Glazed Roofing Tiles Offer Color Permanence, Durability & Resistance to Nature’s Elements
by Richard Wasowski, Ferro Corporation
The proper selection of roofing tile for a building or home can be as important as an artist selecting a frame for an art masterpiece. The artist strives to select aframe that will enhance the artwork, while maintaining the beauty of the painting. When choosing clay roofing tile, a product with up to a 75 year warranty, it is also important to select tile that provides a special look to enhance the building structure. Ceramic glazed roofing tile is often the best choice.
Available in a wide range of colors in glossy or matte finishes, glazed roofing tiles will never fade or change in appearance. The glazed surface is an impervious, durable inorganic coating that resists mildew and seals the surface of the natural clay body. The glaze is composed of carefully selected materials which melt and fuse with the tile during the firing process. The glaze raw materials are naturally occurring minerals such as clay, feldspar, calcium carbonate and often frit, a pre-reacted glass melted from minerals and oxides. Just as the glaze coating is a combination of carefully selected natural materials, the coloring materials are often oxides of natural materials such as iron, copper, cobalt, manganese and chrome. Blues, greens, white, black, grays, yellows and even fire?engine red are all possible in ceramic glazes.
Glazing a natural clay product has a long and distinguished history. What history museum would be complete without several examples of fine Greek pottery featuring red and black slip glazes? The red and black figured vases are early examples of ceramic glazes used to decorate and seal the surface of the natural clay body. It is not uncommon that many of these ceramic artifacts are more than 25 centuries old, and still look as fresh and vivid in color as the day they emerged from the potter’s kiln. This is truly a testament to the timeless beauty of glazed ceramic products.
In like fashion, the beautiful polychromatic glazes on natural terra cotta bodies produced during the Italian Renaissance are a tribute to this art technique. (Photo Two) Often used as architectural ornamentation on royal palaces, churches and cathedrals, glazed terra cotta exhibits inherent beauty, while withstanding continuous outdoor exposure for more than five centuries.
Traditionally, several manufacturing techniques are used to create the variety of color appearances in ceramic roofing tiles. First, the selection and blending of colored clays produces the well?known reddish, red orange and buff shades of tiles. In addition, by thoroughly blending natural oxides of metals, such as iron and manganese into the clay body, the color range is extended. Another method is to apply a coating material rich in coloring oxides to the tile, or use materials present in the kiln atmosphere to produce a flash?effect on the tile’s surface. The production method with the widest color range is the application of a glaze coating to the tiles. This technique involves applying a durable, inorganic coating that allows for a very broad range of both colors and textures on the tiles. The glaze and tile are fired together in the kiln, fusing the glaze and sealing the surface of the once porous clay body tile. This same manufacturing method is used in producing ceramic floor and wall tile. Consequently, the entire range of colors and textures available in ceramic floor and wall tile are available for roofing tile as well.
Ceramic glazed roofing tiles allow the architect, builder or homeowner to create their own distinctive style on their home or building, while maintaining color permanence, durability and unique resistance to the elements of Nature. Ceramic glaze is truly an art of timeless beauty.