sustainability

Article Housing Buildings’ Characterization at Corvo Village () Historical Center: Towards a Sustainable Rehabilitation Process

Ana I.P. Salvador 1 , Catarina P. Mouraz 1 ,Lídia Catarino 2,* , Victor Mestre 3 and José Mendes Silva 4

1 Department of Civil Engineering, University of Coimbra, 3030-788 Coimbra, ; [email protected] (A.I.P.S.); [email protected] (C.P.M.) 2 Geosciences Center, Earth Sciences Department, University of Coimbra, 3030-790 Coimbra, Portugal 3 Department of Architecture, University of Coimbra, 3000-143 Coimbra, Portugal; [email protected] 4 ADAI, Department of Civil Engineering, University of Coimbra, 3030-788 Coimbra, Portugal; [email protected] * Correspondence: [email protected]

Abstract: Corvo is the smallest of the Portuguese archipelago of the Azores and an unexplored territory, with one single village. Scarce studies have been conducted regarding its built heritage, and deep knowledge of the constructions is necessary for conservation actions to be carried out. This article presents the architectonic and constructive characterization of housing building features that compose Corvo village’s historical center, focusing on its characteristics, dissonances, and conservation state. A case study regarding one housing building is presented. This research intends to contribute to a deeper knowledge of these buildings’ identity, constituting the first step towards future rehabilitation processes that can improve the inhabitants’ quality of life and simultaneously   value the territory’s singularity.

Citation: Salvador, A.I.P.; Keywords: architectonic characterization; constructive characterization; heritage; rehabilitation Mouraz, C.P.; Catarino, L.; Mestre, V.; processes; sustainable construction; resilient communities; architectonic identity Silva, J.M. Housing Buildings’ Characterization at Corvo Village (Azores) Historical Center: Towards a Sustainable Rehabilitation Process. 1. Introduction Sustainability 2021, 13, 2352. https://doi.org/10.3390/su13042352 is the smallest island in the Autonomous Region of the Azores, Portugal (Figure1). Formed by volcanic activity, it presents an area of 17.12 km 2 and has been listed as a Academic Editor: Asterios Bakolas Biosphere Reserve by UNESCO since 2007. The only village on the island, with 440 inhabitants, is located on its south side, in a lava delta (a small area of flat fertile land at the bottom of Received: 20 January 2021 a seaside cliff composed of volcanic and geomorphological debris, Figure2). The village’s Accepted: 17 February 2021 historical center (Núcleo Antigo da —NAVC) has its origin in the 16th century Published: 22 February 2021 and has been classified as a protected urban site of public interest by the Azores Regional Government since 1997 [1]. This classification is applied when the site’s protection and Publisher’s Note: MDPI stays neutral enhancement represent a cultural value of national importance, but for which the regime with regard to jurisdictional claims in formally classified as “national interest” is disproportionate [2]. published maps and institutional affil- Unlike other Azorean , Corvo remains an unexplored territory in many ways, iations. usually described by the small number of inhabitants rather than the singularities of its identity. Several works have been developed regarding the characterization of the built heritage in other Azorean islands [3,4]. However, due to the Azorean archipelago location within the boundary between the Eurasian, African, and American plates [5], which has Copyright: © 2021 by the authors. led to severe seismic activity and even catastrophic events, research is mainly conducted Licensee MDPI, Basel, Switzerland. towards the assessment of buildings’ seismic vulnerability, both in the Azores in general [6] This article is an open access article and on specific islands [7–9]. Despite the importance of this topic, studies in several distributed under the terms and Azorean territories such as Corvo Island are still scarce [10,11], especially regarding its conditions of the Creative Commons built heritage. Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

Sustainability 2021, 13, 2352. https://doi.org/10.3390/su13042352 https://www.mdpi.com/journal/sustainability Sustainability 2021, 13, x FOR PEER REVIEW 2 of 26

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Azorean territories such as Corvo Island are still scarce [10,11], especially regarding its built heritage.

Figure 1. Location of the Azores archipelago (Portugal) and Corvo Island [12]. Figure 1. Location of the Azores archipelago (Portugal) and Corvo Island [12]. Since 2014 there has been extensive work developed by the Regional Directorate for Since 2014 therethe has Culture been of the extensive Azores (Direção work Regional developed de Cultura dos by Açores the) to Regional promote and Directorate develop for Corvo Island’s Ecomuseum project, with the main goal of recognizing and identifying the the Culture of the Azoresisland’s (identity,Direçã takingo Regional into account de Culturathe participation dos Açores of its community) to promote and perceiving and develop Corvo Island’s Ecomuseumthis territory project, as a catalyst with forthe local main socioeconomic goal of development recognizing capable and of generating identifying the wealth and serving community interests [13]. This project includes the conservation of island’s identity, takingNAVC into’s built account heritage, which the began participation with extensive of work its of community in loco characterization and perceivingand this territory as a catalystan analysis for of NAVC local buildings’ socioeconomic identity, which development was developed by capable the Local Technical of generating wealth and serving communityOffice created for that interests purpose, composed [13]. This of a team project of architects includes and engineers the conservation since 2018. of This process is particularly meaningful due to the importance of deep technical NAVC’s built heritage,knowledge which of began the buildings’ with architectural extensive and work constructive of in features, loco characterization contributing to sus- and an analysis of NAVC buildings’tained choices identity, of conservation which and rehabilitation was developed solutions.by the Local Technical Office created for that purpose, composed of a team of architects and engineers since 2018. This process is particularly meaningful due to the importance of deep technical knowledge of the buildings’ architectural and constructive features, contributing to sustained choices of Sustainability 2021, 13, x FOR PEER REVIEW 3 of 26 conservation and rehabilitation solutions.

Figure 2. General aerial and topographic view of Corvo Island and the location of Corvo village [14]. Figure 2. General aerial and topographic view of Corvo Island and the location of Corvo village [14]. Due to the fact that studies regarding Corvo Island are scarce and outdated, it is im- portant to identify the architectonical and constructive characteristics of the village’s con- structions, contributing to a progressive knowledge of this territory’s identity and laying the foundations for future rehabilitation processes. In order to support actions aiming to preserve and enhance the quality of the human environment [15], it is necessary to better integrate urban heritage conservation strategies within the larger goals of overall sustain- able development. Strategies such as the Ecomuseum project are important approaches that value the territory’s identity through its conservation, with the main goal of improving the inhabit- ants’ quality of life. However, different contexts require different approaches, which can be clearly identified in other Azorean islands and in other European contexts. Considering international contexts, there is a wide range of examples of research studies dedicated to the characterization of building types in historic centers, which are fundamental to these territories’ conservation. Regarding Mediterranean countries, the Italian studies conducted on Sardinia island and the technical manuals developed are im- portant references [16]. In other territories, such as the Abruzzo region, there are also ex- amples of detailed documents published [17]. In , significant technical advances have also been made considering different historical territories [18,19]. Regarding the Azorean context, and taking as an example, studies are being conducted considering the housing dwellings that compose “Bairro do Aero- porto,” a residential neighborhood of significant dimensions near the airport of , built in the middle of the 20th century [20]. A strategy towards the conservation of the place and its revitalization is being carried out, considering the rehabilitation of hous- ing dwellings as well as the implementation of economic, tourist, and cultural activities. A different approach was followed in Angra do Heroísmo, . The main pro- cess that took place towards the town’s conservation was in 1980, after a major that destroyed a significant part of its buildings. In addition, the objective of attaining the Sustainability 2021, 13, 2352 3 of 23

Due to the fact that studies regarding Corvo Island are scarce and outdated, it is important to identify the architectonical and constructive characteristics of the village’s constructions, contributing to a progressive knowledge of this territory’s identity and laying the foundations for future rehabilitation processes. In order to support actions aiming to preserve and enhance the quality of the human environment [15], it is necessary to better integrate urban heritage conservation strategies within the larger goals of overall sustainable development. Strategies such as the Ecomuseum project are important approaches that value the territory’s identity through its conservation, with the main goal of improving the inhabi- tants’ quality of life. However, different contexts require different approaches, which can be clearly identified in other Azorean islands and in other European contexts. Considering international contexts, there is a wide range of examples of research studies dedicated to the characterization of building types in historic centers, which are fundamental to these territories’ conservation. Regarding Mediterranean countries, the Italian studies conducted on Sardinia island and the technical manuals developed are important references [16]. In other territories, such as the Abruzzo region, there are also examples of detailed documents published [17]. In Spain, significant technical advances have also been made considering different historical territories [18,19]. Regarding the Azorean context, and taking Santa Maria Island as an example, studies are being conducted considering the housing dwellings that compose “Bairro do Aero- porto,” a residential neighborhood of significant dimensions near the airport of Vila do Porto, built in the middle of the 20th century [20]. A strategy towards the conservation of the place and its revitalization is being carried out, considering the rehabilitation of housing dwellings as well as the implementation of economic, tourist, and cultural ac- tivities. A different approach was followed in Angra do Heroísmo, Terceira Island. The main process that took place towards the town’s conservation was in 1980, after a major earthquake that destroyed a significant part of its buildings. In addition, the objective of attaining the classification of UNESCO World Heritage site contributed to a strict process of conservation actions, which led to the classification in 1983 [21]. These cases represent examples of how different territories involved different approaches regarding large-scale rehabilitation actions, underlining the existence of diverse contexts that are important to consider individually in order to coherently achieve specific goals. Considering the Ecomuseum project contributions so far, the results of an MSc thesis on building rehabilitation [22], and previous technical and scientific contributions made towards the characterization of NAVC [23], the aim of this article is to summarize and present the architectonic and constructive characterization of the housing buildings in NAVC, laying the foundations for future conservation and rehabilitation processes within the scope of the Ecomuseum project. Information regarding the materials and local re- sources of Corvo Island and NAVC is presented, as well as a state of conservation synthesis and the buildings’ most relevant dissonances. Additionally, a case study regarding a NAVC building rehabilitation intervention is presented.

2. Historical Context and Community Description The discovery of the Azores and the settlement of its population are themes shrouded in uncertainty. However, it is commonly accepted that the Azores archipelago was first discovered, depopulated, in 1427 by , Santa Maria Island being the first to be discovered. In 1439, the introduction of sheep on seven islands of the Azores was ordered by Afonso V (all islands except Flores and Corvo) [11]. However, other sources document the arrival of Gonçalo Zarco to Santa Maria Island in 1431 followed by the (re)discovery—or recognition—of six other islands from east to west in the subsequent years [24]. Nonetheless, the remaining islands, Flores and Corvo, were identified in 1452 by Diogo de Teive, while returning from an exploratory trip to the northeast Atlantic [25]. Information related to the population settlement in the Azores refers to it as slow and arduous, occurring in phases from east to west, starting in Santa Maria and taking almost Sustainability 2021, 13, x FOR PEER REVIEW 4 of 26

classification of UNESCO World Heritage site contributed to a strict process of conserva- tion actions, which led to the classification in 1983 [21]. These cases represent examples of how different territories involved different approaches regarding large-scale rehabilita- tion actions, underlining the existence of diverse contexts that are important to consider individually in order to coherently achieve specific goals. Considering the Ecomuseum project contributions so far, the results of an MSc thesis on building rehabilitation [22], and previous technical and scientific contributions made towards the characterization of NAVC [23], the aim of this article is to summarize and present the architectonic and constructive characterization of the housing buildings in NAVC, laying the foundations for future conservation and rehabilitation processes within the scope of the Ecomuseum project. Information regarding the materials and local re- sources of Corvo Island and NAVC is presented, as well as a state of conservation synthe- sis and the buildings’ most relevant dissonances. Additionally, a case study regarding a NAVC building rehabilitation intervention is presented.

2. Historical Context and Community Description The discovery of the Azores and the settlement of its population are themes shrouded in uncertainty. However, it is commonly accepted that the Azores archipelago was first discovered, depopulated, in 1427 by Diogo de Silves, Santa Maria Island being the first to be discovered. In 1439, the introduction of sheep on seven islands of the Azores was or- dered by Afonso V (all islands except Flores and Corvo) [11]. However, other sources doc- ument the arrival of Gonçalo Zarco to Santa Maria Island in 1431 followed by the (re)dis- covery—or recognition—of six other islands from east to west in the subsequent years [24]. Nonetheless, the remaining islands, Flores and Corvo, were identified in 1452 by Di- Sustainability 2021, 13, 2352 4 of 23 ogo de Teive, while returning from an exploratory trip to the northeast Atlantic [25]. In- formation related to the population settlement in the Azores refers to it as slow and ardu- ous, occurring in phases from east to west, starting in Santa Maria and taking almost a acentury century to to be be extended extended toto the the other other islands islands [25]. [25 With]. With the the discovery discovery of America of America and and of the of thesea searoute route around around Africa Africa on on the the way way to to India India in in 1498, 1498, the the Azores Azores became anan invaluableinvaluable territoryterritory inin thethe middlemiddle ofof thethe northnorth Atlantic.Atlantic. UntilUntil 1853 the island island of of Corvo Corvo was was ruled ruled by by an anowner owner to whom to whom the inhabitants the inhabitants (cor- (vinoscorvinos) had) had to pay to pay taxes taxes (Figure (Figure 3). 3The). Thefirst firstsettlement settlement phase phase was wasimplemented implemented in 150 in3– 1503–15081508 with low with success. low success. After Afterthat initial that initialphase, phase, only the only the cattleremained. remained. Two other Two settle- other settlementment phases phases were werecarried carried out in out 1548 in 1548and 1593. and 1593.

FigureFigure 3.3.Corvo Corvo Island’sIsland’s timelinetimeline ofof thethemain main events.events. During the 16th and 17th centuries, attacks by pirates were frequent and the island During the 16th and 17th centuries, attacks by pirates were frequent and the island had no communications with the outside. had no communications with the outside. In 1853, after several complaints, the tax system was removed, and farmers were able to buy their own land to raise cattle. The municipality became official and the selling of groceries to the ships’ crews was a new way of achieving some profit. Until the 19th century, the communication with the exterior, including others island of the archipelago, remained minimal. Emergency communications were carried out by smoke signals to the nearest island (Flores). Boats, even for fishing, were nonexistent. It is likely that this situation helped prevent workers from escaping. In 1893 the first ferry started a regular route to other islands of the archipelago every three months. The 20th century brought some improvements to the lifestyle of the corvinos with a radio receiver and piped water supply. After Portugal’s Carnation Revolution in 1974, the improvement in living conditions and habitability was a priority, and the construction of the airport and other infrastructure was carried out. The implementation of sustainable practices to reduce dependence on imported goods is currently being developed. In 2011–2012, regarding liquefied petroleum gas usage, solar thermal systems and heat pumps were installed in each home to provide domestic hot water [26]. Regarding Corvo’s population, the inhabitants always had a self-sufficient life and a strong sense of community, yet with limited resources. The way of life and social dynamics were based on communitarianism, where residents had their private properties and access to a collective set of rights to be enjoyed by all families, based on a reciprocity of duties and rights known as community solidarity [10]. A large part of the island’s area owned by the community was occupied by common land where animals were raised, wood was collected, and birds were hunted. Corvo’s population composed an agro-pastoral community where everyone collabo- rated and family work corresponded to both domestic and agricultural tasks. The island’s economy was based on agriculture and grazing [27] and several reports indicate the extreme poverty of the people [22], which prevailed until the 20th century. In addition to the exchange of several agricultural and cattle products, free or recipro- cal work was also done for specific needs, such as the construction of houses. Corvinos also Sustainability 2021, 13, 2352 5 of 23

collaborated on the conservation work of the common land, or on the conservation and improvement works of the village [10]. In terms of human relationships, they were conditioned by age and sex. The elders had full authority over the youngest, and the men over the women. The domestic group usually constituted three generations. At the community level, the relations were egali- tarian, with no hierarchy between domestic groups. Decisions that had to be made and implemented for the benefit of the community were solved together by all families, through their spokespersons and representatives, such as the elders and the priests. Currently, most of the active population works in the secondary and tertiary sectors, such as the city hall, municipal library, schools, public delegations, private services, or the airport, among others. Agriculture and fishing practices still exist, although there are only four full-time farmers and five professional fishing vessels. The services that require more training or higher education are, as a rule, occupied by foreign people. There are no unemployed inhabitants. In addition, in the last years the number of inhabitants has increased, and the living conditions have also significantly improved due to significant developments in terms of communications, accessibility, and access to health. Usually visitors have a predetermined idea that Corvo is an isolated, inhospitable, and gloomy place, as well as mysterious, curious, and even magical. After visiting, some are delighted and recognize the unusual characteristics of the island and the community, valuing its resilience. There are also others who feel surprised about how people can live with so many difficulties. There is still a strong sense of community among the inhabitants, who highly value safety and quality of life. This aspect is also mentioned by tourists, especially the ones who stay on Corvo for more than one day and choose to stay longer on the island.

3. Materials and Local Resources The geological formation of Corvo Island is reported as the most recent from the Azores archipelago, with 0.71 Ma [28]. The two main geomorphologic entities correspond to the larger central with a summit , and a younger crater row on the southern flank of the central volcano, from which lava flowed down the slope, which eventually created a coastal lava delta at the southern part of the island [29]. In this delta, the platform where the village is located has a slope between 5–15% (the small area where the airport was built has a slope under 5%). Only 16.9% of the island has an altitude lower than 150 m, and most buildings face south and east [28], being protected from the excessive wind. The island’s climate presents characteristics of being maritime temperate with low ther- mal amplitude, high precipitation, high air humidity, and persistent wind [30]. The mean annual rainfall corresponds to 1145 mm and the distribution of precipitation throughout the year is uneven, with higher precipitation values recorded during the season between September and March [29]. Climate conditions played an important role in the dwellings’ evolution, especially the wind, which is a factor of primordial importance for the orientation and location of the chimneys and threshing floors. Located to the west of the Middle Atlantic Ridge and integrated into the , the island does not reveal significant effects of seismic action, as other Azores islands do [6]. From the geological point of view, the existing rocks are mainly basalts, trachyte and trachybasalt, tuff (sometimes with palagonite), and volcanic breach [28,31]. Vacuole basalts have sometimes interspersed levels of pyroclastic material composed of cinder, ash, and lapilli in levels [28], as can be observed in the ancient quarry. Different stones can be found in the buildings’ masonry walls without a selective category, but commonly mixed in the same wall. The small area used for the implantation of the villa on the southeast side of the lava delta is formed by pyroclastic friable material with cinder, ash, and pumices tuff [28,32]. The chemical degradation and weathering of these pyroclastic materials facilitate the formation Sustainability 2021, 13, 2352 6 of 23

of clay, which is useful as raw material in construction and roof tiles. The material was collected in the proximity of the places where homes were to be built. For the roofs and several other uses in construction, the wood originated from two different sources: the forest of Azorean laurisilva, and shipwrecks. Generally, acacia, oak, chestnut, and cedar were the ones composing the native forest. In 1850 only 5.44 km2 of the island was native forest [33], and it was extinguished during the mid-20th century [34]. Pine tree wood was not present in the original forest, and its current presence in construction materials and elements indicates that this material came from shipwrecks that occurred near the island. The proximity to the sea frequently damages metallic elements used in construction. Due to this fact, one of the buildings’ singularities can be found in the traditional door locks, which are exclusively made of wood, and still function after decades of usage.

4. Characterization of the Case Study 4.1. Architectonic Characterization 4.1.1. Overview and Urban Context This section presents the architectonic characterization of NAVC buildings and brief considerations regarding the village’s urban context. Then, a detailed volumetric and functional characterization of the case study is presented. This information is particularly important not only to comprehend the buildings’ organization, but also to support the definition of future intervention strategies in which the preservation of identity values should be compatible with a sustainable approach and the improvement of the quality of life. Regarding its urban context, NAVC’s core has a consolidated structure that is orga- nized around a dozen small streets that lead to the port area and are drawn parallel to the sea, with a sinuous and irregular matrix. Small public squares and threshing floors, once shared by the community, are prominent in this structure. Although this work is centered on the common built heritage, it is important to note that NAVC’s urban organization and the history of its evolution was limited by the need to adapt to the place and its climate, establishing housing dwellings in a lower area, closer to the port, providing the most fertile land for agriculture and preparing the grouping of buildings for mutual help and protection.

4.1.2. Volumetric and Functional Characterization of NAVC’s Typical Housing Dwelling Analysis Parameters The identification and registration of the buildings’ most common volumetric and functional characteristics in an urban complex, as well as their variants, is essential for understanding. The most relevant variables in this context are (i) floor plans and elevation dimensions, (ii) the geometry of implantation, (iii) the number of floors, and (iv) the relationship with the surrounding topography. The exterior shape of the buildings, characterized by these indicators, is directly related to the urban, social, and economic organization of the place, reflecting its history and the evolution of the communities’ way of life and also the construction materials and techniques. The exterior shape limits the functional organization of the home and is also influenced by it, being relevant in the context of (i) the shape of the compartments, (ii) their relative location, and (iii) the way they interconnect, either through (iiia) horizontal or (iiib) vertical circulations. Considering NAVC buildings’ functional organization, elements such as the kitchen and the stairs, whether outside or inside, are particularly important. In previous studies [10,11] several types of relationships between the shape and the functional organization of these buildings were identified: 1. Rectangular-shaped floor plan, divided into a lower floor (kitchen and “cellar”) and upper floor (“dining room” and bedrooms, which can be organized in a single row in smaller buildings, or, in larger buildings, in other spatial organizations); Sustainability 2021, 13, 2352 7 of 23

2. Rectangular-shaped floor plan, divided into a lower floor (kitchen and “cellar”) and upper floor (“dining room” and bedrooms, spatially organized in a single row, but in which the access is granted through an entering space); 3. Rectangular-shaped floor plan, divided into a lower floor (“cellar”) and upper floor (central “dining room” with two accesses, one to the bedroom and the other to the kitchen); and 4. L-shaped floor plan divided into a lower floor (kitchen and “cellar”) and upper floor (central “dining room” that grants access to the bedrooms, which can be connected). To clarify the terminology used in this text, it should be noted that “cellar” refers to a compartment on the ground floor not intended for living, which can have different functions: cellar, in the common sense, storage of food and agricultural tools, as well as, although more rarely, shelter for small animals. In addition, regarding housing itself, the designation “dining room” corresponds to a multipurpose space for common use in which the predominant piece of furniture is a table. Given the dwellings’ small dimensions, this space can be used as a dining room, living room, or even to accommodate other common uses. In the study area, there are currently 185 buildings with a predominant residential function: 140 (75.68%) have a rectangular-shaped floor plan, 29 (15.68%) have an L-shaped floor plan, 9 (4.86%) present other shapes, usually composed of different volumes, and the remaining 7 (3.78%) are in ruin and were excluded from this analysis. Figure4 shows the distribution of these different types of buildings in the urban area. In the following sections, Sustainability 2021, 13, x FOR PEER REVIEW 8 of 26 buildings with a rectangular or L-shaped floor plan are addressed, as they represent 91.36% of the island’s residential buildings.

Figure 4. Location of the different types of buildings in the urban grid. Figure 4. Location of the different types of buildings in the urban grid. Volumetric Characterization and Functional Organization of Buildings with a Rectangular-ShapedVolumetric Floor Plan Characterization and Functional Organization of Buildings with a Rectangular-Shaped Floor Plan The buildings withThe a buildings rectangular-shaped with a rectangular floor-shaped plan usually floor plan present usually apresent perimeter a perimeter char- char- acterized by a smalleracterized side, by 4a tosmaller 6 m long,side, 4 and to 6 am larger long, and side, a larger 12 to side, 13 m 12 long. to 13 Them long smaller. The smaller facade is, in general,facade parallel is, in general, to the street, parallel which to the determinesstreet, which the determines urban design. the urban The design. smallest The small- dimension is closelyest dimension related to is the closely geometry related andto the technology geometry and adopted technology for adopted the construction for the construc- of gable or hip-shapedtion of roofs. gable Inor exceptionalhip-shaped roofs. cases, In theexceptional smallest cases, dimension the smallest can decreasedimension up can de- to 3 m and the largestcrease dimension up to 3 m and can the reach larges 16t dimension m. can reach 16 m. To define types of buildings with similar characteristics within the group of rectan- To define types of buildings with similar characteristics within the group of rectangular gular buildings, (i) the number of floors and (ii) the existence or not of interior and exterior buildings, (i) the numberstairs were of floorsconsidered and (ii)(see theTable existence 1 for differe or notnt types of interior of buildings and exterior with a stairsrectangular- shaped floor plan and Figure 5 for these types’ spatial distribution on the urban grid). Sustainability 2021, 13, x FOR PEER REVIEW 9 of 26

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were considered (see Table1 for different types of buildings with a rectangular-shaped floor plan andFigure Figure 5. Distribution5 for of these the types types’ of rectangular spatial-shaped distribution floor plan buildings on in the the urban urban grid. grid).

Table 1. Different types of rectangular-shaped floor plan buildings. Table 1. Different types of rectangular-shaped floor plan buildings. Figure 5. Distribution of the types of rectangular-shaped floor plan buildings in the urbanNumber grid . % of % Buildings with rectangular plan Examples Number (grouped) Table 1. Different types of rectangular-shaped floor plan buildings. buildings % Buildings with Rectangular Plan Examples of % Number (Grouped) Buildings % of % Buildings withA rectangularSingle space plan Examples 2 1.08(grouped) A SingleFigure space 5. Distribution of the types of rectangular-shaped floor plan buildings in the buildingsurban grid . 2 1.08 Type 1: 1 floor 6.48 Table 1. Different types of rectangular- shaped floor plan buildings. ASeveral Single inside space 2 1.08 Type 1: 1 floor B Number 10 5.41 Several inside % 6.48 Type 1: 1 floor spaces of % 6.48 B Buildings with rectangular plan Examples 10 (grouped) 5.41 spacesSeveral inside buildings Type 2: 2 floors B 10 5.41 spaces Lower floor: cellar A WithoutA stairsSingle space 2 1.082 1.08 Type 2: 2 floors and attached kitchen, Type 1: 1 floor 6.48 which mayLower floor: cellar A Without Severalstairs inside 2 1.08 A Without stairsB 10 5.41 2 1.08 Type 2: 2 floors eventuallyand be attachedon an kitchen, spaces which may B Outside stairs 2 1.08 intermediate level or Type 2: 2 floors Lower floor: cellar and attached kitchen, which mayeventually be on an on the upper floor. eventually be on an intermediate level or on the intermediate levelLower or floor: cellarB OutsideA Withoutstairs stairs 2 2 1.08 1.08 2.70 Upper floor:on "dining" the upper and floor. attached kitchen, upper floor. room and rooms justB whichOutside may stairs 2 2.70 1.08 2.70 Upper floor: "dining"eventuallyC be onInside an stairs 1 0.54 75.68 Upper floor: "dining" room and rooms just overover the room cellar. and roomsintermediate just levelC or InsideB stairsOutside stairs 2 1 1.08 0.54 Rooms distributedover the in cellar. on the upper floor. cellar. Rooms distributed in rows, with a corridor or C Inside stairs 1 2.70 0.54 75.68 Rooms distributedUpper in floor: "dining" 75.68 rows, with a corridor room and rooms justInside and occupying the available space in a differentor occupying way.rows, thewith a corridor InsideC andInside stairs 1 0.54 or occupying theoverD the cellar. 1 0.54 Rooms distributedInsideD in and 1 0.54 available spaceavailable in a space in a outside stairs 75.68 D rows, with a corridor outside stairsInside and 1 0.54 different way.different way.or occupyingoutside the stairs D 1 0.54 available space in a outside stairs different way. A AWithout Without stairs stairs 11 11 5.95 5.95 Type 3: 2 floorsType 3: 2 floors A Without stairsA Without stairs 11 5.95 11 5.95 Type 3: 2 floors Lower floor: cellar Type 3: 2 floors Lower floor: cellar and kitchen.Lower floor: cellarB Outside stairs 20 10.81 Lower floor: cellar and kitchen. and kitchen.Upper floor: B "dining"andB kitchen.OutsideOutside stairsB stairsOutside stairs 20 10.8120 20 10.81 10.81 Upper floor:room "dining" and bedrooms. Upper floor: "dining" 66.49 66.49 Upper floor: "dining" room and bedrooms. Rooms room and bedrooms. 66.49 room and bedrooms.Rooms distributed Rooms in distributed in 66.49 distributed in rows, with a corridor or occupyingRooms distributedrows, with inC a corridorrows, with Insidea corridorC stairsInsideC stairsInside stairs 26 26 14.05 2614.05 14.05 the available space in a different way.rows, with a orcorridor occupying orthe Coccupying theInside stairs 26 14.05 Sustainability 2021, 13, x FOR PEER REVIEW available spaceavailable in a space in a 9 of 26 or occupying the different way. D Inside and different way. InsideD andInside and 66 35.68 outside stairs 66 35.68 available space in aD outside stairs 66 35.68 different way. D outsideInside stairs and 66 35.68 outside stairs

Figure 5. Distribution of the types of rectangular-shaped floor plan buildings in the urban grid. Figure 5. Distribution of the types of rectangular-shaped floor plan buildings in the urban grid. The importance of types 3_D, 3_C, and 3_B of rectangular-shaped buildings in the TableNAVC 1. Different characterization types of rectangular is unquestionable,-shaped floor since plan they buildings represent. about 60% of all residential buildings. In Figure6, detailed drawings of four examplesNumber of type 3_D buildings are % of % Buildings with rectangularpresented plan (which only differExamples from types 3_B and 3_C in having exterior stairs(grouped) and interior stairs, respectively). These examples’ functional organizationbuildings can be briefly described as follows: A Single space 2 1.08

Type 1: 1 floor 6.48 Several inside B 10 5.41 spaces Type 2: 2 floors

Lower floor: cellar A Without stairs 2 1.08 and attached kitchen, which may eventually be on an intermediate level or B Outside stairs 2 1.08 on the upper floor. 2.70 Upper floor: "dining" room and rooms just C Inside stairs 1 0.54 over the cellar. Rooms distributed in 75.68 rows, with a corridor Inside and or occupying the D 1 0.54 available space in a outside stairs different way.

A Without stairs 11 5.95 Type 3: 2 floors

Lower floor: cellar and kitchen. B Outside stairs 20 10.81 Upper floor: "dining" room and bedrooms. 66.49 Rooms distributed in rows, with a corridor C Inside stairs 26 14.05 or occupying the available space in a different way. D Inside and 66 35.68 outside stairs Sustainability 2021, 13, x FOR PEER REVIEW 10 of 26

Sustainability 2021, 13, 2352 The importance of types 3_D, 3_C, and 3_B of rectangular-shaped buildings in the 9 of 23 NAVC characterization is unquestionable, since they represent about 60% of all residen- tial buildings. In Figure 6, detailed drawings of four examples of type 3_D buildings are presented (which only differ from types 3_B and 3_C in having exterior stairs and interior I. stairsRooms, respectively are distributed). These examples’ in a corridor; functional interior organization wood-fired can be oven,briefly whosedescribed chimney as is a follows:column of hot air; skewed exterior stairs—with balcony; “dining room” is located I. oppositeRooms are the distributed kitchen; in a corridor; interior wood-fired oven, whose chimney is a II. Roomscolumn areof hot accessible air; skewed through exterior a stairs “dining—with room” balcony; space; “dining interior room”wood-fired is located oven, whoseopposite chimney the kitchen; is a column of hot air; exterior stairs skewed in relation to the II. Rooms are accessible through a “dining room” space; interior wood-fired oven, facade—with balcony; “dining room” is located opposite the kitchen; whose chimney is a column of hot air; exterior stairs skewed in relation to the fa- III. Roomscade—with are distributedbalcony; “dining through room” a is “dining located opposite room” space, the kitchen; without a corridor; exterior III. wood-firedRooms are distributed oven, whose through chimney a “dining is a room column” space, of hot without air; exterior a corridor; stairs exterior parallel, but notwood close,-fired to oven, the whose facade, chimney with balcony;is a column “dining of hot air; room” exterior is stairs located parallel, opposite but to the kitchen;not close, and to the facade, with balcony; “dining room” is located opposite to the IV. Roomskitchen; areanddistributed in a row, with corridor; exterior wood-fired oven, whose

IV. chimneyRooms are is distributed a column in of a row, hot with air; exteriorcorridor; exterior stairs perpendicular wood-fired oven, to whose the facade—withchim- ney is a column of hot air; exterior stairs perpendicular to the facade—with balcony; balcony;living room living is located room opposite is located the kitchen. opposite the kitchen.

Figure 6. Detailed drawings of four examples of type 3_D rectangular-shaped floor plan buildings. Figure 6. Detailed drawings of four examples of type 3_D rectangular-shaped floor plan buildings. Volumetric Characterization and Functional Organization of Buildings with an L-Shaped Floor Plan Buildings with an L-shaped floor plan result, in general, from the combination of two rectangles with a width similar to the smaller dimension of the rectangular buildings, but with a shorter length. The two rectangles may have different dimensions, but their scale is generally similar. For the definition of types of buildings with similar characteristics within the group of L-shaped floor plan buildings, the same parameters were adopted: (i) number of floors and (ii) the existence, or not, of either interior or exterior stairs. Table2 shows the different types of buildings with an L shape. Figure7 shows these types’ spatial distribution on the urban grid. Sustainability 2021, 13, x FOR PEER REVIEW 11 of 26

Sustainability 2021, 13, x FOR PEER REVIEW 11 of 26 Sustainability 2021, 13, x FOR PEER REVIEW 11 of 26 Volumetric Characterization and Functional Organization of Buildings with an L-Shaped Floor Plan VolumetricBuildings Characterization with an L-shaped and floorFunctional plan result, Organization in general, of Buildingsfrom the combination with an L-Shaped of two VolumetricFloorrectangles Plan Characterization with a width similar and to Functional the smaller dimensionOrganization of the of rectangular Buildings buildings, with an butL-Shaped Floorwith PlanBuildings a shorter withlength. an TheL-shaped two rectangles floor plan mayresult, have in general, different from dimensions, the combination but their of scale two rectanglesis generally with similar. a width similar to the smaller dimension of the rectangular buildings, but withBuildings Fora sho therter withdefinition length. an L The -ofshaped types two rectangles of floor buildings plan may result,with have similar indifferent general, characteristics dimensions, from the within butcombination their the group scale of two rectanglesisof generally L-shaped with similar. floora width plan similarbuildings, to thethe same smaller parameters dimension were ofadopted: the rectangular (i) number buildings,of floors but withand a sho (ii)Forrter thethe existence, length.definition The or of not, typestwo of rectangles ofeither buildings interior may with or exterior havesimilar different characteristicsstairs. dimensions, within the but group their scale is generallyof L-shapedTable similar. 2 floor shows plan the buildings, different types the same of buildings parameters with were an Ladopted: shape. Figure (i) number 7 shows of floors these andtypes’For (ii) the spatial the definition existence, distribution ofor not,types on of the eitherof urban buildings interior grid. orwith exterior similar stairs. characteristics within the group of L-shapedTable floor 2 shows plan the buildings, different types the same of buildings parameters with an were L shape. adopted: Figure (i)7 shows number these of floors types’Table spatial 2. Different distribution types onof L the-sh apedurban floor grid. plan buildings. Sustainability 2021, 13, 2352 and (ii) the existence, or not, of either interior or exterior stairs. 10 of 23 Number Table 2 shows the different types of buildings with an L shape. Figure 7 %shows these Table 2. Different types of L-shaped floor plan buildings. of % Buildings with “L” shape plan Examples (grouped) types’ spatial distribution on the urban grid. buildings Number % of % Buildings with “L” shape plan Examples (grouped) Table 2. Different types of L-shaped floor plan buildingsbuildings. Table 2. Different types of L-shaped floor plan buildings. Type 1: 1 floor A Single space 2 1.62 1.62 Number % of Number% Buildings with “L” shape plan Examples (grouped) % Buildings with “L”Type Shape 1: 1 Planfloor A Single space Examples 2buildings 1.62 of 1.62 % (Grouped) Buildings A Without stairs 0 0 Type 2: 2 floors Type 1: 1 floor Type 1: 1 floor A A SingleA Single spaceWithout space stairs 0 2 0 2 1.62 1.621.62 1.62 Lower floor: cellar B Outside stairs 0 0 andType adjacent 2: 2 floors kitchen. 3.24 Upper floor: "dining Lower floor: cellar B Outside stairs 0 0 room" and rooms just C Inside stairs 2 1.1 and adjacent kitchen. over theA cellar. Without stairs 0 3.24 0 Upper floor: "diningA Without stairs 0 0 15.68 Type 2: 2 floors room" and rooms just C InsideInside stairs and 2 1.1 over theB cellar. Outside stairs 0 0 Lower floor: cellar andType 2: 2 floors D 4 2.2 outside stairs 15.68 adjacent kitchen. 3.24 C B InsideOutside stairsInside stairs and 0 2 0 1.1 Upper floor: "dining room"Lower and floor: cellar D 4 2.2 and adjacentType kitchen. 3: 2 floors A outsideWithout stairs stairs 0 0 15.68 rooms just over the cellar. 3.24 Upper floor: "dining Inside and Two overlappingD 4 2.2 room" and rooms just outside stairs Typerectangles. 3: 2 floors C A InsideWithout stairs stairs 0 2 0 1.1 over the cellar. B Outside stairs 0 0 LowerTwo overlapping floor:A cellar Without stairs 0 0 15.68 rectangles. Type 3: 2 floors and kitchen. Inside and 10.81 Two overlapping rectangles. Upper floor:B "dining"Outside B stairsOutside stairs 0 0 0 0 Lower floor: cellarD C Inside stairs 3 4 1.6 2.2 Lower floor: cellar and kitchen.room and bedrooms. outside stairs (Accessand kitchen.to the rooms 10.81 C Inside stairs 10.81 Upper floor: "dining" room andUpperthrough floor: the "dining" "dining 3 1.6 bedrooms. (Access to the roomsroom androom"). bedrooms. CD InsideInside stairs and 3 1.6 Type 3: 2 floors 17 9.2 Sustainabilitythrough 2021 the, "dining13, x FOR room"). PEER(Access REVIEW to the rooms A Inside Without andoutside stairs stairs 0 0 12 of 26 through theD "dining 17 9.2 outside stairs Two overlappingroom"). D Inside and Like rectangular-shaped floor plan buildings, type 3_D 17buildings’ 9.2 predominance is rectangles. outside stairs B Outsidesignificant stairs (two floors with indoor and outdoor stairs). In Figure 08, detailed 0drawings of Lower floor: cellar two Likeexamples rectangular of buildings-shaped of floorthis type plan are buildings, presented, type whose 3_D buildings’functional predominanceorganization can is and kitchen. significantbe briefly described(two floors as with follows: indoor and outdoor stairs). In Figure 8, detailed drawings10.81 of Upper floor: "dining" room and bedrooms. C InsideV.two stairs examplesRooms are of distributed buildings of practically this type iaren a row,presented, with a whose corridor; functional inexistence3 organization of1.6 wood -fire cand (Access to the rooms be brieflyoven; described chimney asis afollows: column of hot air; exterior stairs parallel to the facade—with bal- through the "dining V. Roomscony; “ aredining distributed room” is practically located opposite in a row, the with kitchen; a corridor; kitchen inexistence space occupies of wood a section-fired room"). D Inside and oven;of the chimney L; and is a column of hot air; exterior stairs parallel to17 the facade9.2— with bal- outside stairs VI. cony;Rooms “dining are distributed room” is inlocated a row, opposite with corridor; the kitchen; existence kitchen of exterior space occupies wood-fire a sectiond oven Likeofand rectangular the exterior L; and chimney;-shaped exterior floor planstairs buildings,parallel to the type facade; 3_D “ buildings’dining room predominance” is located is significantVI. Roomsopposite (two are floorsthe distributed kitchen; with kitchen indoorin a row, occupies and with outdoor corridor; a section stairs). existence of the InL. of Figure exterior 8, wood detailed-fired drawings oven of two examplesand exterior of buildings chimney; of exterior this type stairs are parallel presented, to the facade; whose “ diningfunctional room organization” is located can opposite the kitchen; kitchen occupies a section of the L. be briefly described as follows: V. Rooms are distributed practically in a row, with a corridor; inexistence of wood-fired oven; chimney is a column of hot air; exterior stairs parallel to the facade—with bal- cony; “dining room” is located opposite the kitchen; kitchen space occupies a section of the L; and VI. Rooms are distributed in a row, with corridor; existence of exterior wood-fired oven and exterior chimney; exterior stairs parallel to the facade; “dining room” is located opposite the kitchen; kitchen occupies a section of the L.

Figure 7. Distribution of L-shaped floor plan building types in the urban grid. Figure 7. Distribution of L-shaped floor plan building types in the urban grid. Like rectangular-shaped floor plan buildings, type 3_D buildings’ predominance is significant (two floors with indoor and outdoor stairs). In Figure8, detailed drawings of two examples of buildings of this type are presented, whose functional organization can be briefly described as follows: V. Rooms are distributed practically in a row, with a corridor; inexistence of wood-fired oven; chimney is a column of hot air; exterior stairs parallel to the facade—with balcony; “dining room” is located opposite the kitchen; kitchen space occupies a section of the L; and VI. Rooms are distributed in a row, with corridor; existence of exterior wood-fired oven and exterior chimney; exterior stairs parallel to the facade; “dining room” is located opposite the kitchen; kitchen occupies a section of the L.

Figure 8. Detailed drawings of two examples of 3_D-type L-shaped floor plan buildings.

4.2. Constructive Characterization This section presents the constructive characterization of the housing stock that com- poses NAVC. Information regarding walls, windows, interior stairs, and floors is pre- sented. The characterization of roofs, exterior stairs, and smoke evacuation systems is pre- sented in the next section, which is specifically dedicated to these singular features that are described. Exterior walls of the NAVC buildings are composed of local volcanic stones, espe- cially basalt, trachyte, and volcanic tuff. The masonry walls present a medium thickness of 64 centimeters. This dimension is consistent with other masonry constructions in the Azores, especially considering an ancient construction measurement of length used in construction (equivalent to 1 côvado, corresponding to 66 cm) [3]. Exterior walls are usually Sustainability 2021, 13, x FOR PEER REVIEW 12 of 26

Sustainability 2021, 13, 2352 11 of 23 Figure 7. Distribution of L-shaped floor plan building types in the urban grid.

FigureFigure 8. 8.Detailed Detailed drawings drawings ofof twotwo examplesexamples of 3_D 3_D-type-type L L-shaped-shaped floor floor plan plan buildings buildings..

4.2. Constructive Characterization 4.2. Constructive Characterization This section presents the constructive characterization of the housing stock that com- This section presents the constructive characterization of the housing stock that com- poses NAVC. Information regarding walls, windows, interior stairs, and floors is pre- poses NAVC. Information regarding walls, windows, interior stairs, and floors is presented. sented. The characterization of roofs, exterior stairs, and smoke evacuation systems is pre- The characterization of roofs, exterior stairs, and smoke evacuation systems is presented in sented in the next section, which is specifically dedicated to these singular features that the next section, which is specifically dedicated to these singular features that are described. are described. ExteriorExterior walls walls of of the the NAVC NAVC buildings buildings are are composed composed of of local local volcanic volcanic stones, stones, especially espe- basalt,cially basalt, trachyte, trachyte and, volcanic and volcanic tuff. tuff. The The masonry masonry walls walls present present a a medium medium thicknessthickness of 64of cm.64 centimet This dimensioners. This dimension is consistent is consistent with other with masonry other masonry constructions constructions in the in Azores, the especiallyAzores, especially considering considering an ancient an construction ancient construction measurement measure of lengthment usedof length in construction used in (equivalentconstruction to (equivalent 1 côvado, corresponding to 1 côvado, corresponding to 66 cm) [3 to]. Exterior66 cm) [3]. walls Exterior are usuallywalls are double usually leaf and are usually composed of stones of varied shape and size, although the use of regular prepared stone is usually reserved for a few buildings. There are several solutions regarding joint material: clay, soil, or lime mortar. In some buildings the joint is not filled and other cases that have already suffered interventions have cement mortar. The most common type of external wall coating is white-painted render, especially on the main and south facades, whereas the other walls are usually not covered with any kind of coating. However, there is also a significant number of buildings in which the stone masonry walls do not present any type of coating. In these cases, the gap between masonry joints of the external walls is either visible or cement mortar has been applied, presenting a wide variety of forms and shapes. The internal partition walls on the upper floor are made of timber planks covered with plaster render (tabique). In the cases where recent interventions were carried out, some of the original partition walls were replaced with laminated plasterboard walls. Regarding windows, most buildings have wood window framings, although alu- minum and PVC solutions are becoming more common, indicating the existence of inter- ventions where the original framings are being replaced. Buildings with different window framing materials are also very frequent. Considering window typologies, single-hung wood framing solutions are the most common, sometimes painted white or left unpainted. The general lack of window sills was also observed, which are frequently materialized by the stone supporting the window framing. When there are stairs inside the dwellings, they are characterized by their steepness and narrowness, and usually made of wood. Their configuration is usually straight or winder (L-shaped), granting access to the upper floor through the kitchen, located on the ground floor. Sustainability 2021, 13, 2352 12 of 23

The ground floor pavement is characterized by being a simple earthen floor or screed, which usually has a ceramic coating or is left uncoated. On the upper floor, the structure of the pavement is composed of wooden beams, embedded in the gable end walls of the building and usually separated in 40–60 cm intervals. This structure is covered with wood plank flooring. Sustainability 2021, 13, x FOR PEER REVIEW 14 of 26 Figures9 and 10 present several examples of the NAVC buildings’ construction solutions described above.

General view of NAVC building facades (1), a group of buildings facing a narrow street (2).

Examples of the different solutions of masonry apparatus and laying joint execution.

Examples of the masonry quoins, where the stones’ disposition is essential for structural safety.

Examples of masonry framings bounding the openings for windows and doors in masonry facades.

Examples of the chimneys.

FigureFigure 9.9. ExamplesExamples of of NAVC NAVC buildings’ buildings’ construction construction solutions solutions (part (part1). 1). Sustainability 2021, 13, 2352 13 of 23 Sustainability 2021, 13, x FOR PEER REVIEW 15 of 26

External view of pitched roofs, generally with two slopes, covered with clay tiles.

Internal view of pitched roofs, showing the wood structure.

Timber floors of the upper floor and supporting structure: natural wood beams (1) and rectangular- shaped wood beams (2).

Examples of external stone masonry stairs.

Examples of narrow internal stairs.

FigureFigure 10.10. ExamplesExamples of ofNAVC NAVC buildings’ buildings’ construction construction solutions solutions (part 2). (part 2).

4.3. Singular Elements Besides the elements described in the previous section, the houses of NAVC have several singular characteristics that are clear indicators of the buildings’ architectural and constructive value, justifying a detailed description and understanding of them. The roof is typically a two-sloped pitched timber structure or, less frequently, hip shaped. Like other constructions in the Azores without timber trusses [3], the roof structures in NAVC are typically composed of a ridge beam and a set of rafters connected to the ridge beam at the top. Nonetheless, the ridge beam does not bear any load, only guaranteeing the position of the rafters. At the bottom, the rafters are supported by a load-bearing element Sustainability 2021, 13, 2352 14 of 23

connected to the inner leaf of the masonry wall, which runs throughout the perimeter, constituting a type of ring beam. To prevent horizontal movements on the wall due to the load of the structure, horizontal wooden tie beams are placed every 2 m (or four rafters), supporting the wall without any additional impulse. The timber element that supports the rafters fits on open spaces on the tie beams, immobilizing the rafters without exerting any horizontal impulse on the wall [23]. Roof coating is laid on tile battens that are placed over the rafters. The most common type of coating is ceramic tile, especially barrel type (pan and tile) [35], although there also is a significant number of solutions with fiber cement panels. The second singular element of NAVC are the exterior stairs, observable in almost every building. These elements connect the first floor of the dwellings with the street and are composed of volcanic masonry blocks with significant dimensions. The stair configuration is straight, and they are usually parallel to the south facade. When there is a gap between the stairs and the wall next to them, the space under the stairs is usually used as storage, a bathroom space, or as a place to keep animals. The last singular element consists of smoke evacuation systems composed of smoke- houses, wood-fired ovens, and chimneys. Not all buildings have all these elements, but most of them have at least one, chimneys being the most common. Traditionally, most NAVC houses had a wood-fired oven and a smokehouse, both located inside the kitchen compartment on the ground floor of the dwelling. Smoke evacuation chimneys that went through the upper floor all the way through the roof were built later, to avoid smoke concentration inside the building. By this time, wood-fired ovens started to be built on the exterior, inside a small compartment next to the kitchen but outside of the building perimeter. The current nonexistence of these elements in some of Sustainability 2021, 13, x FOR PEER theREVIEW buildings is most likely due to the changes that have been made to housing17 of 26 dwellings

over time, eliminating some of these elements that are no longer used. Figure 11 presents examples of the described NAVC building singularities.

Some new buildings adopt the traditional stone masonry for the external wall.

External stair solutions.

One of the most traditional singularities of the buildings are the wooden door locks, avoiding corrosion problems.

FigureFigure 11. ExamplesExamples of ofNAVC NAVC buildings’ buildings’ details details and singularities. and singularities.

5. Conservation and Rehabilitation Challenges 5.1. Basis for Integrated Interventions The awareness of the need for an integrated intervention for the conservation and rehabilitation of buildings in NAVC is not recent, but it was only formally recognized in late 2015 with the publication of the Regional Regulatory Decree No. 20/2015/A, from 27 October, which approved the “Specific Regime for the Protection and Enhancement of the Built Cultural Heritage of the Old Centre of Vila do Corvo (NAVC)” [36]. In the preamble of this regulatory framework defined by the Regional Government of the Azores the following can be read: “(…) In fact, the NAVC today shows evident signs of physical degradation and abandonment of properties, many of which are in an advanced state of ruin, to which is added a significant range of changes to the traditional typology of buildings, which over time have been taking place in immediate response to the natural desire for better conditions of habitability and comfort, however constituting itself as an improvised response, often precarious and counterproductive from the point of view of safeguarding and promoting heritage values that justify protection in cause (…).” The main rehabilitation challenges are thus clearly established and can be summarized as follows [23]: Sustainability 2021, 13, 2352 15 of 23

5. Conservation and Rehabilitation Challenges 5.1. Basis for Integrated Interventions The awareness of the need for an integrated intervention for the conservation and rehabilitation of buildings in NAVC is not recent, but it was only formally recognized in late 2015 with the publication of the Regional Regulatory Decree No. 20/2015/A, from 27 October, which approved the “Specific Regime for the Protection and Enhancement of the Built Cultural Heritage of the Old Centre of Vila do Corvo (NAVC)” [36]. In the preamble of this regulatory framework defined by the Regional Government of the Azores the following can be read: “( ... ) In fact, the NAVC today shows evident signs of physical degradation and abandonment of properties, many of which are in an advanced state of ruin, to which is added a significant range of changes to the traditional typology of buildings, which over time have been taking place in immediate response to the natural desire for better conditions of habitability and comfort, however constituting itself as an improvised response, often precarious and counterproductive from the point of view of safeguarding and promoting heritage values that justify protection in cause ( ... ).” The main rehabilitation challenges are thus clearly established and can be summarized as follows [23]: a. Structural stability, including the replacement of the buildings’ resistant capacity or its reinforcement; b. Durability, so as to stop progressive degradation processes and the replacement or creation of protective barriers, in particular against atmospheric agents such as the wind and sea; c. Healthiness and comfort, ensuring better conditions of humidity and temperature, tactile and visual comfort, and safety in current use; and d. Architectural and constructive enhancement, either by reinforcing or restoring con- structive coherence, or by reinforcing and enhancing the identity of the buildings. To provide an integrated response to these challenges, it was necessary to conduct an exhaustive characterization of the buildings composing NAVC, already presented in previous sections, and also a profound assessment of their conservation conditions and of the dissonances introduced over time. Despite not being the main focus of this article, the most relevant results of these studies are presented in the following sections. However, it is not enough to correct anomalies and eliminate dissonances to achieve the goals of protecting and valuing the existing heritage. Furthermore, improving environ- mental performance and, fundamentally, improving quality of life, in response to residents’ expectations and the ambition of local development policies, are also fundamental steps towards this final goal. This work implies [23]: a. Comprehensive and structured local survey of buildings; b. Understanding traditional solutions, and their advantages and constraints; c. Identification of new construction techniques and their compatibility with existing solutions; and d. Careful design processes that combine respect for the general principles set out above with the uniqueness of each dwelling and each family, not forgetting the severity of the climate on the island of Corvo. The Local Technical Office prepared around 80 proposals in response to these concerns, using, whenever necessary and in a judicious way, new technologies and new materials, with the aim of maintaining the identity of both the building and the urban setting. It is also important to consider the evolutionary process of the buildings, which have been, in some cases, modified throughout the years to respond to specific needs of the inhabitants. These alterations have led to the creation of singularities and, consequently, represent specific challenges that are necessary to consider individually and attentively. In the last section of this chapter, one of these projects is briefly presented. Sustainability 2021, 13, 2352 16 of 23

5.2. NAVC Buildings’ Conservation State From the observation of the buildings of NAVC and the analysis of their state of conservation, four levels of degradation were defined: a. Degradation level IV—The existing building is mainly composed of remaining parts of the previous wall structures, which have already collapsed (ruin state); b. Degradation level III—The building is only composed of the exterior walls (the roof, intermediate floor structures or both, have already collapsed). The building thus maintains its external structure intact, yet without resistance capacity; c. Degradation level II—The building has walls, a roof, and an intermediate floor. However, the structure of the middle floor is unstable, has evidence of structural damage to the roof, or both. The buildings have pathologies such as lack of material, namely with voids in their stone walls, among others; and d. Degradation level I—The building does not have structural damage, despite having other anomalies capable of being corrected. Sustainability 2021, 13, x FOR PEER REVIEW 19 of 26 Degradation level I, related to non-structural anomalies, was the object of a detailed complementary study to identify the different types of anomalies [22], where defects in roofs,Degradation wall coverings, level I, related and windows to non-structural were highlighted, anomalies, was with the object problems of a detailed of humidity, cracking, agingcomplementary of materials, study and to identify maladjustment the different in types view ofof anomalies current [22], functional where defects requirements. in Figure 12 roofs, wall coverings, and windows were highlighted, with problems of humidity, illustratescracking, aging the different of materials, levels and of degradationmaladjustment andin Figureview of 13 current shows functional the location of buildings in the urban grid according to this classification. Sustainabilityrequirements. 2021, 13, x FOR PEER Figure REVIEW 12 illustrates the different levels of degradation and Figure 13 shows19 of 26 the location of buildings in the urban grid according to this classification.

roofs, wall coverings, and windows were highlighted, with problems of humidity, crack- ing, aging of materials, and maladjustment in view of current functionalExamples requireme of levelsnts. Figure 12 illustrates the different levels of degradation and Figure 13 shows the location of degradation I of buildings in the urban grid according to this classification. (non-structural anomalies) and II (specificExamples structural of levels degradation).of degradation I (non-structural anomalies) and II (specific structural degradation).

Examples of degradation levels III (partialExamples ruin) of deg- andradation IV (total levels ruin). III (partial ruin) and IV (total ruin).

FigureFigure 12. Examples12. Examples of of buildingbuilding degradation degradation situations. situations. Figure 12. Examples of building degradation situations.

Figure 13.FigureNumber 13. Number and and location location of ofbuildings, buildings, according according to the level of degradation. to the level of degradation.

5.3. NAVC Buildings’ Dissonances As mentioned in the Regulatory Decree [36], many interventions carried out over the years were not framed by a global strategy, nor supported by a detailed project, often Figure 13. Number and location of buildings, according to the level of degradation.

5.3. NAVC Buildings’ Dissonances Sustainability 2021, 13, 2352 17 of 23

Sustainability 2021, 13, x FOR PEER REVIEW 20 of 26

5.3. NAVC Buildings’ Dissonances As mentioned in the Regulatory Decree [36], many interventions carried out over the yearsAs mentioned were not in framed the Regulato by ary global Decree strategy, [36], many nor interventions supported bycarried a detailed out over project, the oftenyears leading were not to dissonancesframed by a thatglobal need strategy, to be evaluatednor supported and, whenby a deta necessaryiled project, and possible,often corrected.leading to From dissonances the observation that need of theto be NAVC evaluated buildings, and, 26when types necessary of alterations and possible, performed oncorrected. buildings From were the considered observation to of have the NAVC led to significantbuildings, 26 dissonances. types of alterations The buildings performed were groupedon buildings into levelswere considered of dissonance to have according led to significant to the following dissonances. criteria: The Level buildings I—Does were not presentgrouped dissonances; into levels of Level dissonance I—Low: according one to threeto the dissonances;following criteria: Level Level II—Medium: I—Does not four topresent six dissonances; dissonances; Level Level III—High: I—Low: one contains to three seven dissonances; to nine dissonances;Level II—Medium: Level four IV—Very to high:six dissonances; contains more Level than III—High: 10 dissonances. contains seve Figuren to nine 14 illustrates dissonances; some Level of IV—Very the dissonances high: observedcontains more and Figure than 10 15 dissona showsnces. the Figure location 14 illustrates of buildings some in of the the urban dissonances grid according observed to thisand classification. Figure 15 shows the location of buildings in the urban grid according to this classification.

Examples of dissonances due to (left) illegal enlargements and (right) the use of non-traditional building materials.

Examples of dissonances in roofs due to irregular expansion of buildings and the use of metal and fiber cement panels.

Examples of dissonances in facades due to the installation of technical equipment and advertising panels without proper integration.

FigureFigure 14. 14.Examples Examples ofof observedobserved dissonances in in NAVC NAVC buildings. buildings.

5.4. Example of NAVC Building’ Rehabilitation Intervention The example selected to exemplify the projects developed for about 80 residential buildings in NAVC, within the scope of the integrated rehabilitation project, is a small building with a rectangular-shaped floor plan, two floors, and a traditional gabled roof, with external stairs. All construction solutions are characteristic of typical NAVC buildings: exterior supporting walls in stone masonry, and interior walls in a traditional wood system (tabique) covered with plaster render. Sustainability 2021, 13, x FOR PEER REVIEW 21 of 26

SustainabilitySustainability 20212021, 13, 13, x, 2352FOR PEER REVIEW 21 18of of26 23

Figure 15. Level of the dissonance number and the location of the buildings in the urban grid.

5.4. Example of NAVC Building’ Rehabilitation Intervention The example selected to exemplify the projects developed for about 80 residential buildings in NAVC, within the scope of the integrated rehabilitation project, is a small building with a rectangular-shaped floor plan, two floors, and a traditional gabled roof, with external stairs. All construction solutions are characteristic of typical NAVC buildings: exterior sup- FigureFigure 15 15.. LevelLevel ofporting of the the dissonance dissonancewalls in stone number number masonry, and and the the and location location interior of of thewalls the buildings buildings in a traditional in in the the urban urbanwood grid. grid.system (tabique) covered with plaster render. Figures 16 and 17 present general views of the building and the architectural survey, respectively. 5.4. ExampleFigures of 16NAVC and 17Building’ present generalRehabilitation views of Intervention the building and the architectural survey, respectively. The example selected to exemplify the projects developed for about 80 residential buildings in NAVC, within the scope of the integrated rehabilitation project, is a small building with a rectangular-shaped floor plan, two floors, and a traditional gabled roof, with external stairs. All construction solutions are characteristic of typical NAVC buildings: exterior sup- porting walls in stone masonry, and interior walls in a traditional wood system (tabique) covered with plaster render. Figures 16 and 17 present general views of the building and the architectural survey, respectively.

FigureFigure 16. 16.General General views of of the the building building surveyed. surveyed.

OnOn the the lowerlower floorfloor there are two spaces spaces separated separated by by a amasonry masonry wall wall made made of con- of concrete blocks,crete blocks, which which resulted result fromed from unfinished unfinished work work for for the the eventual eventual creation creation of of a bathroom. a bathroom. The largerThe larger space space has a mixed has a mixed function function between between “cellar” “cellar and” kitchen,and kitchen, with with an exterior an exterior wood-fired oven.wood The-fire pavementd oven. The consists pavement of a consists mortar of screed a mortar executed screed directly executed on directly the ground. on the ground. The interior connection between the two floors is made through a reinforced concrete The interior connection between the two floors is made through a reinforced concrete stairwaystairway that that isis totallytotally differentdifferent from the the original original construction construction system. system. The The upper upper floor floor has a wooden structure and is in a significantly bad state of conservation. The degradation of

the roof is also severe. Figure The16. General upper views floor consistsof the building of a single surveyed. habitable compartment, used as a bedroom. The habitability conditions of the building are very bad, not only due to its degradation, but alsoOn due the to lower the small floor space there and are thetwo lack spaces of basic separated equipment by a andmasonry functionalities. wall made of con- crete blocks,The difficulties which result resultinged from from unfinished partial work and very for the poor eventual interventions creation carried of a bathroom. out over Thetime larger also contributespace has a to mixed the lack function of suitable between living “cellar conditions.” and kitchen, Thus, the with challenge an exterior of the woodintervention-fired oven. was The to make pavement the most consists of the of space a mortar and screed provide executed the house directly with onsuitable the ground.living conditions, respecting the guidelines of the specific regulations created in 2015 by theThe Regional interior Government connection between of the Azores. the two Figure floors 18is made presents through architectural a reinforced plans concrete for the stairwayintervention that is proposal. totally different from the original construction system. The upper floor Sustainability 2021, 13, x FOR PEER REVIEW 22 of 26

Sustainability 2021, 13, 2352 19 of 23 has a wooden structure and is in a significantly bad state of conservation. The degradation of the roof is also severe.

FigureFigure 17. 17.Example Example of of thethe architecturalarchitectural survey survey of of one one building. building.

TheThe dismantling upper floor ofconsists the stone of a single stairs habitable and their compartment, subsequent reuse used isas foreseen,a bedroom. as The well as thehabitability construction conditions of a small of the space building to install are very a bathroom, bad, not only which due would to its degradation, be articulated but with thealso original due to building.the small space and the lack of basic equipment and functionalities. TheThe lower difficulties floor resulting level would from be partial lowered and very to increase poor interventions the space’s carried height. out This over floor wouldtime also be reorganized contribute to to the maintain lack of andsuitable improve living the conditions. kitchen functions,Thus, the challenge now including of the the “diningintervention room” was function. to make Here, the most the dissonantof the space elements and provide would the house be demolished. with suitable The living interior conditions, respecting the guidelines of the specific regulations created in 2015 by the Re- access to the upper floor would be replaced by a wooden staircase, which would replace gional Government of the Azores. Figure 18 presents architectural plans for the interven- the concrete staircase. On the upper floor the spatial organization would be maintained, tion proposal. but with improved comfort and healthiness and with the exclusive function of a bedroom. In view of the poor conservation state of the existing wooden floor of the upper floor, it was decided to reconstruct it with an identical technical solution. The windows and doors would also be replaced by traditional wooden solutions, but with better performance than the existing ones. The same strategy would be adopted with the roof, taking the opportunity to make a slight correction of geometry and to create a technical element of lighting and ventilation. Sustainability 2021, 13, x FOR PEER REVIEW 23 of 26

The dismantling of the stone stairs and their subsequent reuse is foreseen, as well as the construction of a small space to install a bathroom, which would be articulated with the original building. The lower floor level would be lowered to increase the space’s height. This floor would be reorganized to maintain and improve the kitchen functions, now including the “dining room” function. Here, the dissonant elements would be demolished. The interior Sustainability 2021, 13, 2352 20 of 23 access to the upper floor would be replaced by a wooden staircase, which would replace the concrete staircase. On the upper floor the spatial organization would be maintained, but with improved comfort and healthiness and with the exclusive function of a bedroom.

FigureFigure 18. 18.Architectural Architectural plans for the the intervention intervention proposal. proposal. This project, like all those that were developed in this integrated plan of valorization of NAVC by the Local Technical Office, aimed to answer the rehabilitation challenge considering, simultaneously, the principles of protection and valorization of the existing environmental preservation and progressive improvement of quality of life. Although the policy, strategies, methods, and technologies are the same, as required in an integrated action, the implementation of interventions requires adequate solutions for each dwelling.

6. Conclusions For its inhabitants, living in Corvo represents safety, happiness, peace, friendship, cohesion, solidarity, and pride. Despite being isolated and still suffering from certain Sustainability 2021, 13, 2352 21 of 23

difficulties, this territory has unique characteristics that are valued by its community and visitors. The settlement of Corvo Island is characterized by its originality: an island with only one inhabited place. Vila do Corvo is a testament to the evolution of the community and its houses, which date back to 16th and 17th centuries. The village is proof of the continuous effort to adapt to the adverse climate and the scarcity of local resources. Here, any intervention on the buildings should have as a main objective the improve- ment of the quality of life of its inhabitants. However, this objective must also consider the concerns of protecting and valuing the identity of existing buildings and the concerns of environmental sustainability. To achieve these objectives, it is necessary to have an integrated action supported by its own regulation by an exhaustive knowledge of the history of the place, the buildings and local construction techniques, expectations of its inhabitants, state of conservation, and dissonance of the buildings. This paper presented the architectural and constructive characterization of NAVC buildings, as well the island’s historical context and its resources. Additionally, a descrip- tion of NAVC buildings’ state of conservation was carried out, as well as the presentation of the dwellings’ dissonances and of a rehabilitation intervention already carried out. The goal of this work is to contribute to a more extensive and profound knowledge of the island’s built heritage, laying the foundations for future rehabilitation interventions that value this territory’s unique identity and improve its inhabitants’ quality of life. The work developed showed a typical building morphology, structured in several variants, where rectangular buildings with two floors are the most frequent. The buildings are compact and are strongly related to construction technology, namely roofing. The internal organization of the dwellings is very much conditioned by the typical vol- ume of the buildings and, in many cases, does not correspond to the current requirements of comfort and healthiness. Thus, many projects have as a main objective the correction of these limitations. Several anomalies were also identified that mainly resulted from climatic aggressive- ness and low maintenance. The projects developed also aim to correct these defects and, as far as possible, contribute to the elimination or mitigation of dissonances resulting from the most disqualified interventions carried out over the years. Through the example presented it is confirmed that it is possible to articulate the different functional objectives, both with the preservation of the buildings’ identity and with sustainability requirements, through a philosophy of minimal intervention and maximizing the buildings’ longevity.

Author Contributions: All authors contributed equally to this paper and approved the final manuscript. Conceptualization, J.M.S.; Formal analysis, V.M.; Investigation, A.I.P.S., C.P.M. and L.C.; Methodology, A.I.P.S.; Project administration, L.C.; Supervision, V.M. and J.M.S.; Validation, C.P.M.; Writing— original draft, C.P.M., L.C. and J.M.S. All authors have read and agreed to the published version of the manuscript. Funding: Financed by national funds through the I&D entity Geosciences Center (CGEO), UIDB/00073/2020 through FCT—Fundação para a Ciência e Tecnologia, I.P. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Acknowledgments: The authors acknowledge the collaboration of Regional Directorate for Culture of Azores. Conflicts of Interest: The authors declare no conflict of interest. Sustainability 2021, 13, 2352 22 of 23

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