Preserving Historic Ceramic Tile Floors

18 Pages·1996·1.9 MB·English

by  Grimmer, Anne, Konrad, Kimberly

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A PRESERVATION
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Preserving Historic Ceramic Tile Floors
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Anne E. Grimmer and Kimberly A. Konrad
PU3U IENTS
Dcp( ITEM
U.S. DepartmentoftheInterior
NationalParkService DEC 18 1996
CulturalResources
HeritagePreservationServices FEDERAL CLEMSON
PUBLICATION
LIBRARY
Witha tradition that dates to ancientcivilizations, ceramic*
tile flooring canbe found in avariety ofsettings indiverse
cultures and structures, including residential buildings
ranging from large apartmentbuildings to small private
houses, institutionalbuildings such as governmentoffices
and schools, and religiousbuildings such as cathedrals and
mosques. Historically, itswidespread use maybe—attributed
to the factthata readily available natural material clay
couldbeconverted by a relatively simple manufacturing
— —
process baking or firing into avery durable, long-lasting
and attractive floortile thatiseasy to maintain. Ceramic
floortiles exhibit a versatility ofcolored glazesand
decoration, and they range from the plainest terra cotta tiles
tohighly decorated individual ceramic tiles and elaborately
patterned tile floors. Theirmodularity, asstandardized
units, make themeasy to fitinto differentsized spaceswhich
alsoexplains much ofthe popularity ofceramic floor tiles
throughouthistory (Fig. 1).
This Briefbeginswith anoverview ofceramic tiles asa
traditional flooring material. Itincludes an explanation of
thevarious kinds ofhistoric floor tilesused in the United
States and how they were made. General guidance is given
onpreservationtreatments, focusing on maintenance, and,
when necessary, selective replacement ofdamaged floor
tiles. The Briefis intended to provide owners and managers
ofhistoricpropertieswith anunderstandingofthe
significance and historicalbackground ofceramicfloortiles,
and abasic awareness ofmaintenance techniques and
various deteriorationproblems to whichtile floors are
especially prone. In the case ofsignificanthistoricceramic
tile floors, a professional conservatorofceramics should be
consulted to advise in matters ofrepair, restorationor
conservation. Historically, ceramic tiles wereused onwalls*
aswainscotting, on fireplacehearths and fireplace
surrounds, and evenon furniture, as well as forflooring.
However, because floortiles are subjectto greaterdamage
and deterioration, they are the primaryemphasisofthis
F(ingouwreth1e.NMatiinotnoanlePnocratruasitticGatlilleefrlyo)o,r,W3arsdhiflnogotro,nP,atDe.nCt.OfOfriciegiBnuaillldying Brief. Highlightsinclude: a shorthistory ofceramic floor Q-
constructedbetween 1836-40underthesupervisionofRobertMills, the tiles; a descriptionofceramic tile types; a summary of i
upperfloorsofthisportionofthebuildingwererestoredandredecoratedin traditional installationmethods; maintenance techniques; o
1877in the "Modern Renaissancestyle"byCluss &Shulze,Architects, and guidance on repairand replacement. o
afteradisastrousfire. Photo:jackE. Boucher, HABS Collection.
I
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1
The Tile-Making Process two metal dies. Dust-pressingreplaced tile-makingby
hand withwetclay, and facilitated mechanizationofthe
Clay isanearthenmaterial, moldable or plastic when wet, tile-making industry. Throughoutthe restofthe 19th
non-plasticwhendry, and permanentlyhard whenbaked
century, dust-pressingenabled faster and cheaper
orfired. Itiswidely distributed geographicall—y, and often productionofbetter quality floortilesina greater range of
found mixed with sand insoilsofa loam type a mixture colors and designs. Inthe 1850sencaustic tileswere
osfurcflaacye, sdielptoasnitd,saalntdh.ouRgehl,atiinvseloympeucraesecsl,ayitimsanyotbuesueaxlploysead WseelsetcmtiednsftoerrsuinchLoinmdpoornt,aantndstQruuecteunreVsicatsotrihae'nseRwoyPaallace at
byerosion. Claytypesvarythroughouttheworld, and
Residenceonthe Isle ofWight. By the latterpartofthe 19th
evenwithina region. Each type ofclaypossesses aunique
century, despite the factthatencaustic tileswere still quite
combination ofspecial properties suchas plasticity, expensive, they hadbecome a common flooringmaterialin
hardnessand lightness, aswell ascolor and texture, which manykindsofbuildings.
makes some claysbettersuited foronekind ofceramicthan
another. The correctclaymixtureneeded foraparticular DevelopmentoftheTile Industry in America. Although
purpose canbe createdbyblending clays and addingother plain, undecorated ceramictileswere traditionally a
materials, butusingthewrongtypeofclay canresultin commonflooringmaterial inmany partsofthe Americas,
expensiveproductionproblems such as crazing (the especially inLatinand SouthAmerica, ceramicfloorand
formationoftiny cracks ina tile glaze) orwarpingofthe rooftileswereprobablynotmadeinthe NorthAmerican
tile itself. Traditionally, chalky clayshavebeenpreferred Coloniesuntil the late-16thorearly-17thcentury. Itwas,
formany kindsofceramictiles, inpartbecausethey however, intheVictorianera thatceramictile flooring first
produce, when fired, awhitebody whichis desirablefor became soprevalentintheUnitedStates. Theproduction
decorating. Othermaterials canbe added, includinggrog ofdecorative tilesinAmericabeganabout 1870 and
(orground-up fired clay)thathelps aerate the clay and flourished until about 1930.
preventswarping, speedsfiring and reduces shrinking, or Likesomany architectural fashions ofthe day, the
calcined flint, tohardenit. popularityofceramictile floorsinAmerica was greatly
Thereare severalmethodsused formakingceramictiles: influencedbythenoted architect and critic, Andrew
extrusion; compactionordust-pressing; cutting froma sheet JacksonDowning. Inhisbook TheArchitectureofCountry
ofclay; ormolded in a woodenormetal frame. Quarry Houses, published in 1850, Downing recommended
tiles areextruded, butmostceramicfloortiles, including encausticfloortiles forresidentialusebecause oftheir
traditional encaustic, geometricand ceramic "mosaic" tiles practicality, especially investibules and entrancehalls.
aremade from refined andblended ceramicpowdersusing
the compactionmethod, knownas dust-pressing. The 1876 Philadelphia CentennialExposition, with its
European and evena fewAmericanexhibits ofdecorative
Encaustictiles, whichweremadeby dust-pressing, are floortile, was a majorfactorinpopularizingceramictile
unique inthattheirdesigns areliterally "inlaid"into thetile floors intheU.S. Initially, mostceramic tiles—otherthan
body, ratherthansurface-applied. Once formed, tiles are purely utilitarianfloortiles—were imported from England,
dried slowly and evenly to avoid warpage, thenfired in a and theirrelativelyhigh costmeantthatonlywealthy
specialkiln thatcontrolshigh, evenheatat temperaturesup Americans could afford them. However, whenEnglish tile
to 1200°C (or approximately2500°F)for30-40hours. companiesrealized the potential forprofitableexport, they
Highertemperatures produce densertileswithharder soonestablished agents inmajorU.S. cities tohandle their
glazes. Mostceramictiles requireonlyone firingto achieve
lowporosity andbecomevitrified orglasslike, butsome,
especiallyhighlydecorated tiles, are fired more thanonce. /Amio... r>iM '<"\fi
Non-vitreous and semi-vitreous tiles are fired atlower
temperatures and aremuchmore porous.
"?""TH"||I
1
Historical Background n^s
Historically, theuseofceramicfloortilesgoesbacktothe
fourthmillenniumB.C. in the Near and FarEast. The
Romansintroduced tile-making inWesternEurope as they iimmrTTTi
a
occupied territories. However, thatartwaseventually
TTTTl
forgotten inEurope forcenturies until the 12thcentury
when Cistercianmonks developed a method ofmaking *********0*0F*4
encausticfloortileswith inlaid patterns for cathedral and XXXJ-JOXCQ
!
church floors. But, this skill was againlostinthe 16th
century followingtheReformation. Exceptforfinely
decorated wall tiles made inTurkey and the Middle East, ununimnnisi
and Delfttilesmade inHolland in the 17th century, ceramic
floortileswerenotmade againinEuropeuntil almostthe
mid-19th century. m
The moderntile industrywas advancedby HerbertMinton J
in 1843 whenhe revived the lostartofencaustic tile- I
makinginEngland. The industry was further Figure2. In the19thcentury,Minton tilesweresoldfrom thiscatalogue
revolutionized in the 1840sby the "dust-pressing" method toAmerican clients—includingtheArchitectoftheCapitol—byMiller&
whichconsisted ofcompressing nearly dry claybetween Coates,279PearlStreet, New York. Photo: DavidW. Look, AIA.
Americanbusiness (Fig. 2). The Englishnearmonopoly
actuallystimulated thegrowthoftheU.S. tileindustryinthe
1870sresultinginsharplydecreased Englishimportsby 1890.
The locationofpotteries and ceramic tile factories is
dependentupon the ready availability ofsuitableball clay
(clay thatballed orheld together), kaolin (a white clay used
as a fillerorextender), and feldspar (a crystalline mineral),
and an accessible market. Since the costofshipping the
manufactured products tended to restrictprofitable sales to
limited areas, thisusually determined whethera factory
would succeed. Although theUnited States Pottery in
Bennington, Vermont, is known tohave made encaustic
tiles asearly as 1853, the Pittsburgh EncausticTile
Company (latertheStar EncausticTilingCompany), was
the first successful Americantile company, and is generally
considered the first to manufacture ceramictilein the U.S.
ona commercialbasisbeginning in 1876.
Atleast25 ceramic tile companies were founded in the
United Statesbetween 1876 and 1894. In the East, several
notable tile firms thatwere established in thisperiod
flourished in theBostonarea, such as the Chelsea Keramic
ArtWorks, theLowArtTileWorks, and theGrueby
Faience Company. Other EastCoastcompanies organized
in the late-19th and early-20thcentury included the
International Tile & Trim Company, inBrooklyn, New
York; theTrentTile Company, Providential Tile Company, Figure3. (a) TheMoravian PotteryandTileWorks,aNationalHistoric
MuellerMosaicTile Company, and the Maywood Tile Landmarkin Doylestown,PA, wasdesignedin theSpanishMissionstyle
Company, all inNewJersey; and the MoravianPottery and a1n91d1c-o1n9s1t7r.ucTtieldesbyweHreenmraynCufhaacptmuarnedMperricmearriolvyerbyahpaernidodinofkeyeepairnsgfwriotmh
TileWorks inDoylestown, Pennsylvania (Fig. 3). Mercer'sArtsandCrafts ideals, (b)Mercer's tiles,seenherein the
Many factorieswere alsoestablished in the Midwest—in lmiobsrtaryi,mpwoerrteanutsecdomtmhirsosuigoh>oiustwhaisshtohuesfel,ooFronotfhtihlel.Pe(ncn-es)ylOvnaenioafMSetartceer's
Indiana, Michigan, and, especially, in Ohio. In the last Capitol in Harrisburg. (f) Thefactoryclosedin 1930afterMercer's
quarterofthe 19th century, the town ofZanesville, Ohio, death, butresumed tile-makingin 1974. Newtilesaredatedandmadein
wasthe largestcenterfor pottery and tile-making in the thetraditionalway. (a) Drawing:LeslieS. Claytor, BenitaC. Welch,
world. Some ofthe factories in Zanesville included: Ohio IsabelC. Yang, HAERCollection; (b)Photo:JackE. Boucher,HABS
Collection; (c-e)Photos:Courtesy,MercerMuseum, TheBucksCounty
EncausticTileCompany; MosaicTile Company; Zanesville Historical Society; Photo:AnneGrimmer.
(f)
Majolica Company; andJ.B. Owens Pottery, later tobecome
the Empire Floor and Wall Tile Company (Fig. 4). The
American EncausticTilingCompany, established in 1876,
wasone ofthe first, and mostsuccessful manufacturers in
Zanesville (Fig. 5). Intheearly 1930sitwas the largesttile
company in theworld, producing large quantities offloor
tile, plain and ornamental wall tile, and arttile until it
closed about 1935, as a resultofthe Depression. The United
States EncausticTile Company, Indianapolis, Indiana;
Rookwood Pottery, Cincinnati, Ohio; Cambridge ArtTile
Works, Covington, Kentucky; and Pewabic Pottery, Detroit,
Michigan, were some oftheotherwell-known potteries in
the Midwest.
Around the turnofthe century, the industrybeganto
expand as tilemakers moved Westand established potteries
there. Joseph Kirkham started the ceramictile industry on
Figure4. ThetiledPresidentialSealin thecourtyardofthePension theWestCoastin 1900whenhesetup the PacificArtTile
Building(nowtheNationalBuildingMuseum), Washington, D.C., was Company inTropico, California, afterhis company inOhio
installedin honorofPresident WilliamMcKinley'ssecondinauguration
in 1901. The"heavyDamaskdesign,"resemblingfabric, thatwas usedto was destroyed by fire. In 1904the companybecame the
decoratethetiles, indicates theywereprobablymanufacturedbyThe WesternArtTile Company, surviving forfiveyearsuntil it
MosaicTileCompany, Zanesville, Ohio, whichfirstintroducedthis wentoutofbusiness in 1909. Duringtheearly-20th
design. Photo:KimberlyA. Konrad. century, othercompanieswere foundedinSouthern
California, inand around LosAngeles (Fig. 6). Batchelder
& Brown, inparticular, ofPasadena (laterBatchelder-
WilsoninLos Angeles), waswell-known forits Arts and
Crafts-style tiles in theteens and 1920s. By theearly 1940s
Californiahadbecome oneofthe leadingproducers oftile,
especially faience, intheU.S. (Fig. 7)
.
Ceramicengineers, potters and artists notonly moved
frequentlyfrom one pottery to another, butoftenstruckout
ontheirown and established new factories when
dissatisfied with a formeremployer. Also, itwas not
uncommonforonecompanyto reuse a defunct factoryor
purchase anotherpotterybusiness, change the name and
increasetheproductline. As a result, manyofthe
companies inexistencetoday are descendants oftheearly
pioneering firms.
Changes intheTile Industry. Themajority ofceramicfloor
tilemadeintheU.S.before 1890wasencaustic, butvarious
Figure5. GeometrictilesmadebytheAmerican EncausticTiling factoriesgraduallybegantodevelop and produceother
PCeonmspiaonnyB,uaillsdoinign Zinan1e8sv8i8l,les,evwerearleyienasrtsalalfetderinthtehebuciolrdriindgo'rsscoofmptlheetion. kindsoftiles. TheTrentTileCompany, amongothers,
Photo:KimberlyA. Konrad. started tomanufacturebothwhiteand colored ceramic
mosaictilesby themid-1890s (Fig. 8). White vitreouswall
tilebecameavailable, aswell as moredecorativetileswith
colored glazes, such asthevariegated faience glazes
intendedtogiveamorehand-crafted appearancethatwere
originatedby theGruebyFaience andTileCompanyin 1894,
andsoonadoptedby otherpotteries (Fig. 9).
Inthe 19thandearly-20th century, many ceramic tile firms
had theirownengraving departments, while someused
commercial designs suppliedby professional printers.
Well-knowndesigners were often commissioned towork
on specificproduct lines for a particular firm. These
designersworked forone firm afteranotherwhich resulted
in similardesignsbeingproduced by different companies.
(Historicceramicfloortileswere usually identified bya
manufacturer's ordesigner'smark on theback, iftheywere
marked atall.) By the latterpartofthe 19thcenturyready-
mixed glazes and colors were also available. Thiswas a
greatadvantage forpotterswho, priorto this, had to mix
theirown colors and glazes.
Figure6. TheLosAngeles Union PassengerTerminalfeaturesceramic During the 20th century, the floortileindustry continued to
tilefloorsin theArtDeco-style. Photo:HABSCollection. evolve as much as ithad in the previous century. Modern
,
Figure7. "Scotty'sCastle"in Death Valley, California, wasbuiltovera
10-yearperiod, beginningin 1922. Manyoftherooms, thesalon (a),as
wellas thekitchen (b),havetilefloors. Somearecomposedofboth local,
California-madetiles,andSpanish tiles. Photos:JackE. Boucher,HABS
Collection.
Figure8. TheTrentTileCompanyadvertisedits "CeramicMosaic
Floor"tiles in the1906editionof"Sweet's"IndexedCatalogueof —
BuildingConstruction. Photo:Sharon C. Park,AIA.
hFreiilggihuelrfiedgeh9st.igpBnl,eaigsniunccnehirnaasgmitichniwstahclellalstasitileec.-a1l9Pethghogtcoea:nntKduirdmyab,retarlmdoyetciAof.r,aKwtoianvsreafodrf.iteezneawdidtehdato .tJUTmmmmmmmdmm MyTifcuwi |m^|mmmmtJ^Tm*.. "If
methods ofproductionemployed sophisticated machinery, forbathrooms, and evenkitchens (Fig. 12). Quarry tile,
new materials and decoratingtechniques. Intheyears which was largerand thickerthan other ceramic floor tile of
followingWorld WarII, there weremany advances in the tfhoirsepnetrriaondc,ewhaalslso,fstmenalulssetdudiinesp,ublliibrcabriueisl,didnignsi,ngasrwoeolmlsaasnd
industry. Commerciallymanufactured dust-pressed tiles,
which had previously required more than 70hoursjust in evenlivingroomsinprivatehomes. But, by the 1930s, the
the kiln, couldbe made inless thantwohours from the raw fashionfor arttile had diminished to the pointwhere floor
material stage to finished tiles, boxed and ready to ship. tiles were, forthe mostpart, generally regarded as
primarilyutilitarian, as opposed to important decorative
Dried, unglazed tiles were sprayed withcolored glaze
elements.
evenly and automatically as conveyors carried the tilesinto
the tunnel kilns, and theextrusionprocessensured thatthe
Ceramic Floor Tile Types
tileswere cutto auniform thickness and size. The changes
and developmentsintheproduction offloortilebrought The thickness ofhistoricceramic floortiles varied
forthawide range ofshapes and sizes, alongwithnew considerably accordingto their intended use and when they
colors, glazes and decorating techniques. weremade. Floortileswere thickerand harderthanwall or
Afterthe turnofthe century, fewerencausticfloortiles ceilingtiles. Stove tiles, meantto retain theheatofthe
wereused, particularly in residential architecture. The stove, were sometimes asmuchas several inches thick.
introductionofceramicmosaic floor tileswas afactorin Medieval floortiles wereusually one inchthick; encaustic
their decline (Fig. 10). The developmentofrubber tilesoftheVictorianera tended tobeslightly thinner.
interlocking floor tilesin 1894, alongwithother, more Modern, 20th-century tiles, withthe exception ofsome art
resilient, flooringmaterials, was instrumental inthe pottery tiles, are thethinnest, asa resultofmodern
decreased popularitynotonly ofencaustictiles, butalso
other ceramic tile flooring. These new materialswere not
only cheaper, theywerenotas fragile; theywere also lighter
and thinner, and easier to install.
Ceramic mosaic tiles remained incommonuse through the
1930s in partbecause aninnovative developmenthad made
laying such small tileseasier. Thetileswerepre-mounted
in decorative patterns on 12" x 12" sheets ofpaper, and sold
ready to lay in cement. This greatly simplified the tile
setter's work, and no doubtwas a significant factorin the
increased popularity ofceramic mosaictiles. Sophisticated
mosaicfloordesignsbecame common inentrance foyersof
public and privatebuildings (Fig. 11). Small, white,
unglazed tiles in round, square, octagonal orhexagonal
shapes were promoted for theirsanitary qualities,
particularly forbathroom floors, while larger, rectangular,
Figure10. Ceramicmosaictilefloorswerepracticalforstructureslikethis
white, glazed tiles were used forbathroom wallsor BathHouse,HotSprings,Arkansas (1914-1915). Photo:JackE. Boucher,
wainscotting. Colored tileswere also popular, especially HABS Collection.
manufacturingmethods. Thebacks ofmost, butnotall,
ceramic floortiles are covered with raised (orsometimes
recessed)ridges, circles orsquares which help to increase
thebondingcapability ofthe tile.
Unglazed and Glazed Tiles
Ceramicfloor tiles can generallybe divided intotwo types:
unglazed and glazed. Unglazed tiles include: quarry tiles;
encausticand geometric tiles; and ceramicmosaic tiles,
whichcanbeeitherglazed orunglazed. Mostotherceramic
floor tiles are glazed.
Unglazed Tiles
ggBJg^Bgi^S
Quarrytiles are the mostbasictypeofhistoric ceramicfloor fFaiznai
tile (Fig. 13). Originally madefrom quarried stone, they are
machine-madeusing theextrusionprocess. Quarry tiles are
unglazed, semi-vitreousorvitreous, and essentially are
square orrectangularslabsofclaybaked ina kiln. The Figure11. Ceramicmosaictileswereuseddecorativelyon theentrance
colors ofquarry tiles arenatural earthenshadesofgray, red floorofthisearly-20thcenturyschoolbuilding. Photo: KimberlyA.
Konrad.
andbrown determinedby the clay and, to someextent, the
temperature and durationoffiring. Quarrytiles, which eliminatethepossibilityofstainingthebody ofthe tilewith
range from 1/4" to 1/2" in thickness, are availableinsquare othercolorsand permitted theuseofmore colorsona
and rectangularshapesinsizes thatinclude3", 4-1/4", 6" singletile. Thus, anencaustic tilecan sometimesbe dated
(one ofthe mostcommonsizes), 9" and 12" squares; 6" x 12", accordingto the complexity and the numberofcolors inits
6" x9", 4-1/4" x9", 3" x6", and3" x 9" rectangles; and4" x 8" pattern. Red tileswithwhite figurativepatterns were
hexagonshapes. (Pavers orpavertiles are a simpler, and generally theearliest, followedbybrown andbuffcolored
tend tobe somewhatcruder, versionofquarrytiles. Like tiles. Inthe 1860s, bluetileswith yellow orbuffpatterns
quarry tiles, they are usually unglazed, butslightly thicker. were popular, succeededbymore subtle colorschemes
Machine-made paversareeithersemi-vitreousorvitreous, featuringa "chocolate" red with a softgrey. By 1860, up to
and generally formedby dust-pressing, although six colors wereused in a single tile to form a pattern.
sometimes areextruded. Hand-made paverswhich are Toward theend ofthe century, whiteencaustictileswith a
common in Mexico and southernEurope arenon-vitreous.) blackorgold designwere common, aswell as tileswith
— complicated colorpatternsofwhite, black, gold, pink, green
Encaustict—ilesareatypeoftraditionalunglazed yet and blue. Encaustic tileswere decorated withtraditional as
decorative floortile, manufacturedbythedust-pressed well asoriginal designs. Some, particularly intricate,
method. Whereasmostceramictilesaresurface-decorated designs were painted onthe surface ofthetilewith opaque
ordecoratedwithimpressed orembossed designs created
colored glazes, instead ofbeinginlaid (Fig. 15). Mostmajor
byamold, encaustictilesareuniqueinthattheirdecorative tilemanufacturers sold many ofthe same pre-formed
designsarenotonthe surface,butareinlaid patterns created
encaustic floor tilepatterns through catalogues. Encaustic
aspartofthemanufacturingprocess. First, a thin, tileswere produced in a variety ofsizes, mostly squareor
approximately 1/4" layeroffine, almostpowder-dry, clay octagonal inshape, and almost any designcouldbe custom-
wwhaiscphrefsosremdedinatodaepmroelssdiwointihnathreelfiaefcedeofsitghneattilet.heAbosetctoonmd, Hmiasdtoerifco,r1a9stphe-ccieanltupruyrpeoncsaeusotritcotfiiltesawpearrteicguelnaerraslpalcyes.lightly
thickerlayerofcoarserclay waslaidoverthefirstlayer, then less than 1" thick, about 15/16." Cheaper tiles oflesser
coveredwithanotherlayeroffine clay. This "sandwich" qualitywere also made ofclay orcement. These designs
helped preventwarpingandensured thatthebodyofthe
tilewasstrong andhad a fine, smoothsurface. Thelayersof
clay "dust" werecompactedbypresses, afterwhich the
mold wasinverted and thedie removed, thus producing a
tilewithanindented orintaglio patternontop. Afterthetile
dried, colored slip (liquid whiteclay colored with dyes), was
poured to fill intheintaglio pattern. Eachcolorhad to dry
before anothercolorofslip wasadded. Therecessed area
wasoverfilled to allow forshrinkage, and afterdryingfor
severaldays, andbefore firing, theexcessslipwas scraped
offthesurfaceby a rotating cutterthatcreated a flat,
althoughnotcompletely smooth, face. Problemsmightarise
duringthe firing. Duetothe dissimilarratesofcontraction
ofthe differentclays, the inlaid clay could shrinktoo much
and fall outofthetile recesses;or, thetile couldbestained
by thedifferentpigmentsused forthedesignifimpureor
unstable (Fig. 14).
Bythe 1840s, encaustictiles weremadeentirelywith almost- Figure12. Thesecolorful(yellow,blackandwhite),andboldlypatterned
dryclayusingthe dust-pressed method. Thisserved to ArtDeco-styleceramictilesweremadeinFrance. ErnestHemingway's
wife, Pauline,broughtthem backto the U.S. in the1930sandhadthem
installedinabathroom in theirhousein KeyWest,Florida. Photo:
Susan Escherich.
trapezoidal shapes. Both vitreous and semi-vitreous
mosaictiles were available, unglazed insolid orvariegated
colors with a matte finish, orglazed in unlimited colors.
Single, one-piecetiles were also fabricated to give the
appearance ofmultiple mosaicpieces. This was achieved
with a mold, which gave the appearance ofrecessed
mortarjointsseparatingindividual "mosaics" (Fig. 18).
Glazed Tiles
With theexceptionofquarry tiles, encaustic tiles, and
some mosaic tiles, mostceramic floortiles aredecorated
with a glaze. While unglazed tiles derive their color solely
from the clay, or from oxides, dyesorpigments added to
the clay, the colorofglazed tilesisprovidedby the glaze,
either shiny ormatte. Somepotteries specialized incertain
Figure13. Quarrytileswereusedin thecorridorson manyoftheupper kindsofglazes and were famous for them. Theearliest
fwleororesloaifdthienaU.pSa.ttDeerpnairdtemnteinctaloftothteheInmtoerrieorexBpueinlsdiivnegm(a1r9b3l5e-f1l9o3o6r).tilTehsey and most common method ofclay tiledecorationmade use
thatwereusedin thepublicspaces. Photo: BrooksPhotographers,HABS oftin-glazeswhich wereessentially transparentlead
Collection. glazes. Tiles wereeither dipped into the glaze orthe glaze
wasbrushed on the tile surface. Glazeswere generally
resembled those commonly found onencaustic tilesbut madewithwhite lead, flint, or china claysground up and
applied as a transferprinted pattern, orusing a multi-color mixed with finelyground metallic oxides thatprovided
lithographicorsilkscreenprocess. These arestill manu- the color. Colored glazeswere commonly knownas
factured and popularinmanypartsofthe world (Fig. 16). "enamels". Colorsincludedblue derived from cobalt,
green from copper, purple from manganese, yellow from
Swmhaellnera,ssseimngbllee-dcotloogreetdhevrerfsoironmsaogfeeonmceatursitcicpatitlteesrtnh,ata,re antimony and lead, and reds and browns from iron. An
called geometric tiles inEngland. However, inthe United opaque glaze was createdby addingtinoxide.
States they are generallynot differentiated fromencaustic
tiles. Based onthe geometric segments ofa six-inch square, Laying Ceramic Tile Floors
they were typically rectangular, square, triangularor
hexagonal in shape, and aboutthe same thickness as 19th CenturyTechniques. Aside fromtheuseof
patterned encaustictiles (Fig. 17). Geometric tileswere improved tools and modernmaterials, installation
especially well suited fordecorativeborders, and a wide methodshave changed little since the mid-19th century.
vsahraipeetsy,osfizfelsooarnddescoilgonrss—coueiltdhebreaclroenaeteodrwciotmhbtihneeidrmwaitnhy Mce.ntDuirgybyenWcyaautstti,catnilearmcahnituefcatcftourroernseionfBtrhietamianj,oMra1w9th&
patterned encaustic tiles. The costofproducinggeometric Co., described this procedure forlayingencaustic and
tiles was much lessthanofencaustictilesbecauseeach tile geometrictiles in 1857:
involved only one type ofclay and one color. Bytheend of First, either anevenlayerofbricks, a2-1/2"bed of
the 19thcentury, over60 differentshapes and sizes of concreteofquicklime and gravel, ora mixtureofPortland
geometric tiles were available inup to tencolors, including cementand cleansharp sand was laid toprepare a solid
buff, beigeortan, salmon, lightgrey, darkgrey, red, foundationforthetiles. Ifthe tileswere tobe laid over an
chocolate, blue, white andblack. existingwooden floor, the floorboardshad tobepulled
Ceramic mosaic tiles are essentially smallerversionsof up, sawnintoshortlengths and fittedbetweenthejoists.
geometric tiles (usuallynolarger than2-1/4", and no Concrete filled inthe spaces and made thebase flushwith
thickerthan 1/4")ranging in size from 1/2" to2 3/16", in theupperfaceofthejoists, and created a levAel surface
square, rectangularoroblong, hexagonal, pentagonal and finished within 1" ofthe finished floorline. layerof
Figure14. Makingencaustictiles. Whenfinished,areproductionencaustictileresemblesahistorictile,butthereproductionprocessisquitedifferentfromthe
traditionalmethod. Designsforreproduction tilesarerecreatedbyacomputerfromdrawingsoftheoriginaltile, (a)Thecomputerimageofthedesign istransferred
to,andmachine-cutinto,aPlasterofParismold. Plastic,buff-coloredclayispressedintothemoldtoformthemainbodyofthetile,andlefttodryfor24hours, (b)
Coloredslip,orliquidclay, ispouredintotheindentedportionsofthetiletocreatethepattern. (Eachcolorofslipmustdrybeforeanothercolorcanbepoured.) (c)
Afterdrying,andbeforefiring,excessslipisscrapedoff, leavingthesurfaceofthetilesmooth,buttheslip-filledareasstillslightlyrecessed, (d)Asideviewofthe
19th-centurytileatthetopofthephotographclearlyshows the3-layerclay "sandwich,"aswellasthe2colorsofslipthatform theinlaiddesign. Thenewtile,below,
isslightlythinnerandismadefromonly1 layerofclay. Photos:(a-b)H&RJohnsonTilesLtd.;(c-d)WayneFirth, OfficeoftheArchitectoftheCapitol.
Figure15. Thedetailedfeaturesoftheportraiton thisroundtilein the Figure16. Historiccementfloortilesinahouseat103 CalleSanJose, Old
U.S. Capitolwerepaintedon thesurfaceofthetileratherthan inlaid. SanJuan, PuertoRico,featureadesign intendedtoresemblewoodparquet.
Photo:DavidW. Look,AIA. (Notethemismatchedrepair.)Photo:JackE. Boucher,HABSCollection.
cementmortarwasthen laid on top. This allowed the tiles A newly-laid tile floorcould notbewalked on for4-6days
to fitin the same amountofspace as the floorboards they until the cementhardened properly. Occasional washing
replaced.* would remove the saline scum thatoften appeared onthe
Before laying the tiles, skirtingboardsorshoemoldings surface rightafterthe tileswere laid.
were tobe removed, and replaced after thetiles were laid. 20th CenturyTechniques. Almost50years later, in 1904,
Thiseliminated havingto cutthe outer tiles to fitexactly, theTileManufacturers ofthe United States ofAmerica
and resulted in a neaterappearance. published Suggestionsfor Setting Tilewiththeintentof
Next, thefloordesignwasmarked offwithmason's string bringing tile-layingup to a uniformstandard. This
orchalklines which divided the space into equal quadrants. guidancewasvery similarto thatgivenbyWyatt. But,
The firstsectiontobe laid outwas definedby two parallel there were some differences, such as usinghollow clay tile
strips ofwood, orguide pieces, about4" wide. A level as a foundationmaterial and heavy tarpaperwhenlaying
thicknessofcementwas spreadbetween thesestrips. The tile overawoodenfloorto protectthe floorboards from the
tiles, thoroughly soaked inwater, werelaid in the cement moisture ofthe mortarmix. Emphasiswas placed onusing
and leveled witha straight-edge. The foundationhad tobe thebestquality cement, sand, and purestwaterto obtain a
keptwetwhilethe tileswerebeinglaid. Small stripsof durable tile floor. Soakingthetilesbefore settingwasno
wood temporarily placed atrightangles tothe guide pieces longernecessary, butusing stiffermortarwas suggested to
helped keep elaboratepatterns straight. preventit from risingupbetweenthe tiles.
Wcehmeenntthmeorbteadrw—assohmaertdi,mtehsecjoolinotrsedwewriethfilllaemdpwibltahckp,urreed T2i0lteh-lcaeynitnugrym,emtohsotdlsycdhuaengtoedthseoamveaiwlhabaitlimtyoroefnlaetwermiantetrhieals
ochre orothernatural pigments—mixed tothe consistency and techniques. By the 1920s small ceramicmosaictiles
ofcream. Excess mortarwaswiped offthe tileswith a weremanufactured as 12" square sheetsheld togetherby a
piece offlannel or sponge. face-mounted paper "skin." Thismade itpossible to lay the
12" squareoftiles as a unit ratherthaneach ofthe small tiles
individually. Mountingthe tiles directly in the cement
resulted ina very strongbond. Butthe face-mounted paper
t*Thheemtbreatdwietieonnatlheprjaoicsttisc,esotifllsauwsiendgtothdeayortiogimnaailnftlaoionrabolaorwdsfiannidshfeidtftilnogor obscured the tiles fromview makingitdifficultforthe tile-
profile,hasresultedin numerouscracked tilesandotherfailures. Instead, setter tosee ifthetiles werebeinglaid straight. The fact
abetterapproach is toleavetheexistingfloorboards, iftheyareingood thatthe paperwas notremoved until afterthe tiles were
shape,andinstallacementitiousbackerboard(CBU)availablein firmly setin the cementbond coat furthercomplicated
thicknessesrangingfrom 1/4"to5/8"as thesettingbedforthetiles.
fi **
hi r r"Ti r"t*i r'fi
Figure17. Shownherearetypicalgeometrictilepatternspopularin the Figure18. One-piecetilesweremadewithamoldthatcreatedthe
late-19th century,asillustratedinDecorativeTileDesigns in Full appearanceofmortarjointsandindividualmosaics,as illustratedin
Color. SelectedandarrangedbyCarolBelangerGrafton. NY:Dover DecorativeTileDesigns inFullColor. Selectedandarrangedby
Publications, Inc., 1992,pp. 73,83. Carol BelangerGrafton. NY:DoverPublications,Inc., 1992,p. 87.