Structural clay tile

Pre 1850s-1870s Clay tiles have been used in various ways for thousands of years. The Romans were among the first to use clay tile in construction by building clay pots to lighten vaulting loads. However the first recorded structural use of terra-cotta forms was in sixth-century Italy in the dome of the Church of San Vitale in Ravenna. Clay pots lined with plaster of paris lightened the load of the dome in a similar way to earlier Roman construction. Increasingly, clay tile was used inside concrete flooring to make it lighter, or as centering/formwork for concrete construction. With the rise of reinforced concrete flooring and metal decking, structural clay tile fell out of popularity for use in horizontal applications. While the use of structural clay tile in flooring and roofing declined, its use in walls enjoyed popularity into the 1950s. Wall tile blocks continue to be manufactured, but specialty tile units often require custom commissions. Clay tile arches are no longer manufactured and due to a lack of skilled artisans to lay the arch systems, they are never replaced. ==Horizontal Application==

Tile Floor Arch Types Side Pressure Arch Construction Side pressure arch construction, the first method used in tile floor arches, is composed of hollow tiles laid parallel to I beams. End Pressure Arch Construction End pressure arch construction is composed of hollow tiles laid perpendicular to I beams. This method enjoyed popularity after it was discovered to be fifty percent more efficient than side pressure arches. Book Tile A popular use of structural clay tile was book tile, a flat hollow tile, that was used in roofing systems. Book tile was also used in raised flooring to allow plumbing and other systems to be run in buildings. == Composite Construction ==

In the late 1890s, the most popular system of tile floor arches combined both side and end pressure construction. With the increase in popularity of concrete construction, composite construction began to use both methods in conjunction with reinforced concrete. Later systems used clay tiles and reinforced concrete to replace tile floor arches in the 1930s. == Vertical Application ==

The most popular and enduring form of structural clay tile is its use in vertical applications as a structural element. In the vertical application, structural clay tile blocks are used in both columns and load bearing walls. Likewise, structural clay tile blocks were frequently used as backing for exterior walls, often filling the voids behind architectural ornament, stone, or brickwork. SGFT has been replaced in some applications by glazed masonry units, a composite of concrete masonry and a tile-like surface coating. Specialized kinds of structural clay tile were produced with a vitrified or glazed curved surface for use in building farm silos. Other shapes, called "telephone tiles", were used as underground multi-celled conduits for telephone cables. == Manufacturing and Classification ==

Manufacturing Structural clay tile is still manufactured according to historical processes: clay is kneaded to an appropriate consistency, extruded, sliced and fired in large kilns. Structural clay tiles are manufactured in a variety of standard sizes, including , , , and thicknesses, and typically x or x face dimensions. ==See also==