heritage

Article A Multidisciplinary Approach for Historic Buildings Diagnosis: The Case Study of the Kaisariani Monastery

1, , 1, 1, 2, Ekaterini T. Delegou * †, Georgia Mourgi †, Elisavet Tsilimantou †, Charalabos Ioannidis † 1, and Antonia Moropoulou † 1 Laboratory of Materials Science & Engineering, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou str, 15773 Athens, Greece; [email protected] (G.M.); [email protected] (E.T.); [email protected] (A.M.) 2 Laboratory of Photogrammetry, School of Rural and Surveying Engineering, National Technical University of Athens 9, Iroon Polytechniou str., 15773 Athens, Greece; [email protected] * Correspondence: [email protected]; Tel.: +30-210-772-3075 These authors contributed equally to this work. †


Received: 22 February 2019; Accepted: 17 April 2019; Published: 20 April 2019


Abstract: In this work, a multi-disciplinary approach regarding diagnostic study processes is presented, using as an example the Catholicon of Kaisariani Monastery in Attica, Greece. Kaisariani Monastery is considered one of the most important Byzantine architectural complexes in Greece. The Catholicon of Kaisariani Monastery was built during the middle Byzantine period, and has undergone many reconstructions during the centuries. It is a semi-complex, four-columned, cross-in-square church, with a cloisonné masonry. The suggested diagnostic processes included the creation of multidisciplinary thematic maps in Computer Aided Design (CAD) environment, which incorporated: (a) data of historical and architectural documentation; (b) data of geometric documentation; and (c) data of building materials characterization and decay diagnosis. The historical and general architectural data were acquired by thorough bibliographical/archival research. Geometric documentation data were acquired by three-dimensional (3D) laser scanner for the creation of the Catholicon section drawings, whereas image based photogrammetric techniques were utilized for the creation of a 3D textured model, from which orthoimages and architectural drawings of the Catholicon façades were developed. In parallel, characterization of building materials and identification of decay patterns took place after the onsite application of the nondestructive techniques of digital microscopy, infrared thermography and ground penetrating radar. These vast array kinds of data were elaborated and integrated into the architectural drawings, developing thematic maps that record and represent the current preservation state of the monument, a concerning major construction phases, the most important conservation intervention projects, building materials and decay. Furthermore, data quantification regarding the extent of building materials and decay at each monument’s façade took place. Therefore, correlation and better understanding of the environmental impact on building materials according to façade orientation and historical data, e.g., construction phases, was accomplished. In conclusion, the presented processes are multidisciplinary tasks that require collaboration among architects, surveyor engineers and materials scientists/engineers. They are also prerequisites for the planning and application of compatible and efficient conservation/restoration interventions, for the ultimate goal of the sustainable protection of a monument.

Keywords: multi-disciplinary approach; diagnostic study; geometric documentation; non-destructive techniques; thematic maps; sustainable protection; church; cultural heritage

Heritage 2019, 2, 1211–1232; doi:10.3390/heritage2020079 www.mdpi.com/journal/heritage Heritage 2019, 2 1212

1. Introduction The conservation and preservation of important cultural heritage assets has become a concern of the interdisciplinary scientific community. Current studies illustrate that, through a multidisciplinary approach, in the field of cultural heritage, a cohesive documentation incorporating information regarding not only the architectural and geometric documentation but also historical and archaeological research, building material and decay documentation and structural research provide crucial information regarding the preservation state of a monument, possible conservation interventions and rehabilitation. Since the resources for constructing new buildings in Europe has declined, the scientific and construction community has gained growing interest in restoring and rehabilitating old buildings and monuments [1,2]. To achieve sustainable protection and restoration of such assets, a multidisciplinary approach is a prerequisite. In addition, the characterization of building materials and decay is of utmost importance, especially in terms of intervention conservation practices. For the protection of a monument, in most cases, it is forbidden to take samples [1,3]. Therefore, the scientific community turns to non-invasive and no-contact practices to acquire the necessary information. In the geometric documentation and architectural documentation field, this practice is performed with the use of laser scanning and image based techniques, keeping the monument intact. For the building materials characterization, non-destructive techniques (NDT) are utilized for the determination of the pathology of a monument. These vast amounts of data can contribute to the protection of cultural heritage assets and also for the decision making on conservation approaches [2–5]. Over the last decade, there is an immerse use of digital documentation processes, especially for the creation of textured three-dimensional (3D) models [6–8]. The 3D architectural surveys nowadays utilize techniques provided by surveying and photogrammetric scientific field and use two methodologies: close-range based modeling and image-based modeling [6]. The first one includes the use of laser scanning techniques to obtain a 3D dense point cloud in the same reference system with below sub-centimeter accuracy [8,9]. The other survey includes computer vision algorithms combined with photogrammetric procedures and provides a 3D model with radiometric information importing the texture in the model [10,11]. Currently, the scientific community tends to utilize both surveys, especially in cultural heritage documentation where the building materials play a pivotal role in the documentation process. In this case, both survey methods are elaborated and integrated, providing a textured 3D model [12–15]. For the protection of a cultural heritage asset, the classification and representation of a monuments’ pathology aims to control the decay progress and to improve planning of conservation interventions [1]. Within the framework of cultural heritage assets protection, practical needs emerge regarding the integrated study—management and the knowledge deriving from incompatible interventions towards an interdisciplinary integrated approach. Especially in the case of ancient masonry structures, additional inspection of the monument is necessary and certain factors are important to be obtained. Nowadays, the research community is beginning to investigate multidisciplinary methods of data acquisition and further elaboration of information in a multispectral, multilateral and multidisciplinary manner. Moreover, the academic community adopts such approaches, especially for the investigation of assets construction phases, deformations and restoration practices, for their visualization and projection in multiple digital platforms. The tendency is to create 3D models (via Geographic Information System (GIS) or Building Information Model (BIM) software) [16–18] incorporating information of the abovementioned disciplines as well as other depending on the project’s scope (documentation, visualization, dissemination, restoration etc.). This study aimed to investigate a multidisciplinary approach, starting from the documentation of multidisciplinary data, which includes their architectural, historical, geometric and building material documentation data, and studying their interrelation for historic building structures, that contributes to the structure’s current state assessment. Using documentation information system, and in particular two-dimensional (2D) maps that derive from the 3D documentation process, in accordance with the use and results of NDT and evaluation (E) techniques, the interdisciplinary diagnosis of decay Heritage 2019, 2 1213 patterns and their causes can be supported [19,20]. Additionally, this approach and the developed thematic maps can facilitate, as the first and crucial step, the planning and application of compatible conservation interventions. The selected monument for the implementation of this process is the Kaisariani Monastery church. The whole complex consists of Byzantine baths, kitchen, and hearth, reflectory, cells, Benizelos tower and the Catholicon [21]. The long prosperity of the Kaisariani Monastery is owed to its privileges and fertile surrounding land property. A significant library was located also in the monastery. The devastation of the monastery after the 18th century had a dramatic impact over the church [22]. The monastery, due to its history, has undergone many construction phases throughout the centuries with three main phases prevailing.

2. Materials and Methods The technological advances in the field of geometric documentation offer many different combinations for the 3D geometric documentation of monuments, depending on its size, the level of complexity, the desired and required accuracy of the developed outputs and the equipment. In this study, a combination of different methods was the ideal solution for the geometric and architectural documentation to achieve the intended results. In this section, the materials and methods for the multidisciplinary documentation are presented.

2.1. Geometric Documentation

2.1.1. Photo-Based Data Acquisition A 3D textured model of the Catholicon was realized with the integration of Structure from Motion (SfM) and Multi-View Stereo (MVS) with classic photogrammetry procedures. The 3D textured model of the exterior of the monument provides the necessary geometric information of the façades and the surface details of the structure as well as the radiometric information necessary for the development of the building materials maps. For the photo-based data acquisition, a Canon EOS 1Ds Mark III digital camera, manufactured in Japan with a CMOS sensor (36 mm 24 mm), with a fixed 24-mm lens and a NIKON D70 manufactured × in Bangkok, Thailand with a 6.1-megapixel sensor (23.7 mm 15.6 mm), with a fixed 18-mm lens, both × provided by the Laboratory of Photogrammetry, of the School of Rural and Surveying Engineering, National Technical University of Athens, were used. These cameras were used for the terrestrial photogrammetry and photorealistic texture mapping for the quality of the produced images. A specific number of digital images was taken according to the part of the monument that should be documented and the difficulties that arose in each case. In addition, tree trunks, nearly in contact with the west façade, added difficulties in the data gathering process. Digital images were taken from different angles and distances. In the case of the north façade, the documentation was very difficult, especially in the higher part because of the proximity of an exterior wall of the Monastery; therefore, the images were taken at a close distance (in many cases, less than 1.5 m). In total, approximately 150 images for each façade were taken from various distances and multiple angles, covering the exterior façades of the Catholicon. The development of the 3D point cloud and the textured model deriving from the photo-based methods was accomplished with the Photoscan Agisoft®software, by Agisoft LLC, St Petersburg, Russia. Furthermore, in the developed model of the Catholicon, all the exterior walls incorporating texture, surface variation, material differentiation and alterations were obtained.

2.1.2. Laser Scanning Data Acquisition The 3D model of the Catholicon (both interior and exterior as a model), obtained by a Leica Scan Station 2 laser scanner was provided by the Laboratory of Photogrammetry, with an average spatial resolution of 5–6 mm. The 3D point cloud consists of all the referenced point of the surveyed ± area creating a Dense Digital Surface Model (DDSM). This model facilitates as a blueprint for further Heritage 2019, 2 1214 elaboration of the architectural documentation of the monument. A proper selection of points was made to formulate the various plans and sections of the structure. The distance between the points is less than 1 cm due to its density. Therefore, it was possible to obtain specific details that otherwise would be difficult to acquire in terms of time.

2.2. Architectural and Historical Documentation Bibliographical research was carried out to collect all the available information regarding the architectural analysis of the monument (Byzantine church) since it was documented in 1952 [15]. In addition, a research on previous interventions on the church was accomplished. All the interrelated information regarding the documentation and the investigation of the church’ current state of preservation consists of various data. Starting from the historical documentation, a complete and in-depth understanding of the structure and history through a thorough bibliographical research, including older photographs, plans and draft sketches the historical documentation, was accomplished. Along with this documentation process and in-depth research, additional research on past architectural documentation studies was obtained, regarding existing deformations and anomalies, analysis of the deterioration state and possible past incompatible interventions, architectural drawings, plans and sections, which are necessary for the construction assessment, possible damages and alterations leading to the static integrity assessment of the monument [23]. For the architectural documentation process, the 3D model was elaborated. The 3D point cloud was imported in 3DCAD Map 2015 information system without losing its resolution or georeference. The section levels were determined. For the creation of the sections and the segmentation of the 3D point cloud based on the predefined sections, Geomagic Studio®software by 3D Systems, US, was utilized.

2.3. Building Materials Characterization For the documentation and analysis of the Catholicon’s masonry,non-invasive, and non-destructive techniques were performed. Digital Microscopy (DM), Infrared Thermography (IRT) and Ground Penetrating Radar (GPR) were applied in selected areas in the exterior of the Church after in situ inspection. In addition, Schmidt hammer test was applied for the evaluation of the building material’s compressive strength [24]. Digital microscopy was utilized for acquiring in-situ magnified visual spectrum images of a selected surface and provided an initial building material characterization along with an assessment of the decay. It also contributed to the determination of different construction phases’ building materials or even non-documented restoration works. In this survey, a Digital microscopy i-scope—Moritex was applied at several magnifications ( 30, 50 and 120). The Ground Penetrating × × × Radar uses radar pulses to examine the sub-surface area of a structure. Voids and inclusions can be documented and the state of preservation of the structural system can be examined. In addition, with GPR measurements, the morphological and geometrical characteristics can be revealed in a layered and brick masonry structure. In addition, past interventions can be evaluated. In this survey, the ground penetrating radar system used was a MALÅ Geoscience ProEx system by Guideline Geo AB, Sundbyberg, Sweden, with 1.6 GHz and 2.3 GHz antennae. For data acquisition, the MALÅ Geoscience Groundvision 2 software by Guideline Geo AB, Sundbyberg, Sweden was used. The MALÅ Geoscience RadExplorer v.1.41 software was used for data processing. The Infrared thermography detects the radiation in the infrared range emitted by the building materials and the structures surface. Variation in construction phases and past restoration works can be detected. It can detect areas with humidity issues and moisture transfer phenomena on monumental scale. The infrared camera used in the survey was a FLIR Systems Therma Cam B200, with a detector of focal plane array microbolometer in the spectral range of 7.5–12 µm, with thermal sensitivity of 0.08 ◦C. During the survey, the environmental conditions were measured [24]. Heritage 2019, 2 1215

Heritage 2019, 2 FOR PEER REVIEW 5 3. Results

3.1. HeritageGeometric 2019 ,Documentation 2 FOR PEER REVIEW Data 5 3.1. Geometric Documentation Data The next step was the elaboration of the orthoimages of each façade with a pixel (groudel) size 3.1. Geometric Documentation Data of 2The mm. next Initially, step was each the façade elaboration was elaborated of the orthoimages as a different of each project, façade using with masks a pixel in (groudel)the areas sizeof of 2occlusions mm. Initially,The (Figure next each step 1). façade was After the was elaborationthe elaborated elaboration of asthe a oforthoima di thfferente datages project, forof each all using façadethe façades, masks with ina pixela the 3D areas (groudel)model of occlusionsof size the (FigureCatholiconof 12). mm. After was Initially, theproduced. elaboration each façadeFor the ofwas thegeoreference elaborated data for allas of a the thedifferent façades, façades project, ain 3D a using modelcommon masks of reference the in Catholiconthe areas system, of was produced.characteristicocclusions For points(Figure the georeference of1). theAfter 3D the ofmodel theelaboration façadesalready of inobtained th ae common data byfor a referenceall laser the scannerfaçades, system, awere 3D characteristic modeldepicted. of theThe points ofaccuracy theCatholicon 3D modelobtained was already forproduced. each obtained façade For bythe after ageoreference laser the scanner elaboration of werethe façadesand depicted. correction in a The common accuracyof the reference point obtained cloud system, forwas each characteristic points of the 3D model already obtained by a laser scanner were depicted. The façadeapproximately after the 1–1.7 elaboration cm, within and acceptable correction limits of the for point the further cloud development was approximately of the thematic 1–1.7 cm, maps. within accuracy obtained for each façade after the elaboration and correction of the point cloud was acceptable limits for the further development of the thematic maps. approximately 1–1.7 cm, within acceptable limits for the further development of the thematic maps.

(a) (b) (c) (a) (b) (c) Figure 1. (a) Camera positions during the process of the alignment; (b) dense point cloud of the east Figurefaçade;Figure 1. and(a 1.) ( Camerac(a) )3D Camera mesh positions positionsof the east during during façade. the the processprocess of of the the alignment; alignment; (b) ( bdense) dense point point cloud cloud of the of east the east façade;façade; and and (c) 3D(c) 3D mesh mesh of of the the east east façade. façade. For the elaboration of the orthoimages of each façade, selected images were used to assure For the elaboration of the orthoimages of each façade, selected images were used to assure qualityFor thetexture. elaboration To proceed of the with orthoimages the multidisciplin of eachary façade, process, selected four imagesorthoimages were usedwere tocreated, assure one quality quality texture. To proceed with the multidisciplinary process, four orthoimages were created, one texture.for each To façade proceed of withthe Catholicon the multidisciplinary (Figure 2). Th process,ese orthoimages four orthoimages acted as were blueprints created, for one further for each for each façade of the Catholicon (Figure 2). These orthoimages acted as blueprints for further façadeelaboration of the of Catholicon thematic maps (Figure incorporating2). These orthoimages not only qualitative acted as blueprintsinformation for but further also quantitative elaboration of elaboration of thematic maps incorporating not only qualitative information but also quantitative thematic maps incorporating not only qualitative information but also quantitative data. data.data.

Figure 2. Orthoimage of the south façade of the Catholicon. Figure 2. OrthoimageOrthoimage of of the the south south façade façade of ofthe the Catholicon. Catholicon.

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ForFor thethe developmentdevelopment ofof 2D2D drawingsdrawings (plans(plans andand sections), sections), severalseveral methods methods were were used. used. TheThe For the development of 2D drawings (plans and sections), several methods were used. The required resolution was ±1.5 cm. Apart from the architectural documentation of the structure, the requiredrequired resolution resolution was was1.5 ±1.5 cm. cm. Apart Apart from from the the architectural architectural documentation documentation of of the the structure, structure, the the survey aimed to detect various± deformations and alterations in comparison with the initial state of surveysurvey aimed aimed to detectto detect various various deformations deformations and and alterations alterations in comparison in comparison with thewith initial the initial state of state the of the structure. Initially, the section levels were determined (Figure 3a,b); two sections that constitute structure.the structure. Initially, Initially, the section the section levels werelevels determined were determined (Figure (Figure3a,b); two 3a,b); sections two sections that constitute that constitute the the main symmetry axes of the monument and one additional section level of the Narthex, which mainthesymmetry main symmetry axes of axes the monument of the monument and one and additional one additional section level section of the level Narthex, of the whichNarthex, crosses which crosses the highest level of the temples dome. In addition, a horizontal section was set at +2.10 m thecrosses highest the level highest of the level temples of the dome. temples In addition, dome. aIn horizontal addition, sectiona horizontal was set section at +2.10 was m elevationset at +2.10 to m elevation to cross the majority of the temple’s openings. crosselevation the majority to cross of the majority temple’s of openings. the temple’s openings.

(b) (a) (a) (b) Figure 3. (a) 3D point cloud of the Catholicon as imported in the 3DCAD environment; and (b) FigureFigure 3. ( a3.) 3D(a) point3D point cloud cloud of the of Catholicon the Catholicon as imported as im inported the 3DCAD in the environment; 3DCAD environment; and (b) cropped and (b) cropped point cloud from the predefined section in the Geomagic Studio environment. pointcropped cloud point from thecloud predefined from the sectionpredefined in the sect Geomagicion in the Studio Geomagic environment. Studio environment. 3.2. Historical Documentation Data 3.2.3.2. Historical Historical Documentation Documentation Data Data The Catholicon of Kaisariani Monastery is the conventual church of a prosperous monastery TheThe Catholicon Catholicon of of Kaisariani Kaisariani Monastery Monastery is theis the conventual conventual church church of of a prosperousa prosperous monastery monastery complex, constructed in the 12th or late 11th century; the exact date of construction is not known. It complex,complex, constructed constructed in thein the 12th 12th or or late late 11th 11th century; century; the the exact exact date date of constructionof construction is notis not known. known. It It was dedicated to the Presentation of the Virgin to the Temple and is located in mount Hymettus, at waswas dedicated dedicated to theto the Presentation Presentation of of the the Virgin Virgin to theto the Temple Temple and and is locatedis located in mountin mount Hymettus, Hymettus, at at the outskirts of Athens. The Kaisariani Catholicon Main Church is mentioned or analyzed by various thethe outskirts outskirts of Athens.of Athens. The The Kaisariani Kaisariani Catholicon Catholicon Main Main Church Church is mentionedis mentioned or or analyzed analyzed by by various various researchers of Byzantine architecture, as it represents a typical sample of the mid Byzantine Greek researchersresearchers of of Byzantine Byzantine architecture, architecture, as as it representsit represents a typicala typical sample sample of theof the mid mid Byzantine Byzantine Greek Greek school, following the four columned cross in square type (Figure 4a,b) [22]. Morphologically, it is school,school, following following the the four four columned columned cross cross in squarein square type type (Figure (Figure4a,b) 4a,b) [ 22 [22].]. Morphologically, Morphologically, it isit is characterized as “strict” [25], as it consists of clear geometrical volumes and premium construction characterizedcharacterized as as “strict” “strict” [25 [25],], as as it consistsit consists of clearof clear geometrical geometrical volumes volumes and and premium premium construction construction quality. Its singularity concerns that the internal structure manages to be externalized in a simple quality.quality. Its singularityIts singularity concerns concerns that that the internalthe internal structure structure manages manages to be externalizedto be externalized in a simple in a waysimple way and without exceeding the human scale. According to the era formula, the building andway without and exceedingwithout exceeding the human the scale. human According scale. to According the era formula, to the the era building formula, construction the building is construction is mainly brick and stone cloisonné masonry style, which is better performed on the mainlyconstruction brick and is stonemainly cloisonn brick éandmasonry stone style,cloisonné which masonry is better style, performed which onis thebetter eastern performed façade, on the the eastern façade, the dome and the cross arms, where porous ashlar is used. The rest masonry is built domeeastern and façade, the cross the arms, dome where and porousthe cross ashlar arms, is where used. Theporous rest ashlar masonry is used. is built The with rest semi- masonry cloisonn is builté with semi- cloisonné style and limited parts of rubble masonry. stylewith and semi- limited cloisonné parts of style rubble and masonry. limited parts of rubble masonry.

(a) (b) (a) (b) FigureFigure 4.4.( (aa)) DocumentationDocumentation ofof thethe southwestsouthwest ofof thethe CatholiconCatholicon byby DellDell inin 18891889 (Adopted(Adopted fromfrom [[22]);22]); Figure 4. (a) Documentation of the southwest of the Catholicon by Dell in 1889 (Adopted from [22]); andand (b(b)) PhotographicPhotographic documentationdocumentation ofof thethe easteast façadefaçade ofof thethe CatholiconCatholicon inin 1888–18901888–1890 (Adopted(Adopted and (b) Photographic documentation of the east façade of the Catholicon in 1888–1890 (Adopted fromfrom [ 22[22]).]). from [22]). The first construction phase includes the original building that was a complex cross-in-square The first construction phase includes the original building that was a complex cross-in-square four-column domed church, constructed during middle Byzantine period (second half of the 11th four-column domed church, constructed during middle Byzantine period (second half of the 11th

Heritage 2019, 2 1217

The first construction phase includes the original building that was a complex cross-in-square Heritage 2019, 2 FOR PEER REVIEW 7 four-column domed church, constructed during middle Byzantine period (second half of the 11th century or early 12th century). In the 17th century, the domed Narthex was added during the Turkish century or early 12th century). In the 17th century, the domed Narthex was added during the domination and the barrel-vaulted chapel dedicated to Aghios Antonios, located in the southwest of the Turkish domination and the barrel-vaulted chapel dedicated to Aghios Antonios, located in the Catholicon, was the third addition to the church, probably in the same century (Figure4a). Therefore, southwest of the Catholicon, was the third addition to the church, probably in the same century the Kaisariani Church consists of three main construction phases and a 4th with the construction of the (Figure 4a). Therefore, the Kaisariani Church consists of three main construction phases and a 4th tower bell, added probably during 18th to 19th century. Therefore, the construction phases are the with the construction of the tower bell, added probably during 18th to 19th century. Therefore, the Main Church (11th–12th c.), the Narthex (17th c.), the St. Antonios chapel (17th–18th c.) and the tower construction phases are the Main Church (11th–12th c.), the Narthex (17th c.), the St. Antonios chapel bell (18th–19th c.) (Figure5)[26]. (17th–18th c.) and the tower bell (18th–19th c.) (Figure 5) [26].

FigureFigure 5. Ground 5. Ground Plan Plan of the of Kaisariani the Kaisariani Church Church with withthree three construction construction phases; phases; Main MainChurch Church (1st C. (1st Ph.);C. Narthex Ph.); Narthex (2nd C. (2nd Ph.); C. St. Ph.); Antony St. Antony Chapel Chapel (3rd C. (3rd Ph.–4th C. Ph.–4th C. Ph.). C. Plan Ph.). of Plan the ofCatholicon. the Catholicon.

In theIn the lower lower masonry masonry layers, layers, many many big-sized big-sized stones stones are are built built in second in second use. use. A horizontal A horizontal cornice cornice dividesdivides the the south south and and north north façade façade on onthe the same same level. level. The The north north cross cross arm arm is highlighted is highlighted with with a a perfectlyperfectly built built protruding protruding arch arch based based on ontwo two pila pilasters,sters, which which encloses encloses a double-light a double-light window. window. Other Other exceptionalexceptional ornamental ornamental elements elements are are the the dentil dentil cour coursese of of the the octagonal octagonal dome dome and the brickbrick frameframe ofof the theeastern eastern grouped grouped type type double double light light window window where wher ae glazeda glazed bowl bowl was was built built in (Figurein (Figure4b). 4b). Many Many spolia spoliacoming coming from from Roman Roman or later or later buildings buildings were builtwere inbuilt the in structure the structure and some and of some them of bear them Byzantine bear Byzantinerelief decoration relief decoration [26]. The [26]. four The ancient four marble ancient columns marble of columns the interior of the of theinterior Catholicon of the bearingCatholicon Ionian bearingcapitals Ionian carry capitals the load carry of the the octagonal load of dome,the octagonal connected dome, with connected wooden tie with beams wooden above tie the beams capitals abovelevel. the The capitals domed level. Narthex The domed of the 17th Narthex century of the located 17th incentury the west located belongs in th toe latterwest belongs construction to latter phase. constructionIt was built phase. with rubbleIt was built masonry with and rubble the masonr door wasy and built the with door spolia. was built South with of the spolia. Narthex South and of partthe of Narthexthe Catholicon, and part of a the vaulted Catholicon, chapel a was vaulted added, chap alsoel was built added, with rumble also built masonry. with rumble A mural masonry. painting A of muralthe 14thpainting century of the inside 14th the century chapel inside on the the outside chapel surface on the of outside the Main surface Church’s of the south Main wall Church’s raises the southquestion wall raises of the the existence question of an of earlierthe existence building of in an the earlier same building location. Thein the last same construction location. phaseThe last is the constructionbell tower, phase an addition is the bell of the tower, later an centuries. addition of the later centuries.

3.3. Architectural Documentation Data 3.3. Architectural Documentation Data TheThe monument monument comprises comprises a mid-Byzantine a mid-Byzantine cross- cross-in-squarein-square four-column four-column domed domed church. church. It can It can be beobserved observed that, that, in such in such churches, churches, there there is a is connection a connection between between thethe typology, typology, the the morphology morphology and and thethe structure. structure. The Thestructure structure follows follows the basic the basic rules rules while while pursuit pursuit of symmetr of symmetryy is evident. is evident. From the From developedthe developed products products of the of sections the sections and andplans, plans, various various drawings drawings were were elaborated. elaborated. The The exterior exterior dimensions of the Main Church are 9.47 m 8.12 m and the dimensions of the basic orthogonal plan dimensions of the Main Church are 9.47 m × 8.12× m and the dimensions of the basic orthogonal plan are 6.65 m 5.88 m. Towards the west, the Narthex expands 5.43 m and, towards the south, the chapel are 6.65 m × ×5.88 m. Towards the west, the Narthex expands 5.43 m and, towards the south, the chapel expands 2.92 m. The thickness dimensions of the wall structure are 70 cm on the south façade, 75 cm on the north façade, 80 cm in the recesses towards north and 60 cm on the west façade. Drawings of the plans, cross sections and long sections were developed (Figures 6 and 7).

Heritage 2019, 2 1218 expands 2.92 m. The thickness dimensions of the wall structure are 70 cm on the south façade, 75 cm on the north façade, 80 cm in the recesses towards north and 60 cm on the west façade. Drawings of Heritage 2019, 2 FOR PEER REVIEW 8 theHeritage plans, 2019 cross, 2 FOR sections PEER REVIEW and long sections were developed (Figures6 and7). 8

((aa)) (b()b )

FigureFigure 6. 6. ((aa)) LongLong Long SectionSection Section drawingdrawing drawing of of ofthe the the Main Main Main Church; Church; Church; and and and( b(b) )Cross (Crossb) Cross Section Section Section drawing drawing drawing of of the the ofMain Main the MainChurch. Church.

TheThe architectural architectural documentation documentationdocumentation drawings drawingsdrawings (deriving (deriving(deriving from the fromfrom geometric thethe geometric geometric documentation), documentation), documentation), provided informationprovided information regarding theregardingregarding structure’s the the st st stateructure’sructure’s of preservation. state state of of preservation. preservation. Deviations Deviations Deviations from the verticalfrom from the the or vertical alterationvertical or or inalteration the structures in the surfacestructuresstructures were surfacesurface observed werewere andobserved observed validated. and and validated. validated. In the Main In In the Church,the Main Main noChurch, Church, deviation no no deviation fromdeviation the verticalfrom the in thevertical long inin section thethe longlong was sectionsection observed waswas (Figure observed observed6a), (Figurewhereas (Figure 6a), a6a), 5 whereas cm whereas recess a ofa5 5cm the cm recess arches recess of ground of the the arches arches level wasground observed, level was due toobserved,observed, dome’s verticalduedue toto dome’sdome’s loads (Figure verticalvertical6b). loads loads In the(Figure (Figure case of6b). 6b). St. In AntoniosIn the the case case Chapel,of of St. St. Antonios aAntonios 10 cm deviationChapel, a from 10 cm vertical deviationdeviation was fromfrom documented verticalvertical was was (Figure documented documented7a). (Figure (Figure 7a). 7a).

((aa)) (b()b ) Figure 7. (a) Cross Section drawing of St. Antonios Chapel; and (b) plan of the Catholicon. FigureFigure 7. 7.( a(a)) Cross Cross Section Section drawing drawing of of St. St. Antonios Antonios Chapel; Chapel; and and ( b(b)) plan plan of of the the Catholicon. Catholicon.

Moreover, the developed orthoimages from the geometric documentation process were Moreover,Moreover, the the developed developed orthoimages orthoimages from from the geometric the geometric documentation documentation process wereprocess digitized were digitized for each façade, contributing to the multidisciplinary process, as presented in this work. fordigitized each façade, for each contributing façade, contributing to the multidisciplinary to the mult process,idisciplinary as presented process, in as this presented work. Every in this element work. Every element was classified in terms of building material, decay, architectural and artistic details wasEvery classified element in termswas classified of building in material,terms of decay,building architectural material, anddecay, artistic architectural details (Figure and 8artistica,b). During details (Figure 8a,b). During the process of mapping of the classified data, various layers of information the(Figure process 8a,b). of mapping During ofthe the process classified of mapping data, various of the layers classified of information data, various were created, layers of formulating information a were created, formulating a database. Each layer was created once and was attributed to each façade database.were created, Each formulating layer was created a database. once andEach was layer attributed was created to each once façade and was to avoid attributed duplications. to each façade to avoid duplications. to avoid duplications.

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(a) (b)

FigureFigure 8. (8.a) Architectural(a) Architectural drawing drawing of the of south the façadesouth offaçade the Catholicon; of the Catholicon; and (b) architectural and (b) architectural drawing ofdrawing the east façadeof the ofeast the façade Catholicon. of the Catholicon.

3.4.3.4. Building Building Materials materials Investigation investigation DuringDuring the the past past years, years, many many conservation conservation treatments treatments have have been been carried carried out out in in the the monastery monastery complex,complex, including including the church,the church, which werewhich not were fully documented.not fully documented. The only documented The only conservation documented interventionconservation work intervention was performed work wa durings performed two important during reconstructiontwo important projects, reconstruction one in theprojects, early one and in thethe other early one and in thethe middle other one 20th in century. the middle The interventions 20th century. were The mostlyinterventions applied were on buildings mostly thatapplied were on surroundingbuildings that the Catholicon,were surrounding such as thethe bath Catholicon, installations such and as thethe complex bath installations containing and the kitchenthe complex and thecontaining refectory [the27,28 kitchen]. Many and conservation the refectory projects [27,28]. were Many realized conservation within the projects monastery were area,realized by the within 1950s, the suchmonastery as the excavation area, by the of the1950s, east such side as of the the excavation church and of other the limitedeast side repair of the works. church During and other 1950s, limited an extendedrepair works. conservation During project1950s, an was extended accomplished, conservation where project part of was the easternaccomplished, window where frame part and of the the northeastern gate window of the Catholicon frame and were the reconstructed. north gate of Inthe addition, Catholicon a concrete were shellreconstructed. was constructed In addition, in the a exteriorconcrete of theshell foundation was constructed of the eastern in the façade.exterior In of addition, the foundation another of conservation the eastern project façade. was In carriedaddition, outanother by the conservation Ministry of Culture project from was 2002carried to 2008out by to restorethe Ministry the damages of Culture raised from from 2002 the to 1981 2008 and to restore 1999 earthquakes.the damages Moreover, raised from the chapelthe 1981 of and Aghios 1999 Antonios earthquakes. was repointedMoreover, in the 2011, chapel using of a Aghios lime-pozzolan Antonios mortarwas repointed [24]. in 2011, using a lime-pozzolan mortar [24]. TheThe NDT NDT results results were were combined combined to extract to extract information information regarding regarding the building the building materials, materials, the decay the patterns,decay patterns, the monument’s the monument’s state of preservation state of preservation as well as the as detection well as ofthe past detection restoration of past materials restoration and implementedmaterials and interventions implemented (Figures interventi9 andons 10). (Figures From these 9 and results, 10). From along these with inresults, situ visual along inspection, with in situ thevisual identification inspection, and the classification identification of and material classification and decay of material types wasand decay accomplished. types was Thisaccomplished. process enabledThis process also the enabled documentation also the and documentation assessment of and non-documented assessment of interventions non-documented alongside interventions with the materialalongside and with decay the analysis. material and decay analysis. VariousVarious materials materials and and construction construction techniques techniques are present are present due to thedue di toff erentthe different construction construction phases. Thephases. following The buildingfollowing materials building were materials evident were according evident to according NDT diagnostic to NDT study diagnostic and were study evaluated and were andevaluated validated and in labvalidated after sampling in lab after investigation. sampling investigation. Ministry of Culture Ministry gave of permissionCulture gave only permission for the studyonly offor the the exterior study of façades the exterior of the façades monument of the and monument documentation and documentation of the interior of the as wellinterior as otheras well partsas other such asparts the roofsuch could as the not roof be realized. could not In addition, be realized. there In were addition, high sampling there were restrictions high sampling due to therestrictions monument’s due importance to the monument’s and only importance a few mortar and samples only a few were mortar collected samples for lab were investigation collected for [24 ].lab Therefore,investigation it was [24]. not Therefore, possible to it obtain was not pictures possible of theto obtain stratigraphy pictures details of the of stratigraphy the structure, details since of the the Ministrystructure, of Culturesince the did Ministry not allow of coreCulture drilling did andnot theallow information core drilling acquired and the regarding information the structure acquired ofregarding the monument the structure were obtained of the by monument NDT deployment. were obtained Information by concerningNDT deployment. the structure Information of the variousconcerning phases the of structure the Catholicon of the is various illustrated phases in Figure of the9 a,Catholicon which shows is illustrated information in aboutfigure the9a, firstwhich constructionshows information phase of theabout Catholicon, the first construction the masonry phas of whiche of isthe a three-leafCatholicon, one, the as masonry GPR measurements of which is a displayedthree-leaf [24 one,]. as GPR measurements displayed [24]. The documented stones were: fossiliferous limestone, beige off-white porous stone, grey porous stone; compact limestone, limestone of red hue (reddish stone), compact stone of green hue

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(greenish stone) and schist. The bricks were classified as: bricks of red hue (reddish bricks) and bricks of yellow hue (yellowish bricks). The structural mortars of the church were typical lime mortars reinforced by straws. Specific areas of the north, south and most of the east façade of the Main Church were built with ashlar porous stone and compact bricks according to the typical “plinthopericleiston” system of mid-Byzantine masonry (Figure 9a). Rumble stone covered the rest of the north and south façade of the Main Church and the walls of the Narthex and Chapel (Figure 9b). More specifically, three different types of porous stone were encountered in the Main Church. A fossiliferous porous stone constitutes the main building material along with compact bricks, various types of limestones, and two different types of porous stones, schist and marble. Apart from two main building mortars, five additional types of mortars were detected on the north façade. Moreover, a restoration mortar is Heritagelocated2019, 2 around the door opening with four additional layers of repair mortars mapped on the1220 wall of the Narthex. Perhaps two of them are cement, indicative after visual inspection [29,30].

(a) (b) Heritage 2019, 2 FOR PEER REVIEW 11 FigureFigure 9. (a) Characteristic9. (a) Characteristic Results fromResults the from GPR measurements;the GPR measurements; and (b) IRT and image (b) ofIRT the image north façadeof the north façade (Adopted from [24]). (Adopted from [24]). The Main Church (first construction phase) is a typical Byzantine three-leaf masonry, whereas Narthex is a rubble masonry. The porous stone of the east façade is a fossiliferous stone. The original mortar of the east façade, although attributed to the first construction phase, and therefore subjected to environmental factors for a much longer period compared to the subsequent phase materials, is in a good preservation state [24]. In addition, a plethora of decay patterns are evident according to NDT diagnostic study (Figure 10). They can be analyzed as extended bio decay, consisting of black fungi (black bio decay), crustose epilithic lichens, foliose epilithic lichens, mosses, plants, brownish depositions, cracks, material loss/scaling (including mortar depletion), rising damp and penetrating damp, and incompatible conservation interventions, especially in the Narthex.

FigureFigure 10. 10.DM DM images images of of decay decay (various (various types types of of lichens lichens and and black black bio bio decay) decay) (Adopted (Adopted from from [24 [24])]). The documented stones were: fossiliferous limestone, beige off-white porous stone, grey porous 4. Discussion stone; compact limestone, limestone of red hue (reddish stone), compact stone of green hue (greenish stone)4.1. The and Elaboration schist. The of bricksthe Historical were classified Documentat as: bricksion Towards of red the hue Development (reddish bricks) of Thematic and bricks Maps of of yellow hueConstruction (yellowish Phases bricks). The structural mortars of the church were typical lime mortars reinforced by straws. SpecificAs presented areas ofin thethe north,monument’s south andconstruction most of thephases east and façade the ofrestoration the Main interventions Church were (Figure built with11), ashlarthe Main porous Church stone retains and compact the authentic bricks according building tomaterials, the typical apart “plinthopericleiston” from a specific area system located of around the door of the northern façade and the two windows of the eastern façade, where a mid-Byzantine masonry (Figure9a). Rumble stone covered the rest of the north and south. façade of thenon-documented Main Church and restoration the walls ofinterven the Narthextion took and Chapelplace during (Figure the9b). 1950 Mores [24]. specifically, Additionally, three di pastfferent and typesmost of recent porous restoration stone were interventions encountered are in theevident Main and Church. documented A fossiliferous on the porous west and stone north constitutes exterior thewalls main of buildingthe Narthex material and alongthe west with façade compact of bricks,the chapel. various The types eastern of limestones, façade has and undergone two diff erentfewer typesinterventions of porous than stones, the schistothers, and while, marble. on the Apart west from façade, two mainthe restoration building mortars, interventions five additional cover the typesentire of masonry mortars wereand there detected is evidence on the north of repair façade. mortar Moreover, as well a(Figure restoration 11a). mortar is located around the door opening with four additional layers of repair mortars mapped on the wall of the Narthex. Perhaps two of them are cement, indicative after visual inspection [29,30]. The Main Church (first construction phase) is a typical Byzantine three-leaf masonry, whereas Narthex is a rubble masonry. The porous stone of the east façade is a fossiliferous stone. The original mortar of the east façade, although attributed to the first construction phase, and therefore subjected to environmental factors for a much longer period compared to the subsequent phase materials, is in a good preservation state [24].

(a) (b)

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In addition, a plethora of decay patterns are evident according to NDT diagnostic study (Figure 10). They can be analyzed as extended bio decay, consisting of black fungi (black bio decay), crustose epilithic lichens, foliose epilithic lichens, mosses, plants, brownish depositions, cracks, material loss/scaling (includingHeritage 2019 mortar, 2 FOR depletion), PEER REVIEW rising damp and penetrating damp, and incompatible conservation11 interventions, especially in the Narthex. Figure 10. DM images of decay (various types of lichens and black bio decay) (Adopted from [24]) 4. Discussion 4. Discussion 4.1. The Elaboration of the Historical Documentation Towards the Development of Thematic Maps of Construction4.1. The Elaboration Phases of the Historical Documentation Towards the Development of Thematic Maps of Construction Phases As presented in the monument’s construction phases and the restoration interventions (Figure 11), As presented in the monument’s construction phases and the restoration interventions (Figure the Main Church retains the authentic building materials, apart from a specific area located around the 11), the Main Church retains the authentic building materials, apart from a specific area located door of the northern façade and the two windows of the eastern façade, where a non-documented around the door of the northern façade and the two windows of the eastern façade, where a restoration intervention took place during the 1950s [24]. Additionally, past and most recent restoration non-documented restoration intervention took place during the 1950s [24]. Additionally, past and interventionsmost recent are restoration evident and interventions documented are onevident the west and anddocumented north exterior on the walls west ofand the north Narthex exterior and the westwalls façade of the ofNarthex the chapel. and the The west eastern façade façade of the has chapel. undergone The eastern fewer interventionsfaçade has undergone than the others,fewer while,interventions on the west than façade, the the others, restoration while, interventionson the west façade, cover the the entire restoration masonry interventions and thereis cover evidence the of repairentire mortar masonry as welland there (Figure is evidence 11a). of repair mortar as well (Figure 11a).

(a) (b)

(c) (d)

Figure 11. Cont.

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(e) (f) Figure 1. (a) Construction phases thematic map—north façade; (b) construction phases thematic Figure 11. (a) Construction phases thematic map—north façade; (b) construction phases thematic map—southmap—south façade; façade; (c) ( constructionc) construction phases phases thematic thematic map—east map—east façade;façade; ( d)) construction construction phases phases thematicthematic map—west map—west façade; façade; (e) ( historicale) historical phases; phases; and and (f )(f interventions.) interventions

4.2.4.2. Elaboration Elaboration of NDTs of NDTs for for the the Development Development of of Thematic Thematic Maps Maps SinceSince its earlyits early construction, construction, the the Catholicon Catholicon has has undergone undergone manymany andand variousvarious construction interventions,interventions, some some of whichof which were were analytically analytically documented documented andand couldcould bebe found in the archives archives of of the Localthe Local Ephorate Ephorate of Antiquities.of Antiquities. However, However, the the use use of of NDT NDT isis currentlycurrently utilizedutilized by by the the scientific scientific communitycommunity to evaluateto evaluate and and assess assess the the compatibility compatibility of of past past conservation–intervention conservation–intervention works. The The NDTNDT techniques techniques that that were were applied applied for for the the assessment assessment of of the the church’s church’s currentcurrent state of preservation indicatedindicated surface surface morphology morphology variations, variations, texture texture differences differences and variableand variable surface surface composition. composition. These variationsThese variations led to the led classification to the classification of the buildingof the building materials materials and decayand decay data. data. In addition,In addition, areas areas of increasedof increased or reduced or reduced emissions emissions were were revealed, revealed, providing providing information information of structural of structural variation variation of theof masonry,the masonry, information information that was that strengthened was strengthened by the on-siteby the on-site visual inspectionvisual inspection of the constructionof the construction phases andphases the bibliographic and the bibliographic research. research. Recording,Recording, classification, classification, distribution distribution and and representation representation of building of building materials materials on a on surface a surface scale, on thescale, monument’s on the monument’s façade, was façade, applied was for applied the exterior for the of exterior the Catholicon, of the Catholicon, based on visualbased inspectionon visual inspection and NDT evaluation. The combination of the NDTs resulted in the validation of the and NDT evaluation. The combination of the NDTs resulted in the validation of the building materials building materials and decay pattern classification and therefore was integrated within the CAD and decay pattern classification and therefore was integrated within the CAD information system. information system. In Figure 12, the classification of the fossiliferous porous stone with 51 cm In Figure 12, the classification of the fossiliferous porous stone with 51 cm length and 21 cm width length and 21 cm width is one of the building materials type encountered in this typical is one of the building materials type encountered in this typical “plinthopericleiston” system of the “plinthopericleiston” system of the Catholicon masonry, which includes one layer of stone, one layer Catholiconof filling masonry, mortar and which one includeslayer of brick, one layerenclosing of stone, each onestone. layer The of width filling of mortar the brick and as onewell layer as the of brick,width enclosing of the eachfiling stone. mortar The is the width same, of approximately the brick as well 2 cm. as the width of the filing mortar is the same, approximately 2 cm. On the north façade, integration between DM and IRT results in the validation of different type of construction between the Narthex and the Main Church, since the Narthex is an area of high moisture and, additionally, the susceptibility to bio decay and lichens of the north façade illustrated by DM results is evident (Figure 13). On the east façade, integration of visual inspection and DM images, reveal that 8% of the historical bricks present scaling and material loss just above the rising damp zone, probably due to the presence of the concrete ground work base (Figure 14).

4.3. Thematic Maps of Building Material and Decay Thematic maps of building materials and decay of all the façades were developed. The north and the east façade were chosen since they represent two different states of preservation. In addition, the variation of the construction phases, demonstrated in these façades can contribute to the assessment of the state of preservation, the incompatibility of past restoration works is revealed via the decay thematic map. In the thematic map of building materials on the north façade of the Catholicon, the variation of materials is evident (Figure 15). The past restoration works performed in the Narthex of the monument is almost as a patchwork having lost almost completely the structural layer underneath. In the decay thematic map (Figure 16), the mortar microfractures (brown color) can easily provide information of

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the incompatibility with other restoration works. Moreover, there is a significant amount of black bio Heritagedecay 2019 (purple, 2 FOR color) PEER thatREVIEW covers almost the entire structure. 13

Figure 12. Classification and validation of building materials integrating NDT results with geometric documentation.

On the north façade, integration between DM and IRT results in the validation of different type of construction between the Narthex and the Main Church, since the Narthex is an area of high Figure 12. Classification and validation of building materials integrating NDT results with moistureFigure 12.and, Classification additionally, and the validation susceptibility of building to bio materials decay integrating and lichens NDT of theresults north with façade geometric illustrated geometric documentation. by documentation.DM results is evident (Figure 13).

On the north façade, integration between DM and IRT results in the validation of different type of construction between the Narthex and the Main Church, since the Narthex is an area of high moisture and, additionally, the susceptibility to bio decay and lichens of the north façade illustrated by DM results is evident (Figure 13).

FigureFigure 13. 13.Elaboration Elaboration process process during during the the classification classification of of decay decay on on the the north north façade. façade.

Figure 13. Elaboration process during the classification of decay on the north façade.

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On the east façade, integration of visual inspection and DM images, reveal that 8% of the historical bricks present scaling and material loss just above the rising damp zone, probably due to Heritage 2019, 2 1224 the presence of the concrete ground work base (Figure 14).

Heritage 2019, 2 FOR PEER REVIEW 15 Figure 14. Elaboration process during the classification of decay on the east façade. Figure 14. Elaboration process during the classification of decay on the east façade.

4.3. Thematic Maps of Building Material and Decay Thematic maps of building materials and decay of all the façades were developed. The north and the east façade were chosen since they represent two different states of preservation. In addition, the variation of the construction phases, demonstrated in these façades can contribute to the assessment of the state of preservation, the incompatibility of past restoration works is revealed via the decay thematic map. In the thematic map of building materials on the north façade of the Catholicon, the variation of materials is evident (Figure 15). The past restoration works performed in the Narthex of the monument is almost as a patchwork having lost almost completely the structural layer underneath. In the decay thematic map (Figure 16), the mortar microfractures (brown color) can easily provide information of the incompatibility with other restoration works. Moreover, there is a significant amount of black bio decay (purple color) that covers almost the entire structure.

FigureFigure 15. 15.Thematic Thematic mapmap ofof buildingbuilding materialmaterial on the north façade.

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Figure 2. Thematic map of decay on the north façade Figure 16. Thematic map of decay on the north façade. In the elaborated thematic maps of the east façade, it is evident that its structure consists mainly In the elaborated thematic maps of the east façade, it is evident that its structure consists mainly of building material from the first construction phase with some restoration interventions in the of building material from the first construction phase with some restoration interventions in the lower lower zone of the façade (Figure 17). The main issue that should be dealt is the rising damp as well as zone of the façade (Figure 17). The main issue that should be dealt is the rising damp as well as the the moisture problems in the higher zone of the façade, as illustrated in the thematic map of decay moisture problems in the higher zone of the façade, as illustrated in the thematic map of decay patterns patterns (Figure 18). (Figure 18).

4.4. Quantitative Data Integration Through the multidisciplinary process, quantitative and qualitative data were produced and information regarding the preservation state of the monument was obtained. Apart from the visualization of the multidisciplinary data, quantification was possible, providing additional data for further elaboration.

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FigureFigure 17. 17.Thematic Thematic map map of of building building material material on on the the east east façade. façade.

The differences of each façade masonry type were recorded and elaborated for qualitative and quantitative investigation (Figure 19). The structural system of each façade was documented through the thematic maps, validating the architectural and historical research, their construction period and past restoration works. On the east façade, it is evident that there are a higher percentage of stone and lower ones of mortar in comparison to the other façades, depicting the strict cloisonné system that was followed for its construction. This façade has undergone very few restoration interventions and the structural system of the first construction phase is obvious. Moreover, bio decay is one of the most deteriorating factors of the Kaisariani Catholicon. A comparative diagram was elaborated, deriving from the thematic map development to quantify and elaborate further the environmental conditions of the surroundings, which can work as a degradation mechanism for the monument (Figure 20). The north façade presents higher percentages of bio decay in comparison to the other façades, since its orientation favors bio decay growth.

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HeritageHeritage 20192019, 2, 2FOR PEER REVIEW 122718

Figure 18. Thematic map of decay on the east façade.

4.4. Quantitative Data Integration Through the multidisciplinary process, quantitative and qualitative data were produced and information regarding the preservation state of the monument was obtained. Apart from the visualization of the multidisciplinary data, quantification was possible, providing additional data for further elaboration. FigureFigure 18. 18. ThematicThematic map map of of decay decay on on the the east east façade. façade.

4.4. Quantitative Data Integration Through the multidisciplinary process, quantitative and qualitative data were produced and information regarding the preservation state of the monument was obtained. Apart from the visualization of the multidisciplinary data, quantification was possible, providing additional data for further elaboration.

Figure 19. Diagram of the percentage of building materials in three façades of the Catholicon.

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Figure 19. Diagram of the percentage of building materials in three façades of the Catholicon.

The differences of each façade masonry type were recorded and elaborated for qualitative and quantitative investigation (Figure 19). The structural system of each façade was documented through the thematic maps, validating the architectural and historical research, their construction period and past restoration works. On the east façade, it is evident that there are a higher percentage of stone and lower ones of mortar in comparison to the other façades, depicting the strict cloisonné system that was followed for its construction. This façade has undergone very few restoration interventions and the structural system of the first construction phase is obvious. Moreover, bio decay is one of the most deteriorating factors of the Kaisariani Catholicon. A comparative diagram was elaborated, deriving from the thematic map development to quantify and elaborate further the environmental conditions of the surroundings, which can work as a degradation mechanism for the monument (Figure 20). The north façade presents higher percentages of bio decay in comparison to the other façades, since its orientation favors bio decay growth. This data quantification process presents many advantages for the planning and application of conservation–restoration interventions. More accurate calculation of the amounts of the required conservation materials can be accomplished, i.e. restoration mortars, and cleaning and protection materials. Therefore, budget and cost analysis of the rehabilitation project can be organized more Heritage 2019, 2 1228 accurately.

FigureFigure 20.20. DiagramDiagram illustrating the percentage of bio decay decay on on the the façades façades of of the the Catholicon. Catholicon. This data quantification process presents many advantages for the planning and application of 5. Conclusions conservation–restoration interventions. More accurate calculation of the amounts of the required conservationThe methodological materials can process be accomplished, is the outcome i.e. of restoration this work mortars, and is described and cleaning within and this protection paper. materials.Within this Therefore,framework, budget a multidisciplinary and cost analysis approach of the is presented, rehabilitation importing project a can vast be amount organized of morevarious accurately. data correlated and visualized within thematic maps. The four pillars of this process are the historical documentation, the architectural, the geometric and the building materials and decay 5.documentation Conclusions (Figure 21). They all contribute to the creation of multidisciplinary thematic maps and interrelate among each other. The methodological process is the outcome of this work and is described within this paper. Within this framework, a multidisciplinary approach is presented, importing a vast amount of various data correlated and visualized within thematic maps. The four pillars of this process are the historical documentation, the architectural, the geometric and the building materials and decay documentation (Figure 21). They all contribute to the creation of multidisciplinary thematic maps and interrelate among each other. Regarding the four basic pillars of this approach, the preservation state in terms of building materials pathology is illustrated and is in conjunction with the geometric and architectural documentation data. The past restoration works are depicted including the various construction phases of the monument (historical documentation), ensuring sustainability in terms of planning and applying of conservation and restoration interventions. Each documentation process contributes equally in the illustrated diagram for the creation of the multidisciplinary thematic maps. Through this proposed process, it is important to follow specific steps that can lead eventually to the protection of the cultural heritage asset. The recording of the current state of preservation is among the initial and most crucial steps. In the Catholicon of Kaisariani, this was a very demanding task, since the Ministry of Culture did not give permission to perform analytical documentation processes in order to have all the relevant information, due to its high significance. Therefore, the documentation process of the historical data was crucial for the assessment of the construction phases of the monument and also document past restoration projects that were recorded. Heritage 2019, 2 1229 Heritage 2019, 2 FOR PEER REVIEW 20

Figure 21. Diagram of the multidisciplinary process incorporatingincorporating various multidisciplinary data.

InRegarding addition, the the four construction basic pillars style of ofthis the approach, monument the aligns preservation with the state era thatin terms was builtof building (brick andmaterials stone cloisonnpathologyé masonry is illustrated style). and The geometricis in conjunction documentation with the provided geometric information and architectural regarding thedocumentation structural system, data. The including past restoration building materialsworks are dimensions depicted including (width and the length) various in construction the exterior façades,phases of as the well monument as information (histori regardingcal documentation), the structural ensuring section dimensionssustainability of in the terms walls, of validating planning theand documentedapplying of conservation construction and phases restoration Moreover, interventions. correlation Each between documentation geometric process and architectural contributes documentationequally in the illustrated depicted diagram alterations for ofthe the creation monument of the throughmultidisciplinary time, including thematic deviation maps. from the verticalThrough and alteration this proposed in the structures’process, it is surface. important A 10-cm to follow deviation specific from steps vertical that can in the lead St. eventually Antonio’s Chapelto the protection is an example of the of cultural deformation heritage that asset. can occur The recording in the case of of the structures current constructedstate of preservation in different is periods,among the with initial diff erentand most types crucial of materials, steps. In etc. the InformationCatholicon of regarding Kaisariani, the this pathology was a very of the demanding building intask, terms since of the exterior Ministry decay of Culture factors isdid highlighted not give permission within thematic to perform maps analytical incorporating documentation geometric, architecturalprocesses in andorder building to have material all the relevant data investigation. information, The due north to its façade high presents significance. high interestTherefore, since the it incorporatesdocumentation information process of of the the historical first construction data wa phases crucial of thefor Catholicon,the assessment with of the the strict construction cloisonné systemphases andof the main monument decay factor, and thealso bio document decay that past accumulates restoration due projects to environmental that were recorded. factors and location. ThroughIn addition, this the investigation, construction the style proposed of the monument processes, address aligns with various the disciplinesera that was and built stakeholders (brick and andstone utilize cloisonné the thematic masonry maps style). development. The geometric Through documentation these thematic provided maps, information whether they regarding address the constructionstructural system, phases, including building materialsbuilding materials or restoration dimensions works, a(width correlation and andlength) management in the exterior of the variousfaçades, disciplinary as well as information information regarding is accomplished, the structural contributing section to dimensions the planning of of the interventions, walls, validating if and whenthe documented the need arises. construction phases Moreover, correlation between geometric and architectural documentationThe presented depicted processes alterations are multidisciplinary of the monume tasksnt through that require time, collaboration including deviation among architects,from the surveyorvertical and engineers alteration and in the materials structures’ scientists surface./engineers A 10-cm (Figuredeviation 22 from). To vertical conclude, in the the St. Antonio’s proposed methodologicalChapel is an example processes of deformation can be implemented that can occur for in all the cultural case of structures heritage assets constructed to determine in different the preservationperiods, with state different and facilitatetypes of materials, decision making etc. Information for sustainable regarding protection. the pathology In the specific of the building case of the in Catholiconterms of exterior of Kaisariani decay that factors was investigated is highlighted for the within development thematic of themaps proposed incorporating process, permissiongeometric, wasarchitectural given only and for building the study material of the exteriordata investigation. façades of theThe monument north façade in termsof the ofmonument building materialpresents high interest since it incorporates information of the first construction phase of the Catholicon, with

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the strict cloisonné system and main decay factor, the bio decay that accumulates due to environmental factors and location. Through this investigation, the proposed processes, address various disciplines and stakeholders and utilize the thematic maps development. Through these thematic maps, whether they address the construction phases, building materials or restoration works, a correlation and management of the various disciplinary information is accomplished, contributing to the planning of interventions, if and when the need arises. The presented processes are multidisciplinary tasks that require collaboration among architects, surveyor engineers and materials scientists/engineers (Figure 22). To conclude, the proposed methodological processes can be implemented for all cultural heritage assets to determine the Heritagepreservation2019, 2 state and facilitate decision making for sustainable protection. In the specific case of 1230the Catholicon of Kaisariani that was investigated for the development of the proposed process, permission was given only for the study of the exterior façades of the monument in terms of andbuilding decay material characterization. and decay Issues characterization. concerning theIssues stratigraphy concerning of the the stratigraphy structure and of otherthe structure parts of and the Catholiconother parts such of the as theCatholicon interior such and theas the roof interior could bean ad nextthe roof step could of study be a whenever next step permissionof study whenever is given bypermission the Ministry is given of Culture. by the Ministry of Culture.

Figure 22. Diagram representing the steps toward sustainable protection of monuments. Figure 22. Diagram representing the steps toward sustainable protection of monuments. Author Contributions: A.M., E.T.D. and E.T. conceived the research; A.M. supervised the overall writing of theAuthor paper Contributions: and offered the A.M., overall E.D. methodology; and E.T. conceived G.M. performed the research; the historicalAM supervised and architectural the overall writing analysis; of G.M. the elaboratedpaper and the offered results the for overall her Master methodology; Thesis entitled G.M. perfor “Planningmed the and historical management and arch of theitectural Diagnostic analysis; Study G.M. of Materialelaborated and the Decay results Patterns for her for Master the Katholic Thesis of entitled Kaisariani “Planning Monastery” and mana undergement the supervision of the Diagnostic of A.M. Study and C.I.; of C.I.,Material G.M. and Decay E.T. analyzed Patterns the for surveyingthe Katholic data, of Kaisaria designedni Monastery” the photo-based under experimental the supervision data of gathering,A.M. and C.I.; and performed the data gathering, management, elaboration and integration; E.T.D. and E.T., performed the analysis C.I., G.M. and E.T. analyzed the surveying data, designed the photo-based experimental data gathering, and of the thematic map development; A.M., E.T.D. and E.T. conceived and designed the methodology of the study; andperformed E.T., E.T.D. the anddata G.M. gathering, wrote management, the paper. Credits elaboration for the an figuresd integration; that are notE.D. adopted and E.T., by performed other reference the analysis follow theof manuscript.the thematic map development; A.M. E.D and E.T. conceived and designed the methodology of the study; and E.T., E.D. and G.M. wrote the paper. Credits for the figures that are not adopted by other reference follow Funding: This research was funded by the research project “Seismic Protection of Monuments and Historic Structures—SEISMO”the manuscript. which is co-financed by the Greek Ministry of Education and Religions and the European UnionFunding: under This the research action “Thales”- was funded MIS380152, by the withinresearch the projec contextt “Seismic of the Operational Protection Programme—Educationof Monuments and Historic and Lifelong Learning, NSRF 2007-2013. Structures—SEISMO” which is co-financed by the Greek Ministry of Education and Religions and the European Acknowledgments:Union under the actionThe “Thales”- investigation MIS380152, was performed within the within context the of researchthe Operational project Programme—Education “Seismic Protection of Monumentsand Lifelong and Learning, Historic NSRF Structures—SEISMO”, 2007-2013. which is co-financed by the Greek Ministry of Education and Religions and the European Union under the action “Thales”-MIS380152 within the context of the Operational Programme—EducationAcknowledgments: The and investigation Lifelong Learning, was performed NSRF 2007-2013. within the In research addition, project the authors “Seismic acknowledge Protection theof contributionMonuments of and the laboratoryHistoric Structures—SEISMO”, of Photogrammetry and which more is specificallyco-financed ofby Sevasti the Greek Tapinaki Ministry and Sofiaof Education Soile, for and the 3DReligions laser scanning and the model European of the Union Kaisariani under Monastery the action and“Thales”-MIS380152 advice in relevant within information. the context The authorsof the Operational would like to thank M. Korre for his advice regarding the way to evaluate the deviations in the architectural documentation process.Programme—Education The authors would and like Lifelong to thank Learning, the employees NSRF 2007-2013. of the 1st EphorateIn addition, of Byzantinethe authors Antiquities acknowledge for their the cooperation.contribution This of the research laboratory was of orally Photogrammetry presented in itsand initial more form specifically at the 1st of MSc International EDIP Sevasti Conference Tapinaki TMM_CH: and MSc TransdisciplinaryEDIP Sofia Soile, Multispectral for the 3D Modeling laser scanning and Cooperation model of forthe the Kaisariani Preservation Monastery of Cultural and Heritage, advice heldin relevant during 10–13information. October 2018The authors at the Eugenides would like Foundation to thank Emeritus Athens, Professor Greece under M. Korre the title for “Documentationhis advice regarding of the the Building way to Materialsevaluate andthe Decaydeviations Patterns in the of thearchitectural Kaisariani docume Monastery”ntation by process. Ekaterini The T. Delegou,authors would and has like since to thank thenbeen the modified and elaborated with further results and interpretations. employees of the 1st Ephorate of Byzantine Antiquities for their cooperation. This research was orally presented Conflictsin its initial of Interest: form at Thethe 1st funders International had no role Conferen in the designce TMM_CH: of the study; Transdisciplinary in the collection, Multispectral analyses, or Modeling interpretation and ofCooperation data; in the writingfor the ofPreservation the manuscript, of Cultural or in the Heri decisiontage, toheld publish during the 10–13 results. Oc Thetober authors 2018 declareat the Eugenides no conflict ofFoundation interest. Athens, Greece under the title “Documentation of the Building Materials and Decay Patterns of the Kaisariani Monastery” by Dr. Ekaterini T. Delegou, and has since then been modified and elaborated with Referencesfurther results and interpretations.

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