The use of engobe and lacquer allowed for the development of new colours for clay roof tiles. In both cases, we get a fascinating colour effect as well as a much smoother shingle surface that is more resistant to environmental influences. Since clays are rarely found in isotropic deposits, the shade of individual items from a single batch can initially differ. Furthermore, excessive porosity promotes dirt accumulation, moss and lichen germination, especially if the home is near a forest. Dubbing, on the other hand, is a popular way for manufacturers to remove colour mismatch.
Engobed or vitrified porcelain tiling?
Clay roof tile manufacturing technologies are being developed in order to expand the palette of available goods and enhance their technological characteristics. Engobing and glazing are modern tile painting techniques that involve adding a specific material (such as an argillaceous liquid mass of enamel paint) to the tile so that it can be painted in a variety of colours, such as brown, green, blue, black, or grey. view here it has some nice tips on this.
In terms of technological characteristics, engobe has a major impact on tile longevity when exposed to different environmental factors such as contamination, acid rain, hail, and UV radiation. The words “engobing” and “glazing” are often used interchangeably when discussing colouring technology. There are variations to bear in mind when buying building tiles, despite similar functions and properties. They are connected to each other, for example, by their chemical composition. Engobe is made up of a liquid argillaceous mass that has been mixed with corresponding minerals or metal oxides. Porcelain enamel, on the other hand, is made primarily of pulverised previously melted enamel pigment enriched with inorganic additives.
Daubing does not produce a tight texture on the tile’s surface, but instead leaves the pores free, maintaining the roofing material’s strong diffusive properties. Vitrified tiling is distinguished by a shiny top layer that fills in the voids. Glazed shingles’ closed structure ensures that, as opposed to daub, they are more resistant to external agents. This type of tile’s smooth, almost non-porous surface significantly reduces dirt formation and makes cleaning easier, not only from dust and mud, but also from moss and mould.
Tiles with a variety of colours
The colour of clay shingles is primarily determined by the colour of the basic raw material. As a result, brick-red is the most commonly associated coloration for ceramic housetops. Creating a broad tint range necessitates the use of rare earthenware species added to the shingles’ surfaces. Until baking in the oven, an enrobing coating is sprayed on dried-up shingles in the form of a fluid mixture. Under the influence of high temperatures, chemical compounds are stimulated, giving workpieces a coloured and lustrous finish.
When vitrifying, a similar process occurs, with the exception that the glazing compound partially penetrates the tilework, forming an additional intermediate layer. Unlike engobe coating, where the colour of the finished product is solely determined by the thickness of the applied coat, shades produced with glazing are determined by the variety of mineral pigments used.
It’s also important to note that the use of daubing and glaze affects not only the colour effect, but also the smoothness of the item’s surface. Luster results in a more homogeneous system with a lot of reflection. When enamelling ingredients are applied to a stoneware mixture, we get a precious engobe with the same shimmer as porcelain enamel, but with the porous structure that porcelain enamel has.