Presentation of conservation and restoration research and completed work on the church of St Rocco will be held in Draguć on November 8, 2024.
Church of St Rocco, built at the beginning of the 16th century, is located at the entrance to the small Istrian village of Draguć. The choice of dedication, a saint believed to protect against the plague, is consistent with the practice of building churches at the very entrance of settlements in order to protect locals from a disease. The interior is decorated with wall paintings made in two phases, in 1529 and 1537, by a local painter Anthony of Istrian Padua (near the present-day settlement Kašćerga). His name is mentioned in two inscriptions, along with the names of the clients. In addition to this church, the same master painted the church of St Rocco in Oprtalj and the Hum triptych, originally located on the main altar of the cemetery church of St Jerome in Hum. Combining folk expression and simple Renaissance forms, he created an impressive cycle of wall paintings in Draguć with a distinctive artistic expression that has been preserved to this day.
Croatian Conservation Institute started the conservation and restoration of the church of St Rocco in Draguć is 2018, and the work was completed in 2023. The supervisor of the program was Krasanka Majer Jurišić, PhD from the Division for Immovable Heritage. The team consisted of a large number of experts from the Croatian Conservation Institute. Research and work on the mural were coordinated by Kristina Krulić, work on stone elements was led by Ivan Jengić, and Ana Škevin Mikulandra was in charge of architecture and equipment. The program was funded by the Ministry of Culture and the Media of the Republic of Croatia in cooperation with the conservator Marina Boica Staraj (Conservation Department in Pula). Wholehearted support was provided by Sunčica Mustač, MA, head of the House of Frescoes in Draguć (Historical and Maritime Museum of Istria in Pula).
Research
Archival and art history research, research of wall paintings and stone elements, analysis and documentation of the condition before conservation, materials and construction including mechanical research, were all carried out. A survey was also prepared with the valorization of building elements and wall paintings with guidelines for restoration, preservation and presentation.
Archival and art history research enabled the creation of a historical review from the construction of the church to the present day, and gathered relevant material and documentation from church archives and other institutions – Diocesan Archives in Poreč, State Archives in Rijeka, Soprintendenza Archeologia, belle arti e paesaggio del Friuli Venezia Giulia, Archivio della Diocesi di Trieste, Archivio Fototeca di Antonio Morassi, Institute of Art History in Zagreb, Ministry of Culture and the Media of the Republic of Croatia and the Conservation Department in Rijeka. The timeline was established and previous knowledge about construction phases, history of design and interventions was supplemented, and older photographic and architectural documentation of the church and its equipment was consolidated. Radiocarbon dating established the wooden structure of the porch roof was built between the mid-16th and the mid-17th century (construction of the roof or one of the older repairs). After the bell was removed from the bell-gable, it was determined it was the original bell from 1530 (the year was inscribed on the bell). With a detailed survey, in addition to 3D laser scanning and the creation of a 3D polygonal model of the interior, drawings of flat and curved surfaces of the church, and an architectural survey of the existing state were made - floor plan, cross-section and longitudinal section, façade (Vektra d.o.o., Varaždin). Bases for graphic documentation were also prepared. The condition of the church before the work began was also photographed in great detail with the use of several techniques and methods. An analysis of the existing condition, spatial and design characteristics of the church were carried out, as well as an inspection and documentation of the condition of materials (stone, plaster and painted layers), thermal imaging and laboratory testing of moisture, analysis of the presence of salt, conservation and restoration research of wall paintings. An opinion on the condition of the load-bearing structure was also drawn up (Intrados projekt d.o.o., Zagreb). The condition of the foundation was determined by a floor probe, along with archaeological monitoring.
Researching the wall paintings was the most extensive part of the program. It included the inspection, description and documentation of the found condition, and ascertaining the cause of deterioration. Detailed documentation of various areas and individual details was created. By using oblique light, details were recorded that more clearly show the damage and the way the wall paintings were executed. Infrared reflectography (IRR) imaging was used to determine the older stages of the painted layers or preparatory drawings, and ultraviolet fluorescence (UVF) was used to highlight subsequent interventions, individual pigments and damage. The research included the creation of graphic documentation of wall paintings showing damage, technological characteristics and dating. Samples of plaster, salt, pigments and binders of the painted layer were analysed in the Natural Science Laboratory of the Croatian Conservation Institute, and in situ cleaning tests of wall paintings were performed in cooperation with the same laboratory. This was preceded by measuring the pH value of the wall surface and painted layer in several places. The condition of the wall paintings was monitored during the whole construction, conservation and restoration project with additional research in order to adapt the intervention and provide a better interpretation of wall paintings. Microbiological analyses of biological contamination were made in cooperation with the ArcheoLab laboratory from Pula, and pigments were additionally analysed in cooperation with the Faculty of Science of the University of Zagreb and the Ruđer Bošković Institute.
During conservation and restoration research, an inspection of the stone structure was carried out and a catalogue of carved stone elements was created. Through a detailed inspection, recording and analysis of the found condition, several typical causes of deterioration of the stone material were documented. Damage to stone elements, made of several types of local calcareous sandstone (biocalcarenite) and local limestone, and deterioration of their surface was caused by various natural processes or phenomena, and historical interventions also contributed (use of inadequate materials or tools, unprofessional repairs, lack of maintenance). The most common damage caused by natural elements include cracking, spalling, scaling and erosion of stone elements, as well as minor and major mechanical damage and the growth and biological contamination (algae, lichens and mosses, grasses, bushes, etc.). This caused a significant degradation of the stone relief or a change in the appearance of the surface and the loss of traces of the original carving with stone masons' tools. The surfaces of stone and carved elements were partially covered with various types of impurities (scale, layers of soot or dust, etc.). In places where metal elements were embedded in stone blocks, damage was caused by advanced corrosion. Due to gravitational forces, there was damage to some of the built-in stone blocks in the form of a network of cracks or even separation of layers (spalling or flaking). Displacement of stone blocks from their vertical or horizontal plane was also documented (central pillar of the porch, some capitals). The joints between the stone blocks were inappropriately and haphazardly filled with Portland cement-based plaster during the previous stages of renovation, and the same material was also used to fill cracks in the façade wall or to make individual patches on carved stone elements.
Irregularities were observed during the inspection of the walls, vault and porch. In addition to the cracks in the stonework above the main entrance and the southern wall, deformations were also present in the woodwork of the porch roof. Wooden parapets/purlins on the north and south sides were significantly damaged and bent, and had to be reinforced between the church and the first pillar. Some worn parts of the beams and planks, and the porous old cupola had to be replaced. In addition to conservation and archaeological monitoring, a floor probe was opened along the south and east façade of the church since it was previously established that moisture is one of the major problems, especially in the sanctuary, and it had a negative effect on both the condition of the wall paintings and the stone. The condition of the foundations and the lower zones of the walls confirmed the need to redirect stormwater and drainage water away from the church.
Photo album
Renovation
Croatian Conservation Institute completed the restoration of the church of St Rocco in Draguć based on the results of the research and prepared survey, and in cooperation with the Conservation Department in Pula and Marina Boica Staraj. Reconstruction and carpentry were carried out, as well as detailed conservation and restoration of carved stone elements and wall paintings, the backbone of the entire program. The reason this project began was to protect these wall paintings, provide good conditions in the church and ensure their preservation for future generations.
Wall paintings
Given the exceptional importance of wall paintings in the interior of the church, it was important to remove the causes of deterioration and carry out necessary conservation and restoration in order to protect and retain the peculiarities and distinctiveness of the drawings, technique and colours.
Primary protection of all wall paintings was carried out before the reconstruction of the church. The damaged edges of the plaster layers were lined with lime plaster. Facing was performed on wall paintings that had the most damage using Japanese paper and Tylosa MH300 binder solution in distilled water. These areas were then injected with a PLM-A and PLM-AL injection mortar mixture.
The condition of wall painting was regularly monitored during reconstruction of the roof and installation of the drainage system. The salts deposits on the surface of the wall were removed with brushes, wishab sponges and scalpels. There was no recurring efflorescence. Injection of the separated and swollen parts of the plaster was continued and the facing layer was removed. Poorly preserved plaster interventions were removed and replaced with new lime plaster matched with the original. To fill smaller cracks and damage to the plaster, thicker PLM-A and PLM-AL mixtures were used and matched to the original layer. Due to the presence of biological contamination, the affected parts of the walls were preventively treated with a disinfectant solution. The surface of wall paintings was then mechanically cleaned with soft brushes, wishab sponges and surgical scalpels. At the same time, the most vulnerable parts of the paintings were consolidated with the Nanorestore (nanolime) or Tylose MH300 solution. In both cases, the consolidation was carried out over a layer of Japanese paper, and the choice of material, method of application and repetition of the procedure depended on the type of damage and the effectiveness of the procedure.
In the final phase, the painted layer was reintegrated using pigments bound with Tylose MH300 and Klucel G. Larger sections of plaster on the sanctuary wall that had been previously replaced were preserved and matched to the original. The newly added plaster was tinted with a neutral tone lighter than the original. Damage to the original layer was minimally retouched. In some places, retouching was carried out using the tratteggio technique. This achieved uniformity and better readability of the wall paintings. Traces of biological contamination could not be removed, so their visibility was reduced through retouching. The final presentation reduced the visibility of the damage while respecting the historical and artistic value of the wall paintings.
Carved stone elements
Conservation and restoration of carved stone elements, and expert supervision of the work on stone were carried out During the renovation of the church of St Rocco.
The surface of stone sculptures was first washed; those on the exterior of the church were cleaned with water, and the window and door frame were cleaned with pressurized steam cleaner. This removed impurities (dust, soot, etc.), and retained the harmless patina, so the damage was more visible. Mechanical cleaning was carried out using various types of hand tools: scalpels, chisels, paintbrushes and brushes, which removed impurities, patches of inadequate materials (mostly grey cement), accumulations of biological contamination, and mechanically removed plants. All corroded metal elements anchored in the stone were also removed. For more stubborn contamination, the surface of the stone was additionally cleaned with biocidal agents (Asepsol, Cetavlon, Morova paste AB-57). Mechanical cleaning and cleaning with water under controlled pressure was then repeated for architectural elements (floor tiles, stone slabs at the foot of the main façade, parapet walls and bell-gable), while water vapor was used to wash the surface of stone sculptures of the monofora, holy water font, portal and window frames of the west façade. The cracks in the stone elements were repaired by installing stainless steel clamps. The parts that had structural cracks, were spalling and flaking, or had cracks caused by iron corrosion were glued and injected with liquid two-component stone glue. All modified parts of the missing elements of stone sculptures and repaired cracks were matched to the original with painting pigments in solvent. The joints between the stone elements were filled with lime plaster and shaped with hand tools.
Under professional supervision, newly acquired carved stone elements of the bell-gable, altar stone, and porch pillar were installed, and their final finishing was defined.
Architecture and equipment
Kapitel d.o.o. from Žminj carried out all construction and carpentry work on the church between 2019 and 2022, and Intrados projekt d.o.o. from Zagreb and Con-tec d.o.o. from Pula prepared the project documentation. First, stable conditions had to be ensured to start conservation and restoration of the wall painting. Drainage and rainwater drainage around the church was carried out (including water from the roof, and rainwater that flowed from the settlement directly towards the church during heavy rains), the load-bearing structure of the walls was strengthened and part of the lime floor in the interior was repaired and replaced. The badly damaged part of the base of the altar was dismantled and re-formed, and the entire base was plastered under restoration supervision. This was followed by work on the exterior of the wall: the façade was repaired, stonework was cleaned of subsequent and inappropriate grouting and biological contamination, the old mortar was strengthened and the thick lime plaster was preserved in the places where it was found (stone, old joints). The façade was then re-grouted with lime plaster, which contributed to solving the moisture problem in the interior. Although the church was plastered and covered with a thick layer of lime, only lime plaster was ultimately chosen for the finishing of the church's façade, with the approval of the conservator. The vault of the church was repaired and waterproofed with protective mortar, the roof over the nave was repaired and replaced (new roof tiles were installed on the bottom and covered with preserved old ones), roof of the porch and nave were separated. Based on the findings, and to solve the drainage of rainwater from the roof as efficiently as possible, the slope and length of the roof eaves over the side walls of the church were corrected. The elements of the bell-gable and the north-west porch pillar were replaced using grey sandstone and kirmenjak limestone, and the preparation, carving and finishing of the surface, as well as assembly, were carried out by the company Kamen d.d. from Pazin under the supervision of a structural engineer. The dilapidated wooden yoke was also replaced and the old bell was restored. Rotten oak beams and planks of the bell-gable roof were replaced, wall beams on the side facing the were reinforced, fence walls were repaired, all elements of the pillars were fixed and straightened, cracked and worn stone slabs were replaced. New carpentry was made for the church based on the original (a wooden frame with a mesh for the window on the south wall and the entrance with original fittings and grate). The wooden pew in the church was also repaired, the bars on the windows were restored and painted, the metal lamp was cleaned, and a new stone mensa was consecrated on the altar (based on the preserved print on the mural on the east wall), the relic was placed underneath.
The conservation and restoration project of the church of St Rocco was finished in 2023 with the installation of an informational and educational board (prepared by S. Mustač, K. Majer Jurišić, M. Ferlin). Access road to the church was arranged and grass was planted around it so that all interventions on the green plateau would be as subtle as possible. This was done to restore the old entrance to Draguć and area around the church of St Rocco – a modest but impressive highlight in the cultural landscape of central Istria. (KMJ / KK / AŠM)