Clay roof tiles Patzcuaro Mexico (C) Daniel Friedman Clay Tile Roof Inspection & Installation Details
Photo Guide to Clay Tile Roofs

  • CLAY TILE ROOFING - CONTENTS: Types of clay roofing tiles, life expectancy, installation details. Photographs of types of clay tile roofs in the U.S, Korea, Norway, Mexico and other countries, Clay tile roof inspection, failures, repair, product defects, Roof inspection, leak detection, roof diagnosis, roof repair, Key design details & references for clay roofing tiles, Duralita & other clay roof tile alternative products, Sources of clay roofing tiles, clay roof tile manufacturers' list.
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Clay tile roofs:

This article series explains clay tile roofing types, clay roofing tile inspection, tile roofing diagnosis, & tile roof repair.

Our page top photo shows clay roofing tiles installed in Patzcuaro, Mexico. Clay roofing tiles have been used in Europe, the Middle East, and Asia, since the Greek and Roman Empires, and the Americas since Europeans arrived there.

Clay tile roofing material is costly to purchase and install, but it can have an indefinite life expectancy.

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Clay Roofing Tile Types, Patterns, Installation, Inspection & Repair Guide

Clay tile roof with extensive damage (C) D FriedmanReal clay tile roofs compared with cosmetic clay tile roofs:

The clay roof tile systems we discuss in this article series are "real" clay tile roofs on which the tiles themselves are intended to provide the water shedding and drainage necessary to form a dry covering over a building.

At left the very damaged clay tile roof depended on the tiles themselves to carry away rainfall. But other roofs use clay tiles to protect a waterproof underlayment from sun and for aesthetic reasons.

Such "cosmetic" clay tile roofs are commonly installed in some areas (Boca Raton, Florida) over a completely functional waterproof membrane.

Cosmetic clay tile roofs also protect the roof membrane from deterioration from sunlight, but the tiles themselves are not forming the waterproof covering.

A Little History of Clay Roofing Tiles in the U.S & Other Countries

Clay roof pagoda, NamSan Seoul, 1966 (C) D FriedmanClay roof tiles have been used since Roman times, are still widely used in Europe, Asia, throughout North America as well.

Our photo (left, by the author DF- 1966) shows decorative clay roofing on Yongnyong-jon hall, a Korean shrine forming part of the oldest shrine in Korea Jeongjeon, the Jongmyo Confucian shrine constructedby King Jaejo beginning in 1394.

Koreans believed that the royal spirits achieved peace only after their tablets were brought here from Chongjon. Thus, Chongjon enshrined the souls still roaming the earth, while Yongnyong held those who had achieved eternal rest.

As NPS historic preservation expert Sweetser points out,

European settlers used clay tile for roofing as early as the mid-17th century; many pantiles (S-curved tiles), as well as flat roofing tiles, were used in Jamestown, Virginia. In some cities such as New York and Boston, clay was popularly used as a precaution against such fires as those that engulfed London in 1666 and scorched Boston in 1679.


Tile[s] roofs found in the mid-18th century Moravian settlements in Pennsylvania closely resembled those found in Germany. Typically, the tiles were 1415" long, 67" wide with a curved butt. A lug on the back allowed the tiles to hang on the lathing without nails or pegs.

Curving clay tile roof pattern, San Miguel de Allende, Mexico (C) Daniel Friedman

Photo: curving pattern in clay tile roof, San Miguel de Allende, Guanajuato, Mexico. [Click any image for an enlarged, detailed version.]

The tile surface was usually scored with finger marks to promote drainage. In the Southwest, the tile roofs of the Spanish missionaries (mission tiles) were first manufactured (ca. 1780) at the Mission San Antonio de Padua in California.

These semicircular tiles were made by molding clay over sections of logs, and they were generally 22" long and tapered in width.

The plain or flat rectangular tiles most commonly used from the 17th through the beginning of the 19th century measured about 10" by 6" by 1/2," and had two holes at one end for a nail or peg fastener. Sometimes mortar was applied between the courses to secure the tiles in a heavy wind.

In the mid-19th century, tile roofs were often replaced by sheet-metal roofs, which were lighter and easier to install and maintain. However, by the turn of the century, the Romanesque Revival and Mission style buildings created a new demand and popularity for this picturesque roofing material.

Our glazed roof tiles shown below were on homes in freezing climates of Norway (below left) and Duluth, MN (below right). Best Practices Guide to Residential Construction points out that

To make tiles, moist clay is extruded through a die or cast in a mold and then fired in a kiln until the clay “vitrifies,” fusing the particles together. Complete vitrification will create a strong tile with very low water absorption, which protects tile from freeze-thaw damage in cold climates or damage from salt air in coastal areas.

Where regular freeze-thaw cycling is expected, roof tiles should comply with ASTM C1167 Grade 1, which allows minimal water absorption. Grade II tile provides moderate resistance to frost action, and Grade III tile is porous and should not be used in freeze-thaw areas.

Glazed clay roof tiles in Norway (C) Daniel Friedman Glazed clay roof tiles in Duluth Minnesota (C) Daniel Friedman

Photo above left: highly vitrified glazed clay tile roof in Molde, Norway. At abovbe right, a vitrified clay glazed flat tile roof in Duluth, Minnesota. Both of these roofs tolerate freezing climate and other harsh weather conditions.

Antique_Clay_Tile_Roof_Ross_on_Wye_Herefordshire_UK (C) Daniel FriedmanThe antique clay tile roof shown at left is on a building in Ross on Wye, Herefordshire, in the U.K. near Goodrich Castle.

[Click to enlarge any image]

Clay roof tiles, typically 7" x 13" are 1/4" to 1/2" in thickness and are shaped in molds and fired in a kiln to 2000 degF to cause the clay to vitrify. The vitrification (glasification) process makes the tiles hard and waterproof by melting and fusing silicas and aluminas in the clay.

Clay roofing tile surfaces may also be decorated with an embossed pattern to resemble wood, slate, or stone. Un-glazed tiles are terra-cotta red, a color provided by iron oxide in the clay.

Clay roof tiles may also be made with a colored glaze, adding both color and an additional layer of hard surface protection. While traditional clay tile glazing was performed by hand dipping and pouring glazing compound over the tiles, Carson Dunlop point out in their Home Study Course for home inspectors, since the 1970's glazing on clay tiles has been spray applied and the tile backs are left un-glazed, both reducing tile cost and permitting moisture to escape from the back surface of the tile.

Clay tile roof in Phoenix Arizona (C) Daniel Friedman Clay tile roof in Phoenix Arizona (C) Daniel Friedman

In between the soft, fragile un-glazed low-fired clay tiles of Mexico and South America and the hard-fired glazed roofing tiles used in northern climates are harder-fired but unglazed clay roofing tiles we see in frequent use in Arizona where tolerance for sun makes these a long-lived material compared with lower-cost asphalt shingle roof coverings.

Both flat and curved clay tiles are in wide use in the American Southwest. The clay tile roof shown at above left is located near Phoenix, and at above right the clay tile roof is on a building located in Surprise, Arizona.

Higher quality clay roofing tiles are kiln fired to a higher temperature, are harder, less porous, and thus more durable. Inexpensive clay roofing tiles that are fired to lower temperatures insufficient to achieve vitrification are soft, easy to break, and less water resistant.

Description of Tapered Mission Clay Tiles & Barrel Mission Clay Roofing Tiles

Clay tile - tapered mission style (C) Carson Dunlop Associates Clay tile barrell mission style straight (C) Carson Dunlop Associates

Carson Dunlop's sketch (left) illustrates the traditional tapered mission style clay roof tiles, and at right, the less-rounded barrel-mission style clay roof tiles. [Click to enlarge any image]

Description of S-style Clay Roofing Tiles & Flat Rectangular Interlocking Clay Roof Tiles

S-style clay roofint tiles (C) Carson Dunlop Associates Interlocking clay shingle-tiles (C) Daniel Friedman

Carson Dunlop's sketch (left) illustrates the Spanish roofing tile that is roughly "S" shaped, including the pan or drainage trough on the left side of the tile and the raised tile surface on its right side. Variations of these interlocking tiles include a lower-profile "S" tile and also Greek and Roman clay roof tiles.

All of the rounded mission tile roofing materials need to be enclosed at the eaves or lower roof edge to avoid blowing rain and wind (wind-lift damage) and animal entry. Tile end closure is discussed at How clay roofing tiles are secured.

Interlocking clay roof tile (C) Daniel Friedman

Our photo (left) and Carson Dunlop's sketch (above right) illustrate a typical interlocking roofing tile that is flat.

In our photo you can see metal tabs that mark the location of inserted replacement or repair clay tiles. The tabs should be bent up over the tile edges but appeared to have been flattened by snow sliding down the roof.

This clay tile roof was located near New York City. Lots of these tiles were broken, particularly on the low slope roof section: we suspected some of the clay tile roof damage was due to foot traffic.

See ROOF INSPECTION SAFETY & LIMITS where we provide more photographs of this roof (Walking on Clay Roofs) and This article explains roof safety and roof damage issues when inspecting, repairing, or otherwise walking on clay tiles as well as other roof materials such as asphalt, slate, and wood roofs.

We recommend against walking on clay tile roofs as you are likely to damage the roof leading to the need for costly repairs. Our photo of broken clay roof shingle-tiles (above right) was taken during an inspection made without walking on the roof surface - for obvious reasons: we didn't want to shoulder the blame for this damage. our photo of a tarred roof valley and damaged interlocking clay roof tiles (above left) was taken from a ladder at roof edge.

Details about clay roofing tile shapes, profiles, styles, types are at CLAY TILE ROOF STYLES, DESIGNS for detailed descriptions of different clay roof tile styles and characteristics.

Also see ROOFING TILE SHAPES & PROFILES where we discuss the basics of roof tile profiles and what they mean.

How Clay Roof Tiles are Secured On the Roof & How Open Eaves are Closed

The illustrations of of how clay roof tiles are secured (below left) and of typical eaves closure of the open ends of Spanish or mission style roof tiles was provided courtesy of Carson Dunlop Associates. The tile roof eaves closure and drain openings shown below are on homes in Surprise, Arizona. Notice the larger drain opening in the eaves closure for the roof at below right. [Click to enlarge any image.]

Details about clay roofing tile fastening specifications are at CLAY TILE ROOF CONNECTIONS.

Eaves closure on clay tile roof, Surprise AZ (C) Daniel Friedman Eaves closure on clay tile roof, Surprise AZ (C) Daniel Friedman

Photos below: at below left is a mission style clay tile roof with an open eaves design, Buenos Aires, Argentina. At below right is an open eaves clay tile roof design in Molde, Norway.

Clay tile roof, open eaves, Buenos Aires, Argentina (C) Daniel Friedman Clay tile roof, open eaves, Molde, Norway (C) Daniel Friedman

Clay tile roof eaves are also left open routinely in warmer climates such as Mexico, Central and South America, as we illustrate below with this roof from Xotolar, Guanajuato, Mexico.

Clay tile roof, open eaves, Buenos Aires, Argentina (C) Daniel Friedman

Clay Roof Tile Sources & Manufacturers

Best Practices Guide to Residential Construction lists these producers and sources of clay roofing tilies, roof tile fastening systems, and related clay roofing products

Clay Roofing Tile Fasteners & Adhesives - Sources & Manufacturers

-- Adapted with permission from Best Practices Guide to Residential Construction.

As we discussed at SLATE ROOF INSPECTION & REPAIR, the fasteners or metal flashings on clay tile roofs are more likely to wear out than the tiles themselves. However clay tile roofs are often damaged by foot traffic, ice and snow, or by severe storms.

Also see CLAY TILE ROOF STYLES, DESIGNS for detailed descriptions of different clay roof tile styles and characteristics, and see ROOFING TILE SHAPES & PROFILES for the basics of roof tile profiles and what they mean.

Clay Roofing Tile Installation Articles


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