Glazed tiles

Glazed tiles consist of two layers: a shard and a layer of glaze. The use of glaze provides great artistic diversity and increases strength and performance characteristics. Glazed tiles can be: double fired; double, quick firing; single firing; triple firing.

Double firing

This category of tiles includes: majolica , cottoforte , faience . Tiles such as majolica and cottoforte were widespread in the 1960-70s and accounted for 60% of the total tile production in Italy. In the early 1980s, their production began to decline, while the production of single-fired tiles increased. According to the association of Italian ceramic tile producers (Assopiastrelle), their production in 2001 amounted to only 10% of total production. However, thanks to the high aesthetic qualities of majolica and cottoforte, as well as the technological advantages of double firing, these two types retain their market segment.

Majolica

Double-fired glazed tiles with a porous and colored base, press-molded. Majolica tiles are also called faience. However, there is a difference between them. In everyday terminology, faience means any tile coated with a layer of glaze, but faience is white-burning tiles, and majolica is red-burning. The term faience comes from the Italian city of Faenza, an important center for the production of ceramic tiles during the Renaissance. The term majolica presumably comes from the name of the island of Mallorca, the port from which ceramic tiles produced in Valencia and Malaga were shipped to Italy. Firing is carried out in two stages, first the shard is fired, then the glaze. Water absorption ranges from 12 to 22%, the biscuit is fired at a temperature of 950 degrees, the glaze at 1000-1050 degrees. Firing lasts 18-20 hours. Accordingly, the tiles are not frost-resistant and are not highly durable. It is used only for interiors when covering walls.

Cottoforte

Double-fired glazed tiles with a porous, colored base, press-molded. Cottoforte occupies an intermediate position between majolica tiles and red gres. Like majolica, cottoforte is a glazed tile with a colored porous base, but in terms of its raw material composition it is close to red gres (that is, a tile with a compacted shard). Therefore, cottoforte is successfully used for interior floor coverings. Because of this duality, cottoforte received another name - half-gres. Also used for wall cladding. The glaze layer gives the tiles aesthetic and technical characteristics (water permeability, hardness, chemical resistance). Coloristic and decorative possibilities are unlimited. The opaque glaze completely hides the colored shard; its color range varies from pink to red due to the presence of a significant amount of iron in the raw material (more than in majolica tiles). The shard is porous, but the pores are quite small. Water absorption ranges from 6 to 15%. Due to their high porosity, the tiles are not frost-resistant. The average tile thickness of 10-12 mm is quite sufficient to withstand the loads inherent in residential premises. Glaze abrasion index (PEI) can vary from 1 to 4; these figures refer to the glaze layer, not the shard. Characteristic dimensions – 15x15; 20x20; 20x25; 25x25; 30x30 cm.

Faience (double white fired)

Glazed ceramic tiles with a porous and white base, press-molded. The raw material is white clay, which after firing gives the shard a light tone. The production of this type of tile is small due to the high cost of both raw materials and double firing. However, white sponge cake allows you to use transparent glazes or glazes in light colors. These tiles are of high artistic quality. This type of tile occupies a significant place in the total production volume of some factories.

Quick double firing

Glazed ceramic tiles with separate firing of the shard and glaze with a total cycle of 40-50 minutes.

Single firing

The product is obtained by pressing a mixture of selected raw ingredients (clays, feldspars, fluxes and quartz). The pressed mixture is glazed and then fired once, which ensures good adhesion of the glaze to the mixture. The term single firing combines a wide typological variety of tiles with different technical characteristics. The production of single-fired tiles originated in the 1960s, but became widespread in the next decade for economic reasons. The development of this type was facilitated not only by economic advantages, but also by new aesthetic possibilities, expressed in the imitation of natural stone. Initially, single-firing tiles were made less artistically than double-firing tiles, but with the development of applied technologies, the artistic level of surface decoration increased significantly.

The entire variety of single-firing tiles can be reduced to the following types:

• glazed white burning tiles;
• glazed porous white burning tiles;
• glazed red burning tiles;
• glazed porous red-burning tiles;
• glazed ceramic granite.

White-burning single-fired tiles (monocottura bianca)

The color of the shard varies from gray to pale yellow or white. The raw material is a mixture of white clays, feldspar and quartz. Feldspar and quartz give the material greater mechanical strength and reduce water absorption. Firing occurs at a temperature of 1150-1220 degrees Celsius. Increased strength characteristics make them suitable for the production of large format tiles.

Red-burning single-fired tiles (monocottura colorata)

The body of the tile consists of a mixture of red clays, feldspar and quartz. This type of tile originated in the Sassuolo region (Italy) thanks to a deposit of red clay. Tiles of this type are fired at a temperature of 1150 degrees Celsius (biscuit and glaze at the same time). Water absorption 0-3%. Increased strength characteristics make them suitable for floor coverings.

Single fired porous tiles (red and white clay)

The production of porous, one-time-fired tiles (red and white clay) has increased significantly in recent years. First of all, this applies to Spain, where this is the main type of product. They are made from a special mixture designed to prevent shrinkage during the firing process. As for Italy, tiles of this type are crowding out the market segment traditionally occupied by majolica and cottoforte (interior - walls and floors). The production process is similar to the production of single-fired low porosity tiles (white and red clay); the difference is the lower firing temperature and shorter firing cycle. The products have increased porosity and low mechanical strength. Firing temperature – 1050-1120 degrees Celsius. Successfully replace majolica and cottoforte. It is possible to use a wide variety of decorative techniques to enhance the artistic characteristics of the tiles. Used for cladding interior walls.

Glazed porcelain granite (Gres porcellanato smaltato)

The tile consists of two layers - a shard and a layer of glaze. Tiles of this type are characterized by a combination of high technical performance and artistic capabilities of glazed tiles. These qualities have determined the significant growth in production of this type in recent years. The typological diversity of glazed ceramic granite is unusually large: from small-format mosaics to large-sized modular tiles.

Glazed third fired tiles (Terzo Fuoco)

Decorating tiles on a glazed surface. In this technology, after the second firing, another layer of glaze is applied to the surface, which is fired at a lower temperature - 700-800 degrees Celsius. Sometimes the tiles undergo a fourth and fifth firing, but all this is technically and commercially called the third firing. The third firing involves expensive tiles of high artistic value, originating from hand-made tiles using precious metals (gold, precious enamels, chandeliers).