What is meant by the term "calibration" when used by tile manufacturers to refer to tile sizes?
Although a tile size may be stated as 18x18, the nature of the manufacturing process means that it is impossible to ensure all tiles are of an exact equal size. It is for this reason that tile manufacturers produce a number of calibrations for the same tile. The specific calibration provides an indication of the variance from the stated size of the tile. When calibrations are indicated at the outset of a project, the tiles will be as close to a uniform size as you are ever likely to achieve. If this is not done however, there can be problems with the grout lines not running straight as a result of the variance in the tile sizes used.
What are the technical characteristics of porcelain tile?
Porcelain consists of a spray-dried body of selected clays, kaolinitic minerals, quartz and feldspar, shaped by dry pressing to form a ceramic material that is then fired at temperatures up to 1250 degrees centigrade. Porcelain is resistant to wear, deep abrasion, and frost. It is a practically non-absorbent material with great fluxural strength. Quality porcelain will remain constant over time. Porcelain is ideal for interior and exterior floors and walls and even facades of buildings. It is available in natural, smooth, polished and structured finishes.
What are the guidelines regarding exposing ceramic tiles to frost?
Frost damage affects the materials exposed to water in areas where the temperature is liable to fall below zero. Water can penetrate tiles - and therefore a tiled surface - through their pores. If the temperature falls below zero, the water freezes and becomes ice. Since ice occupies a greater volume than liquid water, higher tensions are created inside the pores. These tensions may become so high that portions of the tiles can actually break off. When designing an external floor or wall covering in a location susceptible to cold winters, it is obviously essential to choose frost resistant tiles. However, the choice of frost resistant tiles is not in itself sufficient to guarantee protection of a tiled surface against frost damage. Always choose suitable materials for the bedding layer and the grout joints, as well as a suitable inclination of the floor to prevent water from pooling, etc.
Should you install open or closed grout joints?
With closed joint (or butt-jointed) installation, adjacent tiles are in contact. The thickness of the joint is minimal so it has a very low visual impact. Installation is quick since each tile placed in position provides an immediate reference for the subsequent tile. But this is where the advantages end. The risks (which correspond to the advantages of open joint installation) are certainly more significant. With closed joint installation, the tiled surface is more rigid and considerable stress can arise. These stresses can pose a risk to the integrity of the tiled surface. Furthermore, with closed joint installation it is much more difficult to ensure that the joints are straight and uniform. Every small difference between tiles, even if within the tolerances established by standards, is accentuated. Also, the grout is unable to penetrate properly between the tiles if they are touching. In closed joint installations, there is a high risk of cavities forming in the joint and these will inevitably collect some dirt and grime. So it is certainly not true that a closed joint installation is recommended for hygiene reasons. This is further demonstrated by the fact that open joint tile installations are obligatory in factories where foodstuffs are processed or treated. In short, open joint installation is the most reliable method.
How do you know which adhesive to use when fixing your tiles?
The type of adhesive you use depends on a number of factors: Where are you tiling? What are you tiling on? How much tiling experience do you have? Adhesives can be split into two main categories: THINSET and ORGANIC MASTICS. THINSET adhesives come in powder form and must be mixed with either water, liquid latex or an acrylic additive depending on the type. Thinsets are generally harder to work with because they must be mixed to the right consistency before using. Thinsets have a stronger bond and are more flexible than Organic Mastics (see below). They can also support a lot of weight so they are often used for floor installations. Thinsets can be used in wet areas as well as those exposed to heat. ORGANIC MASTICS are probably the most commonly used adhesives. As they are pre-mixed and ready to use, they are considered easier to work with and less time consuming than thinset adhesives. Mastics are good for setting wall tiles because they start gripping the tile even before it has fully cured. Mastics should not be used in areas that will get wet or will be exposed to extreme heat. Be aware that if you are using a solvent-based mastic the fumes can be potentially explosive and dangerous when inhaled. Always wear a charcoal filtered mask when working with this and keep it away from any naked flames.
Can I use any kind of tile for interior floors?
A product with a highly compact structure such as porcelain tile (which has virtually zero porosity) has both a high mechanical resistance and a high frost resistance. High mechanical resistance is required for floor covering applications in many interior areas. This requirement is met by products such as porcelain tile that also have a high frost resistance. It is good practice to choose porcelain tile on the basis of mechanical considerations. Thinking that any tile will do for interior floors is also not true. Interior floors may be subjected to extremely varied degrees of mechanical or chemical stress according to their application, so they may require tiles with correspondingly different characteristics. A tile with suitable characteristics for the conditions of use on a bedroom floor will not necessarily be able to withstand the stresses that are likely to occur in a kitchen or an entrance hall with direct access to a gravelled outdoor area. In short, it is incorrect to say: "any tile can be used for any interior application". Even for interior applications, it is important to choose "the right tile for the right place".
Are tiles restricted to specific applications or areas of use?
Even though certain types of decoration appear to suggest certain settings (such as for a bathroom), it is not true that tiles are designed and specified (either explicitly or implicitly) for any given application. For example tiles are not specifically designed for use on a kitchen floor or on balconies. Any given kind of tile can be used in a variety of different areas with satisfactory results. So for the vast majority of tiles, specifying just one application would be not only restrictive but also quite unjustified. On the other hand, the conclusion that "any tile can be used in any area and for any application" is definitely false. Each tile may be properly used only in areas where its technical characteristics are suitable for the relevant conditions of use and chemical, physical and mechanical stress. So the choice of the "right tile in the right place" must be made with great care, matching the technical characteristics of tiles with the expected stresses in the area of use.