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Preserving Historic Ceramic Tile Floors
Anne E. Grimmer and Kimberly A. Konrad
With a tradition that dates to ancient civilizations, ceramic* tile flooring can be found in a variety of settings in diverse cultures and structures, including residential buildings ranging from large apartment buildings to small private houses, institutional buildings such as government offices and schools, and religious buildings such as cathedrals and mosques. Historically, its widespread use may be attributed to the fact that a readily available natural material-clay-could be converted by a relatively simple manufacturing process-baking or firing-into a very durable, long-lasting and attractive floor tile that is easy to maintain. Ceramic floor tiles exhibit a versatility of colored glazes and decoration, and they range from the plainest terra cotta tiles to highly decorated individual ceramic tiles and elaborately patterned tile floors. Their modularity, as standardized units, make them easy to fit into different sized spaces which also explains much of the popularity of ceramic floor tiles throughout history (Fig. 1).
This Brief begins with an overview of ceramic tiles as a traditional
flooring material. It includes an explanation of the various
kinds of historic floor tiles used in the United States and how
they were made. General guidance is given on preservation treatments,
focusing on maintenance, and, when necessary, selective replacement
of damaged floor tiles. The Brief is intended to provide owners
and managers of historic properties with an understanding of the
significance and historical background of ceramic floor tiles,
and a basic awareness of maintenance techniques and various deterioration
problems to which tile floors are especially prone. In the case
of significant historic ceramic tile floors, a professional conservator
of ceramics should be consulted to advise in matters of repair,
restoration or conservation. Historically, ceramic tiles were
used on walls as wainscotting, on fireplace hearths and fireplace
surrounds, and even on furniture, as well as for flooring. However,
because floor tiles are subject to greater damage and deterioration,
they are the primary emphasis of this Brief. Highlights include:
a short history of ceramic floor tiles; a description of ceramic
tile types; a summary of traditional installation methods; maintenance
techniques; and guidance on repair and replacement.
*Ceramic: Any product manufactured from a nonmetallic mineral (such as
clay), by
firing at high temperatures.
Clay is an earthen material, moldable or plastic when wet, non-plastic
when dry, and permanently hard when baked or fired. It is widely
distributed geographically, and often found mixed with sand in
soils of a loam type-a mixture of clay, silt and sand. Relatively
pure clay is not usually a surface deposit, although, in some
cases, it may be exposed by erosion. Clay types vary throughout
the world, and even within a region. Each type of clay possesses
a unique combination of special properties such as plasticity,
hardness and lightness, as well as color and texture, which makes
some clays better suited for one kind of ceramic than another.
The correct clay mixture needed for a particular purpose can
be created by blending clays and adding other materials, but using
the wrong type of clay can result in expensive production problems
such as crazing (the formation of tiny cracks in a tile glaze)
or warping of the tile itself. Traditionally, chalky clays have
been preferred for many kinds of ceramic tiles, in part because
they produce, when fired, a white body which is desirable for
decorating. Other materials can be added, including grog (or
ground-up fired clay) that helps aerate the clay and prevents
warping, speeds firing and reduces shrinking, or calcined flint,
to harden it.
There are several methods used for making ceramic tiles: extrusion;
compaction or dust-pressing; cutting from a sheet of clay;
or molded in a wooden or metal frame. Quarry tiles are extruded,
but most ceramic floor tiles, including traditional encaustic,
geometric and ceramic "mosaic" tiles are made from refined
and blended ceramic powders using the compaction method, known
as dust-pressing. Encaustic tiles, which were made by dust-pressing,
are unique in that their designs are literally "inlaid"into
the tile body, rather than surface-applied. Once formed, tiles
are dried slowly and evenly to avoid warpage, then fired in a
special kiln that controls high, even heat at temperatures up
to 1200°C (or approximately 2500oF) for 30-40 hours. Higher
temperatures produce denser tiles with harder glazes. Most ceramic
tiles require only one firing to achieve low porosity and become
vitrified or grass-like, but some, especially highly decorated
tiles, are fired more than once. Non-vitreous and semi-vitreous
tiles are fired at lower temperatures and are much more porous.
Historically, the use of ceramic floor tiles goes back to the
fourth millennium B.C. in the Near and Far East. The Romans
introduced tile-making in Western Europe as they occupied territories.
However, that art was eventually forgotten in Europe for centuries
until the 12th century when Cistercian monks developed a method
of making encaustic floor tiles with inlaid patterns for cathedral
and church floors. But, this skill was again lost in the 16th
century following the Reformation. Except for finely decorated
wall tiles made in Turkey and the Middle East, and Delft tiles
made in Holland in the 17th century, ceramic floor tiles were
not made again in Europe until almost the mid-19th century.
The modern tile industry was advanced by Herbert Minton in 1843
when he revived the lost art of encaustic tile-making in England.
The industry was further revolutionized in the 1840s by the "dust-pressing"
method which consisted of compressing nearly dry clay between
two metal dies. Dust-pressing replaced tile-making by hand with
wet clay, and facilitated mechanization of the tile-making industry.
Throughout the rest of the 19th century, dust-pressing enabled
faster and cheaper production of better quality floor tiles in
a greater range of colors and designs. In the 1850s encaustic
tiles were selected for such important structures as the new Palace
at Westminster in London, and Queen Victoria's Royal Residence
on the Isle of Wight. By the latter part of the 19th century,
despite the fact that encaustic tiles were still quite expensive,
they had become a common flooring material in many kinds of buildings.
Development of the Tile Industry in America. Although
plain, undecorated ceramic tiles were traditionally a common flooring
material in many parts of the Americas, especially in Latin and
South America, ceramic floor and roof tiles were probably not
made in the North American Colonies until the late-16th or early-17th
century. It was, however, in the Victorian era that ceramic tile
flooring first became so prevalent in the United States. The
production of decorative tiles in America began about 1870 and
flourished until about 1930.
Like so many architectural fashions of the day, the popularity
of ceramic tile floors in America was greatly influenced by the
noted architect and critic, Andrew Jackson Downing. In his book
The Architecture of Country Houses, published in 1850,
Downing recommended encaustic floor tiles for residential use
because of their practicality, especially in vestibules and entrance
halls.
The 1876 Philadelphia Centennial Exposition, with its European
and even a few American exhibits of decorative floor tile, was
a major factor in popularizing ceramic tile floors in the U.S.
Initially, most ceramic tiles-other than purely utilitarian floor
tiles-were imported from England, and their relatively high cost
meant that only wealthy Americans could afford them. However,
when English tile companies realized the potential for profitable
export, they soon established agents in major U.S. cities to handle
their American business (Fig. 2). The English near monopoly actually
stimulated the growth of the U.S. tile industry in the 1870s resulting
in sharply decreased English imports by 1890.
The location of potteries and ceramic tile factories is dependent
upon the ready availability of suitable ball clay (clay that balled
or held together), kaolin (a white clay used as a filler or extender),
and feldspar (a crystalline mineral), and an accessible market.
Since the cost of shipping the manufactured products tended to
restrict profitable sales to limited areas, this usually determined
whether a factory would succeed. Although the United States Pottery
in Bennington, Vermont, is known to have made encaustic tiles
as early as 1853, the Pittsburgh Encaustic Tile Company (later
the Star Encaustic Tiling Company), was the first successful American
tile company, and is generally considered the first to manufacture
ceramic tile in the U.S. on a commercial basis beginning in 1876.
At least 25 ceramic tile companies were founded in the United
States between 1876 and 1894. In the East, several notable tile
firms that were established in this period flourished in the Boston
area, such as the Chelsea Keramic Art Works, the Low Art Tile
Works, and the Grueby Faience Company. Other East Coast companies
organized in the late-19th and early-20th century included the
International Tile & Trim Company, in Brooklyn, New York;
the Trent Tile Company, Providential Tile Company, Mueller Mosaic
Tile Company, and the Maywood Tile Company, all in New Jersey;
and the Moravian Pottery and Tile Works in Doylestown, Pennsylvania
(Fig. 3).
Many factories were also established in the Midwest-in Indiana,
Michigan, and, especially, in Ohio. In the last quarter of the
19th century, the town of Zanesville, Ohio, was the largest center
for pottery and tile-making in the world. Some of the factories
in Zanesville included: Ohio Encaustic Tile Company; Mosaic Tile
Company; Zanesville Majolica Company; and J.B. Owens Pottery,
later to become the Empire Floor and Wall Tile Company (Fig. 4).
The American Encaustic Tiling Company, established in 1876, was
one of the first, and most successful manufacturers in Zanesville
(Fig. 5). In the early 1930s it was the largest tile company
in the world, producing large quantities of floor tile, plain
and ornamental wall tile, and art tile until it closed about 1935,
as a result of the Depression. The United States Encaustic Tile
Company, Indianapolis, Indiana; Rookwood Pottery, Cincinnati,
Ohio; Cambridge Art Tile Works, Covington, Kentucky; and Pewabic
Pottery, Detroit, Michigan, were some of the other well-known
potteries in the Midwest.
Around the turn of the century, the industry began to expand as
tilemakers moved West and established potteries there. Joseph
Kirkham started the ceramic tile industry on the West Coast in
1900 when he set up the Pacific Art Tile Company in Tropico, California,
after his company in Ohio was destroyed by fire. In 1904 the
company became the Western Art Tile Company, surviving for five
years until it went out of business in 1909. During the early-20th
century, other companies were founded in Southern California,
in and around Los Angeles (Fig. 6). Batchelder & Brown, in
particular, of Pasadena (later Batchelder-Wilson in Los Angeles),
was well-known for its Arts and Crafts-style tiles in the teens
and 1920s. By the early 1940s California had become one of the
leading producers of tile, especially faience, in the U.S. (Fig.
7) .
Ceramic engineers, potters and artists not only moved frequently
from one pottery to another, but often struck out on their own
and established new factories when dissatisfied with a former
employer. Also, it was not uncommon for one company to reuse
a defunct factory or purchase another pottery business, change
the name and increase the product line. As a result, many of
the companies in existence today are descendants of the early
pioneering firms.
Changes in the Tile Industry. The majority of ceramic
floor tile made in the U.S. before 1890 was encaustic, but various
factories gradually began to develop and produce other kinds of
tiles. The Trent Tile Company, among others, started to manufacture
both white and colored ceramic mosaic tiles by the mid-1890s (Fig.
8). White vitreous wall tile became available, as well as more
decorative tiles with colored glazes, such as the variegated faience
glazes intended to give a more hand-crafted appearance that were
originated by the Grueby Faience and Tile Company in 1894, and
soon adopted by other potteries (Fig. 9).
In the 19th and early-20th century, many ceramic tile firms had
their own engraving departments, while some used commercial designs
supplied by professional printers. Well-known designers were
often commissioned to work on specific product lines for a particular
firm. These designers worked for one firm after another which
resulted in similar designs being produced by different companies.
(Historic ceramic floor tiles were usually identified by a manufacturer's
or designer's mark on the back, if they were marked at all.)
By the latter part of the 19th century ready-mixed glazes and
colors were also available. This was a great advantage for potters
who, prior to this, had to mix their own colors and glazes.
During the 20th century, the floor tile industry continued to
evolve as much as it had in the previous century. Modern methods
of production employed sophisticated machinery, new materials
and decorating techniques. In the years following World War II,
there were many advances in the industry. Commercially manufactured
dust-pressed tiles, which had previously required more than 70
hours just in the kiln, could be made in less than two hours from
the raw material stage to finished tiles, boxed and ready to ship.
Dried, unglazed tiles were sprayed with colored glaze evenly
and automatically as conveyors carried the tiles into the tunnel
kilns, and the extrusion process ensured that the tiles were cut
to a uniform thickness and size. The changes and developments
in the production of floor tile brought forth a wide range of
shapes and sizes, along with new colors, glazes and decorating
techniques.
After the turn of the century, fewer encaustic floor tiles were
used, particularly in residential architecture. The introduction
of ceramic mosaic floor tiles was a factor in their decline (Fig.
10). The development of rubber interlocking floor tiles in 1894,
along with other, more resilient, flooring materials, was instrumental
in the decreased popularity not only of encaustic tiles, but also
other ceramic tile flooring. These new materials were not only
cheaper, they were not as fragile; they were also lighter and
thinner, and easier to install.
Ceramic mosaic tiles remained in common use through the 1930s
in part because an innovative development had made laying such
small tiles easier. The tiles were pre-mounted in decorative
patterns on 12" x 12" sheets of paper, and sold ready
to lay in cement. This greatly simplified the tile setter's work,
and no doubt was a significant factor in the increased popularity
of ceramic mosaic tiles. Sophisticated mosaic floor designs became
common in entrance foyers of public and private buildings (Fig.
11). Small, white, unglazed tiles in round, square, octagonal
or hexagonal shapes were promoted for their sanitary qualities,
particularly for bathroom floors, while larger, rectangular, white,
glazed tiles were used for bathroom walls or wainscotting. Colored
tiles were also popular, especially for bathrooms, and even kitchens
(Fig. 12). Quarry tile, which was larger and thicker than other
ceramic floor tile of this period, was often used in public buildings,
as well as for entrance halls, small studies, libraries, dining
rooms and even living rooms in private homes. But, by the 1930s,
the fashion for art tile had diminished to the point where floor
tiles were, for the most part, generally regarded as primarily
utilitarian, as opposed to important decorative elements.
The thickness of historic ceramic floor tiles varied considerably
according to their intended use and when they were made. Floor
tiles were thicker and harder than wall or ceiling tiles. Stove
tiles, meant to retain the heat of the stove, were sometimes as
much as several inches thick. Medieval floor tiles were usually
one inch thick; encaustic tiles of the Victorian era tended to
be slightly thinner. Modern, 20th-century tiles, with the exception
of some art pottery tiles, are the thinnest, as a result of modern
manufacturing methods. The backs of most, but not all, ceramic
floor tiles are covered with raised (or sometimes recessed) ridges,
circles or squares which help to increase the bonding capability
of the tile.
Ceramic floor tiles can generally be divided into two types: unglazed
and glazed. Unglazed tiles include: quarry tiles;
encaustic and geometric tiles; and ceramic mosaic tiles, which
can be either glazed or unglazed. Most other ceramic floor tiles
are glazed.
Quarry tiles are the most basic type of historic ceramic
floor tile (Fig. 13). Originally made from quarried stone, they
are machine-made using the extrusion process. Quarry tiles are
unglazed, semi-vitreous or vitreous, and essentially are square
or rectangular slabs of clay baked in a kiln. The colors of quarry
tiles are natural earthen shades of gray, red and brown determined
by the clay and, to some extent, the temperature and duration
of firing. Quarry tiles, which range from ¼" to ½"
in thickness, are available in square and rectangular shapes in
sizes that include 3", 4-1/4", 6" (one of the most
common sizes), 9" and 12" squares; 6" x 12",
6" x 9", 4-1/4" x 9", 3" x 6", and
3" x 9" rectangles; and 4" x 8" hexagon shapes.
(Pavers or paver tiles are a simpler, and tend to be somewhat
cruder, version of quarry tiles. Like quarry tiles, they are
usually unglazed, but slightly thicker. Machine-made pavers are
either semi-vitreous or vitreous, and generally formed by dust-pressing,
although sometimes are extruded. Hand-made pavers which are common
in Mexico and southern Europe are non-vitreous.)
Encaustic tiles are a type of traditional unglazed-yet
decorative-floor tile, manufactured by the dust-pressed method.
Whereas most ceramic tiles are surface-decorated or decorated
with impressed or embossed designs created by a mold, encaustic
tiles are unique in that their decorative designs are not on the
surface, but are inlaid patterns created as part of the manufacturing
process. First, a thin, approximately ¼" layer of fine,
almost powder-dry, clay was pressed into a mold with a relief
design at the bottom which formed a depression in the face of
the tile. A second, thicker layer of coarser clay was laid over
the first layer, then covered with another layer of fine clay.
This "sandwich" helped prevent warping and ensured
that the body of the tile was strong and had a fine, smooth surface.
The layers of clay "dust" were compacted by presses,
after which the mold was inverted and the die removed, thus producing
a tile with an indented or intaglio pattern on top. After the
tile dried, colored slip (liquid white clay colored with dyes),
was poured to fill in the intaglio pattern. Each color had to
dry before another color of slip was added. The recessed area
was overfilled to allow for shrinkage, and after drying for several
days, and before firing, the excess slip was scraped off the surface
by a rotating cutter that created a flat, although not completely
smooth, face. Problems might arise during the firing. Due to
the dissimilar rates of contraction of the different clays, the
inlaid clay could shrink too much and fall out of the tile recesses;
or, the tile could be stained by the different pigments used for
the design if impure or unstable (Fig. 14). By
the 1840s, encaustic tiles were made entirely with almost-dry
clay using the dust-pressed method. This served to eliminate
the possibility of staining the body of the tile with other colors
and permitted the use of more colors on a single tile. Thus,
an encaustic tile can sometimes be dated according to the complexity
and the number of colors in its pattern. Red tiles with white
figurative patterns were generally the earliest, followed by brown
and buff colored tiles. In the 1860s, blue tiles with yellow
or buff patterns were popular, succeeded by more subtle color
schemes featuring a "chocolate" red with a soft grey.
By 1860, up to six colors were used in a single tile to form
a pattern. Toward the end of the century, white encaustic tiles
with a black or gold design were common, as well as tiles with
complicated color patterns of white, black, gold, pink, green
and blue. Encaustic tiles were decorated with traditional as
well as original designs. Some, particularly intricate, designs
were painted on the surface of the tile with opaque colored glazes,
instead of being inlaid (Fig. 15). Most major tile manufacturers
sold many of the same pre-formed encaustic floor tile patterns
through catalogues. Encaustic tiles were produced in a variety
of sizes, mostly square or octagonal in shape, and almost any
design could be custom-made for a special purpose or to fit a
particular space. Historic, 19th-century encaustic tiles were
generally slightly less than 1" thick, about 15/16."
Cheaper tiles of lesser quality were also made of clay or cement.
These designs resembled those commonly found on encaustic tiles
but applied as a transfer printed pattern, or using a multi-color
lithographic or silkscreen process. These are still manufactured
and popular in many parts of the world (Fig. 16).
Smaller, single-colored versions of encaustic tiles that, when
assembled together form a geometric pattern, are called geometric
tiles in England. However, in the United States they are
generally not differentiated from encaustic tiles. Based
on the geometric segments of a six-inch square, they were typically
rectangular, square, triangular or hexagonal in shape, and about
the same thickness as patterned encaustic tiles (Fig. 17). Geometric
tiles were especially well suited for decorative borders, and
a wide variety of floor designs could be created with their many
shapes, sizes and colors-either alone or combined with patterned
encaustic tiles. The cost of producing geometric tiles was much
less than of encaustic tiles because each tile involved only one
type of clay and one color. By the end of the 19th century, over
60 different shapes and sizes of geometric tiles were available
in up to ten colors, including buff, beige or tan, salmon, light
grey, dark grey, red, chocolate, blue, white and black.
Ceramic mosaic tiles are essentially smaller versions of
geometric tiles (usually no larger than 2-1/4", and no thicker
than ¼") ranging in size from ½" to 2 3/16",
in square, rectangular or oblong, hexagonal, pentagonal and trapezoidal
shapes. Both vitreous and semi-vitreous mosaic tiles were available,
unglazed in solid or variegated colors with a matte finish, or
glazed in unlimited colors. Single, one-piece tiles were also
fabricated to give the appearance of multiple mosaic pieces.
This was achieved with a mold, which gave the appearance of recessed
mortar joints separating individual "mosaics" (Fig.
18).
With the exception of quarry tiles, encaustic tiles, and some
mosaic tiles, most ceramic floor tiles are decorated with a glaze.
While unglazed tiles derive their color solely from the clay,
or from oxides, dyes or pigments added to the clay, the color
of glazed tiles is provided by the glaze, either shiny or matte.
Some potteries specialized in certain kinds of glazes and were
famous for them. The earliest and most common method of clay
tile decoration made use of tin-glazes which were essentially
transparent lead glazes. Tiles were either dipped into the glaze
or the glaze was brushed on the tile surface. Glazes were generally
made with white lead, flint, or china clays ground up and mixed
with finely ground metallic oxides that provided the color. Colored
glazes were commonly known as "enamels". Colors included
blue derived from cobalt, green from copper, purple from manganese,
yellow from antimony and lead, and reds and browns from iron.
An opaque glaze was created by adding tin oxide.
19th Century Techniques. Aside from the use of improved
tools and modern materials, installation methods have changed
little since the mid-19th century. M. Digby Wyatt, an architect
for one of the major 19th century encaustic tile manufacturers
in Britain, Maw & Co., described this procedure for laying
encaustic and geometric tiles in 1857:
First, either an even layer of bricks, a 2-1/2" bed of concrete
of quicklime and gravel, or a mixture of Portland cement and clean
sharp sand was laid to prepare a solid foundation for the tiles.
If the tiles were to be laid over an existing wooden floor, the
floor boards had to be pulled up, sawn into short lengths and
fitted between the joists. Concrete filled in the spaces and
made the base flush with the upper face of the joists, and created
a level surface finished within 1" of the finished floor
line. A layer of cement mortar was then laid on top. This allowed
the tiles to fit in the same amount of space as the floorboards
they replaced.*Before laying the tiles, skirting boards
or shoe moldings were to be removed, and replaced after the tiles
were laid. This eliminated having to cut the outer tiles to fit
exactly, and resulted in a neater appearance.
Next, the floor design was marked off with mason's string or chalk
lines which divided the space into equal quadrants. The first
section to be laid out was defined by two parallel strips of wood,
or guide pieces, about 4" wide. A level thickness of cement
was spread between these strips. The tiles, thoroughly soaked
in water, were laid in the cement and leveled with a straight-edge.
The foundation had to be kept wet while the tiles were being
laid. Small strips of wood temporarily placed at right angles
to the guide pieces helped keep elaborate patterns straight.
When the bed was hard, the joints were filled with pure cement
mortar-sometimes colored with lamp black, red ochre or other natural
pigments-mixed to the consistency of cream. Excess mortar was
wiped off the tiles with a piece of flannel or sponge.
A newly-laid tile floor could not be walked on for 4-6 days until
the cement hardened properly. Occasional washing would remove
the saline scum that often appeared on the surface right after
the tiles were laid.
20th Century Techniques. Almost 50 years later, in 1904,
the Tile Manufacturers of the United States of America published
Suggestions for Setting Tile with the intent of bringing
tile-laying up to a uniform standard. This guidance was very
similar to that given by Wyatt. But, there were some differences,
such as using hollow clay tile as a foundation material and heavy
tar paper when laying tile over a wooden floor to protect the
floor boards from the moisture of the mortar mix. Emphasis was
placed on using the best quality cement, sand, and purest water
to obtain a durable tile floor. Soaking the tiles before setting
was no longer necessary, but using stiffer mortar was suggested
to prevent it from rising up between the tiles.
Tile-laying methods changed somewhat more later in the 20th century,
mostly due to the availability of new materials and techniques.
By the 1920s small ceramic mosaic tiles were manufactured as
12" square sheets held together by a face-mounted paper "skin."
This made it possible to lay the 12" square of tiles as
a unit rather than each of the small tiles individually. Mounting
the tiles directly in the cement resulted in a very strong bond.
But the face-mounted paper obscured the tiles from view making
it difficult for the tile-setter to see if the tiles were being
laid straight. The fact that the paper was not removed until
after the tiles were firmly set in the cement bond coat further
complicated realignment of crooked tiles. This paper "skin"
was eventually replaced with a fabric mesh backing. This permitted
the tiles to be aligned as soon as the moisture from the bond
coat loosened the mesh from the back of the tile; it also allowed
a single tile to be cut away from the mesh and repositioned immediately.
Although the fabric mesh made tile setting faster, sometimes
it also resulted in a weaker bond by reducing the contact area
between the backs of the tiles and the bond coat.
Following World War II, different methods of preparing a foundation
for a ceramic tile floor were developed to be more compatible
with new materials, such as reinforced concrete, expanded wire
mesh, polyethylene and waterproof plywood. New adhesives and
grouts also facilitated tile installation, and an increased variety
of epoxy and cement mortars allowed for different setting bed
thicknesses. But today, after half a century of practical application,
some of these "new" materials, such as plywood, particle
board, oriented strand boards and other wood panels, are no longer
recommended for use with ceramic tile.
Mortar beds are lighter, more flexible, and much thinner than
they were previously, having shrunk from several inches to as
thin as 3/32". A greater variety of materials are used for
setting ceramic floor tiles, including bonding agents and waterproof
membranes. Basic installation methods have not changed significantly,
but they vary according to the type of subfloor on which the tile
is to be laid. While the same concerns for level underlayment
and strong adhesion exist, advancement has occurred mostly in
the increased speed and ease of laying the tiles.
*The traditional practice of sawing the original floor boards
and fitting them between the joists, still used today to maintain
a low finished floor profile, has resulted in numerous cracked
tiles and other failures. Instead, a better approach is to leave
the existing floor boards, if they are in good shape, and install
a cementitious backer board (CBU) available in thicknesses ranging
from ¼" to 5/8" as the setting bed for the tiles.
Before undertaking any work more complicated than regular maintenance
or a very simple repair on a significant historic ceramic tile
floor, or on any historic tile floor where serious damage has
occurred, it is recommended that a professional conservator of
ceramics, an historical architect, an architectural historian,
or a chemist with particular knowledge and experience in this
field be consulted. This will ensure that all future work, whether
it be regularly-scheduled maintenance or more technical and specialized
repair and restoration, is done in accordance with the Secretary
of the Interior's Standards for the Treatment of Historic Properties.
Cleaning Methods. Ceramic tiles are essentially a practical,
low-maintenance flooring material. Yet, even glazed tiles are
somewhat porous, and can get dirty and stained, especially in
heavy traffic areas or where oil, fat, and grass stains are likely
to occur. Although heavily soiled areas may be difficult or impossible
to clean completely, in most instances, cleaning ceramic tile
floors is relatively easy. Cleaning should always begin with
the gentlest means possible, which may be as simple as warm water.
Regular maintenance should include sweeping, or preferably dry
or damp mopping or vacuuming to reduce grit. Tiles can usually
be cleaned with a non-soap-based household floor cleaner, such
as one of the commercial products intended for cleaning ceramic
tile floors available on the market.
All cleaning and stain-removal products should always be tested
on a small, inconspicuous area before using. Abrasive cleaners
(including powdered cleansers and even "mildly" abrasive
creams) and mechanical equipment can damage and wear away the
protective surface, as well as the decorative design on the tiles,
and should not be used on ceramic tile floors. Generally, acid-based
cleaning solutions should also not be used on ceramic tile floors
because they can damage the complex silicates in a glaze. However,
there are some acid-based cleaners specially formulated for cleaning
and removing coatings from ceramic tile floors that may be acceptable,
but even these must be used with caution. Sometimes an acid-based
cleaner may, in fact, be needed to remove discoloration or staining
caused by lime or cement mortar. But, it should be tested first,
used with caution, and applied only to a thoroughly wetted
tile floor from which excess water has been removed. Pre-wetting
a ceramic tile floor before cleaning is a good policy to observe
with all cleaners. The water saturates the porous tile and prevents
chemicals or other cleaning agents from penetrating into the tile
body. Floor tiles should be always rinsed thoroughly after cleaning.
Plastic pot-scrubbers may be effective in loosening and removing
superficial dirt without abrading the glazed or vitrified surface
of the tiles. Stubborn asphalt or oil stains, scuff marks, or
soiling can sometimes be removed with ammonia or one of the household
spray products intended for cleaning kitchen or bathroom tiles.
If necessary, a solvent may be applied carefully to pre-wetted
tiles, but it should not be left on the surface for an extended
amount of time as it may cause discoloration. If possible, a
stain should always be identified first in order to select the
material best-suited to remove it.
Organic growth, such as mold or mildew, can be eliminated with
a dilute solution of household bleach and a neutral household
detergent, or a dilute (5-10%) solution of tri-sodium
phosphate (TSP). After applying either of these solutions, it
may be necessary to scrub the floor with a natural bristle or
nylon brush, and then rinse with clear water. Even a dilute bleach
solution should not be left on a ceramic tile floor for more than
a few minutes, since the alkali in the bleach can lead to the
formation of a white efflorescent deposit. Efflorescence (a whitish
haze of water-soluble salts) may stain and streak the tile, or
may even cause minor spalling around the joints.
Regular maintenance of a ceramic tile floor should always begin
with vacuuming to remove loose dirt and grit. Then, a mild cleaning
solution may be applied and left on the floor for 10-15 minutes,
without letting it dry on the tiles. Heavily soiled areas may
be scrubbed with a natural bristle or nylon brush to loosen dirt
from the tile surface. Finally, the floor should be thoroughly
rinsed with clean, clear water, preferably twice, and dried with
terry cloth towels, if necessary. Any proprietary cleaning product
should always be used in accordance with the manufacturer's directions
(Fig. 19).
Protective Coatings. In most instances, traditional ceramic
tile floors probably would not have been treated or given a protective
coating other than wax. In the 19th century, some encaustic tile
floors were treated with linseed oil, but this is not a practice
recommended today because linseed oil tends to attract dirt and
discolors as it ages. Most historic ceramic tile floors simply
acquired a natural "polish" or sheen through use. Because
the surface of ceramic tiles is already protected with a fired
skin or a glaze, an additional protective coating should generally
not be needed.
Opinions differ concerning the use of protective coatings, penetrating
sealers, or waxes on ceramic tile floors, and, especially, on
historic ceramic tile floors. If properly applied and regularly
cleaned, a coating can sometimes be an effective maintenance treatment,
but only on interior floors. However, if not adequately or properly
maintained, rather than facilitating maintenance of ceramic tile
floors in high traffic areas, such coatings may tend to emphasize
traffic patterns as they wear away or become scratched. Some
coatings may also peel in spots, or cause tile to appear hazy
or cloudy if the coating is not applied in accordance with the
manufacturer's specifications, or if the tiles are not perfectly
clean when the coating is applied. Furthermore, applying such
a coating may actually increase maintenance costs, since a coating
requires periodic removal and renewal. The frequent removal of
a coating can also damage a ceramic tile floor if it is carried
out with harsh chemicals or abrasive mechanical equipment. If
any coating is considered, a traditional coating, such as floor
wax, may be the most suitable. Wax is easy to remove when it
becomes worn, and does not impart a high, potentially inappropriate,
gloss to the surface.
On the other hand, a penetrating sealer, or impregnator,
may be worth considering to protect patterned encaustic tiles,
or painted or printed tiles featuring a design that might be worn
off, particularly in public buildings with a high volume of foot
traffic. For example, some manufacturers of new, reproduction
encaustic tiles recommend applying a penetrating sealer to the
replacement tiles, as well as to the historic tiles. Impregnators
do not change the color of the tile surface and, unlike some penetrating
sealers, are completely invisible after they have been applied.
They can reduce the porosity or water absorption of the tile
surface, and provide some protection for the tile (and the grout)
against staining. This may be particularly useful on light-colored
floors. Whether to apply an impregnator to an historic ceramic
tile floor, and what type or product to use, are decisions that
should generally made in consultation with a conservator or ceramic
tile specialist. It may also be necessary to comply with certain
safety standards and friction requirements of the ADA (Americans
with Disabilities Act). The ADA Guidelines recommend "a
static coefficient of friction" of 0.6 for level surfaces
and 0.8 for ramps. This may require the application of a non-slip
sealer or wax to historic ceramic tile floors in some public buildings.
Despite the non-traditional shiny finish they may impart
to a floor surface, two-part, acrylic-based coating systems are
commonly used today on historic ceramic tile floors in many public
buildings, primarily because they facilitate easy maintenance.
If it is decided that a sealer is to be used, a product with
a matte or dull finish may be preferable, or more appropriate,
for a historic ceramic tile floor than one with a high-gloss.
In some cases, temporary protection may be the best approach until
a better solution is found. Non-permanent protection for an historic
ceramic tile floor may be as simple as using floor mats at doors
or in heavy traffic areas.
Loss of Tile Surface and Pattern. Ceramic tiles are among
the most durable of historic flooring materials, but natural wear
and a certain amount of deterioration or damage is inevitable.
Some tiles, such as dense, close-textured quarry tiles and ceramic
mosaic tiles, resist abrasion and stain absorption very well.
But many others, especially patterned encaustic and geometric
tiles, are extremely susceptible to abrasion. Heavy traffic can
also result in uneven wear, or even cupping, in certain areas
of tile floors that get more use than others, such as doorway
entrances. The particular clay mix, or the dye or pigment used
to color the clay, can also affect the hardness and durability
of individual tiles or an entire ceramic tile floor (Fig. 20).
Tile Glaze Failure. Occasionally some glazes can become
pitted or powdery as they age. Lead glazes used in the 19th century,
which were fired at low temperatures, deteriorated relatively
quickly. Glazes have different physical properties from the fired
clay tile body itself, and as a result may sometimes crack or
craze. Unless the crazing visibly extends into the porous clay
of the tile body beneath, this is not generally a serious material
failure; however, dirt entering these cracks cannot be removed,
and will discolor the tile. If the crazing penetrates through
the glaze, it may increase the water absorption of the tile.
Tile Breakage. Ceramic floor tiles are very susceptible
to damage and breakage caused when something heavy is dropped.
Repeated passage of heavy objects, or carts, over a floor can
also crack and break ceramic tiles, as well as heavy vibration
from outside traffic (Fig. 21).
Moisture Damage to Tile. Ceramic tile floors have been
traditionally viewed as highly waterproof systems that do not
require protection from moisture. In reality, however, this is
not true. Water-related problems are one of the most common causes
for the deterioration and failure of historic tile floors, particularly
in bathrooms and other rooms where there is a lot of moisture.
Water that is allowed to sit in areas around shower stalls and
bathtubs can eventually damage grout and mortar, and loosen tiles.
Some of the more porous kinds of tiles that are not as hard-fired
may actually begin to powder or spall if subjected to constant
moisture.
Loose, Cracked, Broken or Unbonded Tile due to Mortar Failure.
The durability of ceramic tile floors depends to a great
extent on a sound mortar bed and sound mortar joints. The wrong
mortar type or mortar that is inadequately mixed can also spell
trouble for a ceramic tile floor. Failure of a tile floor system
laid over a subfloor is often the result of weakened or deteriorated
grout or mortar which allows the tiles to become loose. Mortar
may also be weakened or loosened by cleaning solutions that are
too strong.
Proper tile-laying technique includes the use of a material that
will allow for some movement of the tiles. Traditionally, a layer
of asphalt (replaced by a layer of plastic or building paper in
more modern construction) was inserted to separate the base and
the bedding underneath (Fig. 22). This prevents bonding between
the base and the bed, and allows for some "relative"
movement. It is intended to prevent the ceramic tile floor from
arching or ridging, a condition in which single or entire rows
of tiles can pop up to relieve tension and separate completely
from the bed. When this happens, the condition will probably
require taking up and relaying many or all of the tiles.
Tile Damage or Loss caused by Systems Update. The installation
of new plumbing, electrical and HVAC systems, or the attachment
of new fixtures and furnishings, may be one of the most common
sources of damage to an historic ceramic tile floor. Earlier
remodeling projects to remove old pipes or to replace "out-dated"
bathroom fixtures may have resulted in the loss of floor tiles
(Fig. 23). Different shapes and sizes of new fixtures, equipment
or pipes may have exposed previously untiled areas that have been
inappropriately patched with cement. Careless workers and insensitive
installations can also result in damage, breakage or removal of
historic floor tiles. All of these conditions will require matching
replacement tile.
The Secretary of the Interior's Standards for the Treatment
of Historic Properties emphasize the retention and preservation
of historic building material. Preservation and repair treatments
are always preferable to replacement.
Mortar Joint Repair. Deteriorated mortar joints and loose
mortar or grout can generally be repaired. First, the entire
floor should be checked for loose tiles that need to be regrouted.
Damaged mortar should be carefully removed by hand and the joints
wetted or a bonding agent applied in preparation for regrouting.
When making mortar repairs, it is important to use grout that
matches the old in color and consistency as closely as possible.
Tile Repair. Trying to remove one tile can endanger surrounding
tiles. Thus, it may be better to preserve and retain an original
historic tile that is only slightly damaged, rather than replace
it. Sometimes cracks may be repaired, or a corner or piece of
tile that has broken off may be reattached, using an epoxy glue,
or grout. If a tile is chipped or a small corner or edge is missing,
a carefully executed patch of epoxy-mixed with colored enamel,
or mortar tinted to blend with the tile, may be less conspicuous
than trying to replace every tile that has even the slightest
damage. And, it is a better preservation treatment.
In limited instances, glaze failure or surface powdering of ceramic
floor tiles may sometimes be treated successfully by a conservator
with a specially formulated, solvent-based, mineral densifying
agent (such as silicic acid), followed by a siloxane sub-surface
repellent, applied 24 hours later. Under the right circumstances,
such a treatment can harden and bind the surface, and lower the
absorbency of the tile, and still maintain the vapor transmission.
But this is a highly complex undertaking and should only
be attempted by a conservator after appropriate testing. Not
only are these chemicals highly toxic and dangerous to handle,
but if used improperly, they can cause greater damage to the tile!
Tile Replacement. When an individual tile or a larger
portion of an historic ceramic tile floor is missing or so severely
damaged that it cannot be repaired, or if it has become a safety
hazard, then it should be replaced. When a ceramic tile floor
has deteriorated as a result of long term wear and abrasion, or
from settlement or vibration damage to the setting bed, there
are a number of factors that need to be considered before choosing
a preservation treatment. If damage to tiles is the result of
more than normal wear and tear, the source of the problem needs
to be identified, and the problem corrected before replacing the
damaged tiles.
Successful replacement not only depends on the availability of
matching tiles, but on the condition of the substrate on which
the tiles are laid. Before installing the replacement tiles,
any problems, such as settlement or vibration, will have to be
addressed, and the height of the new setting bed may have to be
adjusted for the thickness of the new tiles.
Selective Replacement of Individual Tiles. This cautious
approach, typically an attempt to replace only the most seriously
damaged tiles, is often taken or considered when only a small
number of tiles are involved. Unless old, matching tiles can
be found and reused, replacement often requires specially fabricated
reproduction tiles. In some instances, individual historic tiles
that are damaged may be replaced with matching tiles salvaged
from other, less prominent areas of the floor or from other buildings.
This is most feasible if the tiles to be replaced are either
plain, and easy to match, or decorated with a common historic
floor tile pattern.
In order to replace damaged tiles, it can be helpful to identify
the manufacturer and the approximate date of the tiles, if possible.
However, many mass-produced tiles are not marked and give little
or no information as to their origin, although stylistic similarities
with other marked tiles may sometimes provide a clue as to the
manufacturer. Some decorating firms seldom signed their work,
while many firms made bisque tiles (plain, unglazed, once-fired
tiles) for other companies, as well as their own use. Identifying
marks will generally be found on the back of the tile. A mark
impressed or molded into the back of the tile may give the name
or initials of the company which made the tile or the bisque;
sometimes a printed or painted mark indicates if it was decorated
by a different company, or artist. Historic building records
and construction documents may provide information about the tile
company or supplier. Catalogues of the period may also be useful
in identifying the tile manufacturer of unmarked tiles.
Replacing a single damaged tile is based on the ability to remove
only the deteriorated tile without harming surrounding
tiles. Attempts to remove one or several damaged tiles often
fail because a hammer and chisel are used. The shock of the blows
to the tile being removed travels through the grout into surrounding
tiles and cracks them. To avoid damaging good tiles, all the
grout around the tile must be removed. This is best accomplished
by an experienced tile installer using a hand tool called a grout
saw or, for grout joints wider than 3/8", a dry-cutting diamond
blade, mounted in an angle grinder or circular saw.
Other difficulties may be encountered when selectively replacing
damaged tiles with reproduction tiles. New tiles, especially
encaustic tiles, may be different in thickness and, sometimes,
despite the attention to detail of the reproduction process, slightly
different in color and design from historic tiles. This can cause
both visual and physical problems, especially if the replacements
are being laid in a piecemeal fashion.
If the setting bed does not have enough mortar to grip and hold
the tile, one new tile laid among the originals will eventually
come loose. If the new and old tiles are different thicknesses,
the setting bed in which the new tiles are laid must be at a different
height to create a level finished surface. In addition, the two
levels of setting beds may be of different composition; one may
be harder, stronger and less flexible than the other. This may
also lead to problems, since the setting bed foundation should
act and respond as a unit to the load and stresses placed upon
it.
Sectional Replacement of Tiles. In some instances, the
best approach may be to remove a complete section of damaged original
tiles and replace that section of floor in its entirety with new
reproduction tiles. Advantages of this method include the ability
to lay a level setting bed, as well as achieving a finished product
that is uniform in color and pattern match. Although this approach
may involve replacing more original tiles with reproduction tiles
than may be absolutely necessary, original tiles that remain in
good condition can be saved to be reused in other sections where
only a few tiles are damaged. This technique is generally most
appropriate either when the section being replaced is the most
damaged portion of the floor, or is in a relatively inconspicuous
location and the tiles that are removed will supply enough salvaged
pieces to permit in-kind repair of a more visually prominent area
(Fig. 24).
When laying a section of reproduction tiles, it may be a good
idea to use contemporary materials and installation methods such
as expansion joints or flexible expansion material. One of the
major causes of ceramic floor tile installation failure and cracked,
broken or disbonded tiles is the lack of expansion joints. Expansion
joints were sometimes used in laying historic ceramic tile floors,
and these are frequently the ones that have survived in the best
condition. Many preservation contractors hesitate to use conventional
expansion joint filler materials because of their limited range
of colors. However, there are new flexible sealants in a wide
range of colors that are available in either sanded or unsanded
textures to match the surrounding grout joints. As a result,
the expansion joints are almost invisible. A bonding agent may
also be considered-if recommended by the tile manufacturer-and
any drawings provided by the manufacturer should be used to guide
the installation.
Each preservation technique has advantages and disadvantages that
the historic property owner or manger should take into consideration
before deciding which one is best suited to the particular flooring
problem. For example, slight differences in the shape, size,
color and the pattern between the old and the new tiles are frequently
encountered. If replacing an entire section, the slightest difference
in size and dimension between the original tiles and the reproduction
tiles, even if it is as small as 1/8" or 1/16", can
mean that the new section of tile will not fit inside an existing
border (Fig. 25). Even though drawings and photos are provided
to the manufacturer, there may be some variation in the design
and pattern size on the new tiles. Thus, they may not align perfectly
with the original tiles, and as a result the section of the floor
that has been replaced may be quite conspicuous.
Historic ceramic tiles are a common flooring material in many
different kinds of small, as well as large, private and public,
structures throughout the United States. Whether plain, or decoratively
patterned, traditional ceramic floor tiles are important in defining
the character of historic buildings. Although ceramic floor
tiles are a practical material, they are also fragile, and can
be easily damaged by improper installation techniques, insensitive
remodeling, harsh cleaning methods, and even regular daily use.
Preserving them requires careful day-to-day maintenance. This
should begin with using gentle, non-abrasive methods and materials
to clean them, and, in some instances, using an appropriate coating
or impregnator to protect them.
Some historic ceramic tile floors, due to their manufacturer,
their unique design, or their location in a certain room or within
a particular building, may have greater significance than those
that are purely utilitarian. Such floors should be accorded special
care, and a ceramics conservator or preservation specialist should
always be consulted to prepare responsible maintenance plans and
to provide guidance concerning repair treatments and replacement
techniques for them.
Unless an historic ceramic tile floor is extensively damaged with
many missing and broken tiles and, therefore, potentially hazardous,
it may be preferable to leave it alone. An unevenly worn floor
surface, worn colors or patterns on the tiles, or slight cracks,
chips, or scratches in the tiles themselves does not necessarily
mean that the tiles should be replaced. Such relatively minor
imperfections seldom detract from the character of an historic
ceramic tile floor. They may, in fact, impart character, and
be less noticeable or obtrusive than replacement of a single tile
or a larger section with new tiles that do not match the originals
exactly. Each situation should be evaluated on its own basis
before selecting the preservation approach best suited to the
project.
Austwick, Jill. The Decorated Tile: An Illustrated History
of English Tile-making and Design. New York: Scribners, 1980.
Barnard, Julian. Victorian Ceramic Tiles. Greenwich, CT:
New York Graphic Society Ltd., 1972.
Bruhn, Thomas P. American Decorative Tiles, 1870-1930.
Storrs, CT: William Benton Museum of Art, 1979.
Byrne, Michael. Setting Tile. Newtown, CT: The Taunton
Press, 1995.
Decorative Tile Designs in Full Color. Selected and arranged
by Carol Belanger Grafton. New York: Dover Publications, Inc.,
1992.
Fidler, John. "Protective Custody: John Fidler examines the
options on caring for brick, tile or stone floors." Traditional
Homes. (August 1989), pp. 112-115.
Furnival, William James. Leadless Decorative Tiles, Faience
& Mosaic. Stone, Staffordshire: W.J. Furnival, 1904.
Lavenberg, George N. Ceramic Tile Manual. Los Angeles:
Building News, 1986.
Massey, James C., and Shirley Maxwell. "Decorative Tile:
Art for the Victorian and Arts and Crafts Home." Old-House
Journal. Vol. XIX, No. 2 (March/April 1991), pp. 54-58.
Massey, James C., and Shirley Maxwell. "The Ceramic Circus."
Old-House Journal. Vol. XXIII, No. 2 (March/April 1995),
pp. 46-51.
Riley, Noel. Tile Art: A History of Decorative Ceramic Tiles.
London: The Apple Press, 1987.
Rosenstiel, Helene Von, and Gail Caskey Winkler. Floor Coverings
for Historic Buildings: A Guide to Selecting Reproductions.
Washington, D.C.: The Preservation Press, 1988.
Taylor, Joseph A. "Ceramic Tiles in Commerce." BR
Building Renovation. (Fall 1994), pp. 45-48.
The Secretary of the Interior's Standards for the Treatment of
Historic Properties with Guidelines for Preserving, Rehabilitating,
Restoring and Reconstructing Historic Buildings. Kay D. Weeks
and Anne E. Grimmer. Washington, D.C.: U.S. Department of the
Interior, National Park Service, Cultural Resource Stewardship
and Partnerships, Heritage Preservation Services, 1995.
Tunick, Susan. American Decorative Tiles. Sponsored by
Assopiastrelle (Association of Italian Ceramic Tile and Refractories
Manufacturers), and coordinated by D. Grosser and Associates,
Ltd., New York (1991).
Vandenburgh, Jayne M., IBD. "Restoring the Ohio State Senate
Building: An American Tile Classic Returns." Tile Design
and Installation. Vol. 8, No. 1 (January 1995), pp. 32-35.
Wyatt, M. Digby. Specimens of Geometric Mosaic Manufactured by
Maw & Co. of Benthall, near Broseley. London: M. Digby Wyatt,
1857.
There are a number of companies that offer standard lines of
reproduction tiles, while others focus on custom work. Some
new lines of reproduction tile attempt to be exact replicas of
original tiles from the late-19th and early-20th century, while
others are modern interpretations or adaptations of traditional
designs, and may not be appropriate as replacement tiles in a
preservation or restoration project. For additional sources see:
"Traditional Building's Ceramic Tile SourceList," Traditional
Building, Vol. 9, No. 4 (July/August 1996), pp. 92-93.
Designs in Tile
Custom-made reproduction art tile.
Fulper Tile
Reopened factory reproduces historic tiles using original Arts
and Crafts-period glazes.
H&R Johnson Tiles Ltd.
Stock and custom reproductions of Minton
Hollins encaustic and geometric tiles.
L'Esperance Tile Works
Custom-made encaustic,
Moravian Pottery and Tile Works
Reproduction tiles based on Henry Chapman Mercer's original
designs.
Motawi Tileworks
Reproduction tiles in Arts and Crafts, Art Nouveau and other
styles.
Native Tile and Ceramics
Reproduction decorative tiles in Southern California tradition
of Craftsman, Mission, Art Deco and other styles.
Original Style
Reproduction ceramic tiles from 1750-1902.
Pewabic Pottery, Inc.
Reopened factory reproduces original tile designs and glazes.
Terra Designs Tileworks
Mosaic tessarae experts, and reproduction of historic ceramic
tiles.
Tile Guild
Reproduction of traditional Spanish, Portuguese, Dutch, Italian
and English tiles.
Tile Restoration Center, Inc.
Reproduction of Arts and Crafts-period tiles.
The American Institute for Conservation of
Ceramic Tile Institute of America, Inc.
Friends of Terra Cotta, Inc.
Tile Council of America
Tile Heritage Foundation
Anne E. Grimmer is Senior Architectural Historian, Technical
Preservation Services Branch, Heritage Preservation Services Program,
National Park Service, Washington, D.C. Kimberly A. Konrad
is a Preservation Planner, Boston Landmarks Commission, The Environment
Department, City of Boston, MA. The authors wish to thank the
following individuals for providing technical review and other
assistance in the development of this publication: Marc Tartaro,
AIA, and William Allen, Office of the Architect of the Capitol,
Washington, DC; Mary Catherine Bluder, Bucks County Historical
Society, Doylestown, PA; Michael F. Byrne, Ceramic Tile Education
Foundation, Clemson, SC; Milford Wayne Donaldson, FAIA, Los Angeles,
CA; Gray LaFortune, CTC, Ceramic Tile Institute of America, Inc.,
Culver City, CA; Joseph Taylor, Tile Heritage Foundation, Healdsburg,
CA; Susan Tunick, Friends of Terra Cotta, Inc., New York, NY;
Anne Weber, Ford Forewell Mills and Gatsch, Architects, Princeton,
NJ; Glenn Wharton, Wharton & Griswold Associates, Inc., Santa
Barbara, CA; Charles E. Fisher, Sharon C. Park, AIA, and, especially,
Kay D. Weeks, National Park Service, Washington, DC.
The Tile-Making Process
Historical Background
Ceramic Floor Tile Types
Unglazed and Glazed Tiles
Unglazed Tiles
Glazed Tiles
Laying Ceramic Tile Floors
Historic
Ceramic Floor Tile: Preservation and Maintenance
Historic
Ceramic Floor Tile: Damage and Deterioration Problems
Historic Ceramic
Floor Tile: Repair and Replacement
Summary
Selected Reading
Some Sources for Replacement
Tiles
P.O. Box 358
Mt. Shasta, CA 96067
P.O. Box 373
Yardley, PA 19067
Head Office: Highgate Tile Works
Tunstall, Stoke-on-Trent
England ST6 4JX
U.S. Office: Johnson USA Inc.
P.O. Box 2335
Farmingdale, NJ 07727
237 Sheridan AvenueAlbany, NY 12210
geometric, mosaic and other traditional ceramic tiles.
Swamp Road
Doylestown, PA 18901
33 North Staebler Road, Suite 2
Ann Arbor, MI 48103
4230 Glencoe Avenue
Marina Del Rey, CA 90292
Stovax Ltd.
Falcon Road
Sowton Industrial Estate
Exeter, Devon
England EX2 7LF
10125 East Jefferson Avenue
Detroit, MI 48214
241 East Blackwell Street
Dover, NJ 07801
2840 East 11th Street
Los Angeles, CA 90023
3511 Interlake N.
Seattle, WA 98103
Helpful Organizations
Historic and Artistic Works (AIC)
1717 K Street, N.W., Suite 301
Washington, DC 20006
12061 Jefferson Boulevard
Culver City, CA 90030-6212
771 West End Avenue, 10E
New York, NY 10025
P.O. Box 1787
Clemson, SC 29633
P. O. Box 1850
Healdsburg, CA 95448
Acknowledgements
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. Technical Preservation Services (TPS), Heritage Preservation Services Division, National Park Service prepares standards, guidelines, and other educational materials on responsible historic preservation treatments for a broad public.
Last Modified: Sat, Mar 6 1999 04:15:12 pm EDT
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