ebuild Guide to Clay Roof Tile Specifications

Clay tile roofing is one of the oldest forms of roofing known. It originated in China and the Middle East over ten thousand years ago, and eventually spread throughout the world. Europeans brought the technology to America, and clay roofing is now a common architectural feature in many parts of the US, particularly in southern California, Florida, and throughout the Southwest. Apart from its distinctive appearance, clay tile is highly durable, holds a Class A fire rating, and is available in a wide variety of colors and shapes. At the same time, however, clay tile puts a substantial load on a structure, weighing anywhere from 900 pounds per square to over 1,800 pounds per square. Lightweight versions of some tiles are available, but in any case a roof structure must be specifically designed to handle the weight.

MCA Tile. This clay tile offers a combination of flashings and glazes to provide a variety of colors--and 33 qualify as "cool roof" tiles under Energy Star requirements.

The broad expanses of a roof can be covered with field tiles, but specially shaped tiles are often required at the perimeter of a roof plane. Sometimes called fittings, these specialty tiles complete the installation in areas such as the ridge, eaves, rake, starters, and ends. Some manufacturers even offer sculptural fittings to close off the open ends of tiles at the ends of hips and ridges. Fittings are manufactured for each style of field tile and may require a special order, so it's very important to work up a detailed estimate for clay tile roofing projects.

Before choosing tiles for a roof, check to see if local codes restrict certain types of products or require special methods of installation. This is just as important in coastal areas exposed to hurricanes as it is in areas where tornadoes are common.

Key Specifications

Length--The stated length of a tile is usually the same as the actual length of the tile, though in some cases there are slight differences. Different lengths allow tiles to be scaled to the size of the house. In general, longer tiles reduce material and installation costs.

Width--The width of a tile has an impact on the overall look of the installation, and wider tiles can cover a given area more quickly.

Profile--This specification refers to the shape of a tile, which dramatically alters the overall appearance of the roof as well as the installation methods. Flat slab tiles are simple and appear much like shingles. Other profiles incorporate combinations of straight or tapered shapes. Some, such as pan-and-cover profiles, require two different shapes of field tile: the pan sits flat on the roof while the cover rests on top of the pan.

Texture--A weathered surface can lend a rustic appearance to the installation. Some tiles are scored or raked by hand or machine before firing, resulting in a striated surface texture that gives the tile an aged appearance. Tiles are sometimes sandblasted during manufacturer to impart texture.

Installation type--This specification refers to how tiles fit on the roof to block water intrusion. Some include ridges that interlock with adjacent tiles, a feature particularly common on flatter profiles. Interlocking tiles are particularly suited to use in regions with heavy snow or dense rain because they are more weather-resistant. In arid regions, a tile may simply overlap the upturned edges of tiles beneath, a more traditional installation method.

Generic color--Colors within a given shipment of tile will vary somewhat due to differences in clay composition and kiln firing temperatures. Because tiles are rarely of uniform color, think of this specification as a general description of a color range.

Finish--Glazed tiles have shiny though not necessarily smooth surface and often feature strong colors. The glaze fuses with the tile during the firing process to form an impervious, durable coating that seals the surface of the clay and resists mildew.

BarroNica. A mixture of clay, freshwater sand, and a topsoil rich in minerals combine to offer an array of colors from light reddish-brown to blue-black when subjected to the high temperature of a wood-fired kiln. The hand-made clay roof tiles, which are made in Nicaragua, are available in a two-piece Mission tile and one-piece "S" tiles.

The cost of any roofing product can vary considerably from region to region, which is partly due to the limited availability of some products. Clay tile, for example, isn't a big seller in Vermont, and Vermont slate isn't big in the Southwest. Clay tile roofing calls for specialized installation skills, and contractors with those skills may be difficult to find where the product isn't readily available. It's also important to consider the life cycle cost as well as initial cost of roofing. If it lasts much longer, an expensive product may be more cost-efficient than a less expensive product.

Ludowici Roof Tile. Eight clay tile styles, including flat shingles, slate, and the French style shown, are available in a variety of standard and custom colors. Different finishes can give the tiles an antique, crude, or otherwise textured surface. The tiles, which can be warped and scored for a hand-made look, come with a 75-year warranty.

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