Different types of tiles and natural stones
The term ‘tile’ is used for all types of ceramic coverings found in homes, bathrooms and public swimming pools, and those used outside as ground covers. Be- sides the wide range of colours and shapes their fundamental difference lies in their water absorbency and the firing and making process used in their ma- nufacture.
Stoneware tiles have a white, yellowish or reddish body and are easy to handle for the tiler. They are frequently “drypressed” and fired at a heat of around 1000° C. The porous body features high water absorbency, which excludes their use for exterior areas. They are mainly used as classic tiles for bathrooms and kitchens.
Vitreous stoneware is popular for use in areas with high load scenarios. The clay is fired at temperatures around 1200° C, which results in a much denser body. In contrast to non-vitreous stoneware tiles vitreous tiles can be used as floor tiles. They can be used anywhere – from normal domestic usage right down to use in industrial settings.
Porcelain tiles are fired at roughly 1300° C, which is near the sintering threshold. Due to the density of the body and the low water absorbency they are considered as frost-proof, which makes them suitable for use outside. In the past they used to be popular mostly as floor tiles – both in polished and unpolished form – they are nowadays also frequently chosen for walls in large-scale formats measuring up to 0.60x1.20m.
Nowadays, glass mosaics and glass tiles are industrially manufactured and come readymade on strips of netting or paper. The transparency of the material gives it a sophisticated look. Glass is easy to clean and very resistant against acid. As it comes in many colours and sha- pes it is a versatile design tool and is highly popular.
A natural stone has been a very long time in the making. In contrast to industrially made tiles or slabs it took several millions of years to make a ‚natural stone‘. As a purely natural product its appeal lies in its uniqueness and beauty. What’s more, natural stones come in a wide range of shades, are robust and very resistant.
They are classified based on how they came to be formed.
The following is an overview of the most common natural stones.
Igneous rocks came about through the slow cooling of magma underneath the earth‘s crust. As a result of the high pressure such natural stone has a particularly dense matrix. Igneous rocks are granite, syenite, porphyry and basalt.
Granit is one of the best-known plutonic rocks. It consists of quartz, feldspar and mica-slate in varying proportions. The stone is very hard, weather-resistant and therefore hard-wearing. The colour spectrum ranges from white, light grey to dark grey. Due to its heavy-duty qualities this stone is ideal for use as paving stone, window sills, stairs and in heavy trafficked areas that need to impress. Fitting is generally easy.
Basalt is an extrusive igneous rock that is especially dense, compact and close-grained. The colour ranges from black to a bluish or violet hue.
Basalt is often used for stairs, the entrance steps to front doors, in- terior claddings, as well as win- dow sills or is used for gardening and landscaping purposes. Fitting basalt tends to be easy.
Sedimentary rocks are types of rock that are formed as a result of “weathering and erosion” – ori- ginally during the formation of earth and which then were com- pacted under high pressure. The best-known sedimentary rocks are sandstones, various schist types, limestone and dolomite.
Sandstone is widespread and consists almost entirely of quartz. Its hardness depends on the degree of solidification. The colour spectrum ranges from white, grey and beige to red and green. Sandstones can be used in many diffe- rent areas and are also frequently found in gardening and landscaping projects, e.g. to produce borders and brickstones. Impor- tant to bear in mind is the fact that many sandstones only have moderate frost-deicing salt resistance and are therefore subject to suffer from weather and environmental impacts. This proneness to heavy weathering is easy to see on old church façades.
Probably the best-known meta- morphic rock of all is marble. It is an unpretentious but beauti- ful and rather versatile stone. It is formed as a result of crystal- line metamorphism of limestone. Marble is easy to polish and work with. The colour spectrum ranges from snow-white to almost black and encompasses almost all other colours in between. When fit- ting marble it is important to use light-coloured and rapidly setting adhesives and joint mortars in order to avoid discoloration.
Schist or mica-slate is metamorphic stone derived from shale. Its colour range is black to greyish silver, sometimes with greenish or bluish hues.
Since slate is a rather dense stone which has no capillarity but contains hydrophobic substances (oils), a bonding course always ought to be laid as well when fitting this type of stone