Periodic Reporting for period 1 - CLEA (Reviewing and integrating methods for the Conservation of European architecturaL finishes in urban hEritage townscApes)
Reporting period: 2022-01-01 to 2024-12-31
Interdisciplinary studies of architectural finishes located in historical centres provide a knowledge base loaded with heritage and technological value. Hence, the know-how processes are meaningfully linked with the cultural identity and improve the understanding of colour in urban landscapes that could be applied to current conservation works in order to produce restoration materials by means of the selection of materials and pigments for the preservation of historic aesthetics. Such topics are important for society because the knowledge attained represents an heritage resource that confers special cohesion and identity, and comprehensive studies of architectural finishes represents a preventive measure to the conservation and restoration practices of built heritage and historic landscapes.
The CLEA project has addressed architectural finishes over time via three main objectives: a) to perform a multianalitical study of the historic mortars and colour layers from the built heritage of the cities of Las Palmas and Santa María de Guía (Canary Islands, Spain) built in Traditional style (16th, 17th and 18th centuries), Neoclassical (19th c.) and Academic and Eclectic styles (20th c.), b) to state the original materials and methods used during the construction of buildings in historical centres, and c) to highlight the data to transfer to conservators, restorers and specifiers working in the conservation of façades of building heritage.
The main conclusions are: a) architectural finishes shape the image of the historical cities studied, with colour changes from yellowish to reddish hues from Traditional style, the Neoclassical buildings were built up mostly with reddish, green and blue colours and the Academic and Eclectic styles, whitish hues were extensively used, b) local materials were used in the construction of buildings studied. Earth/clay-based mortars in buildings from 16th century until 19th c. have been applied, and lime-based mortars have been extensively used in all historical periods, c) local pigments have been used in mainly until 18th century, when international trade with the island began and synthetic pigments started to be applied.
The CLEA project has entailed a major impact on the career development of the MSCA fellow, that has worked in an independent way, has strengthened her research profile, has extended her professional network and has enlarged her future prospects.
The CLEA project has addressed architectural finishes over time via three main objectives: a) to perform a multianalitical study of the historic mortars and colour layers from the built heritage of the cities of Las Palmas and Santa María de Guía (Canary Islands, Spain) built in Traditional style (16th, 17th and 18th centuries), Neoclassical (19th c.) and Academic and Eclectic styles (20th c.), b) to state the original materials and methods used during the construction of buildings in historical centres, and c) to highlight the data to transfer to conservators, restorers and specifiers working in the conservation of façades of building heritage.
The main conclusions are: a) architectural finishes shape the image of the historical cities studied, with colour changes from yellowish to reddish hues from Traditional style, the Neoclassical buildings were built up mostly with reddish, green and blue colours and the Academic and Eclectic styles, whitish hues were extensively used, b) local materials were used in the construction of buildings studied. Earth/clay-based mortars in buildings from 16th century until 19th c. have been applied, and lime-based mortars have been extensively used in all historical periods, c) local pigments have been used in mainly until 18th century, when international trade with the island began and synthetic pigments started to be applied.
The CLEA project has entailed a major impact on the career development of the MSCA fellow, that has worked in an independent way, has strengthened her research profile, has extended her professional network and has enlarged her future prospects.
The multianalitical study has comprised spectrophotometry, X-ray powder diffraction, X-ray fluorescence, confocal laser scanner, polarized optical and environmental scanning electron microscopies, with EDS microanalysis, FTIR-ATR and Raman spectroscopy.
The results achieved pointed out that: a) clay mortars with quartz and calcite inclusions were used as coating a number of traditional style façades, in concordance with the composition of the local materials, b) anorthite and sanidine feldspars, calcic clinopyroxene (augite/diopside) and zeolite-type phillipsite constituted the accessory phases, c) a lesser clay content on the earthen mortars were the main technological modifications used to fill in the stone blocks of 19th c. buildings, resulting a main phase of quartz, vastly blended with sanidino feldspar, albite and anorthoclase, d) lime-based mortars are found in all the building styles. High peaks of this group correspond to calcite, i.e. a lime mortar with sand aggregates, mostly quartz, feldspars and micas. Olivine and clinopyroxenes denote the volcanic phases, e) first colour layers applied in all buildings consist of calcium sulphate and/or carbonate (CaSO4 / CaCO3), at times with iron-based pigments (FeO2) and silicate aggregates, e) exotic pigments coming from international commercial exchanges as lapislazuli (Na7Al6Si6O24S3), were introduced during the 18th century, f) poisonous pigments used mainly in building heritage constructed by wealthy owners during the 19th century have been used, such as lead white (PbCO3), and Sheele or Emerald greens 3Cu(AsO2)2Cu(CH3COO)2, g) more recent colour layers are mainly recognized by the use of synthetic pigments, such as the zinc yellow (K2O4ZnCrO43H2O), used in façades built in the middle of the 19th century, g) the evolution of white pigments towards less poisonous ones promoted by the industry, such as Lithopone (ZnS·BaSO4) and Barium white (BaSO4) were detected, and h) dioxide of titanium (TiO2), white pigment widely used from the 1930s indicates recent applications during maintenance after the date of construction of the building analysed.
The present MSCA was characterized by the publication of 2 scientific papers (+2 in progress) -all available in Open Access-, dissemination at 5 international conferences, 2 invited seminar lectures and 4 workshops. Data were also submitted to open access repositories (IT SYGMA tool and IRIS Institutional Archive of UNIPD and Open Research Europe platform). In addition, outreach activities were performed by the fellow with the support of the International Research Office of UNIPD. The European Union funding has been acknowledged in all the dissemination activities developed under the project.
The results achieved pointed out that: a) clay mortars with quartz and calcite inclusions were used as coating a number of traditional style façades, in concordance with the composition of the local materials, b) anorthite and sanidine feldspars, calcic clinopyroxene (augite/diopside) and zeolite-type phillipsite constituted the accessory phases, c) a lesser clay content on the earthen mortars were the main technological modifications used to fill in the stone blocks of 19th c. buildings, resulting a main phase of quartz, vastly blended with sanidino feldspar, albite and anorthoclase, d) lime-based mortars are found in all the building styles. High peaks of this group correspond to calcite, i.e. a lime mortar with sand aggregates, mostly quartz, feldspars and micas. Olivine and clinopyroxenes denote the volcanic phases, e) first colour layers applied in all buildings consist of calcium sulphate and/or carbonate (CaSO4 / CaCO3), at times with iron-based pigments (FeO2) and silicate aggregates, e) exotic pigments coming from international commercial exchanges as lapislazuli (Na7Al6Si6O24S3), were introduced during the 18th century, f) poisonous pigments used mainly in building heritage constructed by wealthy owners during the 19th century have been used, such as lead white (PbCO3), and Sheele or Emerald greens 3Cu(AsO2)2Cu(CH3COO)2, g) more recent colour layers are mainly recognized by the use of synthetic pigments, such as the zinc yellow (K2O4ZnCrO43H2O), used in façades built in the middle of the 19th century, g) the evolution of white pigments towards less poisonous ones promoted by the industry, such as Lithopone (ZnS·BaSO4) and Barium white (BaSO4) were detected, and h) dioxide of titanium (TiO2), white pigment widely used from the 1930s indicates recent applications during maintenance after the date of construction of the building analysed.
The present MSCA was characterized by the publication of 2 scientific papers (+2 in progress) -all available in Open Access-, dissemination at 5 international conferences, 2 invited seminar lectures and 4 workshops. Data were also submitted to open access repositories (IT SYGMA tool and IRIS Institutional Archive of UNIPD and Open Research Europe platform). In addition, outreach activities were performed by the fellow with the support of the International Research Office of UNIPD. The European Union funding has been acknowledged in all the dissemination activities developed under the project.
To further advance the understanding of the connection among architectural finishes manufacturing technologies, built heritage conservation and colour of historic urban landscape knowledge, the CLEA project has shown that: a) materials used in the construction of building heritage entails an identifier both of the manufacturing technologies and of a specific period of the city, b) the knowledge on materials used in façades can be used as quality marker of architectural finishes conservation, in order to infer the restoration of historical urban landscape, c) if new quality architectural finishes that preserve the aesthetical values of the city were produced, the use of local materials may provide eco-innovative and sustainable solutions
The data achieved build the ground for future comprehensive studies of architectural finishes towards the understanding of their materiality over time. The knowledge attained strongly relies on the importance to address such issues considering mortars and pigments / colour as systems within an entire structure that are continuously interacting with the surrounding environment.
Thinking of restoration purposes, quality architectural finishes that would increase the built heritage authenticity considering at the same time eco-friendly solutions would be produced through the knowledge base generated.
Sustainable raw materials supply and eco-friendly production entails a direct industrial application of the research accomplished, being of special interest for the construction industry of the Canary Islands. Such regional industry represents the main potential user of the results, as the current understanding could be implemented into new restoration materials production that would preserve the aesthetical values of the city and would be especially suitable for the conservation of the built heritage.
Given that most of the world's built heritage has used pigments to colour façades around the world, the results obtained also bring an important benefit to society as a whole.
The data achieved build the ground for future comprehensive studies of architectural finishes towards the understanding of their materiality over time. The knowledge attained strongly relies on the importance to address such issues considering mortars and pigments / colour as systems within an entire structure that are continuously interacting with the surrounding environment.
Thinking of restoration purposes, quality architectural finishes that would increase the built heritage authenticity considering at the same time eco-friendly solutions would be produced through the knowledge base generated.
Sustainable raw materials supply and eco-friendly production entails a direct industrial application of the research accomplished, being of special interest for the construction industry of the Canary Islands. Such regional industry represents the main potential user of the results, as the current understanding could be implemented into new restoration materials production that would preserve the aesthetical values of the city and would be especially suitable for the conservation of the built heritage.
Given that most of the world's built heritage has used pigments to colour façades around the world, the results obtained also bring an important benefit to society as a whole.