitreous tiles are therefore particularly hard wearing.
Porcelain stoneware tiles are also dry-pressed and fired to a low absorption (water absorption = 0.5%). They should therefore be laid with "flexible" grouts and adhesives. Due to the dense structure of the material, the tiles do not mark easily and are simple to clean.
Areas of application and special advantages: see vitreous tiles.
Borders are thin, rectangular décor tiles (generally the same width as the basic tile), that are laid as a strip e.g. towards the top of a tiled wall, to increase the impact of a room.
Split tiles are extruded, and the standard water absorption is 3 to 6%. They are particularly well-suited for outdoor use (they can also be laid on the mortar bed).
Special advantages: wide range of plastic moulded parts e.g. "Florentine steps", nosing tiles, skirting, chamfered tiles etc., natural appearance.
Vitreous slabs are also extruded to a low water absorption level of 3%. Due to their frost resistance, they can be used on both external and internal walls and floors.
Special advantages: diverse range of application, wide range of colours, sizes and shaped pieces.
Joints are an important part of a ceramic floor/wall covering – they are functional, to balance out unavoidable, small dimensional tolerances in the tiles, and a design element: the optical/tactile pattern avoids bland monotony. The overall impression is essentially characterised by the colour of the joint and the colour of the tile. The more the joint blends into the tile, the larger the surface will appear. The greater the contrast, the more the pattern will be emphasized. The classic neutral grout joint colours are the various shades of grey, and white. Special waterproof grouts are available for use in the bathroom and kitchen.
Often discussed: the width of the grout joint. On the one hand, it is determined by the manufacturer's technical specifications; on the other, it is dependent on the style of the tile: a classic, rustic tile surface will have a wide grout line. An elegant wall covering, on the other hand will be particularly attractive with a narrow grout line. Ultimately, like many things, it is a matter of taste. However, expansion and border joints are an urgent technical requirement.