Terra-cotta … the great Western paving

Sunset, May, 1992 by Daniel P. Gregory

For indoors and outdoors, handmade or machine-made, genuine or look-alikes. . . here's how to choose tiles

RESEMBLING CRISP cookies fresh from a giant baking sheet, this array of earth-toned tiles illustrates the variety of terra-cotta and mock terra-cotta flooring choices now available.

The informal appearance of terra-cotta's warm natural tones is especially suitable for the West's casual, outdoor-oriented lifestyle. One expert advises, "If you're looking for something perfect, don't consider it. But over the long haul it can be easier to live with than colored tiles."

A diversity of shapes--typically a foot square or less in size--including the pointed picket and hexagon (below), makes these tiles adaptable to any size room or patio.

TIME AND TERRA-COTTA

Thinking of terra-cotta floor tiles as gingersnaps-for-the-ages isn't as farfetched as you might think: terra-cotta means "baked earth" in Italian. More precisely, terra-cotta is fired clay.

Terra-cotta has been used underfoot for thousands of years, especially in countries around the Mediterranean. In ancient Rome, Julius Caesar walked over terra-cotta whenever he crossed the herring-bone-patterned tiles of the Sacra Via. France and Spain, as well as Italy, have long tile-making traditions.

In the American West, terra-cotta flooring enjoyed a renaissance during the 1920s as part of the vogue for Mediterranean-inspired architecture. California architects like George Washington Smith in Santa Barbara and Wallace Neff in Pasadena made extensive use of terra-cotta in many of their houses.

BASIC CHARACTERISTICS

Visually, the differences between terra-cotta types are subtle. Natural colors range from chocolate through ocher to brick and are the result of the particular clay's chemical composition and the way the clay is fired. Traditional terra-cotta color is orange-red (iron in the clay burns red when oxidized). Some tiles are "flashed," that is, exposed to varying temperatures, to create a mottled look.

Different terra-cottas also have different physical properties, again resulting from the clay and method of manufacture. Tile fired at lower temperatures is more porous (less dense) and softer than tile fired at higher temperatures, which create a more vitreous (glasslike) and durable product. Porous tiles absorb moisture more readily than dense ones, and consequently stain more easily.

HAND-MOLDED UNGLAZED TILES

These tiles are made by pouring the clay into wooden or metal molds, removing the molds, drying or curing the tiles, and then firing them. (The shaping of the tiles is sometimes, in fact, done by machine.)

Most hand-molded floor tiles are referred to as pavers, and are soft and porous. They usually have a rustic, grainy, handcrafted look. Surface texture ranges from smooth to rough. Perhaps the best-known hand-molded pavers are Saltillo tiles (named for the city in Mexico where they are made). So-called super Saltillos have rounded edges. Dense, hand-molded unglazed pavers are also made in the United States, Europe, and Peru.

When laying these tiles, you need a wider grout to compensate for uneven edges.

In warm, dry climates, some experts advise allowing time for calcium and lime to efforesce to the surface of newly set tiles (it can take a month) before sealing them. Or, use a breathing sealer, which allows this process to continue without adverse effects. (A nonbreathing sealer can trap efflorescence, creating unsightly areas on tile.) In cool, wet climates, using pavers outdoors is not advisable: mildew and moss will become problems.

MACHINE-MADE UNGLAZED TILES

Also called quarry tiles, these are manufactured by extrusion--forcing the clay through a die (like toothpaste through a tube). Before curing and firing, the clay sometimes goes through a vacuum chamber to draw out any air bubbles.

It can be difficult to tell some machine-made tiles from hand-molded ones. The tip-off is a precisely scored back (a result of the extrusion process). Also, machine-made tiles are generally harder, denser, and more durable.

Europe, Mexico, and the United States are the main sources.

MACHINE-MADE GLAZED TILES

Extruded, glazed tiles are smoother, and usually shinier, than unglazed ones. Glaze is a thin, glassy coating bonded to the clay at a very high temperature in the kiln, producing a hard finish. Surface textures range from high-gloss to mat and pebbly. Even tiles with a rough texture are prone to slickness when wet, so experts advise against using glazed tiles outdoors.

Glazing makes tiles more stain-resistant, and there is no need to seal them. Europe, Mexico, and the United States are primary sources.

CONCRETE TILES

Some concrete tiles mimic terra-cotta in texture and color. These tiles, manufactured in the United States, are extensively used in high-traffic areas like Disneyland because they are extremely strong and durable. They are less porous than Mexican terra-cotta but still need to be sealed when used indoors.

SHOPPING TIPS

Think about whether the tile you like is actually best suited to the job you want it to do. Softer terra-cottas can fracture and crumble at below-freezing temperatures.