Challenges and Strategies for Material Conservation in Tropical Heritage
Buildings:
ACaseStudyofBlairPlainShophouseinSingapore
LiuXingyu
A0299126U
NationalUniversityofSingapore
DepartmentofArchitecture
MasterofArtsinArchitecturalConservation
April2025
Acknowledgement
I would like to extend my deepest gratitude to my supervisor, Ho Puay Peng, for providing me with firm guidance, critical insights, and continuous support throughout the research process. I would also like to thank all the teachers at Architectural Conservation and all the NUS teachers who have helped me, their knowledge and encouragement has been a constant source of motivation when I havefeltconfusedorhesitantandIamhonoredtohavebeenabletocompletethis journeyundertheirguidance.
I am also deeply grateful to my family, whose love and trust have been the cornerstone of all my academic pursuits. Their emotional and financial support gave me the courage to pursue my education abroad. We are separated by thousandsofmiles,butIhaveneverfelttheslightestlossofloveandsupport.Finally,
I would like to thank my friends and classmates in Singapore and back home. You not only enriched my life in Singapore, but also accompanied me and gave me valuable advice on my research and writing. I would like to thank my family and friendsforbeingthereforme.
List of Figures
Figure1.BoundaryoftheBlairPlainconservationarea.(Source:URASPACE)
Figure 2&3. Signboards of the UAR Architectural Heritage Award. (Source: Photographbytheauthor)
Figure 4. Nanyang Technological University's “Earth Room”, Asia's largest wooden building, has been open for more than a year, and its exterior walls are already stainedandmoldy.(Source:LIANHEZAOBAO)
Figure5.AerialviewoftheIseShrine.(Source:ArchDaily)
Figure 6. 92-102 Joo Chiat Place, restoration included the reconstruction of the timberdouble-casementwindowsandfrontdoorsto “retaintheinherentlook” of theshophouse.(Source:Houzz)
Figure7.Ceramicappliqué onfrontfacadeofNUSBabaHouse.(Source:NUSBaBa House)
Figure8.Ceramicappliqué onfrontfacadeofNUSBabaHouse.(Source:NUSBaBa House)
Figure9.Thegallery.(Source:NUSBaBaHouse)
Figure10.Digitalimage.(Source:NUSArClab)
Figure 11. The stagefor teachingand experimentation. (Source:Photograph by the author)
Figure12.Samplingformaterialtesting.(Source:NUSArClab)
Figure 13. The Blair Plain continuous commercial function shophouse along
KampongBahruRoad.(Source:Photographbytheauthor)
Figure 14&15. 711 Modern fixtures and materials for interior and exterior.
(Source:Photographbytheauthor)
Figure 16. The complete color pattern is preserved. (Source:Photograph by the author)
Figure 17. 55 Spottiswoode Park Road well-preserved facade. (Source:Photograph bytheauthor)
Figure18.Mainstairwaywithcastironbalusters.(Source:UARAHA)
Figure 19. Disclosure of information on contractors. (Source:Photograph by the author)
1. Introduction
1.1 Research Background
TheBlairPlainconservationareaisa compact cluster of two- and three-story shophouses and terrace houses in a wide variety of architecturalstyles.Theareaconsists of a cluster of buildings on the south side of Kg Bahru Road and Neil Road andonbothsidesofBlairRoad,withthemajorityofthebuildingsintheareastillin residential use, with the exception of some commercial uses along Kg Bahru Road. Theareawaslistedasaconservationareaon10/25/1991.
The area was first built up on a large scale in the late 19th century, with detached bungalowsbeingdevelopedandlandbeingsubdividedindetailintotownhouserow houses. In the 20th century, further urbanization took place, and Blair Road was plattedin1990,andnamedafterJohnBlair,whowasaseniorofficialoftheTanjong PagarWharfCompanyinthe1880s.Heownedlandintheareaandalsohadalarge house near the harbor. During the early twentieth century, elaborately decorated buildings were constructed along Blair Road and Neil Road, probably due to the increaseddemandforhousingbywealthymerchantfamilies.Theconstructionand
residential historic districts (The Blair Plain included). At the same time, URA has implementedacomprehensiveregulatoryoversightandapprovalprocess,whereby any restoration, remodeling, or replacement of materials in a conserved building must be submitted to the URA forapproval. It is worth mentioning that the Urban Redevelopment Authority Architectural Heritage Award (AHA), which recognizes exemplaryrestorationprojects,hasbeenawardedtosixofTheBlairPlain'sprojects, providingareferenceforthispaperaswellasforfuturepreservationefforts.
1.2 Objectives and Issues
Fig 2&3. Signboards of the UAR Architectural Heritage Award. (Source: Photograph by the author)
The main objective of this paper is to examine the challenges faced in the conservationofhistoricbuildingmaterialsinSingapore,withaspecialfocusonthe shophouses of The Blair Plain.The Urban Redevelopment Authority (URA) of Singapore has articulated preservation guidelines, but analyzing how preservation
balances historical authenticity and contemporary technological interventions remainsasubjectofdebate.Themainresearchobjectivesofthispaperinclude:
1. to define authenticity in the context of physical conservation of residential historicaldistrictsin Singapore,assessinghowURA guidelinesareinterpretedand implemented.
2.toexaminetheuseofmoderntechniquesandmaterialsinconservationpractices andanalyzewhethertheycomplementorcompromisetheauthenticityofheritage.
3. identify conflicts and challenges that arise when applying modern materials or interventionstotraditionalbuildings.
4. analyze the need for retrofitting for the three different types of functional shophouses in The Blair Plain, using successful or failed case studies as aids and bases.
5. Generate a framework of findings to explore how to achieve a balance between preservingauthenticityofmaterialsandmoderntechnology.
Despite the clear and detailed conservation guidelines developed by the URA, the practical implementation of material conservation remains a controversial topic, withthemainchallengebeingthetensionbetweenconservingtraditionalmaterials and using modern technology to improve performance. This study focuses on the issue of how to define and implement authenticity in material conservation. A universal definition of authenticity is lacking, and URA' s conservation guidelines emphasize minimizing interventions and preserving original materials, but how much change is acceptable before authenticity is lost? Different stakeholders
expert interviews are used to examine the practical application of materials conservationinpracticeundertheURA'sconservationguidelines,andtoassessthe current relationship between preserving the authenticity of materials and integratingmoderntechnologies.
The underlying policy literature focuses on URA' s preservation guidelines, with a particularfocusonresidentialhistoricdistrictsandaspectsofmaterialsrestoration, technicalrestorationmanuals,andpreservationcharters(e.g.,VeniceCharter,Nara DocumentonAuthenticity),whichprovideatheoreticalfoundationforauthenticity in preservation. Case studies focusing on The Blair Plain's URA architectural heritage awards-winning projects include 149 Neil Road (1995 AHA awardee) for authentic restoration with minimal intervention, 153 Neil Road (2003 AHA awardee)formodernmaterialsreplacement,55SpottiswoodeParkRoad(2010AHA Awardee)forstructuralreinforcementusingmodernmaterials,andsixothercases.
FieldresearchwascarriedouttoinvestigateanddocumentthearchitectureofThe Blair Plain, observing and recording recognizable material interventions and modern reinforcements, categorizing and recording the different functions of the shophouse, and evaluating the practical application of the URA guidelines. Expert interviews with conservation practitioners, targeting URA heritage planners, conservationarchitectsorrestorationspecialists,andbuildingownersormanagers in the region, to gain insights into the factors influencing the selection and use of materialsintherestorationprocess.
This study focuses on material conservation challenges and strategies within The
Blair Plain conservation area, analyzing the balance and integration of authenticity andmoderntechnologyintheheritagerestorationprocess.Thegeographicalscope of the study is The Blair Plain, residential historic districts regulated by URA Conservation,thereasonsforchoosingthisareaasthetargetofthestudyare,firstly, that it is a relatively independent residential conservation area and its functional zoning is more clearly defined, which makes it easier to study the conservation of materials; and secondly, it is located in the urban zone, which is unavoidably affectedbymodernlife.Themainscopeofthestudyisthechallengesandstrategies of materials conservation, and the perspective of the whole paper is within the conservation guidelines of URA. The limitations of this paper are the absence of experimental material testing, the reliance on site surveys, expert interviews and existing conservation reports, and the limitations of conducting the study solely on theshophouseatTheBlairPlain.
1.4 Hypothesis
ThisstudyhypothesizesthatURA'smaterialconservationpolicyatTheBlairPlain has been mainly successful in maintaining heritage authenticity, but faces challenges in integrating modern techniques due to material scarcity and climate-related deterioration. Hypotheses include that URA' s conservation policy emphasizesminimalinterventionandmaterialretentiontoensuretheauthenticity ofthehistoricshophouseatTheBlairPlain,thatURA'sconservationguidelinescall
for the use of traditional materials, and that URA architectural heritage awards-winning projects exemplify adherence to the principles of authentic restoration. It is assumed that modern techniques can enhance material conservation without compromising authenticity, such as the case study of The Blair Plain which demonstrates structural reinforcement that preserves historic elements, utilizing advanced conservation techniques such as 3D scanning to document and restore original features. It is assumed that while URA' s guidelines protect the authenticity of heritage, they still lack the adaptability to meet modern conservation challenges, especially in the context of Singapore's special climatic conditions and rapid urbanization, where the need to balance conservation and modernizationremains.
2. Literature Review
2.1
materialssuchaswood.2 Inaddition,microbialgrowthandinsectinfestations(e.g., termites) are prevalent in the tropics. These organisms degrade organic materials suchaswood,thatchandnaturaldyes.Forexample,traditionalwoodenstructuresat heritagesitesinSoutheastAsiaoftenrequirefrequenttreatmenttopreventtermite damage,butmanyconventionalfungicidesareincompatiblewithhistoricmaterials or are environmentally hazardous. Biofilms formed by algae and bacteria on stone surfaces further exacerbate erosion by retaining moisture and secreting acidic metabolites.
Intermsofmaterialconservation,restorationwithmodernmaterialsoftenleadsto incompatibility issues. Cement-based mortars, while durable, can accumulate moistureintraditionalporoussubstrates,leadingtosaltcrystallizationandspalling. Materialconservationoftropicalheritagebuildingsshouldalsofocusonsustainable maintenance;traditionalmaterialssuchasmudandlime,whileculturallyauthentic, require frequent maintenance in tropical climates. Life Cycle Assessments (LCAs) haveshownthattheneedforfrequentmaintenanceduetorapidweatheringhasa greater cumulative impact on the environment than more durable modern alternatives. However, modern materials such as hydraulic cements have a higher carbon content and therefore require a trade-off between sustainability and longevity.3
2 Doni, M., Fierascu, I., & Fierascu, R.C. (2024) 'Recent Developments in Materials Science for the Conservation and RestorationofHistoricArtifacts',AppliedSciences,14(23),p.11363.
3 Mazzetto, S. (2025) 'Comparative Life Cycle Assessment of Traditional and Modern Materials in Heritage Building Restoration:ACaseStudyfromUshaigerVillage',Sustainability,17(1),p.25.
Finally,technologyandeconomicsalsopresentchallengestomaterialsconservation, with difficulties in accessing skilled artisans familiar with traditional techniques and the high cost of specialized conservation materials impeding effective conservation. In Malaysia, for example, due to a shortage of artisans skilled in lime plasteringortimberjoinery,conservationprojectsoftenfacedelaysandhavetorely on less sustainable modern alternatives. In addition, owing to funding constraints, short-termrestorationisprioritizedoverscientificallybasedlong-termsolutions.
2.2 Theoretical Framework of Authenticity in Heritage Conservation
The concept of authenticity is central to heritage conservation, serving as a cornerstone for evaluating and preserving cultural heritage. Its theoretical framework has evolved through international charters, conventions, and scholarly discourse,reflectingdiverseculturalperspectivesandpracticalchallenges.Belowis asynthesisofkeyprinciplesanddebates,anchoredinfoundationaldocumentsand contemporaryinterpretations.
The notion of authenticity in conservation traces its roots to the Venice Charter (1964), which emphasized preserving the material integrity and historical continuityofmonuments.Thechartermandatedthatinterventionsmust"notalter the lay-out or decoration" of heritage structures, prioritizing physical authenticity through original materials anddesign.4 However, thisEurocentric perspective was
4 ICOMOS.(1964)InternationalCharterfortheConservationandRestorationofMonumentsandSites(TheVeniceCharter). Venice:ICOMOS.
5. Aerial view of the Ise Shrine. (Source: Arch Daily)
Authenticity in heritage conservation is a multidimensional concept that extends beyond material preservation to encompass design, function, cultural context, and intangible values. Material authenticity, as emphasized in the Venice Charter and Athens Charter (1931), underscores the importance of retaining original fabric to maintain historical integrity.6 Beyond physical elements, functional authenticity plays a significant role in heritage conservation by sustaining traditional uses, exemplifiedbyreligioussiteslikeKyoto’sKiyomizu-dera,whichcontinuestoserve its spiritual purpose. Furthermore, cultural context is integral to authenticity, as articulated in the Burra Charter (1999) and Quebec Declaration (2008), which advocate for the recognition of local values and community practices in
6 International Congress of Architects and Technicians of Historical Monuments. (1931) The Athens Charter for the RestorationofHistoricMonuments.Athens:ICOMOS.
conservation efforts.7 Lastly, the spirit and feeling of a heritage site, often tied to collective memory and intangible cultural significance, is a vital aspect of authenticity,ashighlightedintheNaraDocument.Theseprinciplescollectivelyform the foundation for assessing and maintaining the authenticity of heritage sites, ensuringtheircontinuedculturalrelevanceandhistoricalintegrity. While the theoretical framework of authenticity provides essential guidelines for heritage conservation, its practical application often encounters significant challenges.Onemajorissueistheintegrationofmoderninterventions,suchasthe use of contemporary materials like steel reinforcements in ancient masonry structures.Althoughthesematerialsenhancestructuralstability,theyraiseconcerns regarding compatibility with traditional building techniques and long-term sustainability, as critiqued in the ICOMOS Principles for Architectural Heritage (2003). Another critical challenge lies in the tension between globalization and localism in conservation practices. Standardized methodologies, often promoted by international organizations, risk undermining cultural specificity by imposing uniform solutions thatmay notalign with local traditionsandvalues.This concern is explicitly addressed in the Xi’an Declaration (2005), which advocates for context-sensitive approaches that respect regional heritage identities. These challenges highlight the need for a balanced conservation strategy that upholds authenticitywhileadaptingtocontemporaryrequirements.8
7 ICOMOS.(2008)TheQuébecDeclarationonthePreservationoftheSpiritofPlace.Québec:ICOMOS.
8 ICOMOS. (2005) The Xi’an Declaration on the Conservation of the Setting of Heritage Structures, Sites and Areas. Xi’an: ICOMOS.
2.3 Application of Modern Technologies in Material Conservation
In tropical regions, heritage buildings confront significant conservation challenges duetoharshclimaticconditionssuchashighhumidity,intensesolarexposure,and frequent rainfall. Thus, innovative material applications and sensitive modern interventionsbecomecrucialforsustainableconservationpractices. Recent developments in tropical architecture emphasize the use of environmentally-friendlyandhighlyresilientmaterials.Laminatedbamboo,known for its rapid renewability, exceptional strength, and resistance to humidity, has emerged as an effective structural alternative. Its application reduces reliance on hardwood, mitigating deforestation and enhancing the ecological sustainability of conservation projects. Another cutting-edge example is the use of thermochromic glass,whichintelligentlyadjustsitstransparencyaccordingtoambienttemperature changes.9 Such adaptive materials significantly reduce solar heat gain, improving indoor thermal comfort while minimally impacting the building’ s historic appearanceandauthenticity.
9 Parametric Architecture, 2023. Innovative materials in tropical architecture. [online] Available at: https://parametric-architecture.com/materials-in-tropical-architecture/[Accessed30March2025].
2.4 Impact of URA Conservation Guidelines on Material
The Urban Redevelopment Authority (URA) Conservation Guidelines play a crucial role in shaping material conservation practices for historic buildings in Singapore. Within Residential Historic Districts. These guidelines establish a balance between preserving heritage authenticity and accommodating modern needs, directly influencingtheselection,restoration,andadaptationofbuildingmaterials. One of the primary impacts of URA’ s conservation framework is the mandated retention of original materials where feasible. The guidelines emphasize the preservation of key architectural elements, such as timber windows, clay roof tiles, andlimeplasterfinishes,ensuringthathistoricfabricremainsintact.Whenoriginal materialsaredeterioratedbeyondrepair,URApermitsreplacementwithcompatible materials, provided they match the historical aesthetics and performance of the originals.11 This is particularly relevant in the case of tropical weathering, where traditional materials such as timber are susceptible to high humidity and termite infestations. Conservation projects must use treated timber or sustainable alternativesthatmimictraditionalpropertieswhileofferingenhanceddurability.
11 Urban Redevelopment Authority (URA). (n.d.) Residential Historic Districts, Conservation Guidelines – Part 2: Planning Parameters and Restoration Guidelines. Available at: https://www.ura.gov.sg/Corporate/Guidelines/Conservation/Conservation-Guidelines/Part-2-Planning-Parameters-and-Rest oration-Guidelines/Residential-Historic-Districts[Accessed30March2025].
mitigating common deterioration factors such as efflorescence and salt crystallization,ensuringthelong-termpreservationofheritagematerials.
2.5 Research Gap
AlthoughURA'sguidelinesprovideacomprehensiveframeworkfortherestoration and material conservation of historic buildings and different requirements for different types of shophouses, they do not differentiate preservation strategies accordingtothefunctionaltypeoftheshophouse.ThispapertakesTheBlairPlain asanexample,whereshophousesareprimarilyusedforresidentialpurposes,while some are educational, lab and creative spaces, and commercial spaces. The paper argues that despite the flexibility provided by the URA guidelines, functionally diverse shophouses lack differentiated conservation strategies, and the material properties,structuraladaptations,andtechnologiesrequiredfordifferentfunctions vary widely. This gap highlights the need for adaptable, type-specific conservation frameworks.
Then, in order to achieve differentiated conservation while adequately protecting the authenticity of the heritage, a definition of authenticity is essential. The Nara Document on Authenticity broadens the understanding and criteria of authenticity, and the Barra Charter and the Xi'an Declaration take into account spiritual and environmentalfactors,amongothers.Thequestionofhowtodefineauthenticityof materials in the context of heritage in the tropics, supported by policies, is also an
importantonetobeexploredinthisstudy.
In the following sections of this study, this paper explores how different functional types of shophouses within Blair Plains require unique approaches to material protection. By examining case studiesandpractical applications, this researchwill suggest how conservation strategies can be tailored to balance historic material authenticity with modern technological demands, ensuring that Blair Plain's shophouses are both culturally significant and functionally sustainable in the contemporaryurbanlandscape.
3. Comparative Analysis of Blair Plain Shophouse: Functionality and Material Conservation
For chapter 3, this study categorizes the shophouse of The Blair Plain into three functional types, and explores the main problems encountered in material protection in different functional shophouses. In order to analyze and research moreclearly,oneortwoshophousesamongthefourfunctionaltypesareselectedas research examples. In terms of material protection, the focus is on materials that are susceptible to the tropical environment and affect the use experience and the overallappearance,mainlyfocusingonlime,timber,brickandtile.
3.1 Educational Spaces
At The Blair Plain, NUS BaBa House (at 157 Neil Road) is a prime example as it demonstrates how the conversion of a traditional shophouse into an educational andexhibitionspacebalancestheneedforfunctionalitywithmaterialconservation.
Built around 1895, 157 Neil Road was originally owned by the Wong family, prominent shipping merchants. Located in The Blair Plain Residential Historic Districts,thebuildingwaslistedbytheURAin1991,andthegovernmentinitiateda restoration program in 2007, with the National University Museum, NUS DepartmentofArchitecture,URA, andtheNativeChineseAssociationofSingapore (NCAAS) as the key partners in this preservation project. After meticulous restoration,BaBaHousewasofficiallyopenedtothepublicinSeptember2008asa museumshowcasingtheculturalandarchitecturalheritageofPeranakan.
During the restoration of BaBa House, the restoration team aimed to preserve the original spatial and visual features of the house while ensuring its physical integrity and also the safety of visitors. The team sought to find a balance between authenticity,materialpreservation,modernutilityandsafety.Intermsofmaterials, which is the main focus of this study, BaBa House conducted a material study to determine the early colors of the walls and woodwork in particular, and based on the results of the material study painted the building façade blue and restored the
House to fulfill the authenticity requirements as much as possible. However, transformingaprivatehomeintoapublicmuseum,thepreservationrequirements ofthehistoricmaterialsposedasignificantchallengeinadaptingtherenovationto modern functions. For example, modern lighting and air-conditioning systems had to be installed to meet the needs of exhibitions and visitors; elevators had to be installed to meet the needs of different groups of visitors; and modern restroom facilities had to be installed to meet the needs of modern hygiene. The inclusion of modern facilities is essential, and BaBa House has adopted a careful restoration strategy for the materials, but it has not been possible to avoid the impact of the inclusionofmodernfunctionsontheoverallarchitecturalenvironment,butitmust berecognizedthatthisisunavoidable.TherestorationandreuseofBaBaHousehas been a relatively successful demonstration of how to deal with the challenges of material conservation in educational and exhibition spaces, and how to achieve a balance between historical authenticity and modern functionality. balance between historicalauthenticityandmodernfunctionality.
The Architectural Conservation Laboratory (ArClab) of the National University of Singapore (NUS) at 141 the Neil Road in the Blair Plain is a special case as it is a conversion of a traditional shophouse building into a laboratory and educational
space for architectural research, and is explored here as a unique case study in its own right. The building was constructed in the 1880s and is a stylistically transitionaltypologyspanningtheEarly(1820s-1900s)andLateChannelPeriods. The building contains a series of fine decorative tiles depicting British Art Nouveau andChinesemotifs.DecorativeplaquesinChinesecharactersarelocatedabovethe door frames in both clerical and cursive scripts.The Portabella family donated the buildingtotheNationalUniversityofSingaporearound2022withadonationofS$2 milliontosupportitsrestorationandconservation.
As a place of education and experimentation, ArClab goes beyond the preservation ofmaterials,andmakesabigdifferenceinasmallway,bycombiningresearchand teachingactivitiesatthesametime.Examplesincluderesearchinganddocumenting buildings using innovative techniques such as traditional documentation and 3D modeling; sampling building materials suchas stucco, masonry, andtiles to be sent to professional institutionsfor material testing; developing an integrated approach to energy efficiency and rate and net-zero retrofitting of Singapore's historic buildings; testing and developing traditional building materials and techniques and using innovative techniques for conservation and restoration work in the Singaporean environment; and assessing the the impact of high-density urban environmentsonthemicroclimateofhistoricneighborhoods.
At the same time, however, the problems faced by ArClab as an experimental and researchsitewillbemagnified.Theplasterandsurfacesareinpoorcondition,with largeareasofspallingandplantadhesioninmanyareasduetohumidityandplant
adhesion. However, to provide exhibition and teaching space for students and practitioners,andtoprovideamoreaccuratebasisfortestingandconservation,the site has been maintained in its original condition. In order to provide hands-on experimental learning opportunities for conservation students, some of the mortar will be removed and reworked for teaching and experimentation. Although the load-bearing structure is a brick structure, the indoor staircase, beams and floor slabs are mostly wooden structures, and some of the beams have been eroded by termites,sotheload-bearingcapacityofthewoodhasbeengreatlyreduced,andthe second floor is no longer able to withstand large loads. The indoor terracotta floor tiles are also mostly discolored by moisture, and most of the exquisite decorative tilesareingoodcondition,buttherearealsoerosionanddiscoloration,flakingand lossofthephenomenon.
The restoration of the Arclab is still in the researchand documentation phase, and thebuildingremainsinitsoriginalstate.Fortestingandteachingpurposes,partial samples of materials from various parts of the building have been taken. Some modern measureswereintroducedforeverydayuse,mostlyreversibleinstallations such as vertical projection systems, suspended lighting systems, and no air-conditioning systems were installed to avoid damage to the original materials.
As the first of its kind in Southeast Asia, the Arclab provides a unique platform for researchers, students, and architectural heritage professionals, as well as a professional research venue for materials conservation in Singapore. However, its uniqueness requires particular care in the selection of materials for conservation andrestoration,andthepreservationoftheintegrityofthebuildingwhilstrealizing itsuniquefunctionalityisamajorissueforArClab.
Road.Inthispartoftheresearchprocess,7-elevenlocatedatNo.9wasselectedas themainobjectofstudybecauseofitsbetteraccessibilityasachainofconvenience stores, more complex functional requirements, and higher consumer traffic, which inevitablyputpressureonthelong-termuseofmaterials.
tothefunctionalneedsofthebusinessforserviceaccessorpromotion,butsignage installation receives regulation in heritage districts that visually require that the overallappearanceandintegrityofthefaçadenotbeallowedtobecompromised.So despite these compromises, the store retains its historic appearance and contributes to the streetscape character of the conservation area.The URA's regulatoryfocusonpreservingthearchitecturalappearanceandarticulationofthe façadeensuresthatthestoreisvisuallyinkeepingwiththesurroundingbuildings, even if internal interventions prioritize functionality. In conclusion the case of 7-eleven exemplifies the complexity of material conservation in the placement of commercial functions in a heritage built area, where the loss and replacement of materials is inevitable, but the continued coexistence of functionality and heritage value can be equally ensured under URA's guideline requirements and audit approvals.
3.3 Residential Adaptation
Most of the shophouses in The Blair Plain are still residential in function and the building serves a human being, so the demands placed on the building to ensure human comfort are the biggest issue facing the preservation of materials for this functional type of shophouse. Modern lifestyles require comfort, efficiency, and supporting infrastructure, which often partially conflict with the preservation of originalmaterialsandspatialconfigurations.Thisstudyfocuseson55Spottiswoode Park Road, winner of the 2010 URA Architectural Heritage Award, as a diffuse explorationoftheissuesfacingtheresidentialshophouseatTheBlairPlain.
the traditional Southeast Asian entry doors, metal handrails in the stairwells, concreteventilationshafts,andnewscreensattherear,whichechothestyleofthe pre-war shophouse. One of the most striking features of the project is the introduction of light-filled courtyards and a infinity pool, both of which cater to the tropicalclimatewhilerespectingthearchitecturalrhythmoftheoriginalhouse.The design of these additions clearly distinguishes between the old and the new, maintaining legibility between the preserved elements and the contemporary insertions,anapproachthatinturnisinlinewiththebestpracticesoutlinedinthe Venice Charter. Even though the URA preservation guidelines emphasize prioritizingminimalinterventionandcompatibilityofoldandnewmaterials,inthe renovation of a private residential shophouse, the functionality of the building as well as human comfort is prioritized. The careful spatial planning of the 55 SpottiswoodeParkRoadrenovationproject,withitsrecognizabletransitionfromold to new, suggests that the residential shophouse can also be renovated to meet contemporarylivingstandardswhilepreservingasmuchofthebuilding'scharacter aspossible. However,theproblemsfacedbyresidentialfunctionshophousesarenotonlysolved by a perfect update or replacement design. Preservation can cost more financially than renewal, the addition of sudden modern elements can affect the overall appearance of the building, and inappropriate use of materials can cause more damagetothebuilding,etc.Alloftheseareproblemsfacedbyownersofresidential shophouses, and they are the focus of the government's support as well as its
restraints.
3.4 Comparative Summary: Function-Specific Conservation Approaches
TheaboveanalysisofthethreefunctionalcategoriesoftheBlairPlainshophouses (educational spaces, commercial spaces, and residential conversions) shows that while the challenges of materials conservation in Singapore are basically rooted in the characteristics of its tropical climate as well as the constraints of its urban development, the specific strategies and overriding considerations of conservation varygreatlydependingonthefunctionofthebuilding.
Educationalspaces,suchastheNationalUniversityofSingapore'sBaBaHouse,are somewhat complex and require a high degree of material authenticity to support theirconservation andpedagogicalpurposes. Conservation ofsuchspaces isoften characterized by meticulous restoration, authentic material replication, and integration into modern systems in as reversible a manner as possible. The focus here is on authenticity, enabling students and visitors to experience heritage through a physical environment that is consistent with the historic context and materials. However, there are certain accessibility infrastructures, lighting and air conditioningsystemsthatmustbeintroduced,whichoftencreatetensionsbetween useandpreservation.
In addition more unusual spaces that function as experimental and educational spaces, such as the ArClab at 141 Neal Road, operate under a dual agenda:
Acrossallcategories,comparativeanalysessuggestthatfunctionalityinfluencesthe extentandtypeofmaterialintervention.Forexample,whilelimestuccoandtimber aregenerallyvulnerabletodamageinSingapore'sclimaticconditions,thestrategies for conserving them - ranging from fully documented discreet preservation in educational spaces to direct interventions with new materials in stores - vary depending on the intended use. Conservation approaches must therefore be function-specific,balancingauthenticityandutilitywithadifferentperspectivethat respects the building's cultural values while supporting its contemporary life cycle. In this way, by recognizing the different needs of users, and the properties of materials, a differentiated conservation framework tailored to the building's function is essential for the sustainable management of heritage materials in tropicalurbanenvironments.
Functions
Main Issues
Educational Needauthenticity,publicsafety
Commercial Highwear,hygieneneeds
Residential Comfortneeds,costsensitivity
Current Main Conservation
Approach
Reversibleinstallations,testing
Durable replacements, facade kept
Partial replacements, new insertions
Chart 1.Function-Specific Conservation Approaches
4. Balancing Cultural Authenticity and Modern Needs: Recommendations
Under URA Guidelines
4.1 Implications and adaptations of the URA Guidelines for material selection
URA has developed detailed preservation guidelines for residential historic preservation districts that emphasize the ‘3Rs’ principles of maximum retention, sensitive restoration, and careful repair in the restoration and renovation process. These principles directly influence the selection and application of materials to ensure the historical authenticity and integrity of the building. The URA sets out clearrulesfortheuseofmaterialsintheResidentialConservationArea.
1.Roofingmaterials
TheURArequiresthattheoriginalroofprofile,pitch,andheightbepreservedand restored. Traditional small-size, V-shaped, unglazed, natural-colored clay tiles are specifiedasthepreferredmaterialtomaintainconsistencywiththeoriginaldesign. These materials are permitted only if flat, interlocking clay tiles or reinforced concretewereusedintheoriginalconstruction.
2.FacadeElements
The front façade of a building must retain its original features, including windows, doors,shutters,anddecorativedetails.Wherereplacementisrequired,newelements should match the original design and materials. For example, new windows should havewoodframesandinfillmaterialsmaybewoodorglasstomaintainthehistoric
lookofthebuilding.
3.Rearextensions
In Residential Historic Preservation Districts such as Emerald Hill, Cairnhill, and BlairPlain,rearextensionstothemainpreservedbuildingarepermittedtoprovide additionallivingspace.However,theseextensionsmustbebelowthemainroofand comply with specific design and height restrictions to preserve the scale and characterofthehistoricroofscape.
4.Internalelements
For interior finishes, it is recommended that original interior elements such as stairways, ceiling trim, and flooring materials be retained. Where replacement or restoration is required, materials consistent with the original materials and design shouldbeusedtomaintainthehistoricintegrityoftheinteriorspace.
5.Integrationofmoderntechnology
Whenintroducingmodernamenities(e.g.,airconditioningsystems,elevators,etc.), itisimportanttoensurethattheseadditionsdonotsignificantlyaffectthehistoric character of the building. For example, the outdoor units of air-conditioning should behiddenintherearyardorconcealedbyappropriateshieldingmeasuresasfaras possibletominimizetheimpactontheexterior.
Inadditiontothis,ifanyrestorationorremodelingofabuildingisdesiredwithina historic preservation district, an application should be submitted in the URA website, pending evaluation and approval. In summary, URA's conservation guidelinessetoutclearrequirementsfortheselection andapplication ofmaterials,
aiming to ensure the quality and consistency of restoration and remodeling work. Following these guidelines while flexibly adapting to the needs of modern life is an importantwaytoachievesustainableconservationofhistoricbuildings.
4.2
Material conservation strategies for different functions
Within the Blair Plain Historic Preservation District, although the URA provides a holistic framework for material preservation, material use, spatial alterations, and userneedsvarydependingonthefunctionaluseofthestorehouses.Therefore,this sectionproposesdifferentiatedmaterialpreservationstrategiesforthethreetypes of functional functions (educational space, commercial space, and residential remodeling). These strategies are intended to respond to the specific challenges of eachtypeoffunction,whilefittingintothetheoreticalframeworkofpoliciessuchas URA'scurrentconservationguidelinesandtheNaraAuthenticityDocument.
4.2.1
Educational spaces
Taking Baba House (157 Neil Road) at the National University of Singapore as an example, the focus of the educational and exhibition spaces is on material authenticity and historical restoration. The restoration process prioritized the preservationoforiginalmaterials,suchaslimeplasterlayersandwoodenelements, whilecarefullyrestoringearlycolorschemesandtilepatterns.However,inviewof
4.2.2 Commercial use
For high-traffic commercial spaces such as the 7-Eleven convenience store at 9 Kampong Bahru Road, wear and tear from ongoing operations and modern retail demands cause materials to age at an accelerated rate. While the interior is often replaced with modern, easy-to-clean materials such as ceramic tiles, suspended ceilings, and painted walls, the façade is still subject to the stringent protection requirementsoftheURA.
A“zonedpreservationstrategy”isrecommendedforthisscenario.Thestreet-facing façaderetainstheoriginalmaterials,suchaslimeplasteredwalls,windowanddoor elevations, and detailing. Where replacement is required, treated or composite materialswithsimilar surface texturesarerecommended.Modern materialscanbe used moderately in the interior space, but irreversible impacts on load-bearing structures should be avoided. At the same time, URA has clear specifications for signage and color selection to ensure that the appearance of the stores is in harmonywiththeoverallappearanceoftheneighborhood.
4.2.3 Residential Adaptation
Residentialshophousessuchas55SpottiswoodeParkRoadplacegreateremphasis onresidentialcomfortandmodernamenities,withcommoninterventionsincluding
interiordesignupdates,ventilationsystems,andkitchenandbathupdates.TheURA
ArchitecturalHeritageAwardwinningdesignofthebuildingretainsthefrontfaçade andcorespaceswhileintroducingpatiosandarooftopswimmingpooltomeetthe needsoflivinginatropicalclimate.
The material strategy for the residential features required a balance between traditionalappearanceandmodernpracticality.Treatedtimberandbreathablelime paint were recommended for durability and compatibility. Elements such as electricalconduits,drainagesystems,etc.shouldbeconcealedasmuchaspossibleto preservehistoricelements.Newlyplaced modern elementsarerecommendedtobe compatible in scale and style with the original section, while being recognizable in terms of visual expression. In addition, the consistency of the street façade should remainapriority.
Inconclusion,theabovedifferentiationstrategytakesintoaccounttheuniqueneeds of different functional types and proposes a targeted approach to material interventionthatrespondstotheactualuseandmeetsthelocalpolicyrequirements of the URA while safeguarding the historical authenticity. Material preservation strategies for the Blair Plains Storehouse must be tailored to its specific functioneducational space, commercial use, and residential conversion. While the URA Guidelines provide a general framework, the nuanced needs of each function require a different approach to materials selection, intervention levels, and conservationmethods.
4.3 Possible applications of modern technologies in heritage buildings
InviewofthepracticalneedsoftheBlairPlainReserve,whichhaslimitedfundsand various functions, the application of modern technology should better be based on the principle of “low cost, operability and maintainability”. The following three practical and reference value of the technical program, combined with the implementation of cases and related academic research, to illustrate its practical significanceintheprotectionofmaterials.
1.UseofLocallyCompatibleAlternativeMaterials
Incaseswheretraditionallimematerialsaredifficulttoobtainorthemaintenance cost is too high, locally compatible alternative materials approved by URA (e.g. lime-based ready-mixed mortar with high permeability) can be used to fulfill the dualrequirementsofvisualconsistencyandmaterialrespiratoryproperties.
2.ModularShadingandVentilationSystem
Based on tropical climatic influences, many historic buildings have high interior temperaturesandhumiditythatmayacceleratedamagetomaterialssuchasplaster, wood and tile. Lower cost modular shading elements (e.g., removable wood blinds, canvas shades) can be used to improve the microclimate. These elements can be operated independently of electricity and can be easily cleaned and replaced while maintainingtheintegrityofthehistoricappearance.
3.3DScanningandLow-PrecisionDigitalArchiving
Compared to high-precision 3D laser scanning, low-cost 3D models created using
digitalcamerasincombinationwithfreeandopen-sourcesoftwarearesufficientto support general restoration documentation and component comparisons. For buildings such as BaBaHouse and ArClab, which take on exhibition or teaching functions, detailed material inspection, condition records and high-precision 3D laserscanningarethenselected. In summary, moderate, economical and compatible technological applications are morelikelytobewidelyadopted.Theabovestrategiesnotonlyrespecttheprinciple of authenticity of cultural heritage, but also provide a sustainable practical path for futurecommunity-basedparticipatoryconservation.
4.4 Role of community and users in material conservation
Although policies and documents provide top-level guidance for material conservation, the behavior, willingness to modify, and degree of participation of communityresidentsandactualusers,asthe“dailyguardians”ofheritagebuildings, have a direct impact on the effectiveness of conservation. Especially in the Blair Plain,whichismainlyaresidentialarea,theparticipationofthecommunityandthe usersbecomesapartofthematerialconservationthatcannotbeignored.
Raising the awareness of community perception and participation, if residents understand the historical value of their buildings, they are more inclined to accept thepreservation oftheoriginalmaterialsandavoidinappropriaterenovation.The openhouseandpublicexplanationactivitiesofBabaHouseandArClabareatypical
andeffectivepublicityplatform,whichnotonlyenhancesthepublic'sunderstanding of the architectural styles of the shophouse, but also promotes the neighborhood's awareness of “moderate restoration” and the importance of the preservation of materials.
Daily use habits have a long-term impact on material deterioration. For example, if residents lack awareness of ventilation, shading, and humidity control, walls, wood windows, and floor tiles are more susceptible to moisture, swelling, or mold infestation. For example, when ArClab documented and assessed the house, ArClab found that the communal wall with neighbor had serious moisture damage. We talked to the neighbors and learned that because the patio was closed off and the building was not used for daily living, there was insufficient ventilation, and the indoor humidity was very serious, which caused great damage to the walls, which had to be re-plastered and re-stuccoed almost every year, which is actually the damagethatinappropriatedailyusehabitscandotothematerialsdamage.Rational arrangement of furniture and avoidance of rough construction (e.g. drilling holes) can also help to prolong the life of the original materials. Education and training programs should be conducted to remind residents of the dangers of poor usage habits.
Increase community consensus for joint maintenance. In multi-connected shophouses,externalwalls,ceilingsandguttersaresharedspaces,theprotectionof whichneedstobebasedontheconsensusoftheneighbors.Itisrecommendedthat governmentdepartmentsshouldintroduceappropriateincentivesandjointpolicies
Communities and users are not only users of heritage buildings, but also collaborators in the process of material conservation. Only through the synergy of policy, technology and daily use practices can we realize the sustainable transformation of material conservation from government-led to community governance.
5. Conclusion
5.1 Research Summary
Thisstudydelvesintothechallengesandstrategiesofmaterialconservationofthe tropical heritage building shophouse, using the Blair Plains Conservation Area in Singaporeasacasestudy.Thecentralquestionofthestudyishowtomaintainthe
authenticity of materials in a rapidly urbanizing tropical environment while adaptingtomodernfunctionalneedsandclimaticpressures.
This study utilizes a qualitative research methodology that combines a literature review, field survey, case comparisons and interviews. The study focuses on the UrbanRedevelopmentAuthority(URA)ConservationGuidelinesastheinstitutional framework for heritage building material interventions in Singapore. The paper analyzes the three main functional categories of store houses in the selected conservation areas - educational, commercial and residential, to understand how different functions affect the selection, treatment and replacement of heritage materialssuchaslimeplaster,timber,bricksandtiles,aswellashowthisaffectsthe treatmentorreplacementofothermaterialsrequiredforday-to-dayactivities. ThefindingssuggestthatwhileURAguidelinesprovideaconsistentbasisbasedon principles such as minimal intervention and reversibility of materials, in practice, conservation outcomes still depend in significant part on function. Educational spacesprioritizematerialauthenticityandhermeneuticintegrity;commercialunits focus on durability and code compliance; and residential retrofits tend to focus on comfort.Thesedifferenceshighlightthetensionbetweenstandardizedpoliciesand thecomplexrealityoffunctionalretrofittinginaheritagecontext.Overall,thisstudy suggests that sustainable material conservation of tropical heritage buildings requiresanapproachthatisbasedonsharedvaluesandbalancesfunction.
5.2 Optimal Balance between Cultural Authenticity and Modern Materials
contradictory. Technologies such as new material coatings, modular shading systems or digital documentation are not only compatible with traditional values, butalsoenhancethelongevityandusabilityofbuildingsintropicalconditions.Itis not the newness of the materials that matters, but whether their use respects the essenceofthehistoricenvironment.
Finally, achieving this balance requires not only technical skills, but also a conservation philosophy that is contextualized and concerned with function. An integrated approach to conservation, based on different functions and managed dynamically, will better enable heritage buildings to retain their significance and resilienceinaworldwherepreservationandrenovationmustgohandinhand.
5.3 Suggestions for a Future Detailed Conservation Policy for URA
The findings highlight a key issue in the current URA conservation framework: whileallrenovationoralterationproposalswithinprotectedheritageareasmustbe formally assessed and approved, the guidelines lack sufficient clarity on how to practically apply universally applicable standards to buildings with different functions. While the URA provides a uniform benchmark for material authenticity and minimal visual intrusion, the reality shows that specific functional requirements (e.g. related to flooring and air-conditioning) can lead to widely varying implementations, which are still not sufficiently prioritized in the existing policystructure.
Take flooring as an example: whether it is fivefoot way or indoor flooring, the conservationguidelinesstronglyrecommendretainingtheoriginalfloorfinish,orif the flooring is not original, the use of a traditional material floor finish is also stronglyrecommended.Inpractice,however,commercialspacesfacewearandtear due to high foot traffic and frequent cleaning, so owners tend to use stronger modern materials instead of traditional terracotta or tiles. Educational and exhibitionspaces,ontheotherhand,oftenretaintheiroriginalfloorsbecauseofthe need to preserve historical accuracy and authenticity for viewing and learning. Residential remodels fall somewhere in the middle, often retaining key historic elements in the front areas of the house while allowing greater flexibility in the private and rear spaces. Despite these nuances, the existing URA framework provides little clear guidance, leading to subjective interpretations and inconsistent preservationoutcomes.
Similarly,theinstallationofair-conditioningfurtherillustratestheinadequacyofthe existing “one-size-fits-all” approach. According to URA standards, air-conditioning units should be integrated in recesses at the rear of the building envelope or in openings on the roof of the rear service area, or, if practical constraints dictate, neatly and densely arranged at the rear of the building to minimize visual impact. However,actualcoolingneedsvarybyfunction:commercialbuildingsoftenrequire dense cooling systems, which inevitably require visible modifications such as ductwork.Incontrast,educationalheritagebuildingssuchastheNUSBaBaHouseor ArClab, with their commitment to preserving authenticity and achieving
educational goals, often opt for less intrusive cooling solutions such as fans or non-fixed cooling machines to minimize visual and structural disturbances. Clear policyguidanceonappropriatemethodsisstilllacking.
These observed differences strongly suggest that the URA's overall conservation policy needs to develop more functionally sensitive guidelines. To address this gap, thefollowingdetailedpolicyrecommendationsaremade:
1.Detailedtechnicalannexesbyfunction:
In response to existing conservation guidelines, develop supplementary annexes that explicitly address different building functions - educational, commercial and residential, and are certainly not limited to these functions, but are more comprehensiveintheirconsideration.Eachannexwillprovideclear,scenario-based instructions for common interventions, including, for example, acceptable flooring materialsandspecificairconditioningsolutions.
2.materialandtechnicalspecifications:
Create a catalog of suitable URA-approved modern alternative materials and technical solutions, such as flooring options (e.g., wood, terrazzo, durable tiles) and cooling technologies (e.g., reversible installations), with clear descriptions of functionalscenariosinwhichthesealternativescanbeemployed.
3.Case-basedguidanceandexamples:
Create official guidance publications detailing examples of successful functional retrofits previously approved by the URA. These publications should clearly illustrate approved air-conditioning installations, flooring material replacements,
andinteriorlayoutmodificationsandtheiracceptabilitybasedonfunctionalneeds, providinganeffectivereferenceforretrofitowners.
4.ContinuingProfessionalDevelopmentandTraining:
Introduce training for preservation professionals, architects and contractors that emphasizeshowtopracticallyapplypreservationprinciplesindifferentfunctional environments. Training covers, for example, detailed guidance on selecting and integratingmodernmaterialswithoutcompromisinghistoricintegrity.
As Shophouses are still largely privately owned, the implementation of these targeted and nuanced URA preservation policy improvements to support preservation professionals and owners will help Singapore's historic buildings to better retain their historical authenticity, while also adapting practically and sustainablytocontemporaryfunctionalneeds,andachievingabalancedcoexistence betweenhistoricpreservationandmodernutility.
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