30 PRESERVATION 

BRIEFS 

The Preservation and Repair of Historic 

Clay Tile Roofs 

Anne E. Grimmer and Paul K. Williams 

U.S. Department of the Interior 

National Park Service 

Cultural Resources 

Heritage Preservation Services 

Clay tiles are one of the most distinctive and decorative 

historic roofing materials because of their great variety of 

shapes, colors, profiles, patterns, and textures. Traditionally, 

clay tiles were formed by hand, and later by machine 

extrusion of natural clay, textured or glazed with color, 

and fired in high-temperature kilns. The unique visual 

qualities of a clay tile roof often make it a prominent 

SOUTH ELEVATION KM..I: ~. 1

1 -0. 

feature in defining the overall character of a historic 

building (Fig. 1). The significance and inherently fragile 

nature of historic tile roofs dictate that special care and 

precaution be taken to preserve and repair them. 

Clay tile has one of the longest life expectancies among 

historic roofing materials-generally about 100 years, 

Figure 1. Clay tiles used as roof covering and as vertical cladding on the third story and gable ends are important in defining the historic character of the 

Alfred W McCune Mansion in Salt Lake City. Designed by the architect S.c. Dallas, and completed in 1901, this brick and brownstone structure is a tiled 

variation of the Shingle style. Drawing: Clay Fraser, HABS Collection. 

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and often several hundred. Yet, a regularly scheduled 

maintenance program is necessary to prolong the life of 

any roofing system. A complete internal and external 

inspection of the roof structure and the roof covering is 

recommended to determine condition, potential causes of 

failure, or source of leaks, and will help in developing a 

program for the preservation and repair of the tile roof. 

Before initiating any repair work on historic clay tile roofs, 

it is important to identify those qualities important in 

contributing to the historic Significance and character of 

the building. 

This Brief will review the history of clay roofing tiles and 

will include a description of the many types and shapes 

of historic tiles, as well as their different methods of 

attachment. It will conclude with general guidance for the 

historic property owner or building manager on how to 

plan and carry out a project involving the repair and 

selected replacement of historic clay roofing tiles. Repair of 

historic clay tile roofs is not a job for amateurs; it should 

be undertaken only by professional roofers experienced in 

working with clay tile roofs. 

Historical Background 

The origin of clay roofing tile can be traced independently 

to two different parts of the world: China, during the 

Neolithic Age, beginning around 10,000 B.C.; and the 

Middle East, a short time later. From these regions, the 

use of clay tile spread throughout Asia and Europe. Not 

only the ancient Egyptians and Babylonians, but also the 

Greeks and Romans roofed their buildings with clay tiles, 

and adaptations of their practice continue in Europe to the 

present. European settlers brought this roofing tradition to 

America where it was established in many places by the 

17th century. 

Archeologists have recovered specimens of clay roofing 

tiles from the 1585 settlement of Roanoke Island in North 

Carolina. Clay tile was also used in the early English 

settlements in Jamestown, Virginia, and nearby St. Mary's 

in Maryland. Clay roofing tiles were also used in the 

Spanish settlement of St. Augustine in Florida, and by 

both the French and Spanish in New Orleans. 

Fig. 2. Sunnyside, Washington Irving 's house in Tarnjtown, New York, dates to about 1656. Although extensively remodeled during the years 

1836-1849, the stepped gables and tiled roof still reflect the heritage of its 

original Dutch builders. Photo: Ja ck E. Boucher, HABS Collection. 

Dutch settlers on the east coast first imported clay tiles 

from Holland. By 1650, they had established their own 

full-scale production of clay tiles in the upper Hudson 

River Valley, shipping tiles south to New Amsterdam 

(Fig. 2). Several tile manufacturing operations were in 

business around the time of the American Revolution, 

offering both colored and glazed tile and unglazed natural 

terra-cotta tile in the New York City area, and in neighboring 

New Jersey. A 1774 New York newspaper advertised the 

availability of locally produced, glazed and unglazed 

pantiles for sale that were guaranteed to "stand any 

weather:' On the west coast clay tile was first manufactured 

in wooden molds in 1780 at Mission San Antonio de 

Padua in California by Indian neophytes under the 

direction of Spanish missionaries (Fig. 3). 

By far the most significant factor in popularizing clay 

roofing tiles during the Colonial period in America was 

the concern with fire. Devastating fires in London, 1666, 

and Boston in 1679, prompted the establishment of 

building and fire codes in New York and Boston. These 

fire codes, which remained in effect for almost two 

centuries, encouraged the use of tile for roofs, especially 

Fig. 3. Clay tiles were first produced on the west coast in 1780 at Mission San Antonio de Padua in Monterey County, California. The present church shown here dates from 1810. Photo: Gene Falk. 
1 2 123456 

ttlllill 

Diamond Gothic Round Round New· York Washing· Square 

Corner End Cut ton Cut End 

Fig. 4. Many mid- and late-19th century buildings had roofs with 

uniquely shaped tiles such as fish scale, or another one of the tile shapes 

that Charles Thomas Davis described as "the six form s of roofing tiles 

in most common use in this country," and illustrated in his 1884 book 

A Practical Treatise on the Manufacture of Bricks, Tiles, 

Terra-Cotta, Etc. 

in urban areas, because of its fireproof qualities. Clay 

roofing tile was also preferred because of its durability, 

ease of maintenance, and lack of thermal conductivity. 

Although more efficient production methods had lowered 

the cost of clay tile, its use began to decline in much of the 

northeastern United States during the second quarter of 

the 19th century. In most areas outside city-designated 

fire districts, wood shingles were used widely; they were 

more affordable and much lighter, and required less heavy 

and less expensive roof framing. In addition, new fireresistant materials were becoming available that could 

be used for roofing, including slate, and metals such as 

copper, iron, tinplate, zinc, and galvanized iron. Many of 

the metal roofing materials could be installed at a fraction 

of the cost and weight of clay tile. Even the appearance of 

clay tile was no longer fashionable, and by the 1830s clay 

roofing tiles had slipped temporarily out of popularity in 

many parts of the country. 

Revival Styles Renew Interest in 

Clay Roofing Tiles 

By the mid-19th century, the introduction of the Italian ate 

Villa style of architecture in the United States prompted a 

new interest in clay tiles for roofing. This had the effect of 

revitalizing the clay tile manufacturing industry, and by 

the 1870s, new factories were in business, including large 

operations in Akron, Ohio, and Baltimore, Maryland. 

Clay tiles were promoted by the Centennial Exhibition in 

Philadelphia in 1876, which featured several prominent 

buildings with tile roofs, including a pavilion for the state 

of New Jersey roofed with clay tiles of local manufacture. 

Tile-making machines were first patented in the 1870s, and 

although much roofing tile continued to be made by hand, 

by the 1880s more and more factories were beginning 

to use machines (Fig. 4). The development of the 

Romanesque Revival style of architecture in the 1890s 

further strengthened the role of clay roofing tiles as an 

American building material (Fig. 5). 

Alternative substitutes for clay tiles were also needed to 

meet this new demand. By about 1855, sheet metal roofs 

designed to replicate the patterns of clay tile were being 

produced. Usually painted a natural terra cotta color to 

emulate real clay tile, these sheet metal roofs became 

popular because they were cheaper and lighter, and easier 

to install than clay tile roofs. 

Clay roofing tiles fell out of fashion again for a short time 

at the end of the 19th century, but once more gained 

acceptance in the 20th century, due primarily to the 

popularity of the Romantic Revival architectural styles, 

Figure 5. (a) Clay tile was a popular roofing material during the 

Romanesque Revival period, not only for residential structures including 

these rowhouses in the Dupont Circle Historic District in Washington, 

D.C., and designed and built by Thomas F. Schneider between 

1889-1892, but also for large-scale public buildings such as (b) the Old 

Federal Courts Building (1894-1901) in St. Paul, Minnesota, designed 

by Willoughby J. Edbrooke. Photo: (a) Anne Grimmer, and (b) 

WinsorlFaricy Architects. 

including Mission, Spanish, Mediterranean, Georgian and 

Renaissance Revival in which clay tile roofs featured 

prominently. With the availability of machines capable of 

extruding clay in a variety of forms in large quantities, clay 

tiles became more readily available across the nation. More 

regional manufacturing plants were established in areas 

with large natural deposits of clay, including Alfred, New 

York; New Lexington, Ohio; Lincoln, California; and 

Atlanta, Georgia; as well as Indiana, Illinois and Kansas. 

The popularity of clay tile roofing, and look-alike substitute 

roofing materials, continues in the 20th century, especially 

in areas of the South and West-most notably Florida and 

California-where Mediterranean and Spanish-influenced 

styles of architecture still predominate (Fig. 6). 

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Fig. 6. Like many other house of this period in Florida, the roof of the Chester C. Boltoll House in Palm Beach features tiles imported from Cuba. These tiles, with their richly varied earth colors, were often laid ill thick cement mortar that was intended to give a "rustic" appearance. The residence, which 

includes the main house (1918-1919) designed by James A. Garfield, and an addition built in 1929 designed by Prentice Sanger, has been described as all 

Ellglish manor house with Spallish details. Photo: Jack E. Boucher, HABS Collectioll. 

Early Tiles 

During the 17th and 18th centuries the most common 

type of clay roofing tiles used in America were flat and 

rectangular. They measured approximately 10" x 6" x 

1/2" (25cm x 15cm x 1.25cm), and had two nail or peg 

holes at one end through which they were anchored to 

the roofing laths. Sometimes a strip of mortar was placed 

between the overlapping rows of tile to prevent the tiles 

from lifting in high winds. In addition to flat tiles, 

interlocking S-shaped pantiles were also used in the 18th 

century. These were formed by molding clay over tapered 

sections of logs, and were generally quite large. Alternately 

termed pan, crooked, or Flemish tiles, and measuring 

approximately 141/2" x 91/2" (37cm x 24cm), these 

interlocking tiles were hung on roofing lath by means of a 

ridge or lug located on the upper part of the underside of 

each tile. Both plain (flat) tile and pantile (S-shaped or 

curved) roofs were capped at the ridge with semicircular 

ridge tiles. Clay roofing tiles on buildings in mid-18th 

century Moravian settlements in Pennsylvania closely 

resembled those used in Germany at the time. These tiles 

were about 14"-15" long x 6"-7" wide (36cm-38cm x 

15cm-18cm) with a curved butt, and with vertical grooves 

to help drainage. They were also designed with a lug or 

nib on the back so that the tiles could hang on lath 

without nails or pegs. 

The accurate dating of early roofing tiles is difficult and 

often impossible. Fragments of tile found at archeological 

sites may indicate the existence of clay tile roofs, but the 

same type of tile was also sometimes used for other 

purposes such as paving, and in bake ovens. To further 

complicate dating, since clay tile frequently outlasted 

many of the earliest, less permanent structures, it was 

often reused on later buildings. 

Clay Tile Substitutes 

In addition to sheet metal "tile" roofs introduced in the 

middle of the 19th century, concrete roofing tile was 

developed as another substitute for clay tile in the latter 

part of the 19th century (Fig. 7). It became quite popular 

by the beginning of the 20th century. Concrete tile is 

composed of a dense mixture of portland cement blended 

with aggregates, including sand, and pigment, and extruded 

from high-pressure machines. Although it tends to lack 

the color permanence and the subtle color variations 

inherent in natural clay tile, concrete tile continues to be a 

popular roofing material today because it reproduces the 

general look of clay tile, if not always the exact profile or 

proportions of historic clay tile, at a somewhat lower cost 

and weight. Another modern, slightly cheaper and lighter 

substitute for clay tile more recently developed consists of 

a mixture of mineral fiber and cement with pigments 

added to supply color. While these aggregate tiles also 

replicate the shape and appearance of clay roofing tiles, 

they have many of the same dissimilarities to clay tiles 

that are found in concrete tiles. Thus, like concrete tiles, 

they are seldom appropriate substitutes for clay tiles. 
Fig. 7. (a) Metal " tile" roofs of galvanized steel closely resemble the clay 

tiles they mimic. Often painted to look like terra cotta, their identity can sometimes be revealed In; peeling paint or dented " tiles." (b-c) Concrete 

roofing tiles are generally thicker than clay tiles, and tend to fade and 

lose their color. Photos: (a -b) Anne Grimmer, (c) National Park Service 

Files. 

Traditional Tile Shapes and Colors 

There are two types of clay roofing tiles: interlocking and 

overlapping. Interlocking tiles are designed in pairs so that 

an extrusion or "lip" on one of the tiles "hooks" over the 

other tile thereby "locking" or securing the two together; 

they are also usually nailed to the roof structure. 

Overlapping tiles, which can also function in pairs, 

generally do not have any sort of "lip" and must be nailed 

in place. There is a wide range of shapes of historic clay 

roofing tiles, and many, sometimes with slight variations, 

are still produced today. There are many variations, and 

the country of origin of some of them may be revealed in 

their names, but there are essentially only two kinds of 

shapes: pantiles and flat tiles. Both pantiles and flat tiles 

may be either interlocking or overlapping (Figs. 8-9). 

Pantiles. The shape most commonly associated with 

historic clay roofing tiles is probably that of convex or 

rounded tiles, often grouped together generically as "pan 

tiles" or "pantiles:' These include Spanish tiles-sometimes 

called "S" tiles, or the Similarly shaped Mission tiles, also 

known as Barrel or Barrel Mission tiles, straight or 

tapered, as well as Roman tiles, and their Greek variation . 

Flat Tiles. Flat, shingle tiles are another type of historic 

clay roofing tiles. Flat tiles can be completely plain and 

flat, and, like roofing slates, overlap one another, attached 

with nails to the roof sheathing. Or they may interlock at 

the top and on one side. Although the "interlock" holds 

them together, most interlocking shingle tiles also have 

one or more holes, usually near the top, for nailing to the 

roof sheathing. Flat tiles are mostly variations of English 

or Shingle tiles, and include English Shingle, Closed 

Shingle, Flat, Shingle or Slab Shingle, as well as French 

tiles which have a slightly higher and more contoured 

profile. 

Any of the standard tile shapes may be known by a 

different name in another region of the country, or in 

different parts of the world. For example, what are known 

as Spanish or "S" tiles in the United States, may be called 

Single Roman tiles in England. Sometimes Spanish and 

Mission tiles are equated despite the fact that the former 

are usually I-piece interlocking tiles and the latter are 

single V2 cylinders that overlap. Since missions and the 

Mission style are associated with the Americas, Mission 

tiles in the United States are more commonly referred to 

as Spanish tiles in England and Europe. In a similar vein, 

Spanish or "S" tiles, or Barrel tiles, might seem to be more 

typical of some tiles used in France than what are 

marketed as French tiles by American manufacturers. 

Today some tile manufacturers have given their own 

trademark name to historic tile shapes. Other companies 

market uniquely shaped "S" tiles that are more in the 

shape of a true, but rather low profile "s" without the 

customary flat portion of traditional American "S" tiles. 

Field and Specialty Tile. The tiles that cover the majority 

of the flat surface of the roof are called field tile. Some roof 

shapes, particularly conical towers or turrets, require tiles 

of graduated sizes, and some shapes or patterns of field 

tile also require specially shaped finish tiles to complete 

the roof covering package. Other uniquely-shaped tiles 

were made to fit odd-shaped spaces and places including 

dormers and valleys, roof hips, rakes, ridges and corners. 

There are also finish tiles that fulfill certain needs, such as 

eave closures or clay plugs called "birdstops:' These are 

intended to keep out snow and rain, and birds from 

nesting in the voids under the bottom row of curved tiles. 

Different patterns and designs can also be created by 

combining, or mixing and matching flat tiles with 

dimensional tiles. 

Tile Colors. A terra cotta red is the color most commonly 

associated with historic clay roofing tiles. The reddish 

color comes from clay with a large percentage of iron 

oxide, and there are many variations of this natural color 

to be found in tiles ranging from deep reddish browns to 

softer and paler oranges and pinks. Lighter buff and beige 

colors, as well as black, also appear on traditional tile5 
Traditional Clay Roofing Tile Shapes and Methods of Attachment 

Pantiles 

Type Average Size Description 

-

([] Spanish Spanish or "5" tiles are l-piece interlocking tiles with both a convex .. and a flat, or almost flat, horizontal surface. A raised lip that projects 

or 13 1/4" long x from the edge of the flat portion is designed to interlock with the 

1'5" 93/4" wide edge of the convex, barrel end of the adjacent tile. Spanish tiles are 

usually laid directly on the wood sheathing, or on roofing felt, and 

Interlocking Exposure: 10 1/4" fastened by two nails through holes at the top of the tiles, or 

sometimes mortared in place. Spanish tiles give a roof surface a fairly 

low and undulating profile. 

Tapered Tapered or Straight Mission, Barrel, Barrel Mission, or ran and 

• Cover Tapered or 14"-18" Cover tile roofs are created with both a concave and a convex ,(, 

cylinder-shaped tile. The concave (pan) tiles are laid first in vertical tJ rJ:lfjaighl Mi"ion, up to Q rows, and nailed directly to the roof sheathing. The convex (cover) 

Barrel,o, 22"-24" long tiles are laid to overlap and cover the vertical spaces, or joints, that Y Barrel Mission 

Each half cylinder separate the vertical rows of the concave tiles. The convex tiles may 

about 3" high x be fastened to the roof sheathing with very long nails, hooks or 

about 8" in diameter hangers, or more commonly laid over, and nailed to vertical wood 

Overlapping Exposure: 11"-15" battens underneath. Mission tile roofs have a higher profile than • Spanish or Roman 

Pantile tile roofs. 

Roman, Roman, or ran and Roll, roofs consist of a two-part tile system 

Q Pan and Roll, 123/4" long which includes a convex barrel cover tile with a rather low profile 

placed over a flat tile laid directly on the roof sheathing. Like 

L 7 or Width from center of Mission tiles, the convex tiles may be nailed either to battens laid 

Pan and Cover 1 cover tile to center vertically on the roof or directly onto the roof sheathing. Both the 

of next including convex cover tile and the flat tile may also have nibs at the top by 

Interlocking width of 1 flat tile which they interlock with tiles laid in rows above them. Roman tiles 

is 12" may also be cemented in place. A Roman tile roof appears as a 

and series of fairly wide or broad, flat "vall eys" alternating with rather 

Overlapping Exposure: 10" low ridges or hills, much like a Spanish tile roof but with wider 

"flat" sections. 

rfll Greek Same size 

7 and Greek tiles are essentially a variation of Roman tiles, but the convex 

Interlocking dimensions tiles that cover the vertical joints between the rows of "pan" tiles are 

and as shaped like a gable end or inverted "V". Greek tiles are attached to 

Overlapping Roman tiles the roof in the same manner as Roman tiles. 

Flat Tiles 

English Shingle: 

0 0 13 114" long x 

English Shingle 83/4" wide 

or Exposure: 101/8" 

Closed Shingle long x 73/4" wide 

Closed Shingle: 

• tL_ ....... .::=-...: _ Interlocking 11" long x 

83/4" wide English or Shingle tiles are generally plain and smooth-surfaced, 

Exposure: 8" x 8" but some are intended to imitate slate or wood shingles and are 

12" x 15" long textured accordingly. The underside of these tiles can be either flat 

and smooth, or may have a corrugated appearance with 4-5 

English Flat x 6" x 7" wide, toothlike projections; all are attached with nails. 

DDD or 12" long or x 9"-10" wide 

Slab Shingle Exposure varies 

Overlapping according to size of the 

tile, but is generally 

slig htly less than 112 

length of the tile 

CJJ 

French tiles feature two deep vertical grooves on the surface that 

French 161/4" long x 9" wide 

facilitate drainage, and create interesting light and shadow contrasts. 

A vertical lug projects from the top of these tiles that interlocks with 

Interlocking the bottom of the tile laid over it. French tiles also have two nail 

Exposure: 9" holes at the top for nailing, and are often given a dab of cement for 

added security. 

~ 

Fig. 8. Traditional Clay Roofillg Tile Shapes and Methods of Attachment. Drawing: Karill Murr Link. 

6 
Spanish or "S" 

Straight Mission, 

Barrel, 

Barrel Mission 

or 

Pan and Cover 

Roman 

/f 

English Shingle or 

Closed 

Shingle 

Clay Roofing Tile Installation Patterns 

Greek 

English Flat or Slab Shingle 

Fig. 9. Clay Roofing Tile Installation Patterns. Drawing: Karin Murr Link. 

7 
roofed buildings. Buff-colored tiles were made from nearly 

pure fire clay, and pouring manganese dissolved in water 

over the tile before firing resulted in smoke brown or black 

glazed tiles. Toward the end of the 19th century the 

popularity of colored glazes for roofing tiles increased, 

and their use and the range of colors continues to expand 

today. Most historic glazed roofing tiles are in fairly 

natural hues that range from reds and browns and buffs, 

to blacks and purples, blues (often created with smalt, 

or powdered blue glass), and a wide variety of greens 

(usually created with copper slag). There could be a 

considerable range in the colors of tiles that were baked 

over a wood fire because the temperature within the kiln 

was so uneven; tiles closest to the fire cooked all the way 

through and turned a darker red, while tiles farthest from 

the flames were likely to be smoke-stained, and lighter 

orange in color. 

How Tiles are Attached 

The method used to attach clay roofing tiles varies 

according to the shape, size and style of the particular tile. 

For the most part, traditional and modern methods of 

installing clay roofing tiles are very similar, except that 

modern practice always includes the use of wood 

sheathing and roofing felt. But most of the earliest clay 

roofing tiles were laid without benefit of wood sheathing 

and hung directly on roofing laths and battens that were 

nailed to the roof rafters; this practice continued up into 

the mid-19th century in some regions. While this method 

of attachment allowed for plenty of ventilation, and made 

it easy to find leaks and make repairs, it also meant that 

the overall watertightness of the roof depended entirely 

on the tiles themselves. 

8 

Gradually, the practice evolved of nailing roofing tiles 

directly onto continuous wood sheathing, or hanging 

them from "nibs" on horizontal lath that was attached to 

roof rafters or sheathing. Some kinds of tile, especially the 

later Mission or Barrel tiles were laid over vertical strips or 

battens nailed to the sheathing, or the tiles were fastened 

to wood purlins with copper wire. 

Partly because they do not always fit together very closely, 

some tile shapes, including Spanish, Barrel or Mission as 

well as other types of interlocking tiles, are not themselves 

completely water-repellent when used on very low-pitched 

roofs. These have always required some form of sub-roofing, 

or an additional waterproof underlayer, such as felting, a 

bituminous or a cementitious coating. In some traditional 

English applications, a treatment called "torching," involved 

using a simple kind of mortar most commonly consisting 

of straw, mud, and moss. The tapered Mission tiles of the 

old Spanish missions in California were also laid in a bed 

of mud mortar mixed with grass or straw which was their 

only means of attachment to the very low-pitched reed or 

twig sheathing ([atia) that supported the tiles (Fig. 10). 

More recent and contemporary roofing practices require 

that the tiles be laid on solid 1" (2.5cm) wood sheathing 

felted with coated base sheets of at least 30 lbs., or builtup membranes or single-ply roof membranes. This 

substantially increases the watertightness of the roof by 

adding a second layer of waterproofing. Horizontal and 

vertical chalk lines are drawn to serve as a guide in laying 

Fig. 10. The underside of this roof on the restored barracks at Santa 

Cruz Mission reveals the twig sheathing or latia to which ~he clay tiles were traditionally attached with mud mortar. Photo: Gil Sanchez, FAJA. 

the tile and to indicate its patterning. Most tiles are 

designed with one or two holes so they can be attached by 

copper nails or hangers, and/or with projecting nibs, to 

interlock or hang on battens or lath attached to the base 

sheathing. 

Before laying the tiles, the copper or lead gutters, 

flashings and valleys must be installed, preferably using at 

least #26 gauge (20-24 ounce) corrosion-resistant metal 

extending a minimum of 12" (30.Scm) under the tile from 

the edge, or in accordance with the manufacturer's 

specifications. The long life and expected durability of clay 

tiles require that, as with the roofing nails, only the best 

quality metal be selected for the flashing and guttering. 

"Field tile" is usually ordered by the number of "squares"-

that is, a flat section 10' x 10' (2Scm x 2Scm)-needed to 

cover a roof section. The tile company or roofing contractor 

should calculate the number of tiles needed according to 

the type of roof, and based on architect's drawings to 

ensure accuracy. This should include specialty ridge and 

eave tiles, decorative trim, partial "squares", approximately 

10-20 per cent allowance for breakage, and extra tiles to 

store for repairing incidental damage later on. Once at 

the site, the tile is evenly distributed in piles on the roof, 

within easy reach for the roofers. 

The tiles are laid beginning with the first course at the 

lower edge of the roof at the eaves. The method by which 

roofing tiles are laid and attached varies, depending on 

the type and design of the tiles and roof shape, as well as 

on regional practice and local weather conditions. A raised 

fascia, a cant strip, a double or triple layer of tiles, or 

special "birdstop" tiles for under the eaves, may be used 

to raise the first row of tiles to the requisite height and 

angle necessary for the best functioning of the roof 

(Fig. 11). The tile is positioned to overhang the previously 

installed gutter system by at least 11/2" (4cm) to ensure 

that rainwater discharges into the central portion of the 

gutter. Once this first course is carefully fitted and 

examined from the ground level for straightness and color 

nuances, and adjusted accordingly, successive courses are 

lapped over the ones below as the roofer works diagonally 

up the roof toward the ridge. Positioning and laying tiles 

in a 10'x 10' (2Scm x 2Scm) square may take on the 

average of 16112 man hours. 
FACE. OF Ol::ICK 

~-CA JT ~TJ<: P 

\',>---+-,,-, "T~D I~' 

6UTT~1': 5~P" • '2.'. c,' C.C. 

" '" <"' VEI':I,"Y ANaLE 

lio-!-exJILT · IN =ppe;p'; GUTTeR 

NeW VvtX)C N\OLDINGO 

ALl.. INCCO M~Moe.R~ A.T 

EA.VE~ , 009=FIT 1 FI>G!i>e 10 eE Fl6.INTe.O. 

Fig. 11 . Both a cant strip and a double layer of tiles are used here to raise the first row of tiles to ensure proper roof drainage. This drawing was 

prepared for the restoration of the 1911-1912 Ja1'1aica Pond Boathouse, 

Jamaica Plain, Massachusetts, which is part of the original Boston Park system designed by Frederick Law Olmsted in the late-19th century. 

Drawing: Richard White, Architect/Planner. 

Flat Tiles 

Most flat clay tiles have one or two holes located at the 

top, or on a "nib" or "lug" that projects vertically either 

from the face or the underside of the tiles, for nailing the 

tile to the sheathing, battens, or furring strips beneath. As 

successive rows of tile are installed these holes will be 

covered by the next course of tiles above. Traditionally, 

clay tiles on the oldest tile roofs were hung on roofing 

laths with oak wooden pegs. As these wood pegs rotted, 

they were commonly replaced with nails. Today, copper 

nails, 13/4" (4.5cm) slaters' nails, are preferred for 

attaching the tiles because they are the longest lasting, 

although other corrosion-resistant nails can also be used. 

Less durable nails reduce the longevity of a clay tile roof 

which depends on the fastening agents and the other 

roofing components, as much as on the tiles themselves. 

Clay roofing tiles, like roofing slates, are intended to hang 

on the nails, and nailheads should always be left to 

protrude slightly above the surface of the tile. Nails 

should not be driven too deeply into the furring strips 

because too much pressure on the tile can cause it to 

break during freeze/thaw cycles, or when someone walks 

on the roof. 

Plain flat tiles, like roofing slates, are attached to the 

roof sheathing only with nails. They are laid in a pattern 

overlapping one another in order to provide the degree of 

impermeability necessary for the roof covering. Because 

plain flat tiles overlap in most cases almost as much of one 

half of the tile, this type of tile roof covering results in a 

considerably heavier roof than does an interlocking tile 

roof which does not require that the tiles overlap to such 

an extent. Interlocking flat tiles form a single layer, and an 

unbroken roof covering. Although most interlocking tiles 

on all but the steepest roofs can technically be expected to 

remain in place because they hang on protruding nibs 

from the roofing laths or battens, in contemporary roofing 

practices they are often likely to be nailed for added 

security. In most cases it is usually a good idea to nail at 

least every other tile (Fig. 12). 

Pantiles 

With Mission or Barrel tiles, where one half-cylinder 

overlaps another inverted half-cylinder to form a cover 

and pan (cap and trough) arrangement, the fastening is 

more complicated. While the pantiles that rest directly on 

the sheathing are simply nailed in place, there are two 

ways of attaching the cover tiles that rest on the pantiles. 

They can be secured by a copper wire nailed to the 

sheathing or tied to vertical copper strips running behind 

the tiles (Fig. 13). Another method requires the installation 

of vertical battens or nailing strips on the roof to which 

the cover tiles are nailed, or the use of tile nails or hooks, 

which are hooked to the pantile below and secured with 

twisted copper wire. 

Sometimes cement mortar, or another underlayer such 

as grass, moss or straw, or hair-reinforced mortar was 

added under the tiles. Before the use of felting this was a 

particularly common practice on some of the plain flat tile 

or Spanish tile roofs with low rises that were themselves 

not especially waterproof. Mortar also helped to keep 

driving rain from getting under the pantiles, and it is still 

customary in contemporary roofing to add a dab of 

cement mortar to help secure them (Fig. 14). 

Ridge or Hip Tiles 

At the roof ridge or hip, clay tile is usually attached to a 

raised stringer with nails and a small amount of mortar, 

elastic cement or mastic. The joint is sealed with a flexible 

flashing such as copper or lead. Ridge tiles are often 

somewhat larger and more decorative than the field tile 

utilized on the broad sections of the roof. 

Roof Pitch and Weather are Factors in Tile 

Attachment 

The means by which clay tile is attached to the sheathing 

is also partly determined by the roof pitch. Generally the 

fastening requirements increase with an increase of roof pitch. 

For low-pitched rises of 4"-6" (10cm-lScm) in a 12" 

(30.5cm) run the weight of the tiles is usually sufficient 

to hold them in place on the lath by the ridge or "lug" on 

the underside of the tile, with only the perimeter tiles 

requiring metal clips to secure them to the sheathing. But 

the tiles on even these low-pitched roofs are usually 

nailed for added security, and additional fastening 

measures are necessary on roofs with a higher pitch, or 

in areas subject to high winds or earthquakes. For steeper 

pitched roofs, such as towers, 7" -11" (18cm-28cm), or 

12" -IS" (30.5cm-38cm) in a 12" (30.Scm) run the tiles are 

nailed and a band of perimeter tiles three to four tiles 

thick is secured with clips. For roof rises over 16" (41cm) in 

a 12" (30.Scm) run, and in areas prone to earthquakes or 

hurricanes, every tile may be secured with both a nail and 

a copper or non-corrosive metal clip, and often also with a 

dab of roofing mastic or mortar. 

The installation of clay roofing tiles in areas with 

significant amounts of snowfall-over 24" (61cm) per 

year-also varies somewhat from the normal guidelines. 

Larger battens may be necessary, as well as additional 

clipping or tying of the tile to securely attach it to the 

sheathing. The roof structure itself may also need added 

bracing, as well as the insertion of small snow clips or 

snow birds that protrude above the surface of the tile to 

prevent snow and ice from sliding off the roof and 

damaging the tile. 

9 
b 

10 

Figure 12. When constructed in Frankfort, Kentucky, in 1900, the 

Colonial Revival-style Berry Hill Mansion, and its 1912 Music Room 

addition were both roofed with " Imperial" tiles manufactured by 

Ludowici-Celadon (a). In 1992 the entire roof was replaced because of 

deterioration and surface spalling of many of the tiles (b). It was not 

possible to reproduce the original tiles due to budget limitations, thus 

Ludowici-CeIadon's stock "Classic Interlocking" Shingle tiles were 

selected as replacements which could provide a close, if not exact, match. 

After tearing off and removing the old tiles, 30 lb. roofing felt was laid 

over the existing wood sheathing, new lead gutters and valleys were 

installed, and 90 lb. roll roofing was laid, on which the new tiles were 

laid. Although most of the field tiles were simply attached by 2 nails to 

the substrate (c), many of the tiles that had to be cut to fit hips, valleys 

and dormers were left with only one hole, and had to be wired and then 

nailed in place (d-e). The exact color and glaze of the original tiles also 

could not be duplicated because the coloring material is no longer 

available; however, the new hipped roof terminus for the Music Room roof 

was custom-made and the replacement field tiles are very similar to the 

originals (t>. The original ridge tiles were designed to "nest" and fit 

perfectly over the field tiles beneath them whereas the new ridge tiles 

simply overlap one another, but this is barely perceptible when viewed 

from the ground. Photos: Edwin C. Krebs, AlA. 
Figure 13 (a-b). These custom-made tapered mission tiles are beins attached to the roof using a special system. This consists at twisted 1D-gauge bras: or copper wires that run up the roof slope through a new treated root ridge, and down the other szde of the roof. These tWIsted wIres are placed about 12 

(3D.5cm) apart, and diamond shapes are twisted into them every 6" (15cm). The vertical wires are secured wIth 1D-gaugecopper or brass anchors 

approximately every 4' (1.22m) on center depending on the roof slope. Although these tIles would have orlgznally been laId In mud mortar, thIS method of 

attachment is particularly successful in seismic areas. The random placement of the tdes accurately replIcates the pattern tradItIOnally used on the early 

missions. Photos: Gil Sanchez, FAJA. 

Preservation and Repair 

Identifying Common Problems and Failures 

While clay roofing tiles themselves are most likely to 

deteriorate because of frost damage, a clay tile roof system 

most commonly fails due to the breakdown of the 

fastening system. As the wooden pegs that fastened the 

early tiles to hand-riven battens rotted, they were often 

replaced with iron nails which are themselves easily 

corroded by tannic acid from oak battens or sheathing. 

The deterioration of metal flashing, valleys, and gutters 

can also lead to the failure of a clay tile roof. 

Another area of potential failure of a historic clay tile 

roof is the support system. Clay tiles are heavy and it is 

important that the roof structure be sound. If gutters and 

downspouts are allowed to fill with debris, water can back 

up and seep under roofing tiles, causing the eventual 

deterioration of roofing battens, the sheathing and 

fastening system, or even the roof's structural members 

(Fig. 15). During freezing weather, ice can build up under 

tiles and cause breakage during the freeze/thaw cycle. 

Thus, as with any type of roof, water and improperly 

maintained rainwater removal and drainage systems are 

also chief causes for the failure of historic clay tile roofs. 

Clay tiles may be either handcrafted or machine-made; in 

general, roofs installed before the end of the 19th century 

consist of hand-formed tiles, with machine-made tiles 

becoming more dominant as technology improved during 

the 20th century. Clay tile itself, whether made by hand or 

made by machine, can vary in quality from tile to tile. 

Efflorescence of soluble salts on the surface may indicate 

that a tile has excessive porosity which results from 

underburning during its manufacture. Poor quality porous 

tiles are particularly susceptible to breaking and exterior 

surface spalling during freeze-thaw cycles. By letting in 

moisture, porous tiles can permit the roof battens and roof 

structure to rot. The problem may be compounded by 

waterproof building paper or building felt laid underneath 

which can, in some instances, prevent adequate 

ventilation. 

Clay roofing tiles can also be damaged by roofers walking 

carelessly on an unprotected roof while making repairs, or 

by overhanging tree branches, falling tree limbs, or heavy 

hail. Broken tiles may no longer provide a continuous 

waterproof surface, thereby allowing water to penetrate 

the roofing structure, and may eventually result in its 

deterioration if the broken tiles are not replaced in a 

timely manner. 

Although modern, machine-made clay tiles are more 

uniform in appearance than their hand-made counterparts, 

they also have the potential for failure. Occasionally, entire 

batches of mass-produced tile can be defective . 

Fig. 14. The Spanish or "S" tiles used to re-roof the Mission Revival 

style Holy Cross Episcopal Church in Sanford, Florida, have corrugated 

projections or "teeth" on the underside of the flat portion of each tile 

which adhere to the cemellt mortar holding them to the roof sheathing. 

Photo: Walter S. Marder, AlA. 

11 
Figure 15. (a) A regular cleaning schedule would have eliminated the 

plant growth and leaf build-up in this gutter, which, if not removed, will result In serzous damage to roof sheathing and structure (b) . Photos: (a) Paul K. Williams, and (b) Walter S. Marder. AlA. 

Regular Inspection and Maintenance 

Broken or missing tiles, or leaks on the interior of the 

building, are obvious clues that a historic clay tile roof 

needs repair. Even though it may be clear that the roof is 

leaking, finding the source of the leak may not be so easy. 

It may require thorough investigation in the attic, as well 

as going up on the roof and removing tiles selectively in 

the approximate area of the roof leak. The source of the 

leak may not actually be located where it appears to be. 

Water may come in one place and travel along a roofing 

member some distance from the actual leak before 

revealing itself by a water stain, plaster damage, or rotted 

wooden structural members. 

Temporary Protection during Repair 

In some instances temporary protection and stabilization 

may be necessary to prevent further damage or 

deterioration of a historic clay tile roof. Plywood sheets, 

plastic, roll roofing, or roofing felt can provide short-term 

protection until repair or replacement materials can be 

purchased. Another option may be to erect a temporary 

scaffold that is epcased or covered with clear or semitransparent polyethylene sheeting over the entire roof. 

This will not only protect the exposed roofing members 

during repair or until repairs can be made, but also lets in 

enough natural light to enable the re-roofing work to take 

place while sheltering workmen from cold or wet weather. 

12 

General Repair Guidance 

Once the source and cause of a leak has been identified, 

appropriate repairs must be made to structural roofing 

members, wood sheathing, felt or roofing paper if it is 

part of the roofing membrane, or possibly to vertical roof 

battens to which the tiles may be attached. If the problem 

appears limited to gutters and flashing in disrepair, repair 

or replacement will probably require temporary removal of 

some of the adjacent tiles to gain access to them. If the 

roofing tiles are extremely fragile and cannot be walked on 

even with adequate protection (see below), it may also be 

necessary to remove several rows or a larger area of tiles 

and store them for later reinstallation in order to create a 

"path" to reach the area of repair without damaging 

existing tiles. Even if most of the tiles themselves appear 

to be intact but no longer securely attached to the roof 

substrate due to deterioration of the fastening system or 

roofing members, all the tiles should be labeled and 

removed for storage. Regardless of whether the repair 

project involves removal of only a few damaged tiles, or 

if all the tiles must be removed and relaid, historic clay 

roofing tiles are inherently fragile and should be pulled 

up carefully with the use of a slate ripper. The tiles can be 

reattached one-by-one with new corrosion-resistant copper 

nails, copper straps or tabs, "tingles", or another means 

after the necessary repairs have been made to the roof. 

Replacing Individual Tiles 

The most difficult aspect of replacing a single broken clay 

roof tile is doing so without breaking neighboring tiles. 

While flat shingle tiles can generally be walked on by a 

careful roofer without likelihood of much damage, high 

profile pantiles are very fragile and easily broken. By 

using sheets of plywood, planks, or burlap bags filled 

with sand to distribute weight, the professional roofer can 

move about the roof to fix broken tiles or flashing without 

causing additional damage. Another method involves 

hooking a ladder on the ridge to support and evenly 

distribute the weight of the roofer. 

A broken tile should be carefully removed with a slate 

ripper or hacksaw blade inserted under the tile to cut the 

nail or nails holding it in place. If successive layers of tile 

are already in place covering the nailholes, it will not be 

possible to attach the replacement tile with nails through 

the holes, so an alternative method of attachment will be 

necessary. By nailing a tab of double thickness copper 

stripping on the sheathing below the tile, the new 

replacement tile can be slipped into position and secured 

in place by bending the copper strip up with a double 

thickness of the copper over the tile. A slate hook or 

"tingle" can be used in the same way. This fastening 

system functions in place of nails (Fig. 16). 

When replacing hard-to-match historic tile, and if matching 

clay tile cannot be obtained, it may be possible to relocate 

some of the original tiles to the more prominent locations 

on the roof where the tile is damaged, and insert the new 

replacement tile in secondary or rear locations, or other 

areas where it will not show, such as behind chimney 

stacks, parapets, and dormer windows. Even though 

replacement tile may initially match the original historic 

tile when first installed, it is likely to weather or age to a 

somewhat different color or hue which will become more 

obvious with time. Thus, care should be taken to insert 

new replacement tile in as inconspicuous a location as 
possible. New, machine-made clay tile or concrete tiles 

should generally not be used to patch roofs of old, handmade tile because of obvious differences in appearance. 

Sources for Replacement Tiles 

When restoring or repairing a clay tile roof it is always 

recommended that as many of the original tiles be 

retained and reused as possible. Sometimes, particularly 

when working with "pan and cover" type tile roofs, while 

many of the "cover" tiles may be broken and require 

replacement, it may be possible to reuse all or most of 

the "pan" tiles which are less susceptible to damage than 

the "cover" tiles. But, in most cases, unless matching 

replacements can be obtained, if more than about 30 per 

cent of the roofing tiles are lost, broken, or irreparably 

damaged, it may be necessary to replace all of the historic 

tiles with new matching tiles. When counting the number 

or percentage of missing or broken tiles that need to be 

replaced, it is important to order extra tiles to allow for 

breakage and damage during shipping and on the job 

site. The size of the tiles must be noted, whether they are 

all the same size, the same size but laid with different 

amounts of exposure to compensate for changes in 

perspective, or of graduated sizes according to horizontal 

rows-typical, for example, on conical or tower roofs 

(Fig. 17). 

Many late-19th and early-20th century tiles are marked on 

the back with the name of the company that made them, 

along with the size and the name of that particular tile 

shape. Some companies that were in business in the 

United States at the turn of the century are still producing 

many of the traditional tile shapes, and may be able to 

supply the necessary replacements. But it is important 

to be aware that in some cases, although the name of a 

particular tile pattern may have remained the same, 

the actual shape, size, thickness and profile may have 

changed slightly so that the new tile does not match 

the historic tile closely enough to permit it to serve as a 

compatible replacement for missing or broken tiles. While 

such tiles may be acceptable to use on a secondary or less 

prominent elevation, or to use when an entire tile roof 

needs replacement, they would not be suitable to use on 

an area of the roof that is highly visible. 

Figure 16. Attachments for repair and replacement of clay tiles include: 

(a) copper tab, (b) stainless steel or other non-corrosive metal clip, slate 

hook or "tingle," and (c) nailing and wire nailing. Drawing: Karin Murr Link. 

Fig. 17. The rhythm and pattern of these tiles which is so important in 

defining the character of this roof was created by layzng the tIles wIth 

different amounts of exposure and using graduated tiles that decrease in 

size as they reach the top of the cone. Photo: NatIOnal Park ServIce FIles. 

Even if the particular tile is no longer manufactured by a 

company, the original molds may still exist which can be 

used to make new tiles to match the historic tiles if the 

quantity needed is sufficiently large to warrant a custom 

order. Other companies stock and sell salvaged tile, and 

keep a variety of old tiles available which can be identified 

and matched by the number and company imprint on the 

back of the tiles. Still other companies specialize entirely 

in custom-made reproduction of historic clay tiles for a 

specific preservation project. 

Modern clay tiles are even more varied than historic tiles. 

Many shapes and styles are offered in a wide variety of 

colors and glazes. Several manufacturers produce special 

color-blended tiles, as well as tiles of different hues that 

are intended to be carefully mixed when installed. Yet, it is 

important to remember that many of these modern tiles may not 

be appropriate for use on historic clay tile roofs. The place of 

manufacture must also be taken into consideration. For 

instance, tiles made for use in a hot, dry climate may not 

be able to withstand wet weather, drastic temperature 

changes or freeze-thaw cycles. Some of the tile shapes, 

and many of the colors-especially those that are very 

bright and highly glazed-are completely contemporary in 

design, and do not represent traditional American styles, 

and thus, are not suitable for use on historic buildings. 

Repairing a Failed Fastening System 

Clay roofing tiles, as noted before, frequently outlast their 

fastening systems. Wood pegs rot, nails rust, and even 

copper nails that are not adequately driven in can pull out 

of the roof's structural members. Although it is unusual 

that all of the clay tiles on a roof need to be replaced 

unless matching replacements cannot be obtained, it is 

not uncommon for old tile roofs to be stripped of all their 

tiles in order to re-Iay the tiles with new fastenings and 

battens. When the fastening system has failed, all the roof 

tiles must be removed and reattached with new corrosionresistant fasteners. If possible, all the tiles should be 

numbered and a diagram should be drawn showing the 

location of each tile to aid in replicating the original 

pattern and color variations when the tiles are relaid. 

Ideally, each tile should be numbered to ensure that it is 

reinstalled in its original location. But this may not always 

13 
Clay Tile Roofs of Alfred, New York 

----! 

• • c d 

1 • a 

F 

Takillg advalltage of high quality local shale ideal for makillg terra colla alld clay tiles, the Celadoll Terra Cotta Compally was established ill Alfred, New York, 

ill 1889. As a result, all ullusually large percelltage of historic buildillgs ill this small tOWIl are roofed with clay tiles. This illcludes commercial alld residential 

structures as well as other types of structures Ilot commonly roofed with tile, such as bams alld outbuildings. Evell early-19th cen tury houses were re-roofedsometimes illcollgruously-with clay tiles. Today, the tOWIl roofs display all amazillg variety of styles alld patterns of tiles, mallY of which may have been factory 

seconds orexperilllelltal designs. In operatioll for ollly 20 years when it was destroyed by fire, the compally colltinued lIlanufacturing roofing tiles in New Lexington, Ohio, under the name Ludowici-Celadon. Photos: Terry Palmiter, Courtesy Alfred Historical Society. 

14 
be feasible or practical, and it may be enough simply to 

group the tiles as they are removed by type and size or 

function-such as field tiles, custom tiles for hips, dormers 

and ridges, and specially cut pieces. This will help 

facilitate reinstallation of the tiles. If all of the tiles have 

to be removed, it is probably a good idea to consider 

installing a layer of modern roofing felt over the wood 

sheathing. This will add another layer of waterproofing, 

while providing temporary protection during re-roofing. 

Even if the tiles were originally attached with wooden 

pegs, it is generally recommended that they be rehung 

with corrosion-resistant, preferably heavy copper, or 

aluminum alloy nails or hooks. Today there are numerous 

non-traditional fastening systems for clay tile roofs, and 

many of them are patented. Roofing contractors and 

architects may have individual preferences, and some 

systems may be better suited than others to fit a particular 

roof shape or to meet a specific climatic or seismic 

requirement. Original battens or other roof members that 

may have deteriorated should be replaced to match the 

original using pressure-treated wood. Additional support 

may be necessary, particularly if the original roof was 

inadequate or poorly designed. 

Replacing Flashing 

Deteriorated flashing, gutters and downspouts should 

generally be replaced in kind to match the historic 

material. Copper or lead-coated copper, if appropriate 

to the building, or terne-coated stainless steel, is often 

preferred for use on historic clay tile roofs because of their 

durability and long lasting qualities. However, copper 

staining from downspouts can sometimes be a problem on 

light-colored masonry walls which should be taken into 

consideration when planning replacements to rainwater 

removal systems. Clay tile roofs usually have an open 

valley system where the tiles are separated by metal 

flashing at intersections of roof sections with different 

angles. This makes the insertion of new flashing quite 

easy, as only a few surrounding tiles must be removed in 

the process. New copper flashing that is too "bright" can 

be made to blend in and "mellowed" by brush-coating it 

with boiled linseed oil or proprietary solutions. 

Inappropriate Repairs 

The most important repair to avoid is replacing broken or 

missing roof tiles on a historic building with materials 

other than matching natural clay tiles. Concrete, metal or 

plastic tiles are generally not appropriate substitutes for 

clay roofing tiles. They lack the natural color variations of 

clay tile, and they do not have the same texture, shape, 

thickness or surface irregularities. 

Although much concrete tile and composition tile is 

produced to resemble the general shape, if not the exact 

profile, of clay roofing tiles, concrete tile is generally too 

thick and also lacks the range of colors inherent in natural 

clay tile. Concrete tile is not a compatible substitute 

material to repair or replace individual historic clay tiles. 

Patching a historic clay tile roof with roofing tar, caulk, 

asphalt, pieces of metal, or non-matching clay tiles is also 

inappropriate. Such treatments are visually incompatible. 

They also have the potential for causing physical damage. 

Water can collect behind these patches, thus accelerating 

deterioration of roof sheathing and fastening systems, and 

during the expansion and contraction of a freeze-thaw 

cycle ice build-up at patches can break surrounding tiles. 

Summary 

Clay roofing tile itself, when correctly installed, requires 

little or no maintenance. Often, it is the fastening system 

used to secure the tiles to the sheathing that fails and 

needs to be replaced rather than the tiles themselves. In 

fact, because clay tiles frequently outlasted the building 

structure, it was not unusual for them to be reused on 

another building. When the fastening system has 

deteriorated, or the roofing support structure has failed, 

clay tiles can be removed relatively easily, necessary 

repairs can be made, and the historic tiles can be re-laid 

with new corrosion-resistant nails or hooks. Broken or 

damaged tiles should be replaced promptly to prevent 

further damage to neighboring tiles or to the roof structure 

itself. 

As with any kind of historic roofing material, regular 

maintenance, such as cleaning gutters and downspouts, 

can add to the life of a tile roof. Additional preventive 

measures may include placing wire mesh over downspout 

openings or over the entire gutter to prevent debris from 

collecting and water from backing up. Periodic inspection 

of the underside of the roof from the attic after a heavy 

rain or ice storm for water stains may reveal leaks in their 

early stages which can be eliminated before they escalate 

into larger, more serious repair problems. 

If replacement tile is required for the project, it should 

match the original tile as closely as possible, since a 

historic clay tile roof is likely to be one of the building's 

most significant features. Natural clay tiles have the 

inherent color variations, texture and color that is so 

important in defining the character of a historic tile roof. 

Thus, only traditionally shaped, clay tiles are appropriate 

for repairing a historic clay tile roof. 

Selected Reading 

Azevedo, J. "Tile Roofing." Fine Homebuilding. No. 60 (April/May 

1990), pp. 36-41. 

Belle, John, John Ray Hoke, Jr., and Stephen A. Kliment, editors. 

Traditional Details for Building Restoration, Renovation, and 

Rehabilitation. From the 1932-1951 Editions of [Ramsey/Sleeper] 

Architectural GraphiC Standards:' New York: John Wiley & 

Sons, Inc. 1991. 

Davis, Charles Thomas. A Practical Treatise on The Manufacture of 

Brick, Tiles, Terra Cotta, Etc. Philadelphia: Henry Carey Baird & 

Co., 1884. 

Fidler, John. "Tile, Slate and Stone Roofs." Traditional Homes 

Technical Information Leaflet. Number 1. 1991. 

Labine, Clem. "How to Repair an Old Roof." The Old-House 

Journal. Vol. XI, No.3 (April 1983), pp. 64-69 

Labine, Clem, and Judith Siegel Lief. "The Rise of the 

Ornamental Roof;' and "Traditional Building's Source List of 

Traditional Roofing & Specialties." Traditional Building. Vol. 5, 

No.3 (May/June/1992), pp. 35-46. 

Melville, Ian A., and Ian A. Gordon. The Repair and Maintenance 

of Houses. London: The Estates Gazette Limited, 1973. 

Poore, Patricia. "Tile Roofs." The Old-House Journal. Vol XV, No.5 

(September/October 1987), pp. 22-29. 

"Special Roof Issue ." The Old-House Journal. Vol XI, No.3 

(April 1983). 

15 
16 

Sweetser, Sarah M. Preservation Briefs 4: Roofing for Historic 

Buildings. Washington, D.C.: National Park Service, U.S. 

Department of the Interior, 1978. 

Vogel, Neal A. Roofing Houses of Worship: Roofing Guidance for 

Church and Temple Administrators. Information Series No. 59. 

Chicago: National Trust for Historic Preservation and Inspired 

Partnerships, 1992. 

White, Richard. Olmsted Park System, Jamaica Plain Boathouse, 

Jamaica Plain, Massachusetts: Planning for Preservation of the 

Boathouse Roof. Preservation Case Studies. Washington, D.C.: 

Heritage Conservation and Recreation Service, U.S. 

Department of the Interior, 1979. 

Selected Sources of Clay Roofing Tiles 

Boston Valley Terra Cotta 

6860 South Abbott Road 

Orchard Park, NY 14127 

Custom-made architectural terra cotta and clay roofing tiles 

C.C.N. Oay Roof Tiles (Canteras Cerro Negro S.A.) 

8280 College Parkway, Suite 204 

Ft. Myers, FL 33919 

Distributors of C.C.N. clay roofing tiles from Argentina 

Earth/Forms of Alfred 

5704 East Valley Road 

Alfred Station, NY 14803 

Made-to-order reproduction clay roofing tiles 

Gladding, McBean & Co. 

P.O. Box 97 

Lincoln, CA 95648 

Manufacturer since 1875 of terra cotta and clay roofing 

tiles, and custom reproductions 

Hans Sumpf Company, Inc. 

40101 Avenue 10 

Madera, CA 93638 

Made-to-order Mission-style clay roofing tiles 

International Roofing Products, Inc. 

4929 Wilshire Blvd., Suite 750 

Los Angeles, CA 90010 

New clay roofing tiles, some suitable for historic buildings 

London Tile Co. 

65 Walnut Street 

New London, OH 44851 

Made-to-order reproduction clay roofing tiles 

Ludowici-Celadon, Inc. 

4757 Tile Plant Road 

New Lexington, OH 43764 

Manufacturer since 1880s of clay roofing tiles, and custom 

reproductions 

M.C.A. (Maruhachi Ceramics of America, Inc.) 

1985 Sampson Avenue 

Corona, CA 91719 

New clay roofing tiles, some suitable for historic buildings 

The Northern Roof Tile Sales Company 

P.O. Box 275 

Millgrove, Ontario LOR IVO, Canada 

Traditional clay roofing tiles imported from England and 

South America 

Raleigh, Inc. 

6506 Business U.S. Route 20 

P.O. Box 448 

Belvidere, IL 61008-0448 

Inventory of new and salvage clay roofing tiles 

Supradur Manufacturing Corp. 

P.O. Box 908 

Rye, NY 10580 

Imports Spanish ("S") clay roofing tiles from France 

TileSearch 

P.O. Box 580 

Roanoke, TX 76262 

Computerized network for new and salvage clay roofing 

tiles 

United States Tile Company 

P.O. Box 1509 

909 West Railroad Street 

Corona, CA 91718 

New clay roofing tiles, some suitable for historic buildings 

Note: Measurements in this publication are given in both 

the U.S. Customary System and International (Metric) 

System for comparative purposes. Metric conversions are, 

in some cases, approximate and should not be relied upon 

for preparing technical specifications. 

Acknowledgements 

Anne Grimmer is a senior Architectural Historian with the Preservation 

Assistance Division of the National Park Service; Paul K. Williams is a Cultural 

Resource Manager with the Air Force. Both authors wish to thank the following 

individuals for the technical assistance they provided in the preparation of this 

publication: Edna Kimbro, Architectural Conservator, Watsonville, CA; Edwin 

S. Krebs, AlA, K. Norman Berry Associates, Louisville, KY; Melvin Mann, 

TileSearch, Roanoke, TX; Walter S. Marder, AlA, Division of Historical 

Resources, Tallahassee, FL; Gil Sanchez, FAIA, Gilbert Arnold Sanchez. 

Incorporated, Santa Cruz, CA; Terry Palmiter and Sandra Scofield, Alfred, NY; 

and National Park Service professional staff members. In addition, the authors 

wish to thank Karin Murr Link, who produced the drawings which illustrate 

this Brief. 

This publication has been prepared pursuant to the National Historic 

Preservation Act of 1966, as amended, which directs the Secretary of the 

Interior to develop and make available information concerning historic 

properties. Comments on the usefulness of this publication may be directed to 

H. Ward Jandl, Chief, Technical Preservation Services Branch, National Park 

Service, P.O. Box 37127, Washington, D.C. 20013-7127. This publication is not 

copyrighted and can be reproduced without penalty. Normal procedures for 

credit to the authors and the National Park Service are appreciated. 

ISSN: 0885-7016 Spring 1993 

Cover photograph: Restoration of the I820s Indian barracks at 

Mission Santa Cruz in California included custom-made tapered 

barrel clay roof tiles based on archeological data found at the 

site. Photo: Ron Starr Photography.