Towards a portrayal of the archaeology of architecture in Portugal: 15 years of custodial practice in the city of Coimbra (2001-2016)

1.1. The archaeology of architecture and urban rehabilitation

The archaeology of architecture has been associated with urban rehabilitation since its conception. Once architecture was considered an archaeological document in the late 1970s,⁴For example, Cabona et al. (1978) clearly stated the feasibility of reading the “wall stratigraphy”, used as an analogy of the “excavation method”, to determine the “various construction phases in relative sequence”. the archaeology of historic buildings presupposed a set of theoretical and practical paradigms. These paradigms are particularly favourable to urban rehabilitation since rehabilitation projects take into account not only the formal and functional aspects of the buildings but also the different phases of their construction. Furthermore, knowledge of the different construction phases, as parts of a continuous architectural sequence, transformed the archaeology of architecture. As advocated by Francovich (1979Francovich, R.1979: “Alcuni problemi dei rapporti pratici fra archeologia, restauro e pianificazione territoriale (in margine all’esperienza toscana)”, Archeologia Medievale, VI, pp. 35-46.), the architectural sequence is a well-equipped tool to provide new understandings of a building’s current situation, which is essential for correctly planning its future rehabilitation.

In the 1970s and 1980s, the abundance of construction works in the historic centres of the main Italian cities led to an increase in archaeological interventions in urban contexts, especially in the north (D’Ulizia 2005D’Ulizia, A.2005: “L’Archeologia dell’architettura in Italia. Sintesi e bilancio degli studi”, Archeologia dell’Architettura, X, pp. 9-41.). During this growth, Italian archaeologists began to recognise the imperative of meticulously documenting and interpreting architectural contexts affected by urban rehabilitation initiatives. This recognition was articulated and developed in several key publications (e.g. Mannoni 1974Mannoni, T.1974: “Il castello di Molassana e l’archeologia medievale in Liguria”, Archeologia Medievale, I, pp. 11-17.; Francovich 1979Francovich, R.1979: “Alcuni problemi dei rapporti pratici fra archeologia, restauro e pianificazione territoriale (in margine all’esperienza toscana)”, Archeologia Medievale, VI, pp. 35-46.; Parenti 1988Parenti, R.1988: “La tecniche di documentazione per una lettura stratigrafica dell'elevato”, in R.Francovich and R.Parenti (eds.), Archeologia e restauro dei monumenti, pp. 249-279. All’Insegna del Giglio, Florence.; Brogiolo 1988Brogiolo, G. P.1988: “Campionatura e obiettivi nell’analisi stratigrafica degli elevate”, in R.Francovich and R.Parenti (eds.), Archeologia e restauro dei monumenti, pp. 335-346. All’Insegna del Giglio, Florence.; Doglioni 1988Doglioni, F.1988: “La ricerca sulle strutture edilizie tra archeologia stratigrafica e restauro architettonico”, in R.Francovich and R.Parenti (eds.), Archeologia e restauro dei monumenti, pp. 223-247. All’Insegna del Giglio, Florence.). Following this, the second half of the 1980s was marked by initiatives that aimed to legitimise archaeology as a discipline suited to the analysis of historical architecture. United around this purpose, Riccardo Francovich, Roberto Parenti, Gian Pietro Brogiolo, Francesco Doglioni, and Tiziano Mannoni, among others, chose to combine the experience they had individually acquired in the previous decade. The result was a summer school for archaeologists and architects held in the ancient Sienese monastery of Certosa di Pontignano in 1987 (Milanese and Molinari 1988Milanese, M. and Molinari, A.1988: “Premessa”, in R.Francovich and R.Parenti (eds.), Archeologia e restauro dei monumenti, pp. 5-6. All’Insegna del Giglio, Florence.; Brogiolo 2002Brogiolo, G. P.2002: “L’archeologia dell’architettura in Italia nell’ultimo quinquennio (1997-2001)”, Arqueología de la Arquitectura, 1, pp. 19-26. 10.3989/arqarqt.2002.i1). Under the name Archeologia e restauro dei monumenti, the seminar aimed to project itself precisely as an initiative for architectural restoration and urban rehabilitation in historic centres.⁵Giving rise to Archeologia e restauro dei monumenti, published in 1988, the first manual dedicated to what was then still called “archeologia dell’edilizia storica” (García-Gómez 2019).

Although characterised as "a recent acquisition" at the outset of the 1990s (Parenti, 1992Parenti, R.1992: “Fonti materiali e lettura stratigrafica di un centro urbano: I risultati di una sperimentazione ‘non tradizionale’”, Archeologia Medievale, XIX, pp. 7-62.), the archaeology of architecture developed significantly throughout that decade, particularly in emphasising stratigraphy as a methodological framework for interpreting building remains susceptible to the alteration from rehabilitation projects (Caballero 1995Caballero Zoreda, L.1995: “Arqueoloxía e arquitectura, Análise arqueolóxica e intervención en edificios históricos”, in C.Fontenla San Juan (ed.), Las actuaciones en el patrimonio construido: Un diálogo interdisciplinar, pp. 131-158. Xunta de Galicia, Santiago de Compostela.). After several experiences with custodially promoted rehabilitation projects, this epistemological framework was also adopted by Portuguese heritage custody from 2001 onwards, through implementing Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829..

3.1. While licensing architectural projects

Since the establishment of Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829., projects for construction works on built heritage presented for licensing must include “a report on the (…) historical evaluation of the intervention” (Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829., p. 5815). In compliance with this regulation, a 2009 decree mandated the submission of a preliminary report for “approval or authorisation for construction works”, with the “evaluation of works or interventions proposed to be carried out on cultural assets” (Decree-Law140/2009Decree-Law 140/2009 de 15 de junho, 2009, Diário da República, n.º 113/2009, Series I, Presidência do Conselho de Ministros. Lisbon: Imprensa Nacional, pp. 3653-3659., p. 3655). However in practice, no legislative resolution established the criteria that the report must meet. Certain municipalities, as in Coimbra, have defined typified records according to parameters considered to better describe the heritage relevance of the property affected, although these documents still remain merely suggestive (Regulation381/2017Regulation 381/2017 de 21 de julho, 2017, Diário da República, n.º 140/2017, Series II, Município de Coimbra. Lisbon: Imprensa Nacional, pp. 15146-15189., p. 15156; see Appendix, Ficha de Avaliação de Impacte Patrimonial e Arqueológico).

For licensing the rehabilitation works since 2001 the municipalities have validated the project and the preliminary report. Despite the administrative proximity that these municipalities maintain with their territory, they have little or no decisive power over safeguarding built heritage under their jurisdiction. In fact, it is up to “the competent bodies for the administration of cultural heritage”, until now the DGPC and not the municipalities, to establish the necessary measures to safeguard cultural heritage (Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829., p. 5814). Therefore, even if a municipality deemed the implementation of preventive measures relevant, a rehabilitation project could receive a license without any safeguarding appraisal by the custodial authority. In 2005, for instance, the municipality of Coimbra, lacking a signed protocol with the custodial authorities, chose to notify them about a rehabilitation project slated for the historic centre. Although the building was located less than 100 metres from the medieval church of Santiago and the baroque one of São Bartolomeu, the custodial authorities did not issue any conditions because the building was not in a protected zone.⁸DRCC (63) 06.03/01 File, Edifício sito na Travessa das Canivetas, n.º 8, Coimbra, DRCC archive, letter dated May 18, 2005. The Direção Regional de Cultura do Centro, DRCC, constituted the regional extension of the DGPC responsible for assessing construction projects in Coimbra.

The municipality, however, does not necessarily have to resign its responsibilities over heritage protection. In the northern cities of Braga and Guimarães, for example, municipalities have adopted a more active role. In Braga, the municipality maintains a very close relationship with the custodians and technicians from the Archaeology Unit of the University of Minho, fully trained in the archaeology of architecture. The archaeological interventions in architectural heritage precede the rehabilitation projects. "The process always starts at the City Council", explains Luís Fontes, former project director at the aforementioned Archaeology Unit. "As soon as the promoter wants to develop a project, he has a first meeting at the City Council, where all the conditions are explained”, including “a [previous] archaeology of architecture study to identify elements that could condition the development of the project”.⁹Luís Fontes, in an interview given via videoconference on November 22, 2021. In Guimarães, the historic centre was inscribed on the World Heritage List as a direct result of the rehabilitation of hundreds of buildings, carried out by both public and private entities. The municipality “seeks (…), whenever there is an opportunity to do so, to informally talk with the promoters (…), so that the necessary procedures to safeguard the heritage building are followed”, says Ricardo Rodrigues, coordinator of the city’s Historic Centre Division.¹⁰Ricardo Rodrigues, in an interview given via videoconference on December 7, 2022. As a result, the archaeology of architecture is often performed before the rehabilitation project is designed. It “happens in Guimarães, as a result of long years of collaboration with municipal archaeology, that most architects (…) know that those types of records can serve as a basis for the execution of the preliminary project”, explains Paula Ramalho, archaeologist in the municipality of Guimarães.¹¹Paula Ramalho, in an interview given via videoconference, on December 9, 2022.

Once validated by the municipality, the project is forwarded to the custodial entity, which receives support from its regional extensions, the Direções Regionais de Cultura. An assessment process is then initiated, which, by investigating the expected impact of the construction work, leads to issuing a favourable, non-favourable, or conditioned favourable appraisal. Therefore, it is up to each regional delegation to demand that projects impacting cultural heritage are subject to appropriate safeguarding measures. However, Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. (p. 5821) does not extend beyond the facilitation of protected zones or the requisitioning of “conservation through scientific recording”. The custodian is responsible for “making sure that the works (…) involving (…) the demolition or alteration of buildings” are “in accordance with the legislation” (Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829., pp. 5821-5822), but the law does not specify the parameters for compliance.

In light of current archaeological work regulations, buildings established as cultural heritage should be protected by “preventive and minimisation actions”, whenever they “are in imminent danger of partial or total destruction”, including “archaeological monitoring, registration actions (…) and architectural stratigraphy” (Decree-Law164/2014Decree-Law 164/2014 de 4 de novembro, 2014, Diário da República, n.º 213/2014, Series I, Presidência do Conselho de Ministros. Lisbon: Imprensa Nacional, pp. 5633-5640., p. 5635). But when facing projects that are expected to impact architectural heritage, the regional extension of the DGPC responsible for the territory of Coimbra, the DRCC, has adopted quite different positions.

Of the 84 official appraisals issued for licensing since Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. until 2005, 80 corresponded to projects that envisaged substantial effects on architectural heritage, such as demolition or removal of extensive areas of plaster. However, while 64% of this licensing had at least one condition imposed for archaeology of architecture work, 26% only required ground archaeology work. In 10% of cases, the projects received a favourable appraisal without any type of archaeological work (Fig. 2).

Figure 2 Graph of archaeological requirements issued by the custodians for construction works with substantial impact on buildings in the historic centre of Coimbra between 2001 and 2005 (IPPAR and IPA). 

Of the 136 official appraisals issued between 2006 and 2011, 94 corresponded to works with a substantial impact on architectural heritage. During this period, 89% of the appraisals resulted in licensing with archaeology of architecture work conditions. Under the IGESPAR, as a condition imposed by the custodians, the archaeology of architecture increased by 25% compared to the previous period. Even so, 11% of the appraisals did not require any archaeology of architecture work and 8% did not impose any type of conditions (Fig. 3).

Figure 3 Graph of archaeological requirements issued by the custodians for construction works with substantial impact on buildings in the historic centre of Coimbra between 2006 and 2011 (IGESPAR). 

Between 2012 and 2016, 94 official appraisals were issued, of which 65 corresponded to works with substantial effects on the architectural heritage. In 77% of these appraisals, licensing was granted on the condition that archaeology of architecture work was carried out. Then under the custody of the DGPC, the application of archaeology of architecture decreased by 12%. Also, 23% of official appraisals did not impose archaeology of architecture work and 12% of appraisals did not impose archaeological conditions whatsoever. However, it is worth highlighting that 23% of appraisals placed the rehabilitation project under at least one archaeology of architecture work condition (Fig. 4). This condition explicitly appears for the first time, as such, under the supervision of the DGPC.

Figure 4 Graph of archaeological requirements issued by the custodians for construction works with substantial impact on buildings in the historic centre of Coimbra between 2012 and 2016 (DGPC). 

According to the processes archived in the DRCC, it is clear the interpretative ambiguity with which the custodians approached the archaeology of architecture. Even in cases where demolitions were planned, the conditions imposed were often limited to a mere description of the building, exempting the archaeology field team from conducting the necessary stratigraphic analysis. The conditions issued differed greatly in their scope, with an apparent correlation between the conditions required and the academic training of the issuing technicians.

In the period under analysis, 52% of the custodial technicians issuing archaeological conditions restricted to the ground for licensing works were not specialists in archaeology. Even so, 48% of the official appraisals were issued by archaeologists or teams of technicians including archaeologists (Fig. 5). Of the appraisals that authorised the execution of projects without archaeological conditions, 94% came from specialists in areas other than archaeology, such as architecture or engineering (Fig. 6). On the other hand, 92% of the appraisals imposing archaeology of architecture work condition(s) came from teams comprising at least one archaeologist (Fig. 7). The requirement for conducting archaeology of architecture work came mainly from technicians trained in archaeology. On the other hand, exemption from this type of condition most often originated from technicians with other specialities. In effect, the archaeology of architecture, as a condition required by the custodians, apparently depended on the specialisation of the technicians involved.

Figure 5 Graph of academic training of supervisory technician(s) responsible for conditioning construction works affecting buildings in the historic centre of Coimbra to archaeological works only at ground level between 2001 and 2016. 

Figure 6 Graph of academic training of the supervision technician(s) responsible for providing appraisals on construction works affecting buildings in the historic centre of Coimbra without any type of archaeological conditions between 2001 and 2016. 

Figure 7 Graph of academic training of supervisory technician(s) responsible for providing appraisals on construction works affecting buildings in the historic centre of Coimbra to at least one type of archaeological work at the building level between 2001 and 2016. 

In fact, the academic training of custodial technicians responsible for issuing conditions apparently accounts for the different perspectives on the same projects, even when evaluated within the same custodial institution. A project aimed at rehabilitating a building situated on Rua Fernandes Tomás in Coimbra, noted for its significant architectural implications, underwent an assessment in 2004 by a custodial architect, whose appraisal only stipulated archaeological monitoring of excavation trenches. However, to authorise archaeological operations in 2006, the revised conditions were overseen by a custodial archaeologist, who also incorporated the monitoring of plaster removal.¹²DRCC (2004) 06.03/79 File, Edifício sito na Rua Fernandes Tomás, n.º 85-89 e Joaquim António de Aguiar, n.º 7, Coimbra, DRCC archive, letters dated December 16, 2004 and June 18, 2006. In 2010, a project impacting both the ground and architectural structures along Rua Visconde da Luz in Coimbra prompted a custodial team of archaeologists and architects to advocate for monitoring all activities affecting the ground, as well as the removal of plaster. When in 2015, changes to the project increased the effects on the building, a custodial architect who re-evaluated the conditions only required archaeological work at ground level.¹³DRCC (1978) 06.03/07 File, Edifício sito na Rua Visconde da Luz n.º 69, Coimbra, DRCC archive, letters dated June 18, 2010 and September 10, 2015.

Even so, Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. appears to provide the necessary regulation to impose the archaeology of architecture as a condition for works on architectural heritage. For example, a project with substantial impacts on a building located on Rua Nova in Coimbra was appraised by three different architects at three different times, and ultimately subject to three distinct conditions. Before the law, in 1999, it received approval from the custodians with no archaeological conditions. Just three months before Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. was adopted, a second assessment resulted in the requirement for an "adequate archaeological study". In 2004, a third assessment also required archaeological monitoring of the building demolitions.¹⁴DRCC (1999) 06.03/54 File, Edifício sito na Rua Nova n.º 4-12; 14-16, Coimbra, DRCC archive, letters dated November 30, 1999, June 12, 2001 and January 20, 2004.

At a national level, Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. coincides with a sharp increase in archaeological interventions in architecture. Projects on urban rehabilitation almost doubled and archaeological interventions in buildings increased drastically from 2001 to 2002, going from a residual 0.5% to 23.9% (Fig. 8). Until 2008, the volume of urban rehabilitation projects witnessed a steady increase, nearly quadrupling in comparison to the figures observed in 2001 (Fig. 9). However, between 2001 and 2008, even after IGESPAR was created, the number of archaeological interventions in urban areas or protected buildings decreased sharply from 198 to 26. Nevertheless, the level of activity in the archaeology of architecture never reverted to its pre-existing residual levels, persisting within a range between 7.1% and 23.1% (Fig. 10). By the time Decree-Law164/2014Decree-Law 164/2014 de 4 de novembro, 2014, Diário da República, n.º 213/2014, Series I, Presidência do Conselho de Ministros. Lisbon: Imprensa Nacional, pp. 5633-5640. was enacted, Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. (pp. 5821-5822) had already laid the groundwork in 2001, so that the “modification of constructions” would be subject to the archaeology of architecture. In this sense, the new regulation, which required “architectural stratigraphy” whenever archaeological remains were “in imminent danger” (Decree-Law164/2014Decree-Law 164/2014 de 4 de novembro, 2014, Diário da República, n.º 213/2014, Series I, Presidência do Conselho de Ministros. Lisbon: Imprensa Nacional, pp. 5633-5640., p. 5635), just reinforced what had long been understood by the different custodial technicians.

Figure 8 Graph of archaeological interventions on buildings between 1991 and 2016 (relative to all interventions). 

Figure 9 Graph of rehabilitation works completed between 1991 and 2016 (in absolute value). The author, using data from the Instituto Nacional de Estatística. 

Figure 10 Graph of archaeological interventions on buildings between 1991 and 2016 in urban areas and protected buildings (in absolute value). 

After the enactment of the two statutes, Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. and Decree-Law164/2014Decree-Law 164/2014 de 4 de novembro, 2014, Diário da República, n.º 213/2014, Series I, Presidência do Conselho de Ministros. Lisbon: Imprensa Nacional, pp. 5633-5640., a lack of consensus persisted among various custodial entities regarding the implementation of the archaeology of architecture. Following the downward trend in the number of urban rehabilitation projects, the archaeology of architecture conducted in Portugal decreased between 2014 and 2016 from 22.4% down to 10% of the total rehabilitation interventions (Fig. 8). But while some custodial technicians understood the archaeology of architecture as a legal requirement, others continued to have a different understanding of the law.

A project for rehabilitating the college of São Jerónimo in Coimbra, a UNESCO World Heritage site, was appraised in 2017 by a DRCC technician and conditioned on conducting “prior archaeological diagnostic surveys on all walls affected”. However, the deputy director of the DGPC, who validates regional appraisals, decided, “in accordance with the current legislation”, to approve the appraisal, “except for (…) the removal of plasters and demolition works”.¹⁵DRCC (95) 06.03/50 File, Colégio de São Jerónimo e das Artes, Coimbra, DRCC archive, vol. 3, information nº 1752/DRCC/2017 dated July 26, 2017 and information n.º S-2017/444639 (C.S: 165698) dated November 21, 2017. Another official appraisal from 2018, regarding a rehabilitation project for a building situated on Rua da Sofia, another area registered with UNESCO, required archaeological monitoring of “all impacted walls”. When evaluated by the deputy director of the DGPC, the appraisal was once more approved, “except for the archaeological monitoring of the plaster removal in accordance with current legislation”.¹⁶DRCC (89) 06.03/17 File, Casa de Repouso de Coimbra, Rua da Sofia n.º 150/158, Coimbra, DRCC archive, information n.º 911 – DRCC/2008 (C.S: 174457) dated June 14, 2018 and information n.º S-2018/461963 (C.S: 1272262) dated July 3, 2018.

Through interpretative subjectivity, the same legal decrees made the archaeology of architecture a condition, while paradoxically ensuring that the conditions included all types of archaeological works, except the archaeology of architecture. When the condition includes the archaeology of architecture, architectural heritage rehabilitation projects rely on an instrument for evaluating the pre-existence of archaeological remains. Thus, the poor understanding of the archaeology of architecture, along with the ambiguous interpretation of Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829., sometimes resulted in the execution of rehabilitation projects without leveraging this instrument.

3.2. After licensing construction projects

Once granted a license, the rehabilitation project proceeds to the implementation phase. Taking into account the conditions issued, the archaeology team implements a work plan, previously authorised by the custodians. From an architectural point of view, the archaeological intervention may involve a generic characterisation of the building, monitoring actions affecting the building, or opening archaeological surveys on the walls.

The provision of critical data necessary for the project's execution relies on implementing the work plan devised by the archaeology team, particularly around identifying archaeological remnants. The purpose of providing data for the project seems to be rooted in the history and nature of the archaeology of architecture itself, which was originally associated with urban rehabilitation. In Portugal, a direct correlation appears between the number of urban rehabilitation interventions and the development of archaeology of architecture. From the initial use of this archaeological method at the end of the 1980s until 2001, urban rehabilitation remained relatively stable at around 2,500 annual projects, although decreasing in absolute number. During the same period, the application of archaeology of architecture, although still relatively marginal, stabilised at approximately 0.6% of all archaeological works conducted within the country. From 2001 onwards, however, urban rehabilitation soared from 2,168 to 8,155 annual projects registered in 2008. Following an irregular trajectory, the number of archaeology of architecture interventions also soared from 0.5% to 23.1% of all archaeological interventions in the country (Fig. 8 and 9).¹⁷According to data from the Portal do Arqueólogo and the Instituto Nacional de Estatísticas (INE), in https://arqueologia.patrimoniocultural.pt [consulted February 1, 2022]; INE, 2013, p. 121; INE, 2014, pp. 32–33; INE, 2015, pp. 26–27; INE, 2016, pp. 28–29; INE, 2017, pp. 31–32 [consulted January 2, 2021]. Paradigmatically, the year in which both urban rehabilitation and the practice of archaeology of architecture took off in Portugal was 2001, when Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. was promulgated. Although not related to the increase in urban rehabilitation interventions, this fact is surely related to the rise of archaeology of architecture work.

Initially, Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829. may have boosted the archaeology of architecture. However, archaeology of architecture work remained well below half of the 2001 figures in subsequent years, while urban rehabilitation more than quadrupled, including authorisations for archaeological studies in urban areas and protected buildings (Fig. 8 to 11). Despite this irregular trajectory, authorisations for archaeology of architecture work experienced substantial reductions from 2006 and 2012 onwards, in the periods following the creation of IGESPAR and DGPC. Between 2006 and 2008, archaeology of architecture interventions decreased from 4.6% to 1.7% and, between 2012 and 2015, from 19.7% to 15% (Fig. 12).

Figure 11 Graph of archaeological interventions authorised by the custodians between 1991 and 2016 (in absolute value). 

Figure 12 Graph of the archaeology of architecture interventions authorised by the custodians between 1991 and 2016 (relative to all authorisations in urban areas and protected buildings). 

Although archaeological interventions are authorised, rehabilitation works uncompliant with the archaeological conditions imposed by the custodians bare few or no consequences since legislation fails to define any compensation measures. During the 2010 rehabilitation of a building located on Rua Visconde da Luz in Coimbra, where custodians had mandated archaeological monitoring of ground and plaster-altering actions, the project demolished the interior in the total absence of archaeologists. Upon reassessment in 2012, the custodians themselves conceded that, due to the complete disappearance of all archaeological remnants resulting from the previous work, there remained no basis for further conditioning.¹⁸DRCC (2006) 06.03/44 File, Prédio na R. Visconde da Luz n.º 74-76 e R. Velha nº. 24-26, Coimbra, DRCC archive, letters dated July 18, 2010 and June 21, 2012. In other instances, particularly when archaeological remnants were present, the custodians nonetheless insisted on implementing compensatory measures. Having received a non-favourable appraisal from the custodians, the rehabilitation project of a building situated on Rua Ferreira Borges in Coimbra commenced clandestinely. Embargoed by the municipality, the rehabilitation works resumed in 2007, following a new appraisal from the custodians. This appraisal recognised that “there had not been a prior archaeological study” and demanded “the complete removal of the plaster”, followed by stratigraphic reading, “based on the methodology of archaeological interventions to levels above the ground".¹⁹DRCC (2000) 06.03/46 File, Prédio sito na Rua Ferreira Borges n.º 91-97, Coimbra, DRCC File, letter dated August 3, 2006.

When effectively leveraged during the project execution phase, the archaeology of architecture often detects previously unknown archaeological remains of relevant heritage significance. In these cases, the legislation provides that the “pursuance of any works” is conditioned to “changes to the approved project capable of guaranteeing the conservation (…) of the archaeological structures discovered” (Law107/2001Law 107/2001 de 8 de setembro, 2001, Diário da República, n.º 209/2001, Series I-A, Assembleia da República. Lisbon: Imprensa Nacional, pp. 5808-5829., p. 5821). This regulatory contingency has thus far resulted in the possibility of reviewing a project even during the execution phase, or in extreme cases, the project may be terminated. During the rehabilitation of the so-called Laboratorio Chimico, at Marquês de Pombal Square in Coimbra, the coffee shop within the initial project was never completed. This decision was made by the promoter and custodians due to "archaeological structures" uncovered during the archaeological monitoring of the work, as was the recovery of other remains, like windows “discovered by vertical archaeology”.²⁰DRCC (2001) 06.03/16 File, Laboratorio Chimico, Largo Marquês de Pombal, Coimbra, DRCC archive, letter dated February 2, 2005.

For the preservation and integration of archaeological remains, project restructuring requires a conciliation between promoter and custodians, which is not always easy to achieve. During the rehabilitation of a building located on Rua Velha in Coimbra, the archaeological intervention uncovered a central arch, whose relevance was recognised both by the archaeology team on site and the custodians. The incorporation of the arch was sanctioned by the custodians but clashed with the intentions of both the promoter and architect, who argued that it lacked “significant historical/artistic interest”. Subsequently, the architect suggested dismantling the structure to the custodians, who insisted that "all structures were to be preserved and integrated into the architectural project." This impasse resulted in additional expenses and delays for the rehabilitation project.²¹DRCC (2004) 06.03/20 File, Edifício sito na Rua Velha n.º 7-9 e na travessa Velha n.º 11-19, Coimbra, DRCC archive, letters dated July 21, 2006 and September 29, 2006.

Once the archaeological work is concluded, the archaeology team assumes responsibility for compiling the gathered data into a comprehensive report. They must adhere to the prescribed format, timelines, and content requirements stipulated by law, which includes the “detailed description and interpretation of the nature, chronology and typology of the stratigraphic and structural contexts identified” (Decree-Law164/2014Decree-Law 164/2014 de 4 de novembro, 2014, Diário da República, n.º 213/2014, Series I, Presidência do Conselho de Ministros. Lisbon: Imprensa Nacional, pp. 5633-5640., p. 5639). To date, the archaeological reports submitted for approval by the DGPC must extend beyond a mere stratigraphic characterisation of the building under intervention. They are required to encompass elements essential for scientific and heritage preservation, including: detailed plans and elevations, graphic and photographic documentation, inventory listings, and comprehensive descriptions of proposed and implemented actions for mitigating the impact of rehabilitation efforts on archaeological heritage. In the field of the archaeology of architecture, however, the current legislation does not define specific parameters for compliance with these reports.

Taking the historic centre of Coimbra as a sample, this lack of clarity is revealed in the reports under the archaeology of architecture conditions between 2001 and 2016. Of the 143 reports consulted,²²Of the 251 official appraisals conditioning rehabilitation projects to archaeology of architecture, only 179 led to authorisation for archaeological works, resulting in 158 previous, preliminary, or final archaeological reports (15 of which were unavailable for consultation). only 6% contained stratigraphic analysis of the building, a basic methodological condition for work to be considered archaeology of architecture. Of all the project reports with imposed archaeological monitoring of actions affecting the building or wall surveys, 14% solely described the types of construction and construction materials, while only 15% were accompanied by graphic records for deducing dimensions. Exempt from stratigraphic analysis and graphic records, these descriptions of construction types cannot contribute to understanding the historical evolution of the analysed building, an elementary premise in archaeology of architecture. In 14%, construction phasing proposals were advanced, although without any stratigraphic reading that would allow for corroboration. Only 22% risked a chronological characterisation and only 8% committed to proposals for structural or spatial functionality. With archaeology of architecture work as a specific condition, 6% of the intervention reports lacked any archaeological interpretations of the architecture (Fig. 13).

Figure 13 Graph of results expressed in reports of archaeological interventions carried out in construction works affecting buildings in the historic centre of Coimbra between 2001 and 2016.