In the production and application of terracotta, energy resources and the waste generated during the various stages of the manufacturing process and the subsequent installation of the tiles are handled with care. The surplus clay released after pressing in molds is directly reused in the production process.
Tiles that are no longer marketable, are often crushed into gravel of various sizes and offered to the market as such. Terracotta tiles with a glaze layer, as is the case with wall tiles, can be “tumbled” using a specific grinding technique so that they can be used as mosaic tiles. The cutting waste generated when laying tiles can be recycled cheaply. Most of the cutting waste comes from tiles of non-standard sizes, which are specially made to be laid in a pattern, such as the “Roman bond”.
Generally, terracotta producers all have their own clay mine next to the production site. Consequently, there are no transport costs associated with moving the raw materials to the processing location, which does not burden the environment.
At the processing site, the clay, which contains minerals such as salt crystals that determine the tile's structure after firing, is mixed with water. Although a number of producers also produce mechanically, most process the clay further in an artisanal manner—a labor-intensive process that takes a relatively long time compared to machine-produced terracotta tiles; in mechanical processing, the clay is pressed into molds via conveyor systems.
In the manual, traditional process, (walnut) wooden molds are used. Large earthenware, such as terracotta pottery, is made entirely by hand without the use of molds. The layers of clay that make up the pot are rolled one by one and decorated by hand.
Prior to firing, the clay tiles pressed into molds are laid flat on the ground in an open space to complete the natural drying cycle. Consequently, no additional energy sources are used to dry the tiles. In summer, the drying process proceeds faster than in winter due to lower humidity.
After the drying period, the tiles are fired for six days at a temperature that slowly rises to approximately 1040°C. Firing takes place in energy-efficient gas ovens and, in the case of handmade tiles where it is important that the tile displays the color variations characteristic of terracotta resulting from firing, in (often olive) wood-fired ovens. The shades are the result of the position where the tile is placed in the wood oven. Because the temperature in the upper parts of the oven is higher than in the lower parts, the flames form a natural cooking pattern along each individual tile. This lively pattern, which is different in every tile, creates a warm and welcoming atmosphere once the tiles are laid.
After firing, the tiles are cooled to ambient temperature, after which they are removed from the oven, inspected, and carefully selected. Tiles that do not meet the quality requirements are crushed and reused as raw material.
Finally, approved tiles are immersed in a water bath to break down any remaining saline minerals, which can cause cracks if not cooled sufficiently. Due to the high quality of the clay and the manufacturing process used, the tiles are frost-resistant down to -45°C, making them suitable for use in cold continental climates.
Unlike a floor made of ceramic tiles, which are manufactured from cement in a factory with a uniform thickness, laying a floor of handmade terracotta requires professional expertise. Laying such a floor is fundamentally different from laying a floor made of other materials such as cement, synthetic tiles, or wood.
The handmade terracotta tile, which can vary in thickness because the material is shaped by hand, is made of clay, a natural and inherently porous material that absorbs liquids when applied ‘raw’ to the adhesive layer. For this reason, terracotta tiles must be rinsed with water before laying, and a special flexible adhesive must be used. The use of a notched trowel of the correct size to accommodate the thickness is necessary to level the floor evenly and at the correct height.
Pre-treating the tile with a wax product and using a grout that complies with special regulations prevent the tile from being damaged by the grout.
The choice of grout when installing tiles is worth considering from an environmentally conscious perspective. A grout containing as few colorants as possible appears to be a ‘better’ grout. Generally, a narrow joint between tiles is more durable than a wide one. The reason for this is that the grout is softer and more fragile than the tiles, which can cause it to ‘sand’ over time. Due to this characteristic, wide joints pose a greater risk of damage that would necessitate the replacement of tiles. Although more tiles are needed with a narrow joint than with a wide one, choosing a narrow joint offers two advantages: terracotta tiles are made of a natural material that is manufactured in an energy-efficient manner, and the narrow joint prevents damage and the need for tile replacement.
In addition to choosing the right grout and using a ‘clean’ grout, removing cement haze by cleaning with just water is generally sufficient. More difficult-to-remove stains can be treated with specific commercially available products for that purpose. It is recommended to have the floor pre-impregnated with oil by the manufacturer, preventing liquid stains, such as from wine, from penetrating the tile. If desired, the oil can be dyed to give the natural color of the floor more ‘depth’. Optionally, the floor can be post-treated with a wax product.Although laying a tiled floor seems simpler than it is, for a ‘living’ terracotta floor, it is advisable to use the expertise of a professional tiler with experience in laying terracotta.
Renewal of old, soiled, or damaged terracotta floors. Terracotta floors that are soiled or damaged do not need to be replaced entirely to last a lifetime.
A soiled floor can be professionally cleaned and broken tiles can be renewed, making them look like new again.
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