Methodological Proposal to Resolve the Dichotomy between Improving Energy Efficiency and Preserving Heritage—Case Study: Brutalist Built Heritage
Abstract
The debate about how to conduct energy interventions in built heritage remains open. At present, the various European and national regulations allow the absence of energy intervention in cases where the character of a building with recognized heritage value would be jeopardized. This situation means that heritage preservation and energy improvement are divided into two airtight and unconnected blocs. It is possible and necessary to break that dichotomy by taking steps that enable both blocs to interrelate. Based on a methodology previously proposed by the authors to regulate changes in the urban landscape due to the rehabilitation of residential building façades, as a novel aspect, this article proposes taking a further step in the methodological process. Several criteria to balance the level of energy intervention for all buildings are thus introduced, according to the urban and architectural characteristics of each building, irrespective of their use and degree of protection. It is concluded that such a balance is possible when certain indicators are used and when determined action criteria are applied. However, one of the architectural characteristics more susceptible to being affected when undertaking an energy intervention on a building’s thermal enclosure is the materiality, which becomes especially important in the case of brutalist architecture with reinforced concrete, one of its most identifying features, giving it a specific personality. That architectural movement was therefore chosen for a case study, applying the proposed methodology to three brutalist buildings in the area of San Sebastián, Spain.
Full text
Citation: Uranga, E.J.; Lizundia, I.; Azcona, L. Methodological Proposal to Resolve the Dichotomy between Improving Energy Efficiency and Preserving Heritage—Case Study: Brutalist Built Heritage. Heritage 2024, 7, 3554–3576. https://doi.org/ 10.3390/heritage7070167 Academic Editor: Kristian Fabbri Received: 28 May 2024 Revised: 27 June 2024 Accepted: 28 June 2024 Published: 3 July 2024 Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). heritage Article Methodological Proposal to Resolve the Dichotomy between Improving Energy Efficiency and Preserving Heritage—Case Study: Brutalist Built Heritage Eneko J. Uranga * , Iñigo Lizundia and Leire Azcona Department of Architecture, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain; [email protected] (I.L.); [email protected] (L.A.) *Correspondence: [email protected]; Tel.: +34-943015920 Abstract: The debate about how to conduct energy interventions in built heritage remains open. At present, the various European and national regulations allow the absence of energy intervention in cases where the character of a building with recognized heritage value would be jeopardized. This situation means that heritage preservation and energy improvement are divided into two airtight and unconnected blocs. It is possible and necessary to break that dichotomy by taking steps that enable both blocs to interrelate. Based on a methodology previously proposed by the authors to regulate changes in the urban landscape due to the rehabilitation of residential building façades, as a novel aspect, this article proposes taking a further step in the methodological process. Several criteria to balance the level of energy intervention for all buildings are thus introduced, according to the urban and architectural characteristics of each building, irrespective of their use and degree of protection. It is concluded that such a balance is possible when certain indicators are used and when determined action criteria are applied. However, one of the architectural characteristics more susceptible to being affected when undertaking an energy intervention on a building’s thermal enclosure is the materiality, which becomes especially important in the case of brutalist architecture with reinforced concrete, one of its most identifying features, giving it a specific personality. That architectural movement was therefore chosen for a case study, applying the proposed methodology to three brutalist buildings in the area of San Sebastián, Spain. Keywords: built heritage; energy efficiency; brutalism 1. Introduction Excessive energy consumption and CO 2 emissions have become one of humanity’s most important problems in the early 21st century. The EU has identified the construction sector as one of the key areas where steps must be urgently taken to improve this situation. The energy efficiency of buildings has been among the EU’s most important goals for more than two decades, having reached the conclusion that it is necessary to renew the current building stock because it is one of the sectors with the highest energy consumption. That objective has accordingly been set out in various European directives, among them Directive 2002/91/EC [ 1 ], Directive 2010/31/EU [ 2 ], Directive 2012/27/EU [ 3 ], and Directive 2018/844/EU (amending the latter two) [ 4 ], and in the various transpositions into respective national law, such as Spain’s RD 390/2021 on energy certification [ 5 ]. In any case, since it is clear that pressure to improve energy efficiency will only increase over time, a suitable balance should be sought between environmental sustainability and maintaining cultural significance [6]. The EU counts a large variety of buildings with a heterogeneous historic legacy from different periods. One question pending consideration in European legislation is how to improve energy performance in existing buildings that have recognized heritage value. Although Directive 2012/27/EU speaks of the exemplary function that buildings of public Heritage 2024,7, 3554–3576. https://doi.org/10.3390/heritage7070167 https://www.mdpi.com/journal/heritage
Heritage 2024,73555 institutions should fulfill when introducing measures to improve energy performance, it also states that countries may decide not to apply those criteria in officially protected buildings when compliance with certain requisites would “unacceptably alter their character or appearance”. The conflict posed by energy interventions is therefore evident. Taken to the extreme, they can jeopardize the heritage value of historic buildings; when not undertaken, they lead to excessive energy consumption and eventually to the abandonment of a certain type of architecture. In any case, it is clear that the legislation advocates preserving the “character or appearance” of protected buildings above any other consideration. But it leaves open the possibility of energy improvement using solutions that do not affect the essential architectural characteristics that give them special value, for example, by recourse to a combination of active systems and specific passive interventions. But what happens with buildings of particular architectural value that are still not considered worthy of protection and in which any intervention may irreparably alter their “character or appearance”? The 20th century left us the youngest heritage stock in history, unknown and relatively unvalued, wherein, except for some acknowledged works by the so-called modern masters, most heritage is considered not worth preserving and is therefore particularly vulnerable. Its value or merit for being included in protection lists does not fit in the commonly used selection standards generally based on the buildings’ aesthetic or visual qualities. In some cases, their importance lies mainly in their nature as a link in the chain of events that constitute the historic evolution of the history of architecture [ 7 ]. There are two criteria that reinforce each other in the reevaluation of modern architecture, differentiating it from those applied to older heritage works: the fact of being the origin of the current architecture, and the idea of sustainability, conservation, and reuse as opposed to unjustified replacement and frenetic consumption. The first one points to the current validity of its values, forms, and languages and the second to the current usefulness of such works as an essential quality that justifies their conservation and duration over time and ultimately their sustainability as opposed to simple contemplative or aesthetic enjoyment [8]. Based on the urgent need to enhance their value, here is where the major players involved (administration, architects, and conservation heritage experts) often clash due to the philosophical debates and discrepancies generated by intangible concepts such as the authenticity, significance, and value of heritage. The reasonable replacement of materials, the respect for form, the new language, or the adaptation to new functions and needs, among them being improved energy efficiency, are just some of the issues that generate controversy [ 9 ]. But we know that not all contemporary architectural heritage can be subject to equal protection and conservation. We have here a first and delicate task to define: the establishment of description and selection criteria. Flexibly and knowledgeably addressing the specific qualities of each case became increasingly common in the 20th century pathways of conservation and restoration [ 10 ]. We should protect what is a testimony of history and has recognizable architectural quality, protecting all qualified contemporary architecture, whether or not it is understood as modern in conceptual and stylistic terms. All intervention in 20th century heritage should be rationally regulated, with the establishment of clear protocols that require prior demonstration that the envisaged actions will not disfigure the specific formal and technological legacy of the work [11]. In the area of energy-improvement intervention and taking as a field of action the extensive 20th century building stock, it becomes necessary to focus on all buildings that are particularly sensitive to architectural disfigurement, in which not just their appearance but also their character are at risk. Most energy interventions have centered on the insertion of a new skin in the building’s thermal enclosure, as it is a passive system that, besides improving energy efficiency, also allows the treatment and repair of eventual damage while also providing a renewed and up-to-date image. The consequences of such interventions in buildings where the design, composition, and materiality of the enclosure have significant and evident architectural value, regardless of whether or not it is officially recognized, are irreversible.
Heritage 2024,73556 This study aims to take a further step in the intervention methodology proposed by the authors in 2023 for the rehabilitation of residential building façades [ 12 ]. That methodology, which we shall call CRIRB (Criteria for Rehabilitation Interventions in Residential Buildings), is currently being applied in a pilot experiment involving the rehabilitation of 25 residential complexes included in the Opengela program led by the Basque government in the scope of the whole Basque Country [ 13 ]. It is not, therefore, a new methodological proposal but rather a progressive advance in the CRIRB methodology, a new version that we shall call CRIRB+ to differentiate it from the previous version. It has three major new features: expansion of the scope of application to all contemporary buildings, irrespective of their use and degree of protection; the inclusion of specific new construction elements such as the recesses or the roof; and the introduction of several energy intervention criteria, the aim being to establish a balance between possible energy intervention strategies and preservation of the buildings’ architectural values. The main contribution of the proposed methodology is to endow administrators with an easy-to-apply tool enabling them to regulate aspects concerning the architectural and urban image when a rehabilitation is planned, seeking a balance between the necessary energy improvement and preservation of the built heritage. It is a much-needed methodology for typologies in which the respective skins’ materiality constitutes the maximum expression of their singular nature and whose alteration could lead to catastrophic disfigurement in heritage terms. A clear example of this includes the brutalist buildings with reinforced concrete enclosures, which, in the third chapter of this text, will serve as a case study for the proposed methodology. 2. Materials and Methods 2.1. The Theory for Energy Intervention in Built Heritage (TEIBH) Very few energy interventions being carried out nowadays take into account how those actions affect the architectural and construction characteristics of the original building or the respective urban landscape. The energy-improvement results prevail over any other consideration. Conversely, the energy-improvement option for some buildings is ruled out due to the simple fact of belonging to the group of buildings that do not have to achieve that improvement because they are included on a protection list. It is therefore necessary and urgent to seek solutions to break the existing dichotomy between protection of the building stock and energy intervention so that, in a short time, we do not have to face the paradox of having some cities that are reasonably efficient from the energy standpoint but are hard to recognize. Figure 1shows the division resulting from current legislation on energy intervention in built heritage. The conservation level and the energy efficiency level are divided and separated into two airtight blocs without any interrelation at all, allowing, on the one hand, non-intervention in protected buildings when the character or appearance are considered to be at risk and, on the other, full intervention without any type of limit if no protection is in place. Heritage2024,7,FORPEERREVIEW 3 havesignificantandevidentarchitecturalvalue,regardlessofwhetherornotitisofficially recognized,areirreversible. Thisstudyaimstotakeafurtherstepintheinterventionmethodologyproposedby theauthorsin2023fortherehabilitationofresidentialbuildingfaçades[12].Thatmethodology,whichweshallcallCRIRB(CriteriaforRehabilitationInterventionsinResidentialBuildings),iscurrentlybeingappliedinapilotexperimentinvolvingtherehabilitation of25residentialcomplexesincludedintheOpengelaprogramledbytheBasquegovernmentinthescopeofthewholeBasqueCountry[13].Itisnot,therefore,anewmethodologicalproposalbutratheraprogressiveadvanceintheCRIRBmethodology,anewversionthatweshallcallCRIRB+todifferentiateitfromthepreviousversion.Ithasthree majornewfeatures:expansionofthescopeofapplicationtoallcontemporarybuildings, irrespectiveoftheiruseanddegreeofprotection;theinclusionofspecificnewconstructionelementssuchastherecessesortheroof;andtheintroductionofseveralenergyinterventioncriteria,theaimbeingtoestablishabalancebetweenpossibleenergyinterventionstrategiesandpreservationofthebuildings’architecturalvalues. Themaincontributionoftheproposedmethodologyistoendowadministratorswith aneasy-to-applytoolenablingthemtoregulateaspectsconcerningthearchitecturaland urbanimagewhenarehabilitationisplanned,seekingabalancebetweenthenecessary energyimprovementandpreservationofthebuiltheritage. Itisamuch-neededmethodologyfortypologiesinwhichtherespectiveskins’materialityconstitutesthemaximumexpressionoftheirsingularnatureandwhosealteration couldleadtocatastrophicdisfigurementinheritageterms.Aclearexampleofthisincludesthebrutalistbuildingswithreinforcedconcreteenclosures,which,inthethird chapterofthistext,willserveasacasestudyfortheproposedmethodology. 2.MaterialsandMethods 2.1.TheTheoryforEnergyInterventioninBuiltHeritage(TEIBH) Veryfewenergyinterventionsbeingcarriedoutnowadaystakeintoaccounthow thoseactionsaffectthearchitecturalandconstructioncharacteristicsoftheoriginalbuildingortherespectiveurbanlandscape.Theenergy-improvementresultsprevailoverany otherconsideration.Conversely,theenergy-improvementoptionforsomebuildingsis ruledoutduetothesimplefactofbelongingtothegroupofbuildingsthatdonothaveto achievethatimprovementbecausetheyareincludedonaprotectionlist.Itistherefore necessaryandurgenttoseeksolutionstobreaktheexistingdichotomybetweenprotection ofthebuildingstockandenergyinterventionsothat,inashorttime,wedonothaveto facetheparadoxofhavingsomecitiesthatarereasonablyefficientfromtheenergystandpointbutarehardtorecognize.Figure1showsthedivisionresultingfromcurrentlegislationonenergyinterventioninbuiltheritage.Theconservationlevelandtheenergyefficiencylevelaredividedandseparatedintotwoairtightblocswithoutanyinterrelationat all,allowing,ontheonehand,non-interventioninprotectedbuildingswhenthecharacter orappearanceareconsideredtobeatriskand,ontheother,fullinterventionwithoutany typeoflimitifnoprotectionisinplace. Figure1.Conceptualdiagramofthecurrentregulatoryconsiderationofenergyefficiencyandconservationofbuiltheritage,dividedandseparatedintotwoairtightblocs. Thesolutioninvolvesdefininganequationinwhichenergyinterventioninthebuildingstockandrespectforthebuildings’architecturalconfigurationareintroducedasvarFigure 1. Conceptual diagram of the current regulatory consideration of energy efficiency and conservation of built heritage, divided and separated into two airtight blocs. The solution involves defining an equation in which energy intervention in the building stock and respect for the buildings’ architectural configuration are introduced as variables, the aim being to achieve a reasoned balance between the two. This concept constitutes the basis of what we shall hereinafter call the TEIBH (Theory for Energy Intervention in Built Heritage) [ 14 ]. When the intervention affects construction elements that may alter its architectural configuration and by extension the urban landscape, it will be
Heritage 2024,73557 necessary to weight the energy intervention. In some cases, the energy objectives may reach the maximums; in others, they will be halfway; and in some extreme cases, they may be practically nil because any kind of intervention will be limited. Conversely, and in the same proportion, it will be possible to preserve certain characteristics of the building, depending on its heritage value. To achieve this goal, the first step shall consist of determining the building’s protection degree in order to next establish the action criteria, among which the permitted energy intervention level will be included. The TEIBH establishes four energy intervention levels (EILs) when intervening in elements that may be protected in a building and whose concealment or alteration would be a major loss from the heritage standpoint. Interventions in parts or areas with no architectural value, such as the interior sides of previously lined floors, walls, and ceilings, will always be allowed and fall outside the established classification. The following are the proposed EIL levels: Level 1: Invasive intervention. The aim is to obtain the greatest energy improvement. The passive measures may completely cover the original enclosure. Level 2: Major intervention. Although the energy-improvement objectives prevail, and the intervention may eventually affect the whole enclosure, consideration should be given to preserving certain architectural characteristics of the building. Level 3: Selective intervention. The building has significant heritage values that prevail over the energy intervention, which should be selective after exhaustive prior analysis. Level 4: Conservation, restoration, and reconstruction. This constitutes zero or minimal energy intervention, the aim being to preserve the high heritage values of the original building. The intervention levels are progressive and inversely proportional to the protection degree achieved by the building. The relationship between both is graphically explained by means of a diagonal line that breaks the existing division between the two airtight blocs, interrelating them (Figure 2). Heritage2024,7,FORPEERREVIEW 4 iables,theaimbeingtoachieveareasonedbalancebetweenthetwo.ThisconceptconstitutesthebasisofwhatweshallhereinaftercalltheTEIBH(TheoryforEnergyIntervention inBuiltHeritage)[14].Whentheinterventionaffectsconstructionelementsthatmayalter itsarchitecturalconfigurationandbyextensiontheurbanlandscape,itwillbenecessary toweighttheenergyintervention.Insomecases,theenergyobjectivesmayreachthemaximums;inothers,theywillbehalfway;andinsomeextremecases,theymaybepractically nilbecauseanykindofinterventionwillbelimited.Conversely,andinthesameproportion,itwillbepossibletopreservecertaincharacteristicsofthebuilding,dependingonits heritagevalue.Toachievethisgoal,thefirststepshallconsistofdeterminingthebuilding’sprotectiondegreeinordertonextestablishtheactioncriteria,amongwhichthepermittedenergyinterventionlevelwillbeincluded. TheTEIBHestablishesfourenergyinterventionlevels(EILs)wheninterveninginelementsthatmaybeprotectedinabuildingandwhoseconcealmentoralterationwould beamajorlossfromtheheritagestandpoint.Interventionsinpartsorareaswithnoarchitecturalvalue,suchastheinteriorsidesofpreviouslylinedfloors,walls,andceilings,will alwaysbeallowedandfalloutsidetheestablishedclassification.Thefollowingarethe proposedEILlevels: Level1:Invasiveintervention.Theaimistoobtainthegreatestenergyimprovement. Thepassivemeasuresmaycompletelycovertheoriginalenclosure. Level2:Majorintervention.Althoughtheenergy-improvementobjectivesprevail, andtheinterventionmayeventuallyaffectthewholeenclosure,considerationshouldbe giventopreservingcertainarchitecturalcharacteristicsofthebuilding. Level3:Selectiveintervention.Thebuildinghassignificantheritagevaluesthatprevailovertheenergyintervention,whichshouldbeselectiveafterexhaustiveprioranalysis. Level4:Conservation,restoration,andreconstruction.Thisconstituteszeroorminimalenergyintervention,theaimbeingtopreservethehighheritagevaluesoftheoriginal building. Theinterventionlevelsareprogressiveandinverselyproportionaltotheprotection degreeachievedbythebuilding.Therelationshipbetweenbothisgraphicallyexplained bymeansofadiagonallinethatbreakstheexistingdivisionbetweenthetwoairtight blocs,interrelatingthem(Figure2). Figure2.ConceptualdiagramoftheTheoryforEnergyInterventioninBuiltHeritage(TEIBH),in whichbothconceptsareinterrelated. Althoughitformspartofabuildinggroupandsharescertaincompositionalorconstructionfeatures,eachbuildingisunique.Noconstructionisthesameasanotheronefor variousreasons,suchasthehistorictimewhenitwasbuilt;theurbansurroundings;the intendeduse;thedesigner;thecompositional,volumetric,andformalcharacteristics;the constructiontypology;thematerialsused;theenergyefficiencydegree;thelevelofusage; deterioration;thedegreeofalteration;orthemaintenancereceived.Allthesecharacteristicsdeterminethesingularnatureofeachbuilding,definingthecharactertowhichDirective2012/27/EUalludes.Thetermcharacter,understoodtomeanthesetofqualitiesof abuildingthatdistinguishesitfromallothers,isnotexpresslydefinedinthatdirective andisthereforeopentomultipleinterpretations.Onmanyoccasions,theonlyqualities takenintoaccountwhenspecifyingtheterm’smeaningrefertothebuilding’simageor aesthetics.Webelievethatheritagelistingshouldhaveabroaderfocusandconsiderthe setofcharacteristicsindicatedabove,understandingthecharacterofabuildingasitspersonalityorsoul. Figure 2. Conceptual diagram of the Theory for Energy Intervention in Built Heritage (TEIBH), in which both concepts are interrelated. Although it forms part of a building group and shares certain compositional or construction features, each building is unique. No construction is the same as another one for various reasons, such as the historic time when it was built; the urban surroundings; the intended use; the designer; the compositional, volumetric, and formal characteristics; the construction typology; the materials used; the energy efficiency degree; the level of usage; deterioration; the degree of alteration; or the maintenance received. All these characteristics determine the singular nature of each building, defining the character to which Directive 2012/27/EU alludes. The term character, understood to mean the set of qualities of a building that distinguishes it from all others, is not expressly defined in that directive and is therefore open to multiple interpretations. On many occasions, the only qualities taken into account when specifying the term’s meaning refer to the building’s image or aesthetics. We believe that heritage listing should have a broader focus and consider the set of characteristics indicated above, understanding the character of a building as its personality or soul. The current architectural worth of a building will therefore depend on multiple factors that should be analyzed and correctly valued by technical personnel from the corresponding administration when establishing a determined protection degree. Accordingly, the linear progression reflected in the conceptual TEIBH diagram should be broken, adjusted, and adapted in each case to the specific architectural qualities of the building and the type of intervention foreseen.
Heritage 2024,73558 In sum, this means endowing authorities with a tool that allows them to regulate energy interventions according to the heritage values of a building [ 15 ]. The proposed methodology should ultimately be set out in a municipal rehabilitation catalogue indicating appropriate actions for each and every building and architectural complex in the municipality. 2.2. Design of the Methodology Practical application of the TEIBH requires encompassing all the building typologies found in any municipality. Based on the CRIRB methodology proposed in 2023, during the first phase the building’s vulnerability [ 16 ], in the event of a rehabilitation, intervention will be determined. For this study, that vulnerability is defined as the potential risk that certain architectural characteristics of a building unit may be affected. This shall be called the building vulnerability degree (BVD), specified by a numerical value between 0 and 100. The indicators to be taken into account when calculating it will be compositional value, materiality, construction quality, alteration degree, construction deterioration, energy qualification, recognized quality, and accessibility degree. In the case of residential buildings, and only in their case, the complex vulnerability degree (CVD) should also be defined, likewise on a scale from 0 to 100; it determines the vulnerability of the residential neighborhood or complex where the building is located. To calculate the CVD, the indicators to apply are the unitary nature, typological homogeneity, chromatic homogeneity, alteration degree, recognized quality, and urban relevance. The exclusion of CVD calculation for non-residential buildings with any other use is because, except in specific cases, they are buildings with their own architectural singularity, spread out in location and not usually grouped under homogeneous typologies. In any case, if this is not so, and they do constitute a recognizable building complex, then their CVD should be determined. In the second phase, the protection degree to assign to each building shall be determined, obtaining a value called the rehabilitation protection degree (RPD), graded between I and V, which refers to the varying need for a building to preserve its previous characteristics. For residential buildings, that value is obtained by combining the CVD and BVD values, while, barring the aforementioned exceptions, in other buildings, it solely depends on the BVD value. Once the characterization of each building is completed with the CVD, BVD, and RPD values, in the third phase, the various intervention possibilities are studied, also including the principles established in the TEIBH concerning energy efficiency improvement measures. The buildings and housing complexes already protected and included in the various heritage protection plans or lists are purposely excluded from that analysis so as to not interfere with already envisaged intervention criteria. However, when reworking the methodology to incorporate the TEIBH criteria on energy intervention, it is advisable to include them to assure more in-depth resolution of the conflict between preservation and energy improvement. In cases where the architectural characteristics to safeguard were already previously defined by the corresponding competent authority, the RPD shall be obtained by means of a proportionate and reasoned transfer of the official values. If there is any discrepancy, lack of specificity, or obvious disparity in the criteria used, the building’s RPD value could be obtained by using the proposed methodology and comparing both results. Ultimately, what is proposed is to take a further step in the CRIRB methodology, which initially addressed how to intervene in the façades of residential buildings, highlighting, among others, the inclusion of the following two aspects: on the one hand, broadening the scope of application to all buildings in the municipality, irrespective of their protection degree and use, and, on the other, the extension of the intervention criteria for energy efficiency improvement to the building as a whole, as stipulated in the TEIBH. Figure 3 summarizes the different phases of the proposed methodology:
Heritage 2024,73559 Heritage2024,7,FORPEERREVIEW 6 lighting,amongothers,theinclusionofthefollowingtwoaspects:ontheonehand,broadeningthescopeofapplicationtoallbuildingsinthemunicipality,irrespectiveoftheir protectiondegreeanduse,and,ontheother,theextensionoftheinterventioncriteriafor energyefficiencyimprovementtothebuildingasawhole,asstipulatedintheTEIBH. Figure3summarizesthedifferentphasesoftheproposedmethodology: Figure3.OrganizationoftheCRIRB+researchmethod. TheCRIRBmethodologydefineshowtoobtaintheCVD,BVD,andRPDvaluesin themunicipality’sresidentialbuildings.AftercriticalanddetailedanalysisoftheindicatorsproposedforcalculatingtheCVDandBVD,itwasconcludedthattheycontinueto beperfectlyvalidforcharacterizinganddeterminingthevulnerabilityoftheentirebuildingstockofamunicipality.Hence,itwasnotdeemednecessarytomodifytheircharacteristics,maintainingthenumberofindicators,theirdefinition,theweightingpercentages,andthegradingcriteriaandvalues.Table1summarizes,asareminder,howtoobtaintheCVDandBVDvalues.Thedetailedevaluationcriteriacanbeconsultedinthefull tablesconveyedintheCRIRBmethodologydescribedinthecitedarticlereferencedwithin [12]. Table1.DeterminationoftheCVDandBVD. DeterminationofCVD(ResidentialComplexOnly)DeterminationofBVD(allTypesofBuildings) IndicatorWeight (%)GradeValueIndicatorWeight (%)GradeValue Unitaryproject (UP)20%Yes20 Richnessofcompositionandmaterials (CR) 20% Veryhigh20 No0High15 Typologicalhomogeneity (TH) 20% 1─100%ofbldgs.20Medium10 61─80%15Low5 41─60%10Verylowornone0 11─40%5 Constructionquality (CQ)15% Verylowornone15 0─10%0Low11 Chromatichomogeneity (CH) 20% 1─100%ofbldgs.20Medium7 61─80%15High3 41─60%10Veryhigh0 11─40%5 Alterationdegree (AD)15% Verylowornone15 0─10%0Low11 Alterationdegree (AD)20%0─10%ofbldgs.20Medium7 11─40%15High3 Figure 3. Organization of the CRIRB+ research method. The CRIRB methodology defines how to obtain the CVD, BVD, and RPD values in the municipality’s residential buildings. After critical and detailed analysis of the indicators proposed for calculating the CVD and BVD, it was concluded that they continue to be perfectly valid for characterizing and determining the vulnerability of the entire building stock of a municipality. Hence, it was not deemed necessary to modify their characteristics, maintaining the number of indicators, their definition, the weighting percentages, and the grading criteria and values. Table 1summarizes, as a reminder, how to obtain the CVD and BVD values. The detailed evaluation criteria can be consulted in the full tables conveyed in the CRIRB methodology described in the cited article referenced within [12]. In the case of the RPD, the way to obtain the five protection degrees (I, II, III, IV, and V) varies depending on the type of building. In the case of unprotected residential buildings, the assigned value is still obtained by combining the CVD and the BVD of the building proposed in the CRIRB methodology. In the case of unprotected non-residential buildings, unless they form part of a recognizable complex, the RPD is directly and proportionally linked to the BVD value obtained. If they form part of a complex, its respective CVD will have been calculated beforehand, and the CVD and BVD combination proposed for unprotected residential buildings should be used. And finally, in the case of protected buildings of any type, it is necessary to establish a correlation between the officially recognized protection degrees, different in number and name depending on the body in charge of drawing up the list in each municipality, and the five degrees envisaged in the proposed methodology. Table 2summarizes how to obtain the RPD values in each case.
Heritage 2024,73560 Table 1. Determination of the CVD and BVD. Determination of CVD (Residential Complex Only) Determination of BVD (all Types of Buildings) Indicator Weight (%) Grade Value Indicator Weight (%) Grade Value Unitary project (UP) 20% Yes 20 Richness of composition and materials (CR) 20% Very high 20 No 0 High 15 Typological homogeneity (TH) 20% 1–100% of bldgs. 20 Medium 10 61–80% 15 Low 5 41–60% 10 Very low or none 0 11–40% 5 Construction quality (CQ) 15% Very low or none 15 0–10% 0 Low 11 Chromatic homogeneity (CH) 20% 1–100% of bldgs. 20 Medium 7 61–80% 15 High 3 41–60% 10 Very high 0 11–40% 5 Alteration degree (AD) 15% Very low or none 15 0–10% 0 Low 11 Alteration degree (AD) 20% 0–10% of bldgs. 20 Medium 7 11–40% 15 High 3 40–60% 10 Very high 0 61–80% 5 Construction deterioration (CD) 15% Very high 15 81–100% 0 High 11 Recognized quality (RQ) 8% Exceptional 8 Medium 7 High 5 Low 3 Medium 3 Very low or none 0 Low or none 0 Energy qualification (EQ) 15% G 15 Authorship relevance (AR) 8% Exceptional 8 F 11 High 5 E 7 Medium 3 D 3 Low or none 0 ≥C 0 Location of the complex (CL) 2% Historic centre 2 Recognized quality (RQ) 8% Exceptional 8 Expansion (ensanche) districts 1 High 5 Outskirts 0 Medium 3 Numbers of buildings (BN) 2% >20 2 Low or none 0 4≤X≤20 1 Authorship relevance (AR) 8% Exceptional 8 <4 0 High 5 Medium 3 Low or none 0 Need to improve accessibility (AI) 4% Yes 4 No 0 Once the RPD value is assigned to each building, it only remains to establish the criteria for intervention in the building’s different construction elements, including various energyimprovement guidelines according to the principles set out in the TEIBH. The strategies that can be put forward when the time comes to improve a building’s energy efficiency are divided into two large groups: passive ones and active ones. In the case of new construction, a good urban and architectural approach implicitly contains several passive measures which, as in the Passivhaus standard, may eventually dispense with any active system [ 17 ]. The same does not occur when intervening in existing buildings for which the location, arrangement, orientation, and architectural and construction configuration are already given. In such cases, the passive measures center almost exclusively on improving the
Heritage 2024,73561 building’s thermal enclosure, which should not be limited solely to the simple attachment of new insulating skins but can rather include new architectural volumes to make them more efficient from the standpoint of energy, architecture, and urbanism, as in the case of the intervention carried out by Lacaton and Vassal in the Grand Parc neighborhood of Bordeaux in 2017 [ 18 ]. Interventions to improve the thermal enclosure have experienced a tremendous boom in recent years due to the deficits presented by an aged and obsolete buildings stock and the strong requirements imposed by different administrations in the European national or regional scope. They also count the advantage that integral actions in a building’s enclosure in turn enable repair of the more than likely pathologies generated over the years, and on the other hand, no less important is the improvement of the construction quality of the exterior cladding, updating and modernizing its appearance. And this is precisely where a problem may arise: the original architectural disfiguration that may irreparably affect the building’s character, as referenced in the European legislation. Table 2. Determination of the RPD (rehabilitation protection degree). Unprotected Residential Buildings (and Unprotected Non-Residential Buildings Included in a Complex) RPD BVD Building Vulnerability Degree 0–20 21–40 41–60 61–80 81–100 CVD Complex Vulnerability Degree 0–20 I II III IV V 21–40 II II III IV V 41–60 III III III IV V 61–80 IV IV IV IV V 81–100 V V V V V Unprotected Non-Residential Buildings (not included in a complex) BVD Building Vulnerability Degree 0–20 21–40 41–60 61–80 81–100 RPD I II III IV V All protected Buildings RPD Correlation with official values Hence, when it is time to put forward the different intervention possibilities, it is important to distinguish the different parts of the enclosure to see how each of them will affect the configuration of the aforesaid character and in what percentage and how to eventually intervene in the whole. Obviously, as indicated in the CRIRB methodology, the definition, valuation, and application of the different action options generically set forth will also depend on the criteria of the municipal officials in charge of regulation and even of the construction solutions that can be provided by the market at any given time. It must therefore be a rigorous though flexible tool that helps lawmakers establish intervention guidelines in each case, with the ultimate goal of avoiding the architectural disfiguration of both the building and the urban environment. The action criteria adopted are shown in Table 3. The need for flexibility when interpreting the proposed action criteria must be stressed. Each building is unique, and cases will inevitably arise in which the intervention approach does not fully fit the criteria set out in the table, and it becomes necessary to study it in depth to identify the highest of its values that can be preserved and enhanced as well as the shortcomings and problems to eliminate [ 19 ]. On the other hand, it may happen that, regardless of the BVD and RPD values reached for the building, some specific characteristic of a certain construction element, such as its materiality, should be protected above any other consideration.
Heritage 2024,73562 Table 3. Action criteria. Action Criteria RPD Rehabilitation Protection Degree I II III IV V Façade Composition and volumes Free modifications Occasional modifications after prior analysis Maintenance or recovery of the original solution Color Free modifications Possible modification, subject to analysis by municipal technical personnel Recovery of the original color in all elements Materiality of blind wall cladding Free modifications Possible modification, subject to analysis by municipal technical personnel Similar to the original. Concrete, facing brick or stone: prior analysis Mandatory recovery of the original finish Windows and other gaps Free modifications Replacement of carpentry and glass after prior analysis Maintenance or recovery of the original solution Closure of balconies over time Maintained, unless otherwise required by regulations Elimination recommended and possibility of new unitary design Mandatory elimination Fixtures per façade Maintained, unless otherwise required by regulations Concealment recommended Mandatory concealment Barriers, railings and parapets Possibility of unlimited replacement Changes of design and homogenous material permitted on the entire façade Material similar to the original, with possible change of homogenous design Recovery of the original solution, maintaining the design though allowing change of material in the case of metal railings Roof Composition and volumes Free modifications Occasional modifications after prior analysis Materiality Free replacement of finishes Replacement of finishes after prior analysis Energy efficiency improvement intervention (elements to be protected) Energy Intervention Level (EIL) 1 2 3 4 Area of intervention Façade + gaps + roof after prior analysis Gaps + roof after prior analysis None Active strategies Additional conditions Buildings in complexes with homogeneous original features No limit Similar chromatic solution Similar construction and chromatic solution Same construction, chromatic and accessibility solution A different, unitary and homogenous transformation solution is permitted for the entire complex to optimize energy efficiency, subject to analysis by municipal technical personnel Identical buildings sharing a single block or built volume Same color and same construction and accessibility solution
Heritage 2024,73569 Heritage2024,7,FORPEERREVIEW 15 Figure8.ThreecasesofbrutalisminSanSebastián.Source:GoogleMaps. 3.2.1.Building1:InfantJesusofPragueSchool:M.OriolandG.Lafuente(1965–1967) ThefirstbuildinginthebrutaliststylebuiltinSanSebastiánwastheInfantJesusof PragueSchool[43].Theprojectdesignedin1965byMigueldeOriolandGregorioLafuenteandbuiltinthefollowingyearsusedbétonbrutandwasthefirsttotallybrutalist buildingtoappearinthecity(Figure9).Atpresent,itisnotprotected,eventhoughit signifiesaradicalchangeintheconceptionandstyleofarchitectureuseduntilthattime inSpain.ThisisaclearexampleoftheincursionofthenewarchitecturalmovementsintroducedfromEurope.Itsvaluethereforestemsfromitsoriginalityaswellastheexpressivesolutionofitsarchitecture.Thebuildingmaintainstheoriginalfunctionforwhichit wasdesigned:aCatholicschoolwithareligiousresidence. Figure9.InfantJesusofPragueSchool,M.OriolandG.Lafuente,SanSebastián,1965–1967.Photos: authors,2019. 3.2.2.Building2:OfficialMaritimeSchoolinPasaia:J.L.ZanónandL.Laorga(1966–1968) Between1963and1968,thearchitectsJoséLuisZanónandLuisLaorgadesignedand builtsevenmaritimeschoolsindifferentcitiesinSpain;onewastheOfficialMaritime SchoolinPasaia[44].Thebuilding’smaterialityisreflectedintheuseofconcreteasa structuralandfinishingelement.Specialmentionshouldbemadeoftheauditoriumcompositionintheformofafoldedsheet,withtheseatingonastructureprojecting8.50m outward(Figure10).Thissecondcaseisalsonotprotectedbycurrentheritagelegislation. Itrepresentsthesecondcaseofbrutalistarchitectureintheregion.Itsarchitecturalarrangementestablishedbydifferentexpressivevolumescorrespondstoitsuseasamaritimeschool,recallingtheformsandfunctionsofaboat.Theuseofreinforcedconcreteas thestructureandenclosureofmostofthebuildingrecallsotherbuildingsdesigned aroundtheworldduringthesameperiod. Figure 9. Infant Jesus of Prague School, M. Oriol and G. Lafuente, San Sebastián, 1965–1967. Photos: authors, 2019. 3.2.2. Building 2: Official Maritime School in Pasaia: J.L. Zanón and L. Laorga (1966–1968) Between 1963 and 1968, the architects JoséLuis Zanón and Luis Laorga designed and built seven maritime schools in different cities in Spain; one was the Official Maritime School in Pasaia [ 44 ]. The building’s materiality is reflected in the use of concrete as a structural and finishing element. Special mention should be made of the auditorium composition in the form of a folded sheet, with the seating on a structure projecting 8.50 m outward (Figure 10). This second case is also not protected by current heritage legislation. It represents the second case of brutalist architecture in the region. Its architectural arrangement established by different expressive volumes corresponds to its use as a maritime school, recalling the forms and functions of a boat. The use of reinforced concrete as the structure and enclosure of most of the building recalls other buildings designed around the world during the same period. Heritage2024,7,FORPEERREVIEW 16 (a)(b) Figure10.OfficialMaritimeSchool,J.L.ZanónandL.Laorga,Pasaia,1966–1968.(a)Source:MunicipalArchiveoftheCityofPasaia.(b)Photo:authors,2019. 3.2.3.Building3:CarmeloBaldaFronton:L.J.Arizmendi(1969–1974) Forthisbuildingdesign,thearchitectchosetousethebrutaliststyleasalocalresponsetotheincipientinternationalmovement[45].Thetwopreviouscaseshadalready beenbuiltandprobablyinfluencedthearchitect’schoice.Concreteisusedagainbothas astructuralandfinishingelement,resultinginalargebasicandcompactvolume(Figure 11).Thisthirdcaseisalsonotprotectedbyeitherlocalorregionalheritagelegislation.Its structureandimageneverthelessprojectthisbrutaliststylesorepresentativeoftheperiod. Eventhoughithasundergoneseveraltransformationsovertheyears,withvariousadjacentbuildingsputupthathavehiddentheoriginalconstructionunity,itisaclearexample ofthevaluethatshouldbegiventosuchbuildings.Itstillmaintainsitsoriginaluseasa pelotacourt,towhichotheradministrativeandsportuseshavebeenadded. (a)(b) Figure11.CarmeloBaldaFronton,L.J.Arizmendi,SanSebastián,1969–1974.(a)Photo:authors, 2019.(b)Source:MunicipalArchiveoftheCityofSanSebastián. Photos:authors,2019. AsestablishedintheproposedmethodologyinSection2.2,becausethesearesingularbuildingsthatarenon-residentialandunprotected,thefirststepconsistsofanalyzing theirvulnerabilitydegree,establishingtheBVDvalueforeachofthem.ThisissummarizedinTable4. Table4.BVDapplicationresults. Indicator Weight Grade Value Building1 Building2 Building3 Figure 10. Official Maritime School, J.L. Zanón and L. Laorga, Pasaia, 1966–1968. (a) Source: Municipal Archive of the City of Pasaia. (b) Photo: authors, 2019. 3.2.3. Building 3: Carmelo Balda Fronton: L.J. Arizmendi (1969–1974) For this building design, the architect chose to use the brutalist style as a local response to the incipient international movement [ 45 ]. The two previous cases had already been built and probably influenced the architect’s choice. Concrete is used again both as a structural and finishing element, resulting in a large basic and compact volume (Figure 11). This third case is also not protected by either local or regional heritage legislation. Its structure and image nevertheless project this brutalist style so representative of the period. Even though it has undergone several transformations over the years, with various adjacent buildings put up that have hidden the original construction unity, it is a clear example of the value that should be given to such buildings. It still maintains its original use as a pelota court, to which other administrative and sport uses have been added.
Heritage 2024,73570 Heritage2024,7,FORPEERREVIEW 16 (a)(b) Figure10.OfficialMaritimeSchool,J.L.ZanónandL.Laorga,Pasaia,1966–1968.(a)Source:MunicipalArchiveoftheCityofPasaia.(b)Photo:authors,2019. 3.2.3.Building3:CarmeloBaldaFronton:L.J.Arizmendi(1969–1974) Forthisbuildingdesign,thearchitectchosetousethebrutaliststyleasalocalresponsetotheincipientinternationalmovement[45].Thetwopreviouscaseshadalready beenbuiltandprobablyinfluencedthearchitect’schoice.Concreteisusedagainbothas astructuralandfinishingelement,resultinginalargebasicandcompactvolume(Figure 11).Thisthirdcaseisalsonotprotectedbyeitherlocalorregionalheritagelegislation.Its structureandimageneverthelessprojectthisbrutaliststylesorepresentativeoftheperiod. Eventhoughithasundergoneseveraltransformationsovertheyears,withvariousadjacentbuildingsputupthathavehiddentheoriginalconstructionunity,itisaclearexample ofthevaluethatshouldbegiventosuchbuildings.Itstillmaintainsitsoriginaluseasa pelotacourt,towhichotheradministrativeandsportuseshavebeenadded. (a)(b) Figure11.CarmeloBaldaFronton,L.J.Arizmendi,SanSebastián,1969–1974.(a)Photo:authors, 2019.(b)Source:MunicipalArchiveoftheCityofSanSebastián. Photos:authors,2019. AsestablishedintheproposedmethodologyinSection2.2,becausethesearesingularbuildingsthatarenon-residentialandunprotected,thefirststepconsistsofanalyzing theirvulnerabilitydegree,establishingtheBVDvalueforeachofthem.ThisissummarizedinTable4. Table4.BVDapplicationresults. Indicator Weight Grade Value Building1 Building2 Building3 Figure 11. Carmelo Balda Fronton, L.J. Arizmendi, San Sebastián, 1969–1974. (a) Photo: authors, 2019. (b) Source: Municipal Archive of the City of San Sebastián. Photos: authors, 2019. As established in the proposed methodology in Section 2.2, because these are singular buildings that are non-residential and unprotected, the first step consists of analyzing their vulnerability degree, establishing the BVD value for each of them. This is summarized in Table 4. Table 4. BVD application results. Indicator Weight Grade Value Building 1 Building 2 Building 3 Jesus of Prague School Official Maritime School Carmelo Balda Fronton BVD—Building Vulnerability Degree CR Richness of composition and materials 20% Very High 20 High 15 Medium 10 Low 5 Very low or none 0 CQ Construction quality 15% Very low or none 15 Low 11 Medium 7 High 3 Very High 0 AD Alteration Degree 15% Very low or none 15 Low 11 Medium 7 High 3 Very High 0 CD Construction deterioration 15% Very High 15 High 11 Medium 7 Low 3 Very low or none 0
Heritage 2024,73571 Table 4. Cont. Indicator Weight Grade Value Building 1 Building 2 Building 3 Jesus of Prague School Official Maritime School Carmelo Balda Fronton BVD—Building Vulnerability Degree EQ Energy qualification 15% G 15 F 11 E 7 D 3 ≥C 0 RQ Recognized quality 8% Exceptional 8 High 5 Medium 3 Low or none 0 AR Authorship relevance 8% Exceptional 8 High 5 Medium 3 Low or none 0 AI Need to improve accesibility 4% Yes 4 No 0 64 64 57 Once the BVD values are obtained, the RPD value is also obtained, as indicated in Table 5. It defines the protection degree depending on the resulting vulnerability. Buildings 1 and 2 obtain an RPD value of IV, while building 3 obtains a value of III. Table 5. RPD results for three brutalist buildings. RPD Building 1 Building 2 Building 3 Jesus of Prague School Official Maritime School Carmelo Balda Fronton BVD 0–20 I 21–40 II 41–60 III 57 61–80 IV 64 64 81–100 V 3.3. Discussion of Results After determining the protection degree of each building, the criteria for intervention in the different construction elements of each of them are analyzed, following what is established in Table 3. Among those criteria is that concerning the most suitable energy intervention according to the principles of the TEIBH. Bearing in mind that flexibility is needed when interpreting the criteria set out in the tables, both the energy intervention proposals and the preliminary studies that value them are adjusted to each specific case. Regarding the façade’s composition and volumes, occasional modifications are allowed in the three buildings, as long as they are justified by the proponent of the intervention and accepted by those in charge of applying the methodology. In principle, the architectural composition or volumes of the three buildings can be slightly modified. In the case of Building 2, the roundness of its volumes makes it more sensitive to any change,
Heritage 2024,73572 while the other two cases, due to their size and form, seem less vulnerable to accepting certain modifications. As for color, in cases 1 and 2, the original chromatics should be respected or recovered if altered over time, while in case 3, a change of tone would be allowed after prior analysis. In any case, in the particular case of reinforced concrete brutalist buildings, it seems logical to maintain the natural color of the raw applied material. Something similar happens with the materiality, possibly the most identifying feature of this architectural style, though at the same time, it is vulnerable and delicate. The decision on how to intervene in the bare concrete walls should be studied very thoroughly, and the conclusion in most cases will possibly be to conserve them, subjecting them when necessary to surface repairs that recover and preserve the original appearance. In the case of the three analyzed buildings, the intervention criteria determine that the walls’ materiality should be conserved in the two first cases, though it can be altered in the third after prior analysis. In the latter case, we find that the two main façades still have their original concrete walls, while the other two façades have been partially hidden after the addition of new volumes. So, in the case of building 3, it seems natural that the preliminary study concludes by recommending conservation without any possible alteration of the two original main façades, only allowing changes in the ones that are partially hidden. The latter intervention should, in any case, be reversible and allow future recovery of the original walls. In the case of the windows and other gaps, replacement of the frames and glass is permitted in the three cases as long as the change does not imply a major formal disfiguration. Building 1 has the particularity of having a large curtain wall on one of its façades, with a very high formal and compositional value, which ought to be maintained. In the event that its replacement becomes necessary to improve the energy balance or because of extreme deterioration of its frames and glass, the new closure should respect the original chromatics and arrangement. As for the rest of the façade’s construction elements, none of the three buildings present major alterations, whereby the recommendations on how to act in those elements are set out in Table 3. In the case of building 1 and due to its poor state, the lattices on one of the façades were recently replaced by others harmoniously integrated into the façade. With respect to the roofs, certain modifications are permitted in the composition and volumes of the three buildings. As for the finishing solution, in the first two cases, the proposed solution would have to be analyzed, while in the third case, the change of covering material would be totally free. As this is the most exposed construction element and given the time since their construction, the roofs of the three buildings have already been renovated. In the cases of buildings 1 and 2, both the original composition and the covering type have been respected, while in building 3, a partial modification can be seen in both the form of the roof and the finishing material. Once the main architectural and construction elements that might condition an eventual rehabilitation action are analyzed, it only remains to determine the energy intervention level (EIL), depending on the protection degree obtained in each of the cases, as established in the TEIBH. We can thus see that in the three buildings, the EIL would be 3. That is, a selective intervention would be put forward, which would require analysis of the compatibility between the proposed energy measures and the architectural features to preserve in each case. In the three cases, active measures could be proposed to improve and update their climatic arrangements. Conversely, when proposing passive solutions, the intervention area concerned would have to be studied. In buildings 1 and 2, action should be solely on the roof and in the recesses, while in the case of building 3, action could also be permitted on the walled part. After exhaustive analysis of the three examples subjected to study, it seems clear that the exterior materiality of the reinforced concrete walls should be preserved in all cases, except in the two façades of building 3 that were already substantially modified. Also, in the three cases, it seems feasible to add insulation to the interior face of the façade walls, as they have been lined with diverse materials since the time of their construction.
Heritage 2024,73573 In all cases, replacement of the original architectural elements is necessary when the aim is to prevent gradual deterioration and maintain the buildings’ functionality. It is considered reasonable to use modern materials and techniques whose nature is different from those originally used. In any case, according to the criteria set out in the successive international charters for conservation and restoration [ 46 ], the means used should alter neither the appearance nor the general character of the building subject to intervention. On the one hand, the restoration of the deteriorated concrete surfaces should avoid excessive contrast between the repaired parts and the original parts of the surface. And, on the other, the renovation of the exposed-concrete elements by adding thermal insulation and cladding should be questioned and all the more so when it implies an irreversible loss of the building’s inherent heritage values. 4. Conclusions There are two issues that now seem beyond any doubt: on the one hand, the necessary containment of global warming through environmental protection and, on the other, the conservation of the architectural heritage that humanity has left as a legacy over the course of history. These two questions at times have seemed to clash when actions meant to improve the environment confront the possibility of losing inherited values. In 1987, the Brundtland Commission set out a similar paradox, bringing together two terms that in principle came from contradictory departure points—development and sustainability: “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs” [47]. This same concern applies to the construction sector when energy interventions jeopardize the heritage values of the building stock, posing the dichotomy of how to resolve conservation through action. Current legislation avoids confrontation, permitting nonintervention in buildings with acknowledged heritage value. In the most obvious cases, the exceptional architectural characteristics of certain buildings mean that any energy intervention makes no sense whatsoever, also bearing in mind their very slight impact on the territorial energy balance. But that logic of exceptionality should not be assumed as the norm; criteria to break the dichotomy between intervention and preservation should be established, as defended in the TEIBH. The proposed methodology aims to balance those two aspects, seeking a scale for energy intervention and the protection of built heritage instead of opting to simplify or even avoid the problem. Based on a previous methodological proposal by the authors of this article solely addressing the façades of unprotected residential buildings, what is now proposed is its adaptation and extension to all types of buildings including, among others, energy intervention criteria. Although current legislation does permit the exclusion of protected buildings, it is considered vital to include them in the methodological analysis in order to decide what to do with them from an energy standpoint. In some cases, this analysis may advise not intervening under any circumstance, while in other cases, a range of possibilities could be opened, which should be studied on an individual basis. At the other extreme, in the case of unlisted buildings, the fact that their heritage value has not yet been considered does not mean that many of them cannot be listed in the future. An energy intervention that does not take into account the architectural virtues of the original building may eventually irreversibly mortgage any future valuation. Brutalism, the architectural style chosen as case study, represents one of the clearest examples of an undervalued typology barely acknowledged in the protection lists. Besides including a large number of buildings around the world, it represents a very singular type of architecture and is an international style characteristic of a certain era. This style, which, despite being vilified in the decades after its emergence and development, is now experiencing maximum interest because its heritage value is beginning to be recognized. UNESCO’s recognition of the French city of Le Havre as world heritage in 2005 is a clear example of this [ 48 ]. The reconstruction in exposed concrete of the city center carried out by Auguste Perret after the Second World War, much criticized and vilified until quite
Heritage 2024,73574 recently by the city’s own inhabitants, achieved one of the maximum heritage distinctions sixty years later. Although few brutalist buildings are listed, it is hence foreseeable that a time will come when it is considered a style to preserve and a representative of a historic period of architecture and construction that is unlikely to be repeated. The three buildings in the San Sebastián area selected for application of the methodology represent those many examples of buildings that have been undervalued over the years. Although they currently lack any kind of protection, it is foreseeable that they may end up being included in the protection lists. It is therefore fundamental to analyze how any energy-improvement intervention can eventually affect their architectural characteristics. In short, integrated application of the TEIBH and the CRIRB+ methodology in buildings serves to classify their degree of vulnerability when rehabilitation intervention is planned, to grant a certain degree of protection to each building, and to establish the intervention criteria in each case. This methodology is designed to be applied to any kind of building, regardless of the respective characteristics, use, and heritage value. It is, of course, an open methodology with a high degree of flexibility, allowing it to be interpreted and adapted to each case. The methodology is meant to help regulate rehabilitation interventions in any municipality and to facilitate the work of officials from the corresponding administration who draft what could be called a rehabilitation catalog. That catalog would establish the intervention criteria that the rehabilitation plan of any building should comply with, depending on its vulnerability degree and protection degree. The materials and the solutions for construction and energy efficiency improvement proposed in the corresponding rehabilitation project would have to meet the requisites set out in that catalog. Ultimately, the methodology is designed to be an effective tool that facilitates decision making by the project’s planners and helps municipal technical officials oversee the different rehabilitation proposals. Author Contributions: E.J.U., I.L. and L.A. participated in the entire research process. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Data Availability Statement: The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding authors. Conflicts of Interest: The authors declare no conflicts of interest. References 1. Council of European Union. Directive 2002/91/EC of the European Parliament and of the Council, 16 December 2002, on the Energy Performance of Buildings; OJ L1, of 4.1.2003; Council of European Union: Brussels, Belgium, 2002. 2. Council of European Union. Directive 2010/31/EU of the European Parliament and of the Council, 19 May 2010, on the Energy Performance of Buildings (Recast); OJ L153/13 of 18.6.2010; European Union: Brussels, Belgium, 2010. 3. Council of European Union. Directive 2012/27/EU of the European Parliament and of the Council, 25 October 2012, on Energy Efficiency, Amending Directives 2009/125/EC and 2010/30/EU, and Repealing Directives 2004/8/EC and 2006/32/EC (Text with EEA Relevance); OJ L315/1 of 14.11.2012; European Union: Strasbourg, France, 2018. 4. Council of European Union. Directive 2018/844/EU of the European Parliament and of the Council, 30 May 2018, Amending Directive 2010/31/EU on the Energy Performance of Buildings and Directive 2012/27/EU on Energy Efficiency (Text with EEA Relevance); OJ L156/75 of 19.06.2018O; European Union: Strasbourg, France, 2012. 5. Gobierno de España. Real Decreto 390/2021, de 1 de Junio, por el que se Aprueba el Procedimiento Básico Para la Certificación de la Eficiencia Energética de los Edificios. 2021. Available online: https://www.boe.es/buscar/act.php?id=BOE-A-2021-9176& tn=1&p=20210602 (accessed on 4 May 2024). 6. ICOMOS International Scientific Committee on Twentieth Century Heritage. Madrid Document, Approaches for the Conservation of Twentieth-Century Architectural Heritage. 2011. Available online: https://openarchive.icomos.org/id/eprint/2697/1 /Madrid_Document_2011-EN_FR_ES.pdf (accessed on 4 May 2024). 7. Casqueiro, F.; Colmenares, S.; Maruri, N.; Miranda, A.; Pina, R. Arquitectura y Transformación. In Proceedings of the Criterios de Intervención en el Patrimonio Arquitectónico del Siglo XX, Madrid, Spain, 14–16 June 2011; Secretaria General Técnica—Ministerio de Cultura: Madrid, Spain, 2011.
Heritage 2024,73575 8. Calduch, J. De lo Faisandéa lo Efímero: La Arquitectura Moderna Ante el Paso del Tiempo. In Proceedings of the Criterios de Intervención en el Patrimonio Arquitectónico del Siglo XX, Madrid, Spain, 14–16 June 2011; Secretaria General Técnica—Ministerio de Cultura: Madrid, Spain, 2011. 9. Espinosa, F. Ampliaciones en el Patrimonio del Siglo XX, la Conveniencia de un Lenguaje. In Proceedings of the Criterios de Intervención en el Patrimonio Arquitectónico del Siglo XX, Madrid, Spain, 14–16 June 2011; Secretaria General Técnica—Ministerio de Cultura: Madrid, Spain, 2011. 10. García-Gutiérrez, J. Consideraciones Sobre Algunos Caracteres de la Arquitectura del Siglo XX y su Incidencia en los Criterios de Salvaguardia Patrimonial. In Proceedings of the Criterios de Intervención en el Patrimonio Arquitectónico del Siglo XX, Madrid, Spain, 14–16 June 2011; Secretaria General Técnica—Ministerio de Cultura: Madrid, Spain, 2011. 11. Cassinello, P.; Poveda, R. Intervención en las Thin Concrete Shells. Rastro de Reflexiones. In Proceedings of the Criterios de Intervención en el Patrimonio Arquitectónico del Siglo XX, Madrid, Spain, 14–16 June 2011; Secretaria General Técnica—Ministerio de Cultura: Madrid, Spain, 2011. 12. Lizundia, I.; Uranga, E.J.; Azcona, L. A Methodology to Regulate Transformation of a City’s Appearance Due to Energy Efficiency Building Renovations: A Case Study: Errenteria (Spain). Heritage 2023,6, 6112–6131. [CrossRef] 13. DPTAUDirección de Planificación Territorial y Agenda Urbana del Gobierno Vasco. Opengela. 2019. Available online: https://opengela.eus (accessed on 4 May 2024). 14. Uranga, E.J. La Intervención Energética en el Patrimonio edificado Residencial. Análisis del barrio de Gros en Donostia/San Sebastián. Ph.D. Thesis, University of the Basque Country—UPV/EHU, Donostia, Spain, 2017. Available online: https: //addi.ehu.es/handle/10810/23647 (accessed on 4 May 2024). 15. Sagarna, M.; Senderos, M.; Azpiri, A.; Roca, M.; Mora, F.; Otaduy, J.P. Energy Efficiency versus Heritage—Proposal for a Replicable Prototype to Maintain the Architectural Values of Buildings in Energy Improvement Interventions on Façades: The Case of the Expansion of San Sebastián. Coatings 2024,14, 422. [CrossRef] 16. Kuran, C.; Morsut, C.; Kruke, B.; Krüger, M.; Segnestam, L.; Orru, K.; Naevstad, T.; Airola, M.; Keränen, J.; Gabel, F.; et al. Vulnerability and vulnerable groups from an intersectionally perspective. Int. J. Disaster Risk Reduct. 2020,50, 101826. [CrossRef] 17. Moreno-Rangel, A. Passivhaus. Encyclopedia 2021,1, 20–29. [CrossRef] 18. Lacaton, A.; Vassal, J.P. Vital Neighbourhoods: Lessons from International Housing Renewal 2017, 61–82. Available online: https://www.lacatonvassal.com/data/documents/20181221-14342817_Publica-compressed.pdf (accessed on 4 May 2024). 19. Capitel, A. Notas Sobre la Identidad y la Protección de los Bienes Patrimoniales Modernos. In Proceedings of the Criterios de Intervención en el Patrimonio Arquitectónico del Siglo XX, Madrid, Spain, 14–16 June 2011; Secretaria General Técnica—Ministerio de Cultura: Madrid, Spain, 2011. 20. Pesantes, K.; Tarma, L.E.; La Rosa, D.O.; Boneff, E.I.; Zulueta, C.E. La materialidad en la arquitectura. Cuad. Cent. Estud. Diseño Comun. 2022,175, 201–208. 21. Prieto, J.I. Arquitectura de límites difusos: De la Glasarchitektur a la desmaterialización de la arquitectura. In Proceedings of the International Conference Arquitectonics, Barcelona, Spain, 3–5 June 2015. 22. Mitchell, W.J. E-Topia: Vida Urbana, Jim, Pero no la que Nosotros Conocemos; Editorial G.G: Barcelona, Spain, 2001. 23. Valcarce Labrador, M.T. El Nuevo Brutalismo: Una aproximación y una bibliografía. Cuad. Notas 1999,7, 131–144. 24. Virilo, P. Bunker Archeology; Princeton Architectural Press: New York, NY, USA, 2009. 25. Gargiani, R.; Rosellini, A. Le Corbusier. Béton Brut und der Unbeschreibliche Raum (1940–1965): Oberflächenmaterialen un Die Psychophysiologie des Sehens; Edition Detail—Institut für international Architektur-Documentation GmbH & Co.KG: Lausanne, Switzerland, 2011. 26. Banham, R. The New Brutalism. Archit. Rev. 1955,118, 354–361. 27. Frampton, K. Historia Crítica de la Arquitectura Moderna Tercera Parte. Evaluación Crítica y Extensión en el Presenta 1925–1991. 2. El Nuevo Brutalismo y la Arquitectura del Estado del Bienestar: Inglaterra, 1949–1959; Editorial GG: Barcelona, Spain, 2009; p. 268. 28. Calder, B. Raw Concrete: The Beauty of Brutalism; William Heinemann: London, UK, 2016. 29. Adam, M. Aspectos del Hormigón; Editores Técnicos Asociados S.A.: Barcelona, Spain, 1975. 30. Sagarna, M. Gipuzkoako Arkitekturaren Eboluzioaren Azterketa Hormigoi Armatuaren Garapenari Lotuta—Estudio de la Evolución de la Arquitectura de Guipúzcoa Ligada al Desarrollo del Hormigón Armado. Ph.D. Thesis, Department Architecture, University of the Basque Country—UPV/EHU, San Sebastián, Spain, 2010. 31. UNE 41805-6:2009; IN Building Diagnosis—Part 6—Pathological Study of the Structure of the Building—Concrete Structures. AENOR: Madrid, Spain, 2009. Available online: https://tienda.aenor.com/norma-une-41805-6-2009-in-n0044402 (accessed on 4 May 2024). 32. Piferi, C. Materials and innovative methodologies for restoring fair faced concrete. Techne Matter Is Des. 2018,16, 258–269. 33. Croft, C.; Macdonald, S.; Ostergren, G. (Eds.) Concrete: Case Studies in Conservation Practice; Getty Conservation Institute: Los Angeles, CA, USA, 2018. 34. Vercher, J.; Ga Borràs, J.; Lerma, C.; Gil, E.; Mas, A. State of Preservation and Intervention Proposal in a Modern Architecture Building: The Auditorium of the Labor University of Cheste, Spain. J. Perform. Constr. Facil. 2023,37, 04023030. [CrossRef] 35. UNE. UNE-EN 1504-3:2006 Products and Systems for the Protection and Repair of Concrete Structures—Definitions, Requirements, Quality Control and Evaluation of Conformity—Part 3: Strutural and Non-Structural Repair. 2006. Available online: https: //www.en-standard.eu/search-page-2/?q=en+1504 (accessed on 4 May 2024).
Heritage 2024,73576 36. Balodimou, E.; Rizzuto, J.P.; Shabaan, I.G. Perceptions and Reuse of Concrete Building Structures. Acad. Res. Community Publ. 2024,8, 24–32. [CrossRef] 37. Thoburn, N. The class architecture of Brutalism ‘as found’ at Robin Hood Gardens. Concrete and council housing. City 2018,22, 612–632. [CrossRef] 38. San Sebastián Council. Special Plan for the Protection of San Sebastián’s Built Urban Heritage PEPPUC. BOG 73. 22 April 2021. Available online: https://egoitza.gipuzkoa.eus/gao-bog/castell/bog/2021/04/22/c2102384.pdf (accessed on 4 May 2024). 39. Milosevic, S.; Aksamija, A. Sustainable Retrofitting Strategies for Culturally Significant Brutalist Buildings: Energy-Efficient Strategies for A High-Rise Residential Complex in Sarajevo, Bosnia and Herzegovina. J. Green Build. 2024,19, 95–122. [CrossRef] 40. Studio Egret West. Balfron Tower. 2014–2023. Available online: https://studioegretwest.com/places/balfron-tower (accessed on 4 May 2024). 41. Historic England. Constructive Conservation. Available online: https://historicengland.org.uk/advice/constructiveconservation/ (accessed on 4 May 2024). 42. Carli, P.; Rogora, A.; Trevisan, A. External Insulation Systems for Buildings with Complex Façades in Urban Historic Centers. In Green Buildings and Renewable Energy; Innovative Renewable Energy Book Series (INREE); Springer: Berlin/Heidelberg, Germany, 2019; pp. 305–318. 43. Oriol, M.; Lafuente, G. Construcción de Colegio, Iglesia y Convento en el Ensanche de Amara; San Sebastián City Council Municipal Archive: San Sebastián, Spain, 1965. 44. Laorga, L.; López Zanón, J.L. Proyecto de Escuela Oficial de Náutica en Pasajes; Pasaia City Council Municipal Archive: Pasaia, Spain, 1965. 45. Arizmendi, L.J. Construcción de los frontones Carmelo Balda; San Sebastián City Council Municipal Archive: San Sebastián, Spain, 1969. 46. ICOMOS. Charters for Conservation and Restoration = Chartes Internationales sur la Conservation et la Restauration = Cartas Internacionales Sobre la Conservación y la Restauración (2nd ed). ICOMOS. 2004. Available online: https://openarchive.icomos. org/id/eprint/431/1/Monuments_and_Sites_1_Charters.pdf (accessed on 19 June 2024). 47. United Nations. Our Common Future: Report of the World Commission on Environment and Development’. 1987. Available online: https://sustainabledevelopment.un.org/content/documents/5987our-common-future.pdf (accessed on 4 May 2024). 48. UNESCO. World Heritage List. 2005. Available online: https://whc.unesco.org/en/list/1181/lother=es (accessed on 4 May 2024). Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.