Walls Foundations

7/30/2019 Walls Foundations

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WALLS ANDFOUNDATIONSOF HISTORIC

BUILDINGS


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Walls and above ground foundations are among the mostimportant character-defining elements of historic buildings. Thedesign of walls and foundations is influenced by the types ofmaterials used, the location, proportions and scale of openings fordoors and windows, massing and rhythm of features such as baysand porches, and details and ornamentation. The exterior wallsof most free-standing buildings are also structural, that is theycarry the weight o f the floors and roof to the foundation. Con-versely, the front and rear wal Is of rowhouses and other party-wallbuildings are usually not load bearing; rather the side walls carrythe weight of floors a nd roofs to foundations.Altering, repairingorreplacingprimarycharacterdefiningwalls and foundations - those facing major public streets orsidewalks-must be carefully considered so as not to detract froma buildings character. Changes to secondary non-character-defining walls and foundations (typically on the sides and rear ofbuildings) should also be carefully considered. Greate r flexibilityin selecting methods of construction and materials is possible forchanges to non-character-defining than for characterdefiningwalls and foundations.Above ground founda tion walls are often visually distin-guished from the main wall by a change of plane. For example,

brick and stone foundation walls are often visually sepera ted fromthe wall above by a belt cou rse of molded brick or shaped stone.In other cases, foundation walls are visually distinguished fromwalls by a change of material. The material used for an exposedfoundation wall, how it is finished and how it connects to thewallabove, are all distinguishing characteristics.Most historic buildings in Washington have a primary walland foundation which face a public street. Typically theysignificantly contribute to the character of the building. Theprimary wall usually contains the front entrance, is formallycomposed and uses high quality materials. Primary walls may

also contain elaborate ornamentation and intricate details. Sec-ondary, or side and rear walls that do not face a major publicstreet, are often less formally composed and may employ lesserquality materials as well as have less elaborate ornamentationthan the primary wall.

A belt coume is often used atthe junction between the walland above ground foundation.

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Types of Brick

Pressed

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Roman

Utility

lmbo

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BrickBrick is the most prevalent wall and foundation material inWashington. It isfound in awidevarietyofsizes, shapes, texturesand colors. The most common types of brick a re pressed,common, Roman, and utility. Modular and jumbo brick can alsobe found.Most of Washingtons historic brick was manufacturedusing iron or steel molds and local clay. However, some of theearliest buildings were made of hand-made brick formed in woodmolds. The molds used to manufacture brick give it its texture,shape and size. The type of clay and the temperature of the kilnduring firing gives brick its color and hardness . The manner inwhich headers and stretchers are used, how the rows are laid(called coursing) and the width, profile and color of the mortarjoints also contribute to the character of brick walls and founda-tions.Prior to the 187Os, most bricks were hand-made in woodmolds. Sometimes this brick was fairly porous requiring that it bepainted to protect it from the weather. Pressed brick, smootherand more regular in appearance than hand-made brick, wasintroduced in the 1870s and quickly became a popular buildingmaterial. Machine made common brick was also introducedaround this time.Bythe 1880smostkilnswerefueled bygas allowingmuchhigher temperatures to be achieved and a harder brick to beproduced. These bricks had the advantage of being non-porousand thus could usually be left unpainted. However, not all bricksproduced by gas-fired kilns were of the same hardness . Bricks

stacked in the center of the kiln were less exposed to the heat andthus softer (more porous) than those on the outside of the stack.The softer bricks were frequently used for party-walls or rearwalls, while the hard-fired brick from the outside of the kiln stackwas used for primary elevations.Local clay gives the majority of unglazed brick a red color,although brown and gray brick is also found. Glazed brick, whichis manufactured byaddingglazetothe finished brickand refiring,can be found in a wide range of colors.Walls and foundations are laid in different ways. Pressed

brick is laid in a running bond. Other types of brick are usuallylaid in common and Flemish bond. In addition to the coursing,the width, color and profile o f mortar joints con tribute signifi-cantly to the appearance of the wall. Mortar joints vary froml/8 to l/2 in width, a lthough other widths exist. Commonmortar joint profiles include struck, weather, and flush. O ther lesscommon profiles include raked, vee and concave. Mortar isnaturally a grey-white color, although some mortar used inhistoric brickwallsandfoundations isredorsomeothercolordueto the addition of coloring agents.


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Typical Brick Coursing

c StretcherRunning bond cons isting of all stretchers .

HeaderStretcher

Common bond conisting of five rows of stretchers and one row ofheaders.

_-Stretcher

Flemish bond consisting of alternating rows of stretchers and headers

I Types of Mortar JointsStruck

I Weathered

Flush

Raked

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Typical Stone Coursing

Broken Range

Rubble

ncoursed

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StoneStone is a wall and foundation material commonly foundin residential, commercial, institutional, government and someindustrial buildings. It may be used in combination with brick orother materials such as stucco or terra cotta.The type of stone used, how it is finished and laid, and thewidth, color and profile of the mortar joints all contribute to theappearance of a stone wall or above ground foundation. Stonecommonly used for walls and foundations include granite, lime-stone, sandstone and marble. Each comes in a variety of colorsranging from buff, gray, cream and white to pink, green, brownand yellow depend ing on where it was quarried. Some graniteand most marble have different colored veins or specks through-out.In addition to the type o f stone used, the appearance of astone wall or foundation also depends on how the surface isfinished and how it is cut and laid. The type of mortar joints usedalsocontributestotheappearanceofstonewallsandfoundations.Stone is traditionally finished using a variety of hand tools andmachines including saws, planes and chisels. A stones finishmay also be the result of grinding or rubbing the surface with anabrasive. Popular finishes include tooth chiseled, tooled, sawface and rock face. Stone may be hand or machinecut with squareedges giving it a geometric appearance (called ashlar) or withirregular edges (called rubble or field). Stone coursing may beregular, broken range, rough or uncoursed.

Types of Stone Finishes

Tooled

LSaw Face

Tooth Chiseled

Rock Face


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woodWood siding is most commonly found on free-standing

residential buildings although it can also be found on a fewhistoric rowhouses and commercial buildings. The latter wereprimarily built prior to 1870 before building codes, intended toreduce the spread of fire, were introduced in the city.

Many var ieties and shapes of historic wood clapboardsiding can be found including beveled, German, shiplap, V-rusticand simple-drop. In addition to clapboard, some wood walls aremade of wood shingles. Each type of siding gives a wall a uniquecharacter and is usually associated with a particular buildingperiod or style. In most cases, the corners of clapboard and woodshingle walls feature wood corner boards that seal the joints aswell as give character to the wall. Historically, wood siding waspainted for weather protection.Types of Wood Siding

weled

liplap

erman?I!rustic

hingle

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caststem wasa popularwallmaterial fhm the 1900s to 1940s.

Glass block and stucco are oftenused for Art Deco buildings.

Terra cotta is often used fordetails and ornamentation.

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Other Wall MaterialsAlthough not as prevalent as brick, stone and wood, caststone, stucco, glass block and terra cotta, a re also used for wallmaterial on historic buildings.

Cast StoneCast stone was popular from the 1900s to 1940s as aninexpensive substitute for stone. Made from concrete, theexposed face is finished to resemble rock face ashlar or otherstone finishes.

stuccoStucco is an inexpensive, non-structural, cement-basedmaterial used for walls in many historic districts. Historically,

stucco was applied in two or three coats to wood or masonrystructural walls. Finished in avarietyoftextures, itwassometimespatterned to resemble stone. Stucco can be colored by addingstonedusttothemixtureorbypaintingthesurfaceafter ithardens.

Appearing after 1930, glass block was a popular wallmaterial for Art Deco buildings, although examples can be foundin otherbuildingstyles. Usedaseitherawallor windowmaterial,glass block is found in a variety of textures and appearance .

Terra CottaTerra cotta is a glazed masonry product popular forfacades of commercial buildings built between the 1870s and1930s. It was also extensively used for details and ornamentationon apartment, institutional, government and other types of build-ings. Terra cotta may be natural brown-red in color (hence, itsname) or glazed in a wide range of colors.

Altering or Adding Detailsand OrnamentationMany historic buildings have elaborate wall details andornamentation. Sometimes the details and ornamentation are ofthe same material as the wall; other times they use differentmaterials. For example, terra cotta or stone details are somtimesused in brick walls. No matter what material is used, details and


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ornamentation are character-defining elements of walls andshould be maintained, repaired and, if necessary, replaced.Missingdetailsandornamentation should beduplicated based onphotograph ic or other documentary evidence.Adding new details or ornamentation to an existing pri-mary wall or above ground foundation wall is almost neverappropriate. Their addition will change the character of a wall,

giving a false sense of its historic appearance. On the other hand,it may be appropriate in some cases to add details or ornamenta-tion to a secondary, non-characterdefining wall. If this is done,the details and ornamentation should be compatible with thedesign o f the wall and building, but not seek to make it appearmore historic. Before deciding to add details or ornamentation toa wall the building owner should consult with the HistoricPreservation Division.

Altering Openings in WallsCreating a new open ing or enlarging an existing openingin a primary characterdefining wall for a window, door, through-wall air conditioning unit or other reason is almost never appro-priate. If a new opening must be created, for example to make abuilding functional, it should b e located on a rear, non-character-defining wall. The size, design and detailing of the new openingshould be compatible with the character of the wall.Similarly, it is almost never appropriate to close or cover-up an existing opening in a characterdefining wall. Closing orcovering-up openings in secondary wails may sometimes beappropriate if the material used is compatible with the wall.Before deciding to create a new opening or close or cover-up anexisting one, the building owner should consult with the HistoricPreservation Division.

Covering Non-original WallMaterialsSometimes the walls and above ground foundations of ahistoric building are covered with a non-original wall material.Usually it was installed directly over the historic material to hide

deterioration or to modernize the appearance of the building. Forexample, asbestos and asphalt shingles were used from the 1890sto the 1940s to cover wood walls. After World War II aluminumand vinyl siding were popular non-original wall covering materi-als. Similarly, stucco has been used since the nineteenth centuryto cover historic brick and stone walls. A patterned stucco calledpermastone was popular in the early twentieth century.The removal of a non-original wall covering should becarefully considered. In somecases, it may bedetermined to have

Existing details and ornamenta-tion that contribute to thecharacter of walls and aboveground foundations should notbe altered.

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1). A cavity walls interior andexterior surfacesare seperatedby an air space.

achieved significance in its own right and thus should be main-I tanned and repaired rather than removed. For example, stucco, installed in the nineteenth cen tury over an original brick wallusually should be retained rather than removed. If, however, thenon-original material is inappropriateto thecharacter of a historicbuilding, and is not considered significant, the building ownershould consider its removal. Owners may also consider remov-ing a non-original wall material since it may trap moisture insidethe wall, leading to deterioration of surface and structural ele-ments.

When considering removing existing, non-original wallmaterial, the owner should first investigate the technical issuesinvolved. Stucco, for example, often bonds tightly to brick andstone surfaces. Removing it will often damage the surface of theunderlying material. Removingasbestosshingles isoftendifficultdue to strict controls on handling and disposing of this material.Owners cons idering the removal of non-original wall coveringsshouldalsoexaminetheconditionoftheunderlyingwall materialbefore proceeding. It may have been badly deteriora ted prior toinstalling the covering or damaged during installation. Removingselectedsectionsofthecovering material will allowtheconditionof the original wall to be determined.

Covering primary walls with a new material is almostnever appropriate since it will alter the character of the wall andmay accelerate deterioration. However, it may be appropriate tocover a non-characte rdefining wall if it is done with a newmaterial that is compatible with the existing. If possible, theoriginal material should be left intact underthenew material. Thenew material should also be applied so that it does not contributeto the deterioration of the wall or its structural elements. Beforeremoving oraddinga non-original wall material, building ownersshould consult with the Historic Preservation Division.

Adding Insulation toWalls and FoundationsMost free-standing buildings lose only 20-30% of theirheated or cooled interior a ir through walls and foundations; themajority is lost through windows, doors and roofs. Rowhousesand other party-wall buildings have less exposed wall and foun-

dation surfaces than free-standing buildings. Thus even lessheated or cooled air is lost through walls and foundations. Beforeadding insulation to walls and foundations, a building ownershould consider insulating windows, doors and the roof.If the decision is made, however, to insulate the walls, itis important thatthe insulation material and method of installationdoes not create maintenance problems or harm the appearance ofthewall. Brickandstonecavitywallsareoften insulated by fillingthe cavity with foam.(l) However, since this alters the density of

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the wall, interstitia l condensation may occur.(2) If not properlyvented, the moisture may cause interior paint and wallpaper topeel, plaster to deteriorate or accelerate the deterioration ofmortar joints. Similarly, insulating wood walls with foam orblown-in insulation may cause interstitial condensation to rot thesil l plateorexteriorpainttopeel. Overtime,sometypesofblown-in insulation wil l settle to the bottom of the cavity, thus reducingits effectiveness.

Painting Brick and StoneA few historic walls are made of porous brick that was

painted to protect it from the weather. In most cases however,exterior brick was hard-fired and thus did not need to be painted.If a wall is made of porous brick which has always been painted,it should remain painted. Removing the paint wil l expose thebrick to the weather, accelerating its deterioration. If the brickwas never been painted, it should remain unpainted. Painting anunpainted brick wall may trap moisture inside the walls and willdrastically alter its character.

Most wall and above ground foundation materials requirelittle maintenance. However, all wil l eventually need somemaintenanceand possibly repair. In afewcases thematerials mayneed to be replaced. Rain, snow, hail, wind-borne grit andpollutants can affect all types of wall and foundation materials.Wood is also susceptible to damage from insects. In addition,vegetation, such as ivy, growing on walls and foundations wil laccelerate their deterioration.

Building owners should regularly inspect and maintainexisting walls and foundations. When deterioration is detected,theowner should consultwith an architect, engineerorcontractorknowledgeable in historicconstruction techniquesand materials.Consideration should first be given to repairing only those areasneeding attention, using in-kind materials; in other words, usingthe same types of materials as the existing. If deterioration isextensive, replacing the entire wall or foundation may be re-quired. If this is necessary, the owner should first investigate thefeasibility of replacing it in-kind. Only after in-kind replacementhas been shown not to be economically or technically feasible,should the owner consider replacing the wall or foundation in asubstitute material that is chemically and physically compatiblewith adjacent materials and is simi lar in appearance to theexisting material.

2). lntersti tual condensationoccurs in the cavi ty betweenthe exterior and interior wasurfaces.

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Spalling occurs when waterfreezes behind brick and stonesurfaces.

3). Cleavage planes are thelines along which the stonecleaves or breaks naturally.4). Rising damp is waterwicking-up through pores inbrick or stone.

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Spalling Brick and StoneBrick and stone are among the most maintenance free

materials used for historic buildings. However, they are subjectto deterioration. One of the most common problems, calledspalling, happens when water penetrates the surface throughpores or cracks. In cold weather the water w ill freeze and expandcausing the surface of stone or brick to spall or break-away. Overtime, the face of stone or brick can become deeply eroded.

Spalling may also be a result of the type of stone used inthe wall or foundation or a result of the stone being improperlylaid. For example, certain sandstone and limestone is very porousand thus susceptible to water penetration. In other cases, thestone may have been laid with its cleavage planes exposed,allowing water to penetrate the surface.(X) Spalling walls mayalso be the result of sandblasting or other inappropriate cleaningtechniques that remove the protective surface of stone or brick.Spalling stone or brick foundation walls also may be the result ofrising damp.(4)

Lightly spalled stone may be patched using appropriatecement-based materials. However, it is often difficult to matchthe color of the existing stone. Thus, over time, the patch maybecome moreevidentas itweathersdifferentlyfrom thestone. Analternative to patching light ly spalled stone is to apply an appro-priate stone consolidant. This will not cosmetically improve theappearance ofthestone, but itwill slow itsdeterioration. Heavilyspalled stone or spalled brick should be replaced in-kind.

Cleaning Brick and StoneBrick and stone walls may become disfigured through air-

borne grit or pollutants, or defaced with graffiti. Dirt andpollutants may, over time, contribute to spalling and other brickand stone surface deterioration problems. While unsightly,graffiti is normally not harmful to a wall material.

Cleaning brick or stone should begin with the gentlestmeans possible, proceeding in careful steps to more aggressivemethods until the dirt, pollutant or graffiti is removed. This isdone to protect the physical and visual integrity of the brick orstone. Aggressive cleaning methods, such as blasting with sand,grit, plast ic beans or other substances that erode surfaces causingfuture maintenance problems, should never be used.

Cleaning methods should be tested on a small inconspicu-ousareaofthewall todeterminetheireffectiveness. lfthegentlestmeans does not produce the desired results, the next mostaggressive means should be tested. The gentlest method to cleanbrick and stone is water washing with detergent using a hand-brush. If this proves not to be successful, the owner should try

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power washing with water or steam beginning at low pressure,graduallyincreasingthepressureuntil thedirt, pollutantorgraffitiis removed. The most aggressive appropria te method o f cleaningbrick or stone is chemical cleaning. Selecting an appropria techemical for the substance to be cleaned and for the wall materialis very important. Controlling run-off from chemical c leaning isalso an important consideration.

Sealing Brick atid StoneIn the past twenty years a number of masonry sealants havebeen developed to correct some surface deterioration problemsof brick and stone. In some cases, these problems were causedby sandblasting or other inappropriate methods of cleaning wallsand foundations. A building owner should carefully consider theeffectiveness and potential side effects of using a masonry sealantbeforeapplyingonetoawall. Somesealantswill discolorthewallmaterial, others will trap moisture inside the wall where it candamage interior finishes. Still others may be effective for only a

few years. Before proceeding to seal deteriorated brick or stonewalls or foundations, the building owner should consult with theHistoric Preservation Division.

Preventing Below-gradeWater PenetrationIn thenineteenthcentury, thebelow-gradeoutersurfaceofbrick and stone foundation walls were sealed with a cement-based coating. Foundations constructed in the twentieth centurywere usually sealed with a tar-based material. Both act as a water-proof membrane, keeping the crawl space or basement dry andpreventing rising damp. In addition, most historic free-standingbuildings had French drains madeof perforated clay tile. Installedat the the base of the foundation wall, they carry ground wateraway from the building.Over time, the water-proof membrane may have deterio-rated orthedra in tiles become clogged with soil or roots, allowingwater to penetrate into the basement. The most effective, andusually most expensive, method of repair is to replace themembrane or tiles. Another o ften effective corrective measure isto have an expanding cement-based compound injected into theground against the foundation wall.Historic brick and stone foundations are also subject torising damp. The pores in the masonry act as wicks, drawingground water up into the wall. If the base of the wall or top of theabove ground foundation wall is spalling, but other areas are not,the cause may be rising damp. installing a damp proof course atthe horizontal mortar joint between the foundation and wal,l is thebest solution to this problem.(s) However, since this involves

,ick and stone should becaned usinp. the eentlest meanpossible. - -

A French drain is used to channelground water away from founda-tions.

5). A damp proof course is awaterproof material insertedInto a horizontal mortar jointat the base of the wall.

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6). Weep holes are smallopenings in the mortar at thebase of a wall to allow intersti-tial condensa tion to drain tothe exterior.7). Repointing is also calledtuckpointing.

cutting the mortar joint, it should only be done after consultingwith the Historic Preservation Division.

Repointing Mortar JointsThe mortar used in brick and stone walls and foundationsisalsosubjecttodeterioration. Moisturecondensingbetween the

inside and outside layers of walls migrates to the outside throughthe mortar joints in the absence of weep bo les.(6) Over time thewater carries the mortar away. Deterioration of mortar joints infoundations may also be due to rising damp.When mortarjoints haveeroded l/2 or more behind theiroriginal surface, the building owner should consider repointingthe joints with new mortarJ7) The mortar used to repoint historicbrickandstonewallsshould bechemicallysimilartotheexisting.It is particularly important that modern high-streng th Portlandcement mortar not be used to repoint historic walls containinglow-strength cement mortar. Since modern mortar is harder than

most historic brick and some stone, moisture migration from theinteriortotheexteriorwill movethrough themasonryunitsratherthan the mortar joints. In cold weather this will cause spalling ofthe brick or stone.Old mortar should always be removed with hand tools.Saws and other power tools will chip the edges of brick and stone,disfiguring the wall or foundation. New mortar should be profiledin the same manner as the existing joints. It should also be thesame color as the existing mortar.

Repairing and RepaintingWood WallsAlmost all historic wood walls are painted to protect themfrom the weather which is lost when paint blisters, cracks, flakes,or peels. Loose paint should be removed by hand-sanding and thebare wood primed prior to repainting. To provide better adhesionbetween the new and old paint, the same type of paint toil orlatex) should be applied. Heavily encrusted paint that obscuresdetails and profiles should be stripped to the bare wood by handsanding or appropr iate chemical strippers before priming and

repainting. Power sanding, sandblasting, heat guns or othermethods likely to damage wood should not be used.Many wood walls constructed prior to 1960 were paintedwith lead-based paint. Before repainting historic wood walls, thebuildingownershould havesamplestested byareputable testinglaboratory. If lead-based paint is found, the owner should contacta paint removal contractor that is qualified to properly removeand dispose of lead-based paint.

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Selecting new paint colors is often a difficult decision.One method is to use historic colors, based on analyzing thevarious coats of paint on the building. Another, is to consultvarious books on appropriate colors for historic residential build-ings. Whichever method is chosen, paint colors should comple-ment each other, the colors of unpainted exterior materials, andthecolorsofneighboringbuildings. Typically, nomorethan threedifferent colors shou ld be used for the wall, trim an d details.Minorrotand insect infestation can be repaired byconsoli-dating the affected areas with epoxy or other appropriate woodconsolidants after proper drying an d treatment. If the damage ismore extensive, the affected areas should be replaced in-kind,usingthesameorsimilarspeciesofwood,finishandprofileastheexisting.

Maintaining and RepairingOther Wall and FoundationMaterials

Concrete and cast stone are subject to spalling and dete-riorating mortar joints. Stucco may craze, crack or becomedetached from the backing material.(8) Glass block may crack orthe sealant used between the units may deteriorate. Terra cottamay craze or its anchors may corrode.Minor spalling of concrete or cast stone can be repairedusing an appropriate patching concrete, colored and finished to

match theexisting. Deteriorated mortarjointsshould berepointed.Cracked glass block should be replaced with new matching glassblock. Deteriorated sealant should be replaced with an appropri-ate new sealant. Crazed or detached stucco can be repaired byapplying new stucco that is the same in composition, finish andcolor as the existing.There is no proven method or product available that willhalt the crazing of terra cotta. When the deterioration becomespronounced, the affected units should be removed and replacedwith new ones manufactured to duplicate the existing. On theother hand, if the terra cotta unit is loose due to corrosion of its

anchors, the unit should be removed, new stainless steel anchorsinstalled, and the original unit re-installed.

Substiie MaterialsWhile it is always best to repair or replace wall andfoundation materials in-kind, in some cases this will not betechnically or economically feasible. In these cases, a propertyowner may consider using a substitute material. When selecting

r

Careful ly sanding painted woodsurfaces wi l l expose histor icpaint colors.

8). Crazing is fine hairlinecracks in stucco and terracotta.

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a substitute material, particular attention should be paid to thenew materials expansion, contraction, weathering and chemicalproperties.

Materials expand and contract at different rates due totemperature change and sunlight falling on the wall or aboveground foundation. Installing a new material with very differentexpansion and contraction ratios may cause the joints betweenthe new and old materials to open. Materials also weatherdifferently, changing appearance over time. When a substitutematerial is considered for repair or replacement, its weatheringproperties should be similar to the existing so it does not becomevisually apparent.

The most common substitute materials proposed for his-toric wood walls are metal and vinyl siding, and stucco. Typi-cally, these materials are installed over existing surfaces so thatthe wood does not need to be repainted every seven to ten years.Covering existing wood siding may cause it and its appearance todeteriorate by trapping moisture behind the new surface. Install-ing metal or vinyl siding over existing wood siding will also alterthe depth of window and door surrounds, changing the structuralelements of the wall. Metal siding is almost never appropriatebecause its surface finish, profiles and reflectivity are not similarto wood. Certain types of viny l siding may be appropriate forsecondary elevations that are not visib le from a public street iftheir reflectivity, finish, size, profile and other visual characteris-tics simulate the existing wood and it is installed in a manner sothat the depth and character of window and door surroundsremains the same. Stucco may also be an appropriate substitutematerial for rear walls. Before selecting a substitute material, abuilding owner should consult with the Historic PreservationDivision.


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The following substitute materials may be suitable for replac-ing historic materials on characterdefining and non-charac-terdefiningwalls and foundations. Because character-defin-ing walls and above ground foundations are usual ly moreimportant to the overa ll appearance of a building than thoseon secondary elevations, the numberofacceptablesubstitutematerials is more limited. Before proceeding with a substi -tute material, the building owner should consult with theHistoric Preservation Division.Historic Material Substitute Material

Character-defining Walls and Foundations- Stone - GFRC (glass reinforcedepoxy concrete)- stucco -Acrylic polymer stucco*

Non-Character-defining Walls and Foundations-Stone - GFRC- stuccostucco- Wood

-Acrylic polymer stucco*-Vinyl siding- stucco

- Brick - stucco- Cast stone - stucco

Acryl ic polymer stucco is susceptible to impact damage and thus shouldnormal ly not be used below the second f loor.


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The District of Columbia Historic Preservation Guidelines weredeveloped under a grant from the Historic Preservation Division, Departmentof Consumer and Regulatory Affairs, Government of the District of Columbia.They were funded in part by a grant from the United States Department of theInterior, National Park Service. The United States Department of the Interiorprohibits discrimination on the basis of race, color, sex , national origin, orhandicap. If you believe that you have been discriminated against in anyprogram, activi tyorfacility in this program, or if you desire further informationpleasewriteto: Director,OfficeofEqual Opportunity, NationalCapital Region,National ParkService , U.S. Departmentofthelnterior, 1 OOOhio Drive,S .W.,Washington, D.C. 20242, (202) 619-7020. AN EQUAL OPPORTUNITYEMPLOYER t&/H.

Walls Foundations

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