Structural clay tile

[4] Each of these methods emerged out of a growing need to fireproof buildings following massive fires across the United States during that last quarter of the nineteenth century.

An interlocking system of angular clay tiles that were fit together with a keystone became popular in the early 1870s after designs by Vincent Garcin were mass-produced to create flat segmented arches.

[1] Flat arch construction grew in popularity with the increasing number of buildings using steel and iron structural members in their design.

[3] After 1910, manufacturers began to test and develop stronger and more complex structural clay tile systems that worked better in compression.

Greater compressive strength, found largely in the invention of the end pressure arch, allowed the material to be used in longer floor spans.

[3] However, as reinforced concrete grew in popularity as a cheaper and less complex alternative, structural clay tile use in floors and roofing declined.

[4][3] With the rise of reinforced concrete flooring and metal decking, structural clay tile fell out of popularity for use in horizontal applications.

Likewise, structural clay tile blocks were frequently used as backing for exterior walls, often filling the voids behind architectural ornament, stone, or brickwork.

[3] In early steel construction, clay tile blocks were historically used as infill between structural members, which provided much needed lateral support.

[3] In some cases, entire walls—typically in single-story buildings, seldom higher—were created out of structural clay tile, typically multiple wythes thick.

Structural glazed facing tile has been extensively used in institutional settings where a durable, easily cleanable surface is desired.

A wide variety of shapes have been developed to allow the construction of corners, caps, wall base and other elements using standard sizes.

SGFT cannot be easily cut without damage to the glazed surface, so several dozen special shapes are available to allow most situations to be accommodated.

Specialized kinds of structural clay tile were produced with a vitrified or glazed curved surface for use in building farm silos.

Load-bearing tile is described under ASTM Standard C34, subdivided into grade LBX, for areas exposed to weathering, and LB, for protected applications.

[5] Tile was also manufactured in a series of graduated wedge shapes for installation between steel members as a fireproof flat arch floor structure, to be covered with a concrete wearing surface above.

Advertisement of hollow structural tile circa 1920.
An example of a typical NATCO hollow clay tile as advertised in their 1910 catalogue. "The visible points of superiority, as compared with similar tile of different makes, are the deep dovetail scoring for the better bonding of stucco or plaster, the absence of imperfections and the better general symmetry due to the more accurate machining by this company's unequaled equipment. Equally important qualities not obtainable in other tile are not so apparent to the eye. These consist of finer properties in the raw clay and its more uniform and thorough burning, resulting in greater density and a higher degree of inherent strength. It is to certify these advantages, and to instantly identify the tile possessing them, that the name NATCO is stamped plainly upon the face of each tile." —From NATCO Catalog "Fireproof Construction for Houses and Other Buildings at Moderate Cost," 1910.
Electrical wiring being installed in structural clay tile block used for interior partitions in the vertical application, 2008.
An example of a specialty type of hollow clay tile unit. This example interlocked with other units to increase strength, circa 1905 .