report 1 2018 opti.pdfgrand teton national park task 1 report: stucco assessment john moulton...

John Moulton HomesteadGrand Teton National Park

Moose, WY

Compiled by:

The Architectural Conservation LaboratorySchool of DesignUniversity of Pennsylvania

Prepared for:

National Park Service/USDIFunding from:National Park Service/CESU Project Number: P17AC01226

TASK 1 REPORT

Conditions Assessment, Materials Characterization and Initial Treatment Recommendations for Exterior Stucco on the John Moulton Homestead

June 2018

Grand Teton National ParkTask 1 Report: Stucco Assessment

John Moulton Homestead

Conditions Assessment 1.0Introduction....................................... 2.0 Historic Background........................... 3.0 Methodology..................................... 4.0 Preliminary Assessment 5.0 Digital Analyses.................................. 6.0 Summary Of Findings......................... 7.0Recommendations.............................

Appendices I.ConditionsGlossary.............................. II.LaboratoryTestingResults................... III. Samples Index.....................................

Drawings RectifiedPhotoElevations ConditionsDrawings SampleLocations

TABLE OF CONTENTS

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1

1.0 INTRODUCTION

The John Moulton homestead, located in

Grand Teton National Park, is one of six

building complexes that constitute the

historic district, which was inscribed on the

National Register of Historic Places in 1997.1

Commonly known as “the Pink House,” the

Moulton homestead stands out among the

many vernacular log structures in the park

for its principle character-defining feature:

a pink-painted cement stucco exterior. The

original stucco skin and its finish date to the

construction of the building in 1938 and

together with the interior; the house may well

be the most intact historic residence within

the Mormon Row Historic District (Figure 1.1).

Given its high historical integrity, the current

condition of the exterior stucco is cause

for concern as it appears to be exhibiting

cracking, loss at the foundation, displacement,

and detachmentof the whole system from

the wooden sheathing underneath (Figure

1.2). To date, there has been no substantial

investigation into the overall condition of

the building or its painted cement stucco

skin. In order to better consider the many

possible causes of failure, this study explores

the use of non-destructive digital tools as a

method to investigate the extent, patterns,

and correlation of stucco failure to associated

intrinsic and extrinsic factors. First, the

stucco and its attachment system will be 1 No single structure on the row is individually designated at the present.

analyzed through the findings of a field-

based condition survey and a compositional

analysis of the stucco; this research mirrors

that of a traditional conditions assessment

and materials characterization methodology.

The study then considers the use of three

different digital techniques to analyze the

spatial distribution of data, which builds

upon the information collected during the

conditions assessment. These tools provide

complementary information that ultimately

renders a more thorough assessment,

while minimizing the use of invasive

physical techniques that conflict with good

preservation practice.

The principle goal for the Moulton property

is to determine the cause of the cracking in

the exterior stucco, as well as the extent of

post construction detachment. Geographic

information system (GIS) software, infrared

radiation thermography (IRT), and Structure

from Motion (SfM) photogrammetry are

tools which have the potential to supplement

more traditional modes of documentation

by furthering spatial understandings and

three dimensional characteristics that are

difficult to calculate or record by hand.

Patterns based on the comparison of the

resulting graphics suggest that unseen or

misunderstood conditions could be more

extensive than what is observed in the field



2

Figure 1.1 The John Moulton homestead, also popularly known as the Pink House. (Photo by author, 2017)

Figure 1.2 Primary deterioration concerns at the John Moulton homestead center on the evident cracking and loss of the exterior stucco. (Photos by author, 2017)



3

or can be communicated through typical

conditionsdrawings.Eachofthesetechniques

providesadifferentanduniqueapproachof

enhancingthetypicalmethodsofcondition

survey.Thegoalofthisstudyistoseeifthe

findingsfromthesemethodscanenhance

visiblephenomena.Thesuccessofthis

experimenthingesonthedegreetowhich

thesetechniquescanclarifytheevidenceof

deteriorationconditionsbeyondtraditional

documentation,ultimatelyrenderingthe

analysis more robust.

TheNationalParkServicecontactedthe

ArchitecturalConservationLaboratory(ACL)

attheUniversityofPennsylvaniato1)analyze

theconditionoftheexteriorstuccoatthe

Moulton homestead and 2) examine the

mechanismsofdeterioration.Whilethisstudy

beginstosatisfysomeoftheserequirements,

afullconditionassessmentandtreatment

recommendationsareforthcoming.While

focused primarily on the discussion of modern

digitaltechniquesofsurvey,anadditional

outcomeofthisstudyistheproductionof

baselineconditiondocumentationconsisting

ofaseriesofannotateddrawingsand

stuccocharacterizationandanalysis.Inthe

conclusions,futurefieldandlabresearchis

discussedaswellasotherfactorsaffecting

thelongevityofthebuilding,includinga

prioritizedlistofstabilizationinterventions.



4

2.0 HISTORIC BACKGROUND

The John Moulton homestead is one of

fourstructuresintheMormonRowHistoric

District;distinctforitshighdegreeofintegrity

includingintactinteriorfinishesrepresenting

theentireoccupationperiod.Whilethe

significanceoftheexterioristiedalmost

exclusivelytoitsunusualcementstucco

finish.Thischoicefortheexterior,common

for the period in many urban and suburban

contexts is unusual in this rural Mormon

communitywhereitschoiceexpressedthe

meager success of a late homesteading

family,particularlyintheJacksonHoleValley,

whereanymodicumofsuccessforfarmers

wasuncommon.Themolderingruinsof

neighboringdwellingsthatoncesurrounded

thishouseredoubleitssignificancethroughits

rarity.

2.1 Historic Context

TheJacksonHoleValley,locatedinnorthwest

Wyoming,waspartofthelateperiodof

frontierhomesteadingoftheWesternUnited

States.Sinceitssettlementinthe1890s,the

major industry in the area has been tourism.

Whilerichinnaturalbeauty,theTetonareais

resourcepoorintermsofmineralsandviable

land for agriculture. By the beginning of the

twentiethcentury,JacksonHolehadasmall

populationwhoattemptedtohomestead

andcultivatefederallandgrants.Thiswas

thecaseofJohnMoulton,whomigratedto

theburgeoningMormonRowcommunity

justnorthofJacksonin1908(Figure 2.1,

2.2).JohnMoulton,alongwithhisbrother

Thomas Alma and other emigres from Idaho

and Utah, claimed land grants to the north

ofBlacktailButte,whichhadafortuitous

combinationofdeep,well-drainedsoilswith

access to seasonal streams and shelter from

theprevailingwinds(Figure 2.3). The Mormon

Rowinhabitantsweretheprimarylocal

agriculturalresourceandthereforecritical

to the early Jackson Hole economy and they

providedfreshdairyproductsforthelocal

community and dude ranches alike. 2, 3

2.2 The John Moulton Homestead and

Vernacular Style in Jackson Hole

MostofthestructuresinJacksonHolereflect

theavailablenaturalresourcesintheregion.

Thelocalvernacularbuildingstyleutilized

lodgepolepine,atallandstraightgrowing

pine, sourced from Timbered Island at the foot

oftheTetonsandShadowMountaintothe

northeastofMormonRow.Indeed,manyof

thefirststructuresbuiltbyhomesteaderswere

12x12logcabinstosatisfytherequirements

oftheHomesteadingActof1862.Thelog2 AnnHubberandJaneneCaywood,“GrandTetonNationalParkMultiplePropertySubmission;NationalRegisterofHistoricPlacesMultiplePropertyDocumentationForm”(UnitedStatesDepartmentoftheInteriorNationalParkService,June1991),53.3RobertW.Righter,Crucible for Conservation: The Creation of Grand Teton National Park (Colorado Associ- atedUniversityPress,1982),64.



5

Grand Teton National Park

Wyoming

Montana

ColoradoUtah

Jackson

89

2689

191

26287

191287

5 Miles5 Kilometers

JENNYLAKE

LEIGHLAKE

TaggartLake

PhelpsLake

BradleyLake

StringLake

Grand Teton13,770 ft

Kelly

NATIONALELK REFUGE

TE

TO

N

R

AN

GE

Two Ocean

Snak

e Rive

r

Snak

e Ri

ver

Gros Ventre

River

Gros Ventre River

TetonVillage

Colter BayVillage

SouthJenny Lake

Moose

Moran

JACK

SON

LA

KE

Emma Matilda

GRAND TETO N

NATIO NAL

PARK

1950

Airport

Buffalo Fork River

MORMON ROW

Source: NPS

Figure 2.1 The Moulton homestead and Mormon Row are located within Grand Teton National Park, north of Jackson, Wyoming.

Figure 2.2 Contextual perspective illustration of the Mormon Row Historic District, which shows the extant structures on the row. (Historic American Building Survey, WY-152-A).



6

cabinwastheprimaryarchitecturaltypein

thearea,likelybecausehardwareandtools

requiredforframeconstructionhadtobe

transportedbytraintowesternIdahoand

drivenovertheTetonPass.4Thefirstnoted

instanceofframeconstructionisanaddition

toBillMenor’sstorein1900,whichindicates

thatmilledwoodwasavailableinthevalley

as early as the turn of the century.5 Frame

structuresweremorecommoninthe1910s

duetotheavailabilityoflumberproduced

atlocalcommercialsawmills,although

transportingotherbuildingmaterialsvia

4 TheOregonShortLine(UnionPacific)reachedasfarasRexburg,Idaho,by1899.ThelinewasextendedtoVictorin1912,atown25milesfromJacksonviatheTeton Pass.5JohnDaugherty,“LifeontheHomestead,”inA Place Called Jackson Hole: The Historic Resource Study of Grand Teton National Park,First(Moose,Wyo.:GrandTetonNationalPark,NationalParkService,1999),127.

theTetonPassRoadwasstillconsidered

treacherousuntiltheroadwaswidenedin

1932.6Untilthatpoint,hardwareandbuilding

materialscouldbepurchasedfrommercantile

stores in Jackson at a higher cost.7

Aftercultivatingtheirplotsofland,itwas

generallyacceptedthatthecabinsinitially

builtbyhomesteaderstosatisfythe

HomesteadingActwouldbereplacedwith

morefinishedandrefinedstructuresgiven

timeandresources.AfewoftheMoultons’

neighborsquicklyupgradedtheirhomesinthe

1910s;evenhisbrotherbuiltaframestructure

in1915.John,bycontrast,waitednearly

6JohnDaugherty,“TheTransportationFrontier,”inA Place Called Jackson Hole,193.7JohnDaugherty,“ThePioneers:HomesteadinginJacksonHole,1884-1900,”inA Place Called Jackson Hole,93.

Figure 2.3 View of the historic district, looking southwest. The Mormon Row community was situated on the Jackson Hole valley floor on the leeward side of Black Tail Butte (left). Traces of the Moulton homestead’s pink finish is visible through the aspen screen on the left. (Photo by author, 2017)



7

thirty years to construct his second home.

Aftermoderatesuccessfortheirfarmand

dairyinthe1920sand1930s,theJ.Moultons

hadtheresourcestobuildatwo-storyframe

housestuccoedwithcementin1938.The

housewasoneoftwostuccoedstructureson

MormonRow,andthefirststructureonthe

rowconstructedbyaprofessionalbuilder.8

The John Moulton homestead exterior is

decoratedwithapink-tintedcementpaintand

theraisedfoundationhasadecorative‘water

table’,inwhichthestuccohasbeenscoredto

represent stone and painted a darker purple

todistinguishitfromtherestoftheelevation.

Thewoodenwindowframeswereoriginally

painted a dark green, and the rest of the

woodenelementswerepaintedwhite.The

whimsicalstyleofthehousemayderivefrom

traditionsofdomesticstylinginthewestern

Mormonculturalsphere,whichfavored

durable and highly processed materials to

connoteexpressionofhumanpowerand

refinement.9HearsayamongtheNPSstaffand

JacksoncommunityplacesintentionwithJohn

Moultonhimself,whopurportedlyelectedto

paintthehousepinkbecauseitwashiswife’s

favoritecolor.Inall,thenewvibranthouse

wouldhavestoodoutdramaticallyonthe

valleyflooramongstthelogcabinsandnearby

frame structures alike.

8AnnHubberandJaneneCaywood,“NationalRegisterofHistoricPlacesMultiplePropertyDocumentationForm,”49.9ThomasCarter,“FrontierFashion:DomesticArchitectureandIndividualDisplay,”inBuilding Zion: The Material World of Mormon Settlement(Universityof Minnesota Press, 2015), 102.

2.3 Preservation Philosophy

OftheseveralhomesteadsinMormonRow

communityduringthe1910sand1920s,

onlysixfamiliesremainedontherowinto

thenextgeneration.10 Although Jackson and

itssurroundingcommunitieshadflourished

duringwartimeastheresultofhigherprices

foragriculturalgoods,thefollowingdecade

broughtdrought,fallingbeefprices,andtwo

devastatingfloods.Homesteadersinthevalley

could barely subsist on the meager products

oftheirland;11duringthe1930s,several

familiessoldtheirlandtotheSnakeRiverLand

Company (SRLC).12In1943,themajorityof

thevalleyfloorsurroundingMormonRowwas

incorporatedintotheJacksonHoleNational

Monument;theseareaswereconsolidated

intotheexpandedGrandTetonNationalPark

in1950.Moreover,whilethosefewfamilies

succeeded in maintaining their residency,

mostofthemsoldtheirlandtotheGrand

TetonNationalParkafter1950underleases

to lessen the economic strain of agricultural

lifeinthevalley.JohnMoultonsoldhislandto

theparkin195313afterreachinganagreement

10AnnHubberandJaneneCaywood,“NationalRegisterofHistoricPlacesMultiplePropertyDocumenta-tionForm,”53-54.11MaxwellStruthersBurt,“HomesteadandDesertClaims,”inThe Diary of a Dude-Wrangler(NewYork,:C.Scribner’ssons,1924),124-125.12 Local business people and the state legislature pressured the SRLC to put a moratorium on purchasing landfromtheMormonRowin1930,asitwastheonlyviableagricultureinthevalley.Followingthehardshipsofthelate1920s,anumberofsettlerswrotetothegovernorofWyomingtoappealthedecision.Bylate1930,theMormonRowareawasreinstatedintheSRLCpurchasing program.13CandyVyveyMoulton,Legacy of the Tetons,2ndrev.



8

Figure 2.4 A comparison of photographs from the early 1960s to the present confirms that the John Moulton homestead still has high integrity. The historic photo also shows how the visible the structure would have been during the period of significance when the aspens in the front yard were much smaller. (Source: Best of the Tetons, https://www.bestofthetetons.com/2014/04/08/the-moulton-barns-1963-1965/)

1965 2017

withtheparktoleasebackthelandforthe

restofhislifetime.Johnresidedinthehouse

foranotherfortyyearswithhelpfromfamily

members to maintain the structure. 14,15After

John’sdeathin1991,theMoultonfamily

relinquishedthepropertytotheNationalPark

Service.

The Moulton homestead is the most intact of

anyexistinghistoriccomplexontheMormon

Row.Lifetenantcaretakerstypicallyhad

littleinterestinmodernizingtheirstructures

becausetheyknewthattheirproperties

ed.(Cheyenne:LaFronteraPub.,2007),92.14 AnnHubberandJaneneCaywood,“NationalRegisterofHistoricPlacesMultiplePropertyDocumentationForm,”54.15CandyVyveyMoulton,Legacy of the Tetons,94.

wouldnotbeinheritedbysucceedingheirs,

so most structures remained in their historic

condition.16 Caretakers typically let their

property fall into disrepair in the later years

oftenancy.Bycontrast,thesubstantial

amount of intact historic fabric at the John

Moulton homestead complex indicates that

theMoultonsfastidiouslymaintainedthe

house(Figure2.4).In1997,MormonRowwas

inscribedontheNationalRegisterofHistoric

Places. The NationalParkServicehassince

mothballedthestructure;nomaintenance

16M.Curran,“MormonRowHistoricDistrict,GrandTetonNationalPark;NationalParkServiceCulturalLandscapesInventory”(NationalParkService,DepartmentoftheInterior,2006),https://www.nps.gov/grte/learn/historyculture/upload/Mormon-Row-CLI.pdf, 17.



9

hasbeencompletedsince1991aside

fromboardinguptheaccessiblewindows.

VolunteerprojectsinpartnershipwiththeNPS

haveaddressedmaintenanceofthegrounds

and outlying structures, but not the main

house.17

In summary, the singularity of the structure

derivesfromanumberofconcurrentsources.

First,itsflamboyantarchitecturalstyleand

useofcommercialconstructionmaterials

represent a rare instance of successful

homesteadingintheJacksonHoleValley

wheretheconceptof‘provingup’cameto

fruition.Itspersistingintegrityredoubles

itssignificance,particularlyagainstthe

backdropofthenearlyemptyMormonRow.

If the ruined state of the historic district is

anyindication,thisisthepivotalmoment

forNPSculturalresourcemanagerstostep

17https://www.bestofthetetons.com/2014/08/13/preservation-begins-on-the-john-moulton-homestead/.

inandproactivelyinvestinpreservingthe

original fabric of the structure. According

to the Secretary of Interior’s Standards,

“Preservationisdefinedastheactofapplying

measuresnecessarytosustaintheexisting

form, integrity, and materials of an historic

property.”18 This approach is the most

appropriate for this property since it maintains

ahighdegreeofphysicalintegrity.While

concise, this brief history demonstrates that

thestuccoiskeytoconveyingthestructure’s

significance.Whatremainsatissueisthe

physicalconditionofthestucco,andits

abilitytomaintainintegrityasadecorative

andprotectivefinishontheJohnMoulton

homestead.Thenextsectionwilldiscussthe

resultsoffieldinvestigationandlaboratory

analysisofthestuccoinordertoverify,orcall

intoquestion,theconditionofthestucco.

18AnneE.Grimmer,The Secretary of the Interior’s Standards for the Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring and Reconstructing Historic Buildings(Washington:U.S.DepartmentoftheInterior,2017),2,https://www.nps.gov/tps/standards/treatment-guidelines-2017.pdf.



10

3.0 METHODOLOGY

Aconditionsassessmenttypicallyconsistsof

abriefsiteandstructuralsurvey,followedby

systematicdocumentationandassessment

ofthephysicalconditionoftheresource

basedonaccepteddefinitionsofconditions

and their pathologies. Photography, graphic

conditionsdocumentation,andtechnical

geophysical and structural reports are used

tosupplementtheseevidencesandbolster

conclusions. Historical research is pursued to

confirm,orchallenge,aswellassupplement

interpretationofthesite’spresentcondition.

3.1 Field Survey

Aconditionsurveywasconductedoverthe

course of three days, from October 20 to

October 22, 2017. Once on site, the team

conductedabriefpreliminarysurveyofthe

sitetoidentifytheprimarydeterioration

conditionsandstrategizehowtobest

document them in spite of a number of

disadvantagesinthefield.19 Assessment

wascarriedoutfromthegroundaroundthe

structure.Theinteriorofthebuildingwasnot

accessibleduringthefieldsurvey.

Uponinvestigation,theteamidentifiedthat

theprimarydeteriorationconditionaffecting

the cement stucco is cracking. Secondary

conditions,includingbiologicalgrowthand

discoloredordeterioratingfinishes,were19 These are discussed further in a succeeding limitationssection.

presentonthesurfaceofthestuccobutwere

veryinfrequent.Somenotehasbeenmade

oftheseonelevationdrawingsaspartofthe

conditionsassessment.

a.Limitations

Fieldsurveywaslimitedbyanumberof

factorsthatrelatetounexpectedpractical

difficultiesinthefield.Weatherconditions,

includingfreezingrain,snow,andgustywind,

madethefieldassessmentprocesslessthan

ideal.Allobservationsweremadefromgrade

becausescaffoldingandladderswerenot

practicalinthegivenweatherconditions

(Figure 3.1).Conditionsofthestuccoitself

madeassessmentdifficult.Thestuccowas

toothicktoreliablyidentifyvoidsthrough

ataptest.Finally,thesurveyconsistedof

tworesearcherscompletingtheassessment

overthecourseofthreedays.Thenumberof

limitationsforcedtheresearcherstoprioritize

recordingofprimaryconditionsinthefield,

andtakeotherformsofdocumentationthat

couldsubsequentlybeanalyzeduponreturn

totheUniversityofPennsylvania.

The high integrity of the stucco also acted

asahindranceforfieldinvestigation.While

conditionslikecracking,discoloration,

andpaintlossarevisibleandcanbeeasily

recordedusingtraditionalmeans,other

conditionssuchasblinddetachmentand



11

corrosionofthemetalreinforcementswould

nothavebeenpossibletothoroughlyrecord

withoutsignificantinterventions.Duetohigh

integrity of both the stucco and the interior

finishes,forexample,itwasnotpossibleto

blindly probe or expose the underside of the

stuccoinordertoexaminetheattachments

or detect detachment from the underlying

sheathing.

b.ConditionDrawings

Independentdrawingswerecreatedtodepict

theextentofconditionsforeachelevation.

Forthisfieldproject,fieldconditiondrawings

servetwopurposes.Theyallowforbetter

synthesisofinformationinsubsequent

analysesaswellasprovidingabaselinefor

futureconservation.FortheJohnMoulton

homestead,itisparticularlypertinentto

diminishorremoveunnecessaryvisual

informationthatstandoutinphotography—

suchaslargecracks,andthevariationin

surfacetextureandcolor—inordertobetter

understandthespatialrelationshipand

patternofconditions.

Duetotheenvironmentalfactors,initial

conditionsdrawingsweremadeoffsiteusing

rectifiedelevationphotostodrawvisible

cracks.20Thesedrawingswerethentaken

intothefieldtobeconfirmedandannotated

basedonvisualfieldinspection(Figure 3.2).

20BasedonarchitecturalelevationlinedrawingbasefilescreatedbyA&EArchitectsofMissoula,MT.

Figure 3.1 Access to the upper part of the south, west and north elevations was limited due to poor conditions. A ladder was used to collect samples and make close range observations. (Photo by author, 2017)



12

Alongeachcrack,orportionsoflinesegments,

a‘size’notewasaddedtocharacterizethe

approximatewidthofthediscontinuity

(Figure 3.3). The team members agreed upon

general categories to depict size, ranging

fromextra-smalltoextra-largeorabnormal;

thisinformationisincludedintheconditions

glossary;seeAppendix I. The extent of loss

wastracedandhatched.Displacement,or

areaswhereeithersideofthecrackarenot

onalevelplain,werealsonoted.Secondary

conditionswerealsonoted,whichare

detailedinageneralglossarywithphotosand

definitionsasacompaniontothedrawings.

Theseinclude:

• Discolorationandstainingoftheplaster,

duetomoistureoranimalactivity.

• Biologicalgrowth,includingmossesand

lichen, on the stucco surface.

• Lossofpaintedfinish,howeverthedegree

towhichthishadprogressedwasunique

toeachelevation,rangingfrommost

deterioratedonthesouthelevationto

intactontheeastelevation.

Tocreatethefinaldigitizedconditions

drawings,thefield-annotatedarchitectural

elevationswerescannedandthenewdigital

fileswerere-rectified.Thesefileswerethen

attachedtotheexistinglinedrawingfiles

usingAutoCAD.Polylineswerethentraced

overthefield-corroboratedcracks,each

assignedtodifferentlayersaccordingtothe

sizeannotationaccompanyingthecrack

segment.Afinalsetofdrawingsareincluded

in Appendix II.

c. Photography

Photoswereusefulprimarilytoillustrate

theconditionsobservedinthefield.In

architecturalconservation,photographycan

support the analyses and hypotheses that are

madebytheconservatorbutalsocanenhance

otherkindsofdocumentationinthisreport,

aswellasbeusedasabaselinefromwhichto

judgedeteriorationinthefuture.

Aseriesofphotographsweretakenduring

fieldsurveytodocumenttheconditionsof

the structure and site. The purpose of these

photographscanbebroadlysortedintofive

categories:

• Architecturalsurveyphotographs:These

photographscaptureelevationsandthe

relationshipsbetweenthem,aswellasthe

detailsofthesitecontextthatcanaffect

thepreservationofastructure.

• Conditionsphotography:Detailphotos

thatexhibitavarietyofdifferent

conditionsforthepurposesofbuildinga

visualglossary;seeAppendix I.

• Infraredradiationthermography(IRT)

photos:ThermalimagestakenwithaFLIR

C2CompactCameraofeachelevation,

aswellasclose-uppartialphotosto

bestitchedtogetherlatertoimprove

resolution.

• Photogrammetry:Thisprocesswhichrelies

onaseriesofoverlappingphotographs

whicharesubsequentlyalignedand

convertedtoadensepointcloudin



13

Figure 3.2 Preliminary conditions drawings were confirmed in the field; all observations were made from grade. (Photo by C. Magill, 2017)

Figure 3.3 Cracks were confirmed and then annotated according to size, extra small to ex-tra large; those which were not evident in photos were traced onto elevations in the field.



14

post-processing to capture the three

dimensionalshapeoftheelevationsin

order to detect detachment of the stucco.

3.2 Survey Results

Basedonthesurvey,theprimarydeterioration

conditionsaffectingthestuccoinclude

cracking, loss, displacement, and detachment

ofthesystemfromthewoodensheathing

underneath;secondaryconditions,suchas

discolorationandlossofthepaint,were

infrequentanddeterminedtobesuperficial

andnotcontributingtorisk.Basedon

preliminarydiagnosticsandresearch,the

cracksfallbroadlyintotwocategories.First

arecrackswithdiscerniblelikelycauses,

whicharetypicaltofailureofcementitious

materialsordevelopinresponsetoinstallation

orstructuralmovements.Othercracks,like

theseriesoffinecracksinanorthogonal

patternonthewestandsouthelevations,

arelikelytheresultoferrorsininstallation

(Figure 3.4).Adramaticcrackonthesouth

elevationindicatesthatthestuccosystem

isdetachingfromthewoodensheathing

beneath,buttheextentofthisconditionis

not apparent. Loss has occurred at the base

ofthestructure,wherethetensilestrengthof

thestuccohasbeensurpassed.Whetherthe

causesoftheseconditionsarestatic,dynamic,

orworseningcanbesurmisedatthistime

based on complementary analyses, but must

beconfirmedinthefieldwithmonitoring

protocols.

Theresultofthesurveyisasetofdrawings

withtheextentofconditionsdrawnandkeyed

photographsthatindicatetheseverityof

deteriorationphenomena.Thesearetypical

documentationforarchitecturalconservation,

and can be easily read by a resource manager

or professional. They are useful in that they

arecomparable:thisdrawingsetprovides

baselinedocumentationagainstwhich

succeeding assessments can be compared

todetermineiftheconditionisworsening

orstatic.Butaspreviouslysuggested,these

drawingsbythemselvesdonotindicatethe

extentofunseenconditions,suchasblindor

incipient detachment.



15

Figure 3.4 Fine orthogonal cracks evident on the south elevation are likely the result of differnetial thermal expansion of the metal reinforcements. (Photo by author, 2017)



16

4.0 PRELIMINARY ASSESSMENT

Thisfollowingsectionisanassessmentof

eachofthepossiblecontributingpathologies

affectingthestuccoandthestructure,

synthesizingtogetherevidencesfromfield

investigations,historicproductliterature,

andlaboratoryanalyses.Theinformation

gainedfromlaboratorytestingisrelevantas

itcancontributetothedocumentationand

conditionassessmentofanyconservation

reportaswellasinformaboutthematerial,

bothasitwasoriginallyappliedandasitisin

its present state. In this instance, analyzing the

stuccocansubstantiateordismisstheinitial

pathologyhypothesesthatcallsintoquestion

theconditionofthecementmatrixandthe

embedded ferrous metal reinforcement.

SeveralNPSemployeesandconservation

professionals,eachofwhomhaveaunique

andintimateknowledgeofthestructure,were

askedforinitialopinionsabouttheprimary

factorscontributingtothedeteriorationof

the stucco.21Theinstallationandassemblyof

thestuccoiscalledintoquestionbytwoof

the hypotheses put forth. Other phenomena

includethemechanismsoffailurethataffect

thecementmaterial,metalattachment

21 Respondents included Shannon Denison (formerly NPSGRTE),BetsyEngles(formerlyNPSGRTE),JeffOlsen(formerlyNPSGRTE),JimMcDonald(A&EArchitects),MattMorgan(A&EArchitects),MichaelHenry(PE,AIA;UPenn, lecturer), and Frank Matero (UPenn, professor of architecture).

system, frame structure, and site. Figure 4.1

liststhesehypotheses,alongwithtestsor

methodsrequiredtoconfirmthemasprimary

contributorstodeterioration.

Literatureresearch,fieldsurvey,conditions

graphics, and laboratory material analysis can

substantiateordismissthemajorityofthese

theories,andadditionalmonitoringmaybe

abletoconfirmtheresults.Thesemethods,

however,cannotfullyestablishtheareaof

detachment,deformation,andweathering

damage—theextentofwhicharecriticalto

determineinordertoestimateriskoffailure.

Probing or exposing the interface of the

stuccoandframecouldbegintoconfirmthese

conditions,butduetothehighintegrityof

thestructure,itisimperativetousemethods

that minimize damage to the historic fabric

asmuchaspossible.Othernon-destructive

methods,includingultrasonictestingand

laserscanning,couldpotentiallybenefitthe

surveysinthefuture;however,thesearenot

currentlyavailabletotheACLandcanbecost

prohibitive.

4.1 Comparison to Contemporary Product

Literature

AsidefromaNationalRegisternominationand

documentationfromtheHistoricAmerican

BuildingSurvey,norelevantresourceswere

foundwhichdiscussthebuildingoftheJohn



17

StructuralFoundation

Hypothesis Evidence(s) MethodofConfirmation

Relic roots on the east side of the structure had undermined the foundation.

Diagonal cracking, detachment

Historic research

Rodents undermining thefoundation.


Observation,monitoring

Unevensettlementofthefoundation.


Research, monitoring

Attachment

Meshisbuttedratherthanoverlapping.

Rectilinearcracking Survey

Undersized nails usedtoattachmetalreinforcement.

Detachment Survey

Differentialthermalexpansionbetweenmetal reinforcement andcementand/orwoodframe.

RectilinearcrackingResearch on material properties

Differentialexpansionoffurring strips.

Rectilinearcracking Survey,literatureresearch

Corrosion of metal reinforcement.

Cracking, lossSampleexamination,fieldconfirmation

Cement

Damage due to exposure;thermalcycling, hygric cycling, freeze-thawcycling.

Cracking,particularlyonthesouthandwestelevations.

Laboratory analysis

Environment Earthquakedamage. Diagonal cracking Literature research

Figure 4.1 Theories of deterioration collected from site managers and knowledgeable preservation professionals.



18

Moultonhomesteadindetailoritscondition

whenitenteredintothecareoftheNational

ParkService.Contemporarysourcesthat

discusstheinstallationofexteriorcement

stuccoareessentialinthiscase,asthey

canhelptoelucidateerrorsinapplication

orinstallationthatmaybecontributing

tothedeteriorationofthestucco.Several

theoriesinthisveinhadbeenputforward

byprofessionalsaspotentialcontributorsin

Figure 4.1,andthesewillbereferredtoin

thissection.Thefollowingsectioncompares

theobservationsofthestuccoassemblyat

theMoultonhomesteadtothatwhichwas

prescribed in the literature of the period.

Descriptionsandillustrationsregardingthe

systemofconstructionarebasedoncommon

constructiondetailsforframestructures,with

somedetailsaddedbasedonobservations

fromthefield.

Inthefirsthalfofthetwentiethcentury,

hydrauliccementswereconsideredtheonly

material acceptable for exterior plastering due

totheirdurability,appearance,andeffective

waterproofing.Industriallyproducedartificial

cementwasincreasinglyaccessibleinthelate

nineteenthandearlytwentiethcenturiesdue

tothedevelopmentofthecontinentalrail

networkandexpandingdomesticproduction

intheUnitedStates.Bythe1920s,Jackson

Holewasstillrelativelyisolated.Goods,like

the cement used on the Moulton homestead,

werecarriedviarailroadanddrivenoverthe

Teton Pass to Jackson to be sold at one of the

generalstoresintown.Contemporarycraft

treatises22 and product literature explained

thetechniques,tools,andmaterialsnecessary

toapplycementstuccoandanticipate

potentialpitfalls.

a.SystemExamination

Despitetherelativedifficultyinprocuring

building materials in rural Jackson Hole, the

reinforcement substrates and stucco at the

John Moulton homestead appears to meet

recommendedspecificationsintheliterature,

withonecriticalexception.Contemporary

PortlandCementAssociationliterature

describestheidealinstallationofstuccoon

aframestructureas,inorderofassembly:

woodensheathingnailedtowallstuds;a

moisturebarrierattachedtothesheathing

surface;wovenwirelathreinforcementpanels

attachedtothesheathingoroffsetfrom

the surface by furring nails (Figure 4.2). This

providesthesubstratereinforcementforthe

cement stucco to be applied in a three-coat

system.Asevidencedbytheareaoflosson

thesouthelevation,thestructurehasdiagonal

woodsheathingtosupportthestuccosystem

(Figure 4.3)withatarpapervaporbarrier

attachedtothesheathing(Figure 4.4).

Furringnailswereplacedatadistancefrom

oneanothertoavoidcracking,althoughthe

patternisdifficulttodiscernfromthissmall

22WhetherornottheMoultonswouldhavehadaccesstotheseresourcesisnotknown,butthesearedocumentscontainclarifyingdetailswhicharesometimesabsentfromproductliterature,includinghelpfultechniquestoimprovethedurabilityandworkabilityofexteriorstucco.



19

Figure 4.2 Section detail, based on product literature and observations at the site; this system provides a suitable substrate reinforcement for the stucco to be applied. (Drawn by author, 2018)

VaporBarrier

WireLath

FurringDevice

DiagonalWoodenSheathing

2”WallStud

FinishCoat/Pigmented Finish

BrownCoat

Scratch CoatNail



20

areaofobservation;seeFigure 4.3.23 Furring

devicesatthehomesteadmatchadevice

advertisedinaPortlandCementAssociation

manualfrom1929,whichsuccessfullyoffset

thenailheadsandwirereinforcement1/4in.

fromthesurfaceofthesheathingallowingthe

cement to thoroughly coat and protect the

ferrous metal from corrosion (Figure 4.5).24

Whilethenailswerenotmeasured,aphoto

taken from behind an area of displacement

witharigidborescopeshowsthatthenails

weremostlikely13⁄8in.inlengththat

matches the length of nails recommended

intheproductliterature,disprovingthatthe

nailsmaybeundersizedandcontributingto

detachment of the system.

Thepotentialflawinconstructionisnotthe

attachmentofthemetalreinforcementtothe

sheathing,butrathertheinstallationofthe

mesh.Basedonfieldobservation,itappears

thatthewovenferrouswirelathpanelswere

notoverlappedtherecommended1in.but

buttedtogether,perhapsinanattemptto

economize the materials (Figure 4.6). To form

arigidsurfaceonwhichtheplastercancure,

thereinforcementshouldhavebeenlappedat

least1in.attheedgestoformacontinuous

networkacrosstheentiresurface.Metallic

lathswereoftensecuredattheedgesofthe

sheetstothejoists,whetherwithwire,fixing

23Nailswerepreferabletofurringstripsthatcancauseareasofweaknessinthestucco,resultingincracking.24AfurringdevicewaspresentinasamplesentbytheNPSstafftoPhiladelphia.Thestuccohadalreadybeendetachedfromthesouthelevation.

nails,orstaples;theextenttowhichthiswas

doneisunknown,butitmaynotbesufficient

to secure the panels together. Therefore, the

meshpanelsmayactasindependentfields

that expand and contract under thermal

conditionsratherthanactingasacontinuous

surface, likely the cause of at least some, or

possiblyall,ofthefineorthogonalcrackson

thesouthandwestelevations.

4.2 Materials Characterization

a.TestSelectionandSamplingMethodology

For the purposes of this project, laboratory

testingandanalysisisconfinedto:

• Opticalmicroscopy(petrographic

examinationandcrosssectionalanalysis)

tocharacterizetheweatheredcondition

ofthecementmatrixandpossiblyidentify

the source of the aggregate in the stucco.

• Porositycharacterizationtoestablish

theavailableporespaceinavolumeof

material.

• Mechanicaltestingtodeterminethe

abilityofthestuccotoresistbrittlefailure

through three-point bending.

• Testingtodeterminethepresenceand

relativeamountofsalts(nitrates,sulfates,

and chlorides) in a sample.

Samplelocationswerechosentoensureat

leastonerepresentativesamplefromeach

elevation.Tominimizethevisualimpactof

missingmaterial,samplesweretakenlargely

from the base of the structure near areas that



21

Figure 4.4 Evidence of the underlying vapor barrier, visible through a crack on the south eevation. (Photo by author, 2017)

Figure 4.3 Section detail, based on product literature and observations at the site; this system provides a suitable substrate reinforcement for the stucco to be applied. Hap-hazard holes from the furring nails indicate that the lath was not attached using furring strips. (Photo by author, 2017)

FURRING NAIL HOLES



22

Figure 4.5 Image from 1929 PCA literature exhibiting acceptable furring devices as well as nail sizes for furring out lath. The device indicated matches that found at the Moulton homestead. (from “Plasterer’s Manual for Applying Portland Cement Stucco and Plaster.”)

Figure 4.6 Only one layer of reinforcement is visible in cross section along the vertical edge of a crack. (Photo by author, 2018)



23

werealreadyexhibitingdamage,crackingor

loss.Asaresult,thedataobtainedintesting

mayrepresentthemostdamagedcondition

ratherthanageneraloverallconditionofthe

cement stucco due to proximity to ground

moisture,snowaccumulation,andexposureto

weathering.

Oncelocationswereidentified,sampleswere

detached from the structure mechanically

using a hammer and chisel (Figure 4.7).

Eachsamplewasnumberedsequentially

withlocationsannotatedinfieldnotes.

Photographsweretakenateachsampling

locationandtheselocationsaremarkedon

drawingsattheendofthisreport.Appendix III

hasanindexofeachsample,withbulksample

photographs,adetaileddescriptionand

primarykeywords,andanotationisincluded

that indicates the test applied.

b.TestingResults25

Boththecementitiousmaterialandthemetal

reinforcement,individuallyandasacomposite

unit,areinrelativelygoodcondition.Many

ofthelaboratorytestresultsshowthatthe

stuccoisstillrobust,bothphysicallyand

chemically.Inextremeenvironments,cement

asamaterialwillinevitablyloseitsmaterial

integrityandtheseconditionsmustbetreated

seriously. Some of these future pathologies

canbeextrapolatedbytheobservations

made in these tests. These are not presently

soseriousthattheyarecontributingtothe

present failure of the stucco.

In all, despite eighty years of exposure, the

cementpasteisstillwelladheredtothe

aggregateanddoesnotshowsignificant

damage due to thermal or hygric cycling.

Thereisevidenceofsurfacemicrocrackson

boththeexteriorandposteriorsurfaces;these

areas are more thoroughly carbonated than

the surrounding matrix. In some cases, these

cracksalsoalignedwithsmallunderlyingvoids

likelytheresultofmoistureinfiltrationand

freeze-thawcycling(Figure 4.8). The cement

matrixsurroundingthewovenwirelath

doesnotshowsignificantphysicalstressthat

accompaniesexpansivecorrosionproducts

orthermalcycling.Voidsevidentnearthe

25FurtherinformationinAppendix II.

Figure 4.7 J. Hinchman detaches a sample from an area of existing damage on the east elevation using a ham-mer and chisel. (Photo by author, 2017)



24

metal reinforcement are likely from errors in

applicationratherthandamage.Theresults

from the mechanical tests suggest that the

stuccoisquitedurableinflexuralbending,

whichmeansthatthecompositematerialis

ingoodconditionandasignificantamountof

forcewouldhavebeenrequiredtocausethe

cementtoruptureanddisplace,asisevident

onthebaseofthestructurewherethereis

nowloss.Insamplesthatdemonstratea

modulusofelasticitybelowtheaverage,it

is possible that the adhesion of the cement

matrixtothewireclothwasmoreinfluential

thantheactualconditionofthestuccoitself,

asvoidsdiminishedthetensilestrength

impartedbythewire.26

Theembeddedwovenwirelathreinforcement

datestothe1930s,beforetheadventof

galvanizedsteelandcorrosionresistant

coatings;asthesystemwasoriginally

designed, the alkalinity of the cement should

inhibit corrosion products from forming.

Overtime,however,theprocessofcement

carbonationtakesplacewherebythecement

matrixcombineswithatmosphericcarbon

dioxide to form calcium carbonates. In a

neutralenvironment,themetalelements

aremoresusceptibletocorrosion:thisis

concerning, as the metal becomes more

susceptibletobreaking,andmayinduce

spalling of the cement material due to

corrosion jacking. The Moulton homestead 26ConversationwithDr.AlexRadin,oftheLaboratoryforResearchontheStructureofMatterattheUniversityofPennsylvania.

cementsamplesdemonstratevariabledepths

ofcarbonationinpetrographicexamination,

whichmayberelatedtothedegreeof

exposure. The metallic reinforcement system

showssomeevidenceofferrouscorrosionbut

this does not appear to be inducing physical

damage to the surrounding cement matrix.

Whereobservable,thefurringdevicesand

wirelathlooktohaveviablecrosssection

(Figure 4.9).Therelativelylowlevelsof

corrosionandcementcarbonationcould

beduetothelowlevelsofporosityinthe

cement.27, 28

Inthefuture,however,thecementmaterial

shouldbemonitoredforsignsofdeterioration

relatingtothermalcyclinganditsrelated

pathologies. One such pathology is corrosion

jacking,inwhichtheferrouscorrosion

productscanswellinvolumeandexert

force on the surrounding concrete, stone,

masonry,etc.,whicharereinforcedwith

metalcomponentswhichultimatelyleadsto

damage.29Carbonation,forexample,isan

inevitablephenomenonforcementandwill

eventuallyleavethemetalreinforcements

exposedtodeterioration.Whilesaltattackwas

notpositedasapotentialcontributortothe

deteriorationofthestucco,salttestingstrips

indicate that the stucco contains moderate

27ConversationwithMichaelHenry,PE,AIA,lectureronbuilding pathology at PennDesign.28Inferredfrompercentporositycalculationsbasedontherateofwaterabsorption;seeAppendix II.29DavidWatt,Building Pathology: Principles and Practice,2nded.(Oxford;BlackwellPublishing,2007),120-21.



25

Figure 4.9 Cross section of furring device which shows some evidence of ferrous corrosion. Despite eighty years of exposure, the metal still has a significant amount of heathy cross section. Magnification 20x. (Photo by M. C. Boileau, 2018)

Figure 4.8 Cross section of a subsurface void directly connected to a surface crack, which shows that moisture can percolate through hairline cracks and exert force on the material with cycling temperatures. Magnification 50x. (Photo by M. C. Boileau, 2018)



26

amountsofnitrites(25to50mg/L)and

sulfates(>1500mg/L),30thelattertypicalfor

Portlandcement.Evidenceofcrystallinesalt,

however,werenotobservedinpetrographic

examinationnordothesamplesdemonstrate

damagepatternsconsistentwithsaltattack,

althoughinafewinstancessubfluorescence

wasobservedwithinthecementmatrixand

on the building paper. Soluble salts can readily

undergocrystallizationcyclesinenvironmental

conditionswithvaryinghumidityand

temperature, as is the case in Jackson Hole.31

Otherpotentialpathologieswhichcanaffect

cement, include inappropriate aggregate

thatisphysicallyorchemicallyincompatible

withcement.Forexteriorstucco,riversand

istypicallythebestaggregateduetoitslow

clay content.32InWyoming,decomposed

graniteandtufarockwasconsidereda

suitablesubstitute.33 Sub-angular grains

werepreferredforexteriorplasterwork,as

the shape deters shrinkage from occurring.34

Theaggregateobservedinthesamplesisa

coarse, sub-angular mixture of stable and inert

30 See Appendix II.31Dissolvedsaltscancrystallizeandexertpressureonporewallsinthematerial,inducingmechanicaldamage;whenrelativehumidityincreases,thesaltsre-dissolveand can be transported further into the material utilizingthemechanicaldamageasanextendedporenetwork.32J.T.Sawyer,Plastering(Shaftesbury:Donhead,2007),31.33PortlandCementAssociation,Proportioning Concrete Mixtures and Mixing and Placing Concrete.(Chicago:Portlandcementassociation,1916),9,https://catalog.hathitrust.org/Record/100029668.34JeremyP.Ingham,“Mortar,Plaster,andRender,”

alluvium,whichislikelytobelocallysourced

fromeithertheSnakeorGrosVentreRiver.

Noevidenceofalkalisilicareaction(ASR)or

otherdeteriorationpathologiesaffectingthe

aggregatewereobserved.

4.3 Structure and Environment

Thebuildingsubsurfacecontextiscritical

toanalyzingthepresentconditionofthe

stucco and the structure as it might explain

localizedfailureonthesouthelevation.Site

conditionsthathavedestabilizedpartofthe

southeastfoundationwereputforthasa

major contributor to the diagonal cracks and

detachment of the stucco from the underlying

sheathing.Otherenvironmentalfactors,such

asweatherconditionsandseismicactivityalso

fallunderthiscategoryofinvestigation.

a. Historic and Contemporary Uses

Althoughthefoundationisnotpartofthe

stucco,itsoverallconditionhasadirectimpact

onthelongevityoftheentirebuilding.Infact,

thereissomeevidencethatsuggeststhat

the most serious, albeit localized problems

withthestuccomaybedirectlylinkedtothe

conditionofthefoundation.Whilebriefly

toucheduponhere,thisissuewiththe

foundationwillbediscussedfurtherinthe

conclusions as it has both a direct impact on

the future of treatment and helps to support

someoftheideasputforwardaboutthe

conclusionsofthenon-destructiveanalysis.

Theconditionofthefoundationcanbein Geomaterials Under the Microscope(London:MansonPublishingLtd.,2013),137–62,https://www.sciencedirect.com/science/book/9780124072305,154.



27

inferred from a number of sources. This report

doesnotpurporttobeacomprehensiveor

finalizedanalysisoftheconditionsaffecting

thefoundationbutdiscussestheinferences

thatcanbemaderegardingitscondition.

AccordingtotheNationalRegisternomination,

otherstructuresintheMormonRowdistrict

arebuiltonfoundationwallsmadeofconcrete

ornativestone,butthesearetypicallyshallow

enoughthattheentirestructurecanbuoyantly

restontopofthealluvialclays.TheJ.Moulton

houseissimilarlybuiltonaconcretewall

foundation,butacellarunderthesouthwest

portionofthestructurethatextendsbelow

the frost line renders that part of the house

rigid. The north and east parts of the house

arecantileveredandappeartohavemoved

differentiallytothesouthwest,likelycausing

thelargediagonalcracksevidentonthesouth

andnorthelevations(Figure 4.10). The Reed

MoultonHouse,whichislocatedtothenorth

of the John Moulton property on the Jackson

Moran Road, is an excellent comparison for

thispoint.Thehousedoesnotappeartohave

adeeperfoundationorcellarthanacement

foundationwallandthereforeitsexterior

stucco does not exhibit the same diagonal

cracks.Whetherthismotionistheresultof

freeze-thawofthesoilorsubsidenceshould

bedeterminedwithfurthermonitoringand

the assessment of a structural engineer.

Historicphotographswereusedtoanalyze

previousconditionsofthehouse,including

landscaping and contemporary uses. Proximity

of trees and bushes to the base of the

Figure 4.10 Plan of the John Moulton Homestead basement. (Historic American Buildings Survey, WY-152-A)



28

structuremaycontributetodestabilizationof

thefoundationduetorootjacking,whereby

the root system undermines and destabilizes

thefoundationwall.Theroleoftherelic

tree roots on the east side of the structure

similarlyrequiresfurtherresearch:itwas

suggested in one comment that the tree roots

couldhaveactuallystabilizedtheeastside

ofthefoundationanddeterredmovement,

butnowthatthetreeisgone,35 the roots are

disintegratingandthefoundationisfreeto

subside (Figure 4.11). A thorough structural

35Thetreeisevidentinthe1997HABSphotosandhasbeencutdownby2014,accordingtothedatestamponphotos found online.

investigationisneededtocorroboratethe

precisecauseoffoundationmovement,asit

meansthedifferencebetweenmovementthat

isstableandcyclingandmovementwhichis

eccentricandworsening;bothofwhichwould

greatlyaffecttheconservationtreatments

implemented.

b.SeismicActivity

Recordsoflocalseismicactivityisalso

presented in this research, as ground

disturbancesmaybecontributingto

deteriorationconditions.TheTeton-

Yellowstoneregionhasahighlevelof

Figure 4.11 HABS photos from 1997 reveal trees and bushes encroaching on the east and south sides of structure, potentially impacting the stability of the foundation. (Historic American Buildings Survey, WY-152-A)



29

seismicity due to faults in the surrounding

regionandtheYellowstonehotspot.36 In

theTetonregion,severalthousandsmall

tomoderatemagnitudeearthquakeshave

beenrecordedinthelastthirtyyears;37 these

rarely exceed magnitude 2.5.38 It is possible

that loads from mild seismic tremors could

becontributingtothecrackingphenomena

at the John Moulton homestead. The Reed

Moulton residence, north of the John

Moulton homestead, does not exhibit similar

displaced diagonal cracking in its exterior

stuccocharacteristictolateralloadsinduced

byearthquakes(Figure 4.12).39Eitherthe

stuccoattheotherhousewasinstalledafter

damage occurred to the stucco at the John

Moulton homestead or, if the R. Moulton

stucco is contemporaneous, large cracks at the

Pink House are likely not the result of seismic

activity.

c. Climate

Thermal expansion and moisture gradients

are the most common causes of cracks in

concrete.Initialstrainisinducedasthe

cementcoolsanddries,butsubsequent

fluctuationsintemperatureandmoisture36BonnieJ.PickeringWhiteetal.,“SeismicityandEarthquakeHazardAnalysisoftheTeton-YellowstoneRegion,Wyoming,” Journal of Volcanology and Geothermal Research188(2009):277.37Ibid,783.38“SearchEarthquakeCatalog”,accessed12April2018,https://earthquake.usgs.gov/earthquakes/search/.39TheNationalRegisternominationisunclearastowhenthestuccowasappliedtothestructure.Thehousewaslikelybuiltbypreviousownersinthe1910sor1920s,beforetheJohnMoultonhomestead.

cancausethedifferentmaterialsinthe

assembly to expand and contract. 40,41 These

discontinuitiesaretypically1-2mmwideand

havelittletonoeffectonthedurabilityorthe

strength of the concrete.

TheJacksonHolevalleydisplaysextreme

temperaturevariations.TetonCountyis

classifiedasASHRAE169-2006Climate

ZoneNumber7SubtypeB,verycoldand

dry(43.666065,-110.664857).Duringboth

thesummermonthsandwintermonths,

theaveragedailytemperaturecanfluctuate

betweenthirtyandfortydegreesFahrenheit

(Figure 4.13). 42, 43Freezingconditionsand

temperaturefluctuationsmayinducedamage

tothecement,whichleavestheunderlying

ferrous metal reinforcements exposed to

atmosphericconditionspotentiallycausing

corrosion. The R. Moulton home is again a

goodcomparison;theexteriorofthestructure

islikewisecoveredbyhairlineandsmall

cracks,whichconfirmsthatcementitious

stucco forms small cracks under the strain

ofthermalcycling,manyofwhichreseal

athigentically.

40Concretetypicallycontracts0.37mm/mduringset.41DavidOdgers,ed.,Concrete,vol.8,PracticalBuildingConservation(London:EnglishHeritage,2012),75-76.42“TemperatureExtremes,Annual,Moose(486428)-WyomingStateClimateOffice,”accessedApril2,2018,http://www.wrds.uwyo.edu/temperature/extremes/486428-Annual.html.43Averagesummertemperaturesvarybetweenlowsof37-40°Fandaveragehighsof75-80°F.Inthewinter,bycontrast,theaveragedailyhightemperatureisbetween22and30°Fandtheaveragelowcanreach0to10°F.



30

Figure 4.12 The stuccoed exterior of the Reed Moulton home does not exhibit diagonal cracking, as would be expected from earthquake damage or foundation subsidance. There is evidence of similar orthagonal cracking on the south and north (pictured here) elevations of the R. Moulton home. (Photo by author, 2017)

Figure 4.13 The average temperatures on the valley floor demonstrate extreme seasonal variations; a normal daily temperature cycle can exhibit 25-40 degrees change. (Source: Wyoming Water Resources Data System/State Climate Office)



31

Meanannualsnowfallinthevalleycanreach

13to16ft.44Astudyofsnowdriftsobserved

attheBarBCDudeRanchinGrandTeton

NationalParkfoundthatsnowtendedto

flowwiththewindandaccumulateonthe

northsideofthestructure,butthiswasless

dramaticforgableendsthatareperpendicular

towinddirection.45 Because the gable end of

thestructurefacesthewindperpendicularly,

somesnowaccumulationlikelyoccurson

the north side of the Moulton homestead

atthebaseandontheroof.Thedifferential

accumulationshouldnotbesignificantly

unequalbetweenthenorthandsouthofthe

structureifBeckman’sobservationsfrom

the Bar BC ranch hold true on the other side

ofthevalley.Photographicdocumentation

inthewinterwouldbeusefultoappreciate

howhighthesnowaccumulatesagainstthe

stuccoonthenorthelevation.Whereversnow

accumulates at the base of the structure, the

stuccoisincontactwithasourceofmoisture

and therefore exposed to related damage.

TheprevailingwindsintheJacksonHole

Valleyblowfromsouthtonorth,although

BlacktailButteshouldshieldtheJohnMoulton

homestead. The stucco is completely exposed

onallsidestoweather,withlittleprotection44ChristopherA.Davey,KellyT.Redmond,andDavidB.Simeral,“WeatherandClimateInventory,NationalParkService,GreaterYellowstoneNetwork”(FortCollins,CO:NationalParkService,2006),13.45ChristineL.Beckman,“EvaluatingtheDisplacementModes and Associated Risks of Stacked Log Structures”(UniversityofPennsylvania,2013),https://repository.upenn.edu/cgi/viewcontent.cgi?arti-cle=1547&context=hp_theses.

affordedbytheaspentreesimmediatelyto

theeast.Thesurfaceofthesouthelevation

receivesboththebruntofsolargainaswell

aswinterstorms.Acombinationofdirect

sunlightandexposuretothewindarethe

causeofdramaticpaintlossandpossible

fadingonthesouthelevation.

4.4 Summary of Assessment

Based on these preliminary analyses, half of

theoriginaldeteriorationhypotheseshave

beenfullyeliminatedwhileothershave

alsobeendrawnintoquestion(Table3.14).

Whilethesedonotapproximatespecific

areaswherethestuccoisatrisk,itiscritical

inaconditionsassessmenttodeterminethe

causesofpathologiesandwhetherornotthey

areactiveandworsening.Treatingafflicted

areaswhenthecausesofdeteriorationare

stillactivecanriskacceleratingdamage

andwastingresourcesoninterventions

thatareultimatelyineffective.Treatment

isineffectiveandpotentiallyharmfulifthe

mechanism of failure is not understood. All of

theseissuesdiscussedaboveareimportant

tosystematicallyconsideraspotentially

contributingfactors.Thosewhichremainare

eachapotentialcandidateforthecauseof

failureandyetthequestionremainshowto

identifyifanyorallofthesearefactorsof

equalweight.Mostoftheconclusionsthat

havebeenreachedthusfarhavebeenbased

oninvestigationsthatlimitedtheamountof

destructivecontactwiththestucco.Without



32

doingmoredamage,alternativesneedtobe

consideredtohelpthisprocessofnarrowing

downthecontributingfactors;thisiswhere

theuseofnon-destructiveevaluationand

testingshouldbeconsidered.

StructuralFoundation

Hypothesis MethodofConfirmation Contributing?

Relic roots on the east side of the structure had undermined the foundation.

Historic research Potentially

Rodents undermining the foundation.

Observation,monitoring Potentially

Uneven settlement of the foundation.

Research, monitoring Potentially

Attachment

Mesh is butted rather than overlapping.

Survey Likely

Undersized nails used to attach metal reinforcement.

Survey

Differential thermal expansion between metal reinforcement and cement and/or wood frame.

Research on material properties

Likely

Differential expansion of furring strips. Survey, literature research

Corrosion of metal reinforcement.

Sample examination, field confirmation

Cement

Damage due to exposure; thermal cycling, hygric cycling, freeze-thaw cycling.

Laboratory analysis

Environment Earthquake damage. Literature research

Figure 4.14 Revisedlistofdeteriorationhypotheses.



33

5.0 DIGITAL ANALYSES

Developingamethodologytocomparethe

resultsproducedbythethreedifferentnon-

invasiveapproachesofassessmentchosenfor

thisthesisrequiresunderstandingthevalue

oftheirrelationship.Geographicinformation

systems(GIS),infraredthermography(IRT)

image analysis, and photogrammetry each

havetheirstrengthsandlimitationstoindicate

areas of unseen damage. The graphics

producedbyeachsoftwarecanshowthe

spatialdistributionofconditions,whether

cracks, temperature, or three-dimensional

shape, but none of the results are absolute

or can independently indicate damage.

Anindividualgraphicbyitselfisoftennot

sufficienttocorroboratethepresenceofa

conditionduetoavarietyoflimitationsof

thattool.Overlayingtheresultantgraphics

from each of the three systems together can

helpsubstantiate(orcallintoquestion)areas

ofpresumeddeteriorationbyshowingthe

similaritiesordifferencesbetweentheresults

of the tests.

5.1 Aims

Initialresearchquestionsforeachelevation

aretwofold:1)toidentifytheextentof

deformationanddetachmentand2)to

analyzethepotentialriskthatexposure

toweathercouldposefordeterioration

ofthecementand/oritsferrousmetal

reinforcements.Theresultsthatfolloware

basedonacomparisonoftheresulting

graphics,whicharetheninterpreted

throughmaterialbehaviorsand/orstructural

observationsfromthefield.Thesuccessof

thesegraphicsandsourcesofpotentialerror

dependonthedeteriorationconditions,

qualityofdatagatheredinthefield,and

fieldlimitationsuniquetoeachelevation.

Forthisreason,thefollowingdiscussionis

organizedaccordingtoelevation.Thesouth,

westandnorthelevationarediscussedand

havecorrespondingillustrations.Thermal

imagesforeastelevation,however,didnot

showsufficientvariationstobeusefulfor

comparison.Followingabriefdescription

oftheevidentpatternsisadiscussionof

the likely causes or contributors to these

phenomenaandananalysisofpotential

deteriorationrisks.

a.SouthElevation

Theprocessofinformationcollectionfor

photogrammetry and infrared thermography

inthefieldwasquitethorough,asthesouth

elevationhadpreviouslybeenidentified

asanareaforsignificantconcern.A

photogrammetricmodelwasconstructed

fromaseriesof96photostakentocapture

theelevationbothstraightonandobliquely;

theresultingmodel,therefore,hashighdetail

and is more likely to accurately portray the

planarityofthestucco.Limitationsthatcould



34

haveaffectedtheresultingmodelarethose

whichhaveaffectedtheentireconditions

assessmentprocess;namely,photographshad

to be taken from grade. The photos for the top

oftheelevationweretakenfromapoorangle

and,asaresult,willbeoflowerresolution

and disposed for error than the base of the

structure.Foroptimalphotogrammetrywork,

severaloverlappingphotosarerequiredto

showbothdetailsandbroaderswathsofarea

aswellasheadonandangledphotographs.

Thesouthelevationfacesdirectlysouth

and is unobstructed, so the majority of

theelevation’ssurfacecanreceivedirect

sunlight.46

From a comparison of these graphics,

anchoredbyobservationsinthefield,wecan

makethefollowinghypotheses:

1. Areas of likely attachment and

detachment, according to relative

temperature (Figure 5.1). Theareabelow

theleftcorneroftheeasternwindowon

thefirststoryisknowntohavedetached

stucco;intheinfraredthermograph,this

area is notably cooler than the adjacent

plaster.Itwasdeterminedinthecourse

offieldinvestigationsthattheplasterto

theleftandabovethisarea,alongside

thewindowframe,appearedtobebetter

attachedtotheunderlyingsheathing.

The temperature gradient runs from

coolertowarmerwherethestuccois46Theonlyexceptionistheareadirectlyundertheeaves.

betterattached.Therefore,itcouldbe

assumedthatareaswhichhaveahigher

surface temperature may be the result of

thermal transfer from the sheathing and

theinteriorofthestructure.Whilethis

assumptioniswellframed,thereareother

factorsinhouseconstruction,whichcould

alsoproducecolorvariationinthethermal

image, including changes in the thickness

ofthestucco,variationsininsulationdue

tosettlingorimproperinstallation,and

moisturepenetrationjusttonameafew.

2. Correlating bigger crack sizes with possible

areas of detachment (Figure 5.2). Crack

patternscanoffersuggestionsaboutthe

failureofthestuccoandthosepatterns

can easily be exploited in ArcMap

whererunningdensitiesisarelatively

easyprocess.UsingaGISsoftware,

ESRIArcMap,thespatialdistribution

ofthecrackscanbeconvertedintoan

image(ordensityraster)whichisbased

onconcentrationsofoccurrencesfor

aselectedfeature.Wherethereisa

clusteringofpoints,thatareawillhave

ahighervaluecomparedtofewerpoints

in other areas, producing an image of

hotspotsbasedonthestatisticalanalyses

ofthespatialrelationshipsbetween

points. A series of density maps based

onsizesforthesouthelevationwere

generatedinordertolookforsimilarities

betweenthedistributionofdensehot

spotsandtemperature.Areaswithcooler

temperaturesonthesouthelevationthat



35

25° F60° F

Figure 5.1 Hypothesis: Areas that have lower temperature are associated with detachment. Areas where the weight of the stucco is not adequately supported by nails.



36

Figure 5.2 Hypothesis: Bigger cracks and areas of cooler surface temperature are associated with or indicative of unseen detachment. Possibility of water intrusion through the crack to wet the nails, vapor barrier, and wood sheathing; deterioration could be obscured by the stucco.

25° F60° F

DENSITYOFM,LANDXLCRACKS.

The bigger cracks map can show the distri-bution of cracks which are associated with structural movement and shear forces on the stucco; these tend to occur at the base and corners of the structure, as well as corners of openings.



37

arecoincidentwithareasthathaveahigh

density of medium, large and extra-large

cracks.Whilethissystemworksforthe

southelevation,itdoesnotseemtoapply

aswellfortheotherthreeelevations

wherethermalvariationseemstobe

much smaller. The end result is that the

comparisonoftheIRandGIScanshow

thatthereisapossiblecorrelationbut

itfailstoexplainwhythiscorrelation

is not consistent on the other sides of

thehouse.Theseareaswerefurther

investigatedusingthephotogrammetric

model;severalcrosssectionswerecutin

theseareasandoverlaidinordertosee

ifdisplacementwasoccurringandthe

extentofthiscondition(Figure 5.3). It

wasthroughtheuseofphotogrammetry,

and the usefulness of 3D data, that

providesapossibleclueastowhythe

patternsdescribedabovedon’tseemto

beconsistentwhencomparingthesouth

withtheotherthreeelevations.While

thesouthelevationshowsasignificant

shiftoutofplaneinseverallocations,the

other three sides do not. It is through the

comparisonofthethreedifferenttypesof

digitalassessmentthatthepatterncanbe

uncovered.

3. Surface areas with a higher density of

cracks and warmer temperature are likely

to still be attached to the sheathing. Based

onthefirstobservation,warmerareas

ofthestuccosurfacearelikelybetter

attachedtotheunderlyingsheathing.A

comparison of the infrared thermograph to

theGISdensitygraphicsrevealsthatthese

highlighted areas are strikingly similar

toareaswherethereisahighdensityof

extra small and small cracks (Figure 5.4).

Thispatternwouldimplythatareaswhich

haveahigherdensityofcracksarebetter

attachedtotheunderlyingsheathing.

Therefore, it could be possible that

attachmentofthestuccotothesheathing

inducesorencouragestheformation

Figure 5.3 Cross section from photogrammetric model shows above that detachment (in red) on the south elevation could be more extensive than observed in field investigation. Still of photogrammetric model on the right indicates with area of cross section.



38

Figure 5.4 Hypothesis: Areas with a higher density of cracks could indicate areas where stucco is still attached to the sheathing. Possible areas where ferrous reinforcement is corroding, as microcracking and surface cracking are correlated with deeper carbonation of the cement. Freeze thaw action and salt efflorescence, due to greater potential for water intrusion.

DENSITYOFALLCRACKS.

25° F60° F

In this graphic, the value for each crack is equal (‘1’) as it is difficult to objectively apply differing values to different sizes of cracks.



39

ofsmallcracks.Whilenotasalarming

as the large cracks or detachment, it is

importanttoconsidertheimplications

of micro cracks for the fabric and its

potentialfordeterioration,basedonthe

observationsfromthelaboratorytesting

section.Whilethesesmallercracksare

likelyconfinedtothesurfaceandexpose

lesscrosssectiontowaterinfiltration,

boththecrosssectionandthinsection

samplesrevealthatmico-cracksareoften

accompaniedbyevidenceofatmospheric

andwaterinfiltration.Materialssampled

fromexposedareasrevealedsurfacemicro

cracksandmuchdeepercarbonationthan

less exposed counterparts. Once concrete

has carbonated, the material is no longer

sufficientlyalkalinetodetercorrosionof

metalreinforcements.Whiletheseareas

couldbebetterattachedtothesheathing

beneath, the reinforcement in these areas

could be more predisposed to corrosion

andlossofviablesection.Thesearealso

areaswithagreaterpotentialforwater

transmission and therefore are more likely

toexperiencedamageduetofreeze-thaw

cyclingandsaltcrystallization.

b.WestElevation

Thereisalackofstrongcorrelationbetween

theresultingthermalimageandcrackdensity

graphics (Figure 5.5). The highest crack density

gradientfallsintoareasthathavealower

temperature;thisisoppositetoobservations

fromthesouthelevationwherehigher

densitiescoincidedwithhighertemperatures.

Thehighdensitiesoflargercracksoccursnear

thefoundationofthestructure,areasthat

aredistributedacrossagradientofwarmer

and cooler temperatures in the infrared

thermograph.

Environmentalconditionsandcontingencies

couldaffectthedataorexplainthelackof

correlationsintheimagery.Forone,the

geometry of the ell could be encouraging

anunevenwarmingofthesurfacethat

wouldskewtheresultsfromtheinfrared

thermographs. Another possibility is that

detachment,whichissuggestedbythe

photogrammetricsectiononthesouth

elevation,doesnotoccuronthisparticular

elevation;displacementofthesouthcorner

demonstratesthattheplasterisstillattached

to the sheathing, and that the sheathing

andpossiblytheframeitself,ismovingaway

fromthefoundation.Incontrasttothesouth

elevation,however,itsgraphicsignatureis

unknownandthelackofcorrelationbetween

thecrackdensitiesandthermalimagesmeans

thatitisdifficulttopostulatewhereitcouldbe

occurring.

DuetothislackofcorrelationbetweentheGIS

andthermalimagesforthewestelevation,a

directed approach to select areas, as on the

southelevation,wasnotpossible.Areasof

plasterjustaboveandbelowthewindows,

thewidestexpansesofmaterialonthis



40

DENSITYOFALLCRACKS DENSITYOFM,L,XLCRACKS

Figure 5.5 The thermal images were taken at midday, when solar raditation had only warmed the south elevation of the west ell skewing the distribution of temperatures across the surface of the west elevation.

19°F30° F



41

elevation,wereselectedtocreatetwocross

sectionstolookforpossibledeformationof

thestucco.Asthedrawingindicates,neither

sectionrevealssignificantdeflectionor

detachment of the stucco (Figure 5.6). A slight

bending is apparent on the right side, but

this is more likely the result of a poorly built

photogrammetry model than actual damage

tothestructure.Theplanarityofthewest

elevationcombinedwiththelackofclear

corolationbetweenthedensitymapsand

thermal images implies that detachment does

notoccuronthiselevation,ortothesame

degreeasthesouthelevation.

c.NorthElevation

Thedistributionofcrackdensitiesfortwo

setsofcrackscalculatedintheGISarenot

concentratedinafewlocationsastheywere

onthesouthandeastelevations(Figure

5.7).Theseincludeboththeentiretyofthe

cracksandaswellasonlythebiggercracks

(Medium,Large,andExtraLarge).Instead,the

cracksappeartobewelldistributedacross

thesurfaceoftheelevationinbothgraphics.

Biggercracksarealsomoreprevalentonthe

northelevationthanonothers,asseveral

ofthecoincidentdensitiesbetweentheAll

Cracks and Bigger Cracks graphics suggests.

This is to be expected as the cracking is more

likelytheresultofstructuralmovementrather

than thermal or hygric cycling. There does

notappeartobeacorrelationbetweenthe

crack density graphics and thermal images. It

iscriticaltoconsideragaintheenvironment

and exposure for this part of the structure.

Thenorthelevationhadreceivednodirect

exposure to sunlight, so the thermal transfer

predominantly comes from the interior

Figure 5.6 Cross sections from the west elevation appear to be plane. The stucco on the west elevation of the ell is likely to be in good condition and not detached because it may not be undergoing the same amount of movement as the main structure. Further testing with a higher resolution IR camera will be required to confirm this condition.

TOP

BOTTOM



42

DENSITYOFALLCRACKS DENSITYOFM,L,XLCRACKS

Figure 5.7 The similarity between the density graphics for all cracks and bigger cracks confirms that failure on this elevation is result of structural movement rather than thermal or hygric cycling. Neither density map has a strong correlation to the thermal image, implying that detachment is not present. Photogrammetry will confirm.



43

of the structure, the ambient exterior air,

andtheground.Thethermographshowsa

distinctcoolergradientatthebaseofthe

structure,whichislikelytheresultofsnow

accumulation.

Ahigh-densitypointcloudwasconstructed

usingsevenphotos,alltakendirectlyfacing

themainnorthelevation;duetothelow

number of photographs, this model has

thepoorestresolutionofthesetandisless

accurate.Theresultingcrosssectionappears

tobeconcave,whichislikelyduetoalack

ofphotostakenfromobliqueangles(Figure

5.8).Nonetheless,thesectiondoesnotreveal

significantirregularitiesthatwouldsuggest

detachment of the stucco.

5.2 Discussion of Results

Priortotheconditionsassessment,most

professionalshadassumedthatthepatternof

cracksacrosstheentirehousewasevidence

ofafailingstuccoaswellasphysicalevidence

ofauniformproblemwiththeentirehouse,

requiringalarge-scaletreatment.Since

treatmentisirreversible,andcanintroduce

damagethroughinvasiveapplications,a

cautiousapproachisoftenthebestsolution.

Theoverlayofdigitalanalyses,described

above,waspursuedtoprovidemore

informationabouttheconditionofthestucco.

Ultimately,thisanalysisdidnotindicateareas

ofunseendeteriorationwithcertainty,but

rathertheresultswillguideinvestigationsin

subsequentfieldvisits.

Figure 5.8 The photogrammetric model for the north elevation appears to be concave, which is likely due to a lack of photos taken from oblique angles. Nonetheless, the sections do not reveal significant irregularities that would suggest detachment of the stucco. The thermal signatures are more likely to be the result of external environmental factors than revealing characteristics about the stucco.

TOP

BOTTOM



44

Anexaminationofthisareainthedigital

graphicsestablishesaseriesofvisual

correlations.Fromthese,aseriesof

furtherdeductionsaremade,whichcan

berationalizedbyobservationsfromthe

fieldinvestigationand/orknowledgeof

architecturalconservators.Thisinitialproof

ofconceptprocessofanalysiswasneither

straightforwardnorstrictlyscientific,while

possibletodoso,andreliedontheiterative

processofvisuallycorrelatingsimilaritiesand

thenusingknowledgeofdeteriorationcauses

andeffectstointerpretthepatterns.

Onenotabletakeawayfromthedigitalanalysis

is that there appears to be inconsistencies

whencomparingtheresultsofthesouth

facadewiththeresultsoftheotherthree

elevations.Theprocessofgraphicsoverlay

wasthemostsuccessfulforthesouth

elevation,wheretheanalysisfollowedaseries

ofsuppositions,establishedusingknown

areasofdeteriorationandconfirmedinthe

field.Whencomparingtheresultsofthe

north,west,andeastsides,whichhaveno

largecracksthathavedisplacement,theyall

seemtohavesimilaritiestoeachotherbutnot

to the south. The inconsistent results of the

southelevation,whencomparedtotheother

threeelevations,mayshowthatthesouthside

of the building is in fact an anomaly and that

truefailure—failurewhichcompromisesthe

survivalofthesurvivalofthestucco—isnot

reflectedinthesmallercracksbutinsteadis

onlyassociatedwiththelargestcrackswhich

display shear displacement.

Theconclusionsoftheanalysis,whichinvoked

not just the digital, but also the historical

research, and the laboratory analysis, suggests

thatthecracksacrosstheentirehouseare

notindicationsofafailingsystembutmaybe

duetothethermalexpansionandcontraction

cracks similar to monolithic concrete, stucco

andplaster.Areviewofthehistoricliterature

showsthattheinstallationprocesswas

consistentwiththemanufacturer’sguidelines

oftheday,andlaboratoryanalysisshowsthat

thestuccoiswellformulatedanddisplays

limiteddecayatthemicrolevel.Ifthe

hundreds of smaller cracks are not a threat

tothelongevityofthestuccoorthestructure

thenperhapstheevidencefoundinthedigital

assessment supports a more focused plan for

conservationthatlimitsinitialtreatmentto

onlythelargestcracksonthesouthelevation.

Thefoundationshiftingposesagreaterthreat

to the stucco, as it induces detachment and

lossofsectiontosupporttheweightofthe

systemasitpeelsawayfromthewooden

surface.Thesmall,yetextensive,cracking

patternseenacrossallelevationshaslittleto

dowiththismoredeleteriousphenomenon.

5.3 Next Steps

The possibility of this digital comparison

systemnotworkingisveryplausible.This

methodwaslesssuccessfulonthenorth,

south,andeastelevationsfortwopotential

reasons.First,theoverlayofconditions

is diminished due to inferior thermal and

photogrammetric data. The poor input data



45

could be remedied in the course of future

investigation,therebyimprovingresolution

andconfidenceparametersforinferences

to be established. In fact, the hope is to

doadditionalthermalimagingonthe

structureusingamuchhigherresolution

IRcamerathatwasnotinitiallyusedinthe

2017assessment;thecameraisbothmore

expensiveanddifficulttotransport,butthe

additionalinformationascertainedwiththis

methodisworthwhile.Anotherbarrierin

establishingpatternsmayalsobeattributed

toalackofknownareasofdetachment;

inthecaseofthesouthelevation,thiswas

criticalforcreatinginferences.Although

detachmentiswhatisbeingsoughtoutin

this analysis, a proof of concept approach

suchasthisrequiressomethingonwhich

tobasetheresults.Neitherthenorth,east,

norwestelevationsdemonstrateobservable

instancesofthisconditionsincethesurfaces

arenotopenlycompromisedandtaptesting

hasprovenhighlyinconclusive.Anareaof

detachment could be established through

limitedprobinginafuturesitevisitifthere

wasstrongevidencetosuggestacandidate

areawhereopeningthehistoricfabricwould

beworthwhile.

Withthatsaid,drillingwouldberequiredfor

thepurposesoftreatment.Withoutoutward

evidenceofdetachment,alternativesare

alwayswellaccepted,especiallyifthereis

somebasisfortheirsuccess.Thenotionthat

thesystemdidnotworkatallontheother

threeelevationsisnotwithoutmerit.The

process, as applied to the north, east, and

westelevationswouldsimplyneedtobe

morenuancedanddependonunknownsbut

evidencecouldbedrawnbasedonusingthe

same process. The result is that areas on the

otherthreeelevationscouldbeidentifiedand

subsequentlyfurtherinvestigated.Blindly

drillingtodetectthisconditionisnotan

option,asitrecklesslyintroducesdamageto

thestucco.FurtherNDTanalysisisneededto

begintoidentifyareasofpossibledetachment

ontheseelevations,orconfirmthatthis

conditiondoesnotaffecttheseareasofthe

structure.



46

6.0 SUMMARY OF FINDINGS

ThetaskagreementbetweenGrand

TetonNationalParkandtheArchitectural

ConservationLaboratoryattheUniversityof

Pennsylvaniaaddressesthecharacter-defining

exterior stucco on the exterior of the John

MoultonHomestead.Principalobjectives

includeestablishingthecompositionofthe

stucco,itsapplication,performance,and

causesoffailureinordertobegintodevelop

stabilizationrecommendationsandapilot

treatmentplantopreservetheexteriorstucco.

Thisthesisaddressesthefirstofthesegoals

throughavarietyofavenuesthatarecommon

toconditionassessments.Siteinvestigations

andlaboratoryanalysisprovethatthestucco

is indeed Portland cement based, of local

manufacture, and presently has good physical

integritydespitethenumberofcracksevident

on the surface of the structure. A comparison

of the contemporary product literature to the

stucco system demonstrates that the most

deleteriouspathologiesaffectingthestuccodo

not emanate from the feature or system itself.

From a long list of site- and structure-based

hypothesesinitiallyputforthaspotentially

contributingtothefailureofthestucco,a

fewlikelyphenomenahavebeenselectedto

investigatefurther.Theseinclude:

1. Foundationmovementandsubsidence,

whichhascontributedtotheformationof

large diagonal cracks and displacement of

the stucco, and

2. Differentialthermalexpansionof

the stucco and embedded metal

reinforcements,whichcausesmalland

hairlinecrackstoform;theorthogonal

patternlikelyrelatestoimproper

installationofthesectionsofwovenwire

lath,butthiswillbeconfirmedinfurther

fieldexamination.

The second part of this report focused on

analyzing and comparing digital graphics to

approximatetheextentofunseenconditions

thatposearisktothecontinuingintegrity

of the stucco. Detachment of the stucco

systemfromthesheathingisonlyobservable

onthesouthelevation,andwhenthisarea

wasprobedwithaborescopeduringfield

assessment it had been assumed that the

expanseofdetachmentwaslimitedtothe

immediate area surrounding the crack. Using

amethodologythatcombinesGeographic

InformationSystem(GIS)analyses,infrared

thermography (IRT), and photogrammetry,

the extent of detachment, at least for the

southelevation,appearstobemuchlarger

thanpreviouslyobservedinthefield.Similar

analyseswereattemptedonthewestand

northelevations,buttheresultswere

inconclusiveduetoenvironmentalfactors,

informationcollection,andthelackofknown

deterioration;itispossible,however,that

detachmentdoesnotaffecttheseareasof



47

thestructure.Movingforward,testprobe

locationswillbeselectedonthebaseofthe

southelevationtoconfirmdetachmentinthe

areas suggested by this methodology. Further

studyoftheotherelevationsshouldtakeplace

tolookfordetachmentonotherelevations.

These measures could include using a higher

resolutionIRcameraandaprotocolofactive

sensingwithcontrolledexternalheatsources.

Thedensitygraphics,coupledwithlaboratory

analysis of the composite stucco, also

canindicateareasofpotentialriskwhere

thestuccoismorelikelytobeaffectedby

waterandatmosphericintrusion.Inthe

future,deteriorationintheseareascould

besubstantiatedwithothernon-destructive

tools,includingahigh-resolutionthermal

camera.Thesegraphicsprovideaprioritized

mapwithwhichtostartfutureinvestigation.



48

7.0 RECOMMENDATIONS

Thefollowingisapreliminaryoutlineof

therecommendedinterventions;theseare

organizedbythedeteriorationmechanism

addressed.

I.Stucco:

1. Detachment:Beforeanystabilizationof

theplasterbegins,themovementofthe

foundationneedstobeexaminedbya

structuralengineer.Anystabilizationor

conservationinterventionsperformed

on the stucco should only take place

afteranengineerhasconfirmedthat

thefoundationisstable.Ifdifferential

movementisstilloccurring(either

cyclicallywiththefreeze-thawofsoils

orduetosubsidence)themovement

couldrendertheinterventionsineffective

and detachment could progress, or the

introducedinterventionsmightcause

further damage to the stucco.

Oncethefoundationhasbeenstabilized,

the detachment of the stucco needs to be

addressed.Asitwasinitiallyinstalled,the

furringnailswouldhavehadenoughgrip

intotheunderlyingwoodsheathingto

supporttheweightofthestuccosystem.

Because some of the nails in the system

havedisengagedfromthesheathing,itis

possiblethatthegravityloadonthestucco

could exceed the shear strength of the

nails.Theconservationplanshouldinclude

methodswithwhichthestuccocould

be supported and reintegrated into the

underlying frame. If moisture has entered

behindthestucco,itisalsoconceivable

thatthewoodensheathinghasbeen

compromisedbyrotandinsectattach.

Thiswouldcauseareasofthestucco

attachmenttofail.

2. MoistureandSolarProtection:While

itmaytakesometimetoacquirefunds

to contract an engineer and introduce

stabilizationmeasures,moisturecontrol

interventionsareminimal.Inthe

meantime,measuresshouldbetaken

toweatherizetheareasoflosswhere

woodenelementsareexposed.The

primaryfunctionofthestucco,afterall,is

towaterprooftheexteriorofthestructure

toprotecttheunderlyingwoodenframe

frommoistureandotherenvironmental

impacts that could compromise the

structural integrity of the building. The

mostobviousinstanceisthesouth

elevation,wherelossanddetachmenthas

exposed the sheathing underneath. The

cornersofthestructurewherelosshas

occurred should be checked for exposed

end grain, and similarly treated.



49

A pilot treatment program should include

materialsandprocedurestofillthecracks

inmoreexposedareastodeterwater

intrusionandpotentiallyslowcarbonation

of the cement and corrosion of the metal

reinforcements.Furtherresearchwillbe

conductedtofindaphysicallycompatible

materialthatwillbeminimallyinvasiveand

notdisruptthevisualaestheticofthestucco.

Wherenecessary,reattachmentmethodsalso

need to be considered to supplement failed

attachmentsinwaysthatareinvisibleand

compatiblewiththecurrentsystem.

Indirect moisture control measures also

include altering the site elements that retain

moistureandcontributetothedeterioration

of the stucco. A French drain system should

be installed around the base of the structure,

ideallyafterallfoundationstabilizationhas

been completed. This includes laying a trench

thatwoulddirectwaterawayfromthebaseof

thestructuretoanirrigationditch.

II.Finishes:

1. Analyzetheappliedpaintedfinishesof

thestuccotoidentifyitscompositionand

alteration.

2. Perform performance tests to ascertain

its physical-mechanical integrity including

adhesion to the substrate, cohesion of

the layer (chalking) and photochemical

alterationfromfading.

3. Researchtreatmentoptionsforthe

aboveandperformdurabilitytests

usingacceleratedweatheringmethods

(weatherometer).

Finally,alloftheaboveproposedtreatments

are to be implemented in a selected pilot

treatmentareaonsiteandallowedto

weatherfornolessthanoneyearpriorto

reassessment.



50

Condition: CrackA discontinuity in an architectural surface or wall painting, resulting in a visible separation of one part from another, that extends through one or more layers.

Extra Small (XS) (<0.005 in.)

Small (S) (<0.025 in.)

Medium (M) (<0.050 in.)

Large (L) (>0.050 in.)

Extra Large (XL) (Cross section exposed)

XSS

M

LXL

Graphic:

PRIMARY CONDITION

Appendix I: CONDITIONS GLOSSARY1

1 Conditions definitions based on “Deterioration Sources” and “Deterioration Phenomena” in EwaGlos European Illustrat-ed Glossary of Conservation Terms for Wall Paintings and Architectural Surfaces (2016) edited by Angela Weyer (Span-genberg: Michael Imhof Verlag GmbH & Co.)



51

Condition: Biological GrowthColonization by living organisms on an object which can lead to damage and deterioration. Growth can include simple bacteria and lichens as well as more complex plants and animals.

SECONDARY CONDITION

Condition: DetachmentSeparation of the plaster system from the wood substrate, visible along cracks where displacement is occuring.

Graphic:

+

−

Positive

Negative+−

Condition: LossA missing part of an architectural surface which affects its integrity.

Graphic:

Loss



52

SECONDARY CONDITION

Condition: SoilingAccumulation of extraneous material on a surface leading to discoloration.

Condition: ModificationNon-original material, historic or contemporary, which shows subsequent modification.

Condition: DarkeningA change in the surface color due to a decrease in hue. Darkening can be the result of a local presence of humidity.



53

i.TestSelection

ASTM C1764-12, Standard Test Methods for Non Metallic Plaster Bases (Lath) Used with Portland

Cement Based Plaster in Vertical Wall Applications,containsaseriesofbasictestswhichcanapproximate

theperformanceandmechanicallimitationsofaPortlandCementBasedPlasterunderavarietyoftest

conditionsandexposures.Theseincludemeasuringtheabilityoftheplastertowithstandtransverseand

verticalloads,aswellascharacterizingtheembeddedlathorfurringwithintheplasterandabilityofthe

fastenerstowithstandfailure.Thescaleofthetestsinthisstandardwasdesignedfortestingcommercial

market rather than historic materials. Some of the tests employed to characterize the cement stucco

havebeenadaptedfromstandardsdevelopedforothermaterials,asthestandardrequiresfabricating

largetestframesandpanelsofcementstucconotsuitableorrealisticfortestingsmallsample.

ii.PotentialSourcesofError

Forwaterabsorptionandthreepointbendingtestsasinglelargepieceofstucco,already

detachedfromthestructure,wasdividedintosamplecoupons.1Bothteststraditionallyrequirealarge

volumeofmaterials,butobtainingsamplesfromavarietyoflocationswoulddamagetheintegrity

ofthestuccoandisnotinkeepingwithpreservationethic.Conductingtestsonstuccofromasingle

sourceratherthanmultiplesourcesintroducesadegreeofpotentialerrorasthetestresultsarenot

representativeofthestuccoforthewholestructure.Thispointisofparticularimportanceasthe

mechanicalandchemicalcharacterforcementoneachelevationcouldbedifferentduetofield-mixing.

Additionally,bothsamplesaretakenfromneargradesoitcanbeexpectedthatthesematerialsmay

haveahigherdegreeofdamagethanotherstuccomaterialsonthestructureduetoproximitytoground

moisture,faunalactivity,andvisitors.

1SamplesforwaterabsorptionwerecutfromJMH23,alargestuccopiecefrombaseoftheeastelevationwhichwasfoundalreadydetachedfromthestructure.MaterialformechanicaltestingwassenttotheUniversityofPenn-sylvaniabyGrandTetonNationalParkstaffinMarch2018;thepiecehadfallenoffofthesouthelevationandbeenstored in the kitchen of the John Moulton homestead.

Appendix II: LABORATORY TESTING



54

iii. Petrographic Analysis

ASTMC856-17, Standard Practice for Petrographic Examination of Hardened Concrete,

describesthemethodologyforpreparingandexaminingcementsampleswithastereomicroscopeand

polarizedlightmicroscope.Thinsectionanalysiscancharacterizethephysio-chemicalcompositionand

deteriorationstateofacementmaterial,typicallyforengineeringandconstruction-relatedinvestigation.

Forhistoricpreservation,thesetestscanserveanumberofusefulpurposes:

• Determining the number of layers and their thicknesses.

• Identifyingthetypeofsourceofaggregate

• Identifyingthetypeofbinder:Descriptionofthecementitiousmatrix,includingqualitative

determinationofthekindofhydraulicbinderused,degreeofhydration,degreeofcarbonation

ifpresent,evidenceofunsoundnessofthecement,presenceofsupplementarycementitious

materials,andthenatureofhydrationproducts.

• Identifyingthepresenceofmineraladditions,suchaspigments.

• Quantifyingthematerialspresenttoestimatethemixproportions.

• Assessworkmanship.Determinationofeffectsofuseofdifferentconcretemakingmaterials,

forming,andmoldingprocedures,typesofreinforcement,embeddedhardware,etc.

• Identifyingdefects.

• Diagnosingdecaymechanismsandassessingthelevelofdeterioration.Determinationofwhether

theconcretehasbeensubjectedtoasulfateattackortoearlyfreezing,orotherharmfuleffectsof

freezingandthawing.Alkalireactivityoftheconstituentparts,eitherwithcarbonateorsiliceous

aggregate.

EightsamplesweresenttoNationalPetrographicService,Inc.,alongwithannotated

photographsanddescriptionsforhowtocutandpreparesamples;adescriptionofthesesamplesand

theirlocationsisinFigure II.1.Theorientationofthethinsectionswasdeterminedbyvisualandstereo

microscopicexaminationtobeperpendiculartoplasterlayers.Areaswheremetalplasterbacking

wasevidentwerenoted,andsomeofthesampleswereorderedtobecutonornearthesefeatures

toexaminethestructureofcementmaterialsinproximitytothemetalmesh.Sampleswerecutand

polishedusinganoil-basedlubricanttoensuresaltefflorescence,ifpresent,wouldnotbedamaged

duringsamplepreparation.Standardthinsectionswerepreparedforpetrographicexaminationwitha

polarizedlightmicroscope.Thesectionsweremountedontoglassslideswithclearepoxy;fivereceived

glasscoverslips,whichimproveopticsduringexamination.Threesamplesdidnotreceiveglasscover

slipsforSEMtestingatalaterdate.2

The samples examined are all similar in terms of arrangement plaster coat layers. The samples

followtheprescribedthreecoatsystemtypicallyusedinplastering:coarseorscratchcoat,followedby

thebrowncoat,andthenthefinishcoat.OnlyJMH18and20wereanomalous,astheyarebothmissing

adistinctcoarsecoatlayer;thisislikelyduetoerrorinapplicationandtherespectivelocationsofeach

2 JMH 03, 17, and 23.



55

Test Sample No. Location Notes

JMH 03 SouthSampletakenfromdisplacedcrack(+)onsoutheleva-tion.Pinkfinish.

JMH 12 North

Stereomicrographshowsananomalouswhitesub-stanceunderandwithinthepaintlayer,possiblysalts.Nitratestriptestingmightconfirm,alongwiththinsectionexamination.Purplefinish(base).

JMH 16 SouthSamplecontainsferrousmesh;thinsectiontakenadja-centtowire.Purplefinish(base).

JMH 17 East Purplefinish(base).

JMH18North,West

Curvedsample,takenfromthenorthwestcorneroftheelladdition.Pinkfinish.

JMH 20 North,EastSampledfromundertheeaveontheeastelevation.The bulk sample has poor interlayer adhesion, perhaps duetofaultyapplication/installation.Pinkfinish.

JMH 22 WestSamplewasfounddetachedfromthestructureandcol-lectedfromthegroundadjacent.Purplefinish(base).

JMH 23 East

Samplewasfounddetachedfromthestructureandcollectedfromtheground.Containsferrouswiremesh;thinsectiontakenadjacenttowire.Stereomicrographshowsthattheremaybeareddishbrownlayerunder-lyingthepurplepaint.Purplefinish(base).

Figure II.1. Petrographicsamples,alongwithnotesaboutthelocationandsamplefeatures.

sample.Themineralogyforthebrownandcoarsecoatsissimilar,butthespacingofthegrainsislarger

forthecoarsecoat.Intwocases,theembeddedwirewovenlathwasevidentinthinsection.3

Despitedespitetheharshclimatetowhichitisexposed,theweatheredcementisremarkably

wellpreserved.Thecementmatrixisstillwelladheredtotheaggregateinthefinishandbrown

coats,andthecarbonationdepthvaries(Figure II.2).Inonlyafewinstances,therewasevidenceof

microcrackswhicharelinedwitheithercarbonatedcementorcalcifiedfreelime(Figure II.3).While

saltsubflorescencehadbeenobservedincrosssection,nocrystalizedsaltwasfoundinthinsection

examination.Thecementmatrixwasmostlywelladheredtotheembeddedmetallicreinforcement.

Themetallicelementsshowsomeevidenceofferrouscorrosionincrosssectionandrustdepositswere

visibleinthinsection,butthisdoesnotappeartobeinducingphysicaldamagetothesurrounding

cement matrix (Figure II.4). The matrix surrounding micro-cracks on the exterior and posterior surfaces

ofsamplesweremorethoroughlycarbonatedthanthesurroundingmatrix.Thefinishcoatsare

composedofwhiteportlandcementwithmineralpigmentsadded,whichcolorthecementmatrix.

Theindividualmineralsweretoosmalltobeediscernedinthinsectionsofurtherchemicaltestingwill

requiredtoidentifythesecomponents.

3 JMH 12 and 15.



56

Figure II.2 Samplesshowdifferingdepthsofcarbonation.JMH16(top)hascarbonatedcementmatrixextendingintothebrowncoat,whileJMH18(bottom)demonstrateslittlecarbonation.(XPL,50xmagnification)



57

Figure II.3 Somemicrocrackingwasevidentinsomesamplesontheposteriorsurfaceofthecoarsecoat;inthesecasescarbonationwasaffectingboththeexteriorandinteriorfacesofthestucco.(JMH16,XPL,100xmagnification)

Figure II.4 Thecementmatrixsurroundingthemetalwire(opaque,centerofimage)appearstoonlyhaveminormicrocrakingandcarbonationofthecementmatrix.Norustdepositswereobserved.(JMH16,XPL,100xmagnification)



58

iv.WaterAbsorption

ASTMC97/C97M-15,Standard Test Methods for Absorption and Bulk Specific Gravity of

Dimension Stone,isusefulforindicatingthedifferencesinabsorptionbetweenvariousstonematerials;

thevariabilityinstonecharacteristicsandqualityistypicallycontrolledbyusingasmanysamplesasare

necessaryfordetermininggaterangeofproperties.Forthecementstucco,thismeansusingmultiple

testsamplesinordertodetermineanaveragerateofabsorption.Duetothelimitationsofavailable

material,thedimensionsrecommendedinASTMC97/C97M-15werenotpossible.Instead,thesample

materialwasdividedinto0.75x0.75x0.75in.cubesusingaRIGID7in.tilesawwithacontinuous-rim

diamond blade.

ThesampleswereconditionedpriortotestingaccordingtoASTMC97/C97M-15;thesamples

beingdriedfor48hoursinaventilatedovenatatemperatureof140±4°F.Atonehourintervalsinthe

lastthreehours,thespecimenswereweighedtoensurestableweight.Priortosubmersion,thesamples

werecooledinaroomfor30minutesandthenweighed.Thesixteensamplesweredividedintotwo

groupsbasedonthewhetherplaneswereplane(GroupA)orintersectedvoids(GroupB) (Figure II.5).4

Followinginitialpreparation,thesamplesweresubmersedindistilledwaterat72±4°F(Figure II.6). The

sampleswerethenremovedfromthewaterbathatintervals,surfacedriedwithadampcloth,andeach

weighed.Theabsorptionforeachspecimenwascalculatedasfollows:

Absorption(weight%)=[(B-A)/A]x100

where:A=weightofthedriedspecimen,oz.,andB=weightofthespecimenafterimmersion,oz.

ThesevalueareplottedaccordingtotimeforeachsampleinFigure II.7.

Thepercentporosityiscalculatedasfollows:

%Porosity=(Vp /Va)X100

where:Vp=volumeofpores(cm³)

Va=volumeapparent(cm³).

These results are in Figure II.8.

Ultimately,bothGroupAandGroupBhadsimilarresults.Theaveragewaterabsorptionforall

sampleswasapproximately6%andtheaveragepercentporosityofthesamplesis12.98%±1.47%.This

figureissimilartoresultsforcommerciallyavailablebuildinglimestone(0.95to17%)andsandstone(1.9

to22%),suggestingthatthecementhasasimilarcapacitytoabsorbwaterasstonesdeemeddurablein

exposure.5

4Presumably,cubeswithplanesthatintersectexistingvoidscouldhaveamoreaccessibleporenetwork.5D.W.KesslerandW.H.Sligh,“PhysicalPropertiesofthePrincipalCommercialLimestonesUsedforBuildingCon-



59

Figure II.5Samplesforwaterabsorptiontesting,devidedintoGroupsAandBbasedonthecharacteristicsofthesamplefaces.

Figure II.6 SampleGroupsAandBsubmersedinwater.



60

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0 50 100 150 200 250

Mass(g)

Time(Hours)

WaterAbsoprtion forJMHSamples

A1 A2 A3 A4 A5 A6 A7 A8

B1 B2 B3 B4 B5 B6 B7 B8

Figure II.7. WaterAbsorptionRateforSamples.TherateofabsoprtiondidnotdifferbetweenGroupA(yellow)andGroupB(blue).

Absorpti

on(%

ofo

rigina

lweigh

t)



61

Test Sample No. M0 (g) Ms (g) Vp (cm3) Va (cm3) % Porosity

A1 13.99 14.88 0.89 7 12.71

A2 13.9 14.69 0.79 6 13.17

A3 13.78 14.58 0.8 6 13.33

A4 15.16 16.04 0.88 10 8.80

A5 14.74 15.66 0.92 8 11.50

A6 13.59 14.40 0.81 6 13.50

A7 13.86 14.68 0.82 6 13.67

A8 13.83 14.62 0.79 6 13.17

B1 13.51 14.38 0.87 6 14.50

B2 13.54 14.36 0.82 6 13.67

B3 13.33 14.16 0.83 6 13.83

B4 13.03 13.78 0.75 6 12.50

B5 12.03 12.73 0.7 6 11.67

B6 12.89 13.68 0.79 6 13.17

B7 14.59 15.52 0.93 6 15.50

B8 13.51 14.29 0.78 6 13.00

Figure II.8. PercentPorosityforWaterAbsorptionSamples.



62

v.MechanicalTesting

ThemethodologyforthistestisbasedonASTMC580-02,Standard Test Method for Flexural

Strength and Modulus of Elasticity of Chemical-Resistant Mortars, Grouts, Monolithic Surfacings, and

Polymer Concretes,whichspecifiesdimensions,method,andcalculationsforevaluatingconcrete

mortars.However,becausethisspecificationisdesignedforsamplesthatareformedratherthancut,

referencetoASTMC99M15,Standard Test Method for Modulus of Rupture of Dimension Stone, is useful

in that it dictates that dictates the faces of each sample should be as near to plane as possible, and

roughmaterialsmaybegroundtoasmoothfinishtoavoidpointloading.6

Thesampleswerecutintothirteenrectangularprismsmeasuring6.0in.x1.0in.x11/16in.±

1/32in.Eachsamplecontainedwiremesh,asdemonstratedincrosssectionandonesamplehadanail

headandfurringdevice.7Eachsamplereceivedforcetangentialtothedirectionofthewiremeshand

thestuccolayers.Anareaofonesquareinchwasleveledinthemiddleofthefinishedsurfaceforeach

samplebypassingthesamplebackandforthunderthesamecontinuousrimdiamondblade(Figure

II.9).8Thethicknessforthesamplepopulationwas0.67±0.07in.,basedononemeasurementtakenat

thecenteroftheleveledareaforeachsamplebeforetesting.

AnInstron4206testingmachineattheLaboratoryforResearchontheStructureofMatter

(LRSM)wasusedforthreepointbendingtests.Specimenswereplacedflatwiseonsupportblocks,

spacedtoa4in.span.Thesupportswerethenadjustedtoensurethatlengthofthecenterloading

nosewasflushtothesurfaceofthesample(Figure II.10).Forcewasapplieduntilthesamplebroke.The

flexuralstrengthofthematerialisequaltothestresscalculatedatmaximumload,where

S=3FL/2bd²

where:

S = Stress in the specimen at midspan, psi

F = the maximum load at or prior to the moment of crack or break, lbf

L = span, in.

b=widthofthebeamtested,in.,and

d = depth of the beam tested, in.

structionintheUnitedStates.,”TechnologicalPapersoftheBureauofStandards(Washington:GovernmentPrintingOffice,1927),519-520.6ASTMC580-02alsorecommendsthattheundersideofthesamplesaregroundtoplanetoensurethatthesam-pleislevelwhenplacedonthetestingsupports.Thiswasnotappliedbecausethebottomofsampleswerenearlyplane,andexcessivegrindingcouldpotentiallyintroducemicrocrackstothesample.7 TheshankhadbeenremovedbeforeshipmenttoPhiladelphiabyNPSstaff.8VariancefromASTMC580-02;grindingtheentiresurfacewasdeterminedtonotbedesirableasthemechanicalactionandvibrationscouldhaveintroducedmicrocrackstothestructureofthefabric,artificiallyreducingthestrength of the material.



63

Figure II.9. Thethirteenstuccoprismspreparedforthreepointbending;oneinchsquarewaslevelledinthecentertopreventpointloading.(Photobyauthor,2018)

Figure II.10 Stress-StrainCurvesderivedfromthreepointbendingdata.(Photobyauthor,2018)



64

0

50

100

150

200

250

0 10 20 30 40 50 60 70 80 90 100

Stress(psi)

ThreePointBendingResults

Figure II.11 Stress-StrainCurvesderivedfromthreepointbendingdata.

Withacoupleofexceptions,thebehavioroffailureconformedtoexpectationsforbrittle

materials (Figure II.11).TheModulusofRuptureforsamplestestedvariedwidely;theaveragevaluewas

1493.96psiwithastandarddeviationof376.83psi (Figure II.12).Thisfigureissimilartothelowerrange

obtained for architectural limestone and sandstone. The thickness of the sample had no discernible

correlationtoitsmodulusofrupture;itispossiblethattheadhesionofthecementmatrixtothewire

clothwithinthesamplecontributestostrengthofthematerialinbending.9

9ConversationwithDr.AlexRadin,oftheLaboratoryforResearchontheStructureofMatter.



65

Test Sample No. Breaking Load (lbs) Prism Dimensions Modulus of Rupture (psi)

MT 1 N/A** 6 in. x 1 in. x 0.60 in. N/A

MT 2 119.35 6 in. x 1 in. x 0.70 in. 1478.27

MT 3 101.31 6 in. x 1 in. x 0.72 in. 1189.03

MT 4 82.03 6in.x1in.x0.69in. 1036.78

MT 5 149.04 6in.x1in.x0.68in. 1919.78

MT 6 116.38 6 in. x 1 in. x 0.61 in. 1849.21

MT 7 126.18 6 in. x 1 in. x 0.60 in. 2078.68

MT8 146.65 6 in. x 1 in. x 0.71 in. 1733.26

MT9 78.89 6 in. x 1 in. x 0.70 in. 955.05

MT 10 104.51 6 in. x 1 in. x 0.71 in. 1254.50

MT 11 80.96 6 in. x 1 in. x 0.66 in. 1111.78

MT 12 138.95 6 in. x 1 in. x 0.70 in. 1703.86

MT 13 122.09 6 in. x 1 in. x 0.67 in. 1617.34

**MT1wassubjectedtoaseriesofpreliminaryteststocalibratethesettingsfortheInstron.Theresultswereabnormallylowlikelyduetofatigueimposedbyrepeatedforceappliedtothesampleinthesepreliminarytrials.

Figure II.12. BreakingLoadandModulusofRuptureformechanicaltestingsamples.



66

vi.SaltTesting

Saltefflorescencewasnotvisibleonthestructureduringfieldinvestigation,however

photomicrographsofcrosssectionsrevealedlargewhitemineralsbetweenthebrowncoatandfinish

layer in a number of instances (Figure II.13).Forsalttesting,asamplewassubmergedindeionizedwater

andthenthesolutionwastestedtodeterminethepresenceofsaltionsinthesolution.Nitrite,chloride,

andsulfateteststripswereusedbecausethepotentialsourceofthesaltwasunknown.Asmallsample

wasdetachedfromJMH17withahammerandchisel.Thesamplefragmentwasgroundtoapowder

withamortarandpestletoensurethatanysaltcontentinasamplewouldbedissolvedinthewater.10

Thepowderedsamplewasaddedtoaglassbeakerwith50mldeionizedwater,andagitatedwitha

magneticstirringhotplateforfiveminutes(Figure II.14).Oncetheportionofpowderappearedtobe

dissolvedinthewater,thestripsweredippedintothesolutionandthenlefttodry.Thestripsindicate

thatthesamplecontainsmoderateamountsofnitrites(25to50mg/L)andsulfates(1500mg/L)(Figure

II.15).

Thepresenceofsaltisworrisome,astherepeatedcrystallizationanddissolutioninthepores

can cause cracking and spalling of the surfaces.11 To approximate the risk that these materials pose in

thecement,itisessentialtodeterminewhetherthesaltcontentislikelytoincreaseorremainthesame.

Thesulfateoriginateseitherfromexternalorinternalsources.Soilsurveysintheareaindicatethat

thereisalowlikelihoodthatcomponentswithinthesoilmaycontributetoelectrochemicalandphysical

deteriorationofconcrete;thesearebasedonevaluationsofsulfateandsodiumcontentandacidity

of the soil.12Theprimaryinternalsourceforsulfateisahighcontentofgypsumincludedintheinitial

portlandcementmixturetodeterearlyset.Asecondpossibilityisthemineralcontentofthewaterused

tomixtheconcrete,likelyfromtheKellyWarmSpringviatheMormonDitch.Furthertestingisrequired

toidentifythesourceofthesulfate.

10Itispreferabletogrindthesampletoapowderratherthansubmergeasolidvolumewithdisconnectedpores.11DavidOdgers,ed.,Concrete,vol.8,PracticalBuildingConservation(London:EnglishHeritage,2012),97.12WebSoilSurvey,https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx.



67

Figure II.13PhotomicrographofJMH17revealswhitesubstanceattheinterfaceofthebrowncoatandfinishcoat.Magnification100x(PhotobyM.-C.Boileau,2018)

Figure II.14Thepowderedfractionwascombinedwithdeionizedwaterusingamagnet-icstirrerhotplate(Photobytheauthor,2018).



68

Figure II.15 Test strips indicate that the sample contains both sulfates (top)andnitrates(below).(Photobytheauthor,2018)



69

JMH 12 taken from the base of the north ele-vationneartheeastcorner.Photobyauthor,2017.

JMH 16 taken from base of the south elevationneareastcorner.Photobyauthor,2017.

JMH17takenfrombaseoftheeastelevationnear the south corner. Photo by author, 2017.

JMH3takenfromdisplacedcrack(+)belowleftcornerofeastwindowonsouthelevation. Characterizationofstuccofromanexposedareawhichshoulddemonstrateconditionofcementwitheposuretoweatherandthermalcycling. Photo by author, 2017.

Appendix III: STUCCO SAMPLES



70

JMH 20 taken from corner of north and east el-evationundertheeave.Photobyauthor,2017.

The bulk sample has poor interlayer adhesion, perhapsduetofaultyapplication/installation.Sample taken to characterize unexposed ce-ment matrix.

JMH22wasfounddetachedfromthestructure and collected from the ground adjacenttothesouthwestcornerofthewestLaddition.SampletakeninJuly2017by J. Hinchman. Photo by author, 2017.

JMH23wasfounddetachedfromthestruc-ture and collected from the ground adjacent to thesouthcorneroftheeastelevation.Sampletaken in July 2017 by J. Hinchman. Photo by author, 2017.

JMH18takenfromthenorthwestcorneroftheLaddition.Photobyauthor,2017. Sampleiscurvedandhasathickerfinishcoatpaintlayer,likelytheresultofapplication.

Appendix III: STUCCO SAMPLES



71

Smp

No.

Loca

tion

Des

crip

tion

Elev

ation

(s)

Pain

t col

orTe

sting

Dat

e Co

llect

edCo

llect

ed b

y

JMH

03

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rofeastw

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Sout

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nkPe

trog

raph

icExaminati

on10

/21/20

18J.

Hin

chm

an,

S.Stratt

e

JMH

12

Base

cou

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stuc

co fr

om c

orne

r.North

Purp

lePe

trog

raph

icExaminati

on10

/21/20

18J.

Hin

chm

an,

S.Stratt

e

JMH

16

Base

cou

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stuc

co fr

om c

orne

r.So

uth

Purp

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trog

raph

icExaminati

on10

/21/20

18J.

Hin

chm

an,

S.Stratt

e

JMH

17

Base

cou

rse

stuc

co fr

om d

eter

iora

t-ed

areaatSEcorner.

East

Purp

lePe

trog

raph

icExaminati

on,

SaltTesting

10/21/20

18J.

Hin

chm

an,

S.Stratt

e

JMH18

NWcorne

rofth

eell.

North,W

est

Pink

Petrog

raph

icExaminati

on10

/21/20

18J.

Hin

chm

an,

S.Stratt

e

JMH

20

NEcorner,u

ndereave.

East,N

orth

Pink

Petrog

raph

icExaminati

on10

/22/20

17J.

Hin

chm

an,

S.Stratt

e

JMH

22

SWcorne

rofth

eell.

West

Purp

lePe

trog

raph

icExaminati

onSu

mm

er 2

017

J. H

inch

man

JMH

23

Base

cou

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stuc

co fr

om d

eter

iora

t-ed

areaatSEcorner.

East

Purp

lePe

trog

raph

icExaminati

on,

WaterAbsorpti

onSu

mm

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017

J. H

inch

man

JMH

24

Areaofsignifican

tlossatbaseof

southelevati

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Sout

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poin

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Condition: Crack Sizes Small

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LossLarge

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Windows obscured by plywood

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yom

ing

DES

CR

IPTI

ON

SHEE

T ID

ENTI

FIC

ATI

ON

:

SCALE IN FEET

0 5 101


0 1 5 10



LossLarge

Medium


SCALE IN FEET

0 5 101

Cra

ck

co

nd

itio

ns

on

no

rth

ele

vatio

n.

JOHN

MO

ULTO

N H

OM

ESTE

AD

1304

0 A

nte

lop

e F

lats

Ro

ad

G

ran

d T

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n N

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na

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DES

CR

IPTI

ON

SHEE

T ID

ENTI

FIC

ATI

ON

:

10 5 10


Sam

ple

loc

atio

ns

for e

ac

h e

leva

tion

.

Petrographic Analysis

Paint Analysis

MechanicalTesting Paint analysis will be part of a succeeding

report to be completed in the fall of 2018.

Hollow markers indicate samples that come from the junction of two elevations.

JOHN

MO

ULTO

N H

OM

ESTE

AD

1304

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SHEE

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:

Sam

ple

loc

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ns

for n

ort

h e

leva

tion

.

22

18

JOHN

MO

ULTO

N H

OM

ESTE

AD

1304

0 A

nte

lop

e F

lats

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G

ran

d T

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n N

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na

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DES

CR

IPTI

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SHEE

T ID

ENTI

FIC

ATI

ON

:

Sam

ple

loc

atio

ns

for s

ou

th e

leva

tion

.

03

16

JOHN

MO

ULTO

N H

OM

ESTE

AD

1304

0 A

nte

lop

e F

lats

Ro

ad

G

ran

d T

eto

n N

atio

na

l Pa

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oo

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ing

DES

CR

IPTI

ON

SHEE

T ID

ENTI

FIC

ATI

ON

:

Sam

ple

loc

atio

ns

for e

ast

ele

vatio

n.

20

17

23

JOHN

MO

ULTO

N H

OM

ESTE

AD

1304

0 A

nte

lop

e F

lats

Ro

ad

G

ran

d T

eto

n N

atio

na

l Pa

rk, M

oo

se, W

yom

ing

DES

CR

IPTI

ON

SHEE

T ID

ENTI

FIC

ATI

ON

:

Sam

ple

loc

atio

ns

for n

ort

h e

leva

tion

.

20

12

08

report 1 2018 opti.pdfgrand teton national park task 1 report: stucco assessment john moulton...

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