Significant architectural and historical monuments become an important point of reference for the local population, increasing their sense of security, and act as a factor shaping social identity. An effort to preserve relevant objects in a city is therefore important both for retaining its unique features and for strengthening the local community. A significant role plays here the adaptive reuse of architectural heritage, which allows for the preservation of architectural objects that are important to the local community, promoting the integrity and historical continuity of the city while restoring the objects’ functional and economic value.
The introduction of a new function in architectural heritage is not only an important impulse for the tangible regeneration of urban tissue, but can also help to reconstruct the image and identity of a city. The local cultural and architectural heritage plays a significant role in the process leading to the creation of positive references and elimination of negative connotations related to an economic or social crisis. These remain an important part of the history of a city and, at the same time, its significance may be reimagined and shown in a new context, that relates to the present day. As a result, artefacts of the past gain new meanings, which are subject to a different, contemporary interpretation through the prism of current needs and ideas. Objects or even groups of objects from the past are being consciously taken into consideration in the activities currently undertaken.
The contemporary scale of the phenomenon and complexity of the issues concerning the adaptive reuse of architectural heritage are a consequence of the multi-faceted transformations that have taken place in recent decades in the social, cultural and economic spheres, and, consequently, the contemporary understanding of the role and significance of the architectural heritage.
In the late 20th century and at the beginning of the 21st century, the opinion that cultural heritage should not be seen as constant and static, but instead needs to be constantly redefined to reflect human activity, was gaining popularity in the documents concerning cultural heritage  (art. 2 and Preamble). An important role was played by the emphasis on the complex social values of heritage, visible since the 1970s . This aspect is linked to the clearly visible increase in the importance of intangible heritage assets, which are strongly interlinked with social and cultural factors, and the belief that they need to be taken into account on a par with the material value of a property 
The assumption that conservation aims not only at the protection of material values, but also at the preservation of the cultural meaning of a place important for both past, present and future generations  (Preamble), is connected with the observation that these values are not universal/absolute, since the value of a place may be different for different groups and individuals  (art. 1.2). What is more, the cultural meaning may change as a result of acquiring new information, as well as during the continuous formation of the history of the place  (art. 1.2 with Explanatory notes). Conservation should therefore not only concern the material substance and methods of use, but also the meanings (for example symbolic ones and related to memories) and links understood as social, spiritual and cultural relationships between the people and the place  (art. 1.15, 1.16, 3.1). Accentuating the social meaning of heritage and adopting a value-based approach has shifted the emphasis from the universal values belonging to the site, which can be revealed through a proper investigation carried out by a small group of experts, to values that are important for the development and quality of human life  (pt. c). There is thus a shift from a traditional approach, which sees values as fixed and unchangeable, inherently associated to the site, to values that result from the interaction between the site and the historical, social or spatial context associated with it. In fact, in 2005, the Convention on the Value of Cultural Heritage for Society, known as the Faro Convention, recognised the need for the whole society to participate in a continuous process of defining cultural heritage  (Preamble). This highlights the diverse and variable possibilities of perception and interpretation, which are not subject to clear and set definitions. Cultural heritage itself was defined as a collection of resources from the past that are being approached by people as a form of reflection and expression of their constantly evolving values, beliefs, knowledge and traditions  (art. 15). This significant change in perspective and way of thinking led to the conclusion that the primary goal of protecting cultural heritage is human development and improvements in quality of life  (art. 1, pt. c). In contrast, just over forty years earlier, in the Venice Charter—that was adopted in 1964, and was a fundamental document for the theory of heritage conservation in the 20th century—the importance of protection and conservation of works of art was understood only as the preservation of the material form and substance .
Shifting the emphasis from the importance of the material values of a building, without negating them, to the values related to an individual (a recipient and user), their perception of the cultural heritage, as well as established associations and relationships must be accompanied by a fundamental modification of the way of thinking, taking a broader view of architectural heritage protection and including factors such as cultural, social and economic changes in the analysis . Each time the local context and cultural meaning of the historical building must be taken into account .
At the same time, the preservation of the architectural heritage (structure of historical centres and places) and its integration within contemporary social life  (pt. 7) foster a harmonious social balance and the formation of a complete (holistic) and sustainable living environment  (pt. 1.4). As the Declaration of Amsterdam emphasised in the mid-1970s, “historical continuity must be preserved in the environment if we are to maintain or create surroundings which enable individuals to find their identity and feel secure despite abrupt social changes” .
Recognising heritage as not only a testimony of the past but also of cultural, social and economic capital  leads to a special interaction and dialogue between history and the present. In this context, the introduction of a new contemporary function for architectural heritage plays an important role. In recent years, there has been a clear increase in interest about adaptive reuse, which is starting to emerge as a new, independent scientific discipline . In scientific literature, it is discussed mainly in publications devoted to the protection of cultural assets and approached as a domain relating to the restoration of monuments, or analysed through the prism of strictly architectural issues, and therefore focusing mainly on attempts to identify design methods that could be used to build relations between the original structure and its contemporary transformation . The novel concept is research on the “vernacular adaptation” of built heritage and its role as a catalyst in the transformation of the formal adaptive practice . There are also attempts to create a model for developing adaptive reuse strategies for architectural heritage , as well as a holistic view of the phenomenon of adaptive reuse as a consequence of social changes and changes in the understanding of heritage and its protection .
In heritage conservation practice, adaptation does not necessarily mean the functional change of a building. The Burra Charter clearly states that adaptation means changing a place to suit the existing use or a proposed use  (art. 1.9; 1.10). At the same time, it is mentioned that such changes should only be allowed if they have limited impact on the cultural significance of the place. The fundamental document that formulates recommendations is the Venice Charter (1964), which, although not focusing on the adaptation process itself, does state that the purpose (use) of the architectural monuments “for some socially useful purpose”  (art. 5) promotes their conservation and is therefore desirable, provided that it does not entail changes in the layout and design of the building. An interesting point of view in the context of the issues discussed above can be found in the Recommendation concerning the Safeguarding and Contemporary Role of Historic Areas, from 1976 (Warsaw-Nairobi) . This document points out that the fundamental elements of town planning and land development are both the protection of historic areas and their integration into modern social life. Such areas should be approached from the perspectives of both an important historical and social testimony and the daily environment, and that gives them an additional “humanistic dimension”. Similar ideas are also mentioned in later documents, and their interpretation is slightly more comprehensive. For example, the 1985 Convention for the Protection of the Architectural Heritage of Europe declared support for the use of protected properties in light of the new uses and, where possible, for the adaptation of “old buildings to new uses”  (art. 11), provided that access to cultural objects should not affect their architectural or historical nature, whether in terms of the object itself or the environment in which it is located. The 1987 ICOMOS Charter for the Conservation of Historic Towns and Urban Areas (known as the Washington Charter), which refers to the 1976 Recommendation and other international documents, underlines that the protection of historical towns and areas entails the application of the measures necessary for their “protection, conservation and restoration” and “their development and harmonious adaptation to contemporary life”  (Preamble and definitions). There is a provision in this Charter which states that the introduction of “elements of contemporary character” into an object may possibly enrich it, provided that these do not interfere with “the integrity of its structural harmony”.
These assumptions were later confirmed in the 2011 Valletta Principles for the Safeguarding and Management of Historic Cities, Towns and Urban Areas . However, the document recognises functional changes as a significant threat. Interestingly, these are seen as relating mainly to changes concerning intangible assets, and not to potential interventions in the material architectural tissue. The outflow of the indigenous community might result in the disappearance of local traditions and customs, leading to the erosion of the original character of a place and, possibly, its identity (2.c). The social aspect is being strongly and evidently emphasised, as well as the need to counteract processes such as gentrification and the reduction of historical districts to tourist attractions deprived of normal, everyday life. These documents clearly show a perception of the architectural heritage not only as a protected artefact of the past, a historical testimony, but also an important element of contemporary social life.
In adaptive reuse, as highlighted in the 2010 Charter for Conservation of Places of Cultural Heritage Value (among others), the new function should be compatible with the original . According to the authors of the document, this means that it should be compatible with the cultural values of a place, so that its authenticity and integrity are not adversely affected. It is also emphasised that although adaptive reuse might result in interference with the architectural tissue, for example reconstruction and extensions, these should not dominate the original form and structure. Therefore, the inappropriate juxtaposition of forms, scale, colours or materials should be avoided. The abovementioned documents define and broaden the approach of the Venice Charter to adaption, putting the emphasis on cultural and social values, although de facto they do not always make it more specific.
This article uses the term “adaptive reuse”, which is already widely popular in the literature. It is used by scientists from various fields, including architects, art historians, engineers and representatives of urban studies . By combining the prefix “re” with the word “use”, the aspect of a new function of a building and its reintroduction into the city is highlighted.
The possible issues that can emerge when adapting architectural heritage to its new function are presented in this article from a wider perspective, as an important component in the process of reconstruction of social identity, regeneration of urban tissue and improvement in quality of life, as well as building a positive image of a city. The methodology was based on the juxtaposition of theoretical research with the critical analysis of selected projects, as case studies. Important research material included conservation concepts (primarily changes in the understanding of the social meaning of heritage) and source documents (historical documents as well as official records of Łódź authorities). The historical-interpretive method combined with the case study enabled a comprehensive analysis of the ongoing processes and their conditions. Thanks to the research on international documents devoted to the protection of the architectural heritage, the observed phenomena were placed in a broader context. The main aim of this article is to contribute to a new theoretical understating of the role and importance that adaptive reuse can play in a modern city and its reconstruction after a disaster. The adaptive reuse is seen not only as an opportunity to preserve individual objects characteristic of the urban landscape, but also as an important element of sustainable development, in terms of ecology, economy and socio-cultural aspects.
Figure. Izrael Poznanski's 19th-century industrial complex adapted to the new commercial and entertainment function.
Processes related to the adaptive reuse of architectural heritage may be seen as being in line with contemporary trends, including the principles of sustainable development , and the creation of cities friendly to inhabitants and the environment, where the reuse of previously developed areas is also important.
Apart from restoring socio-cultural significance, a desirable phenomenon following the adaptive reuse of architectural heritage is also the economic revival of the area. The scope of protection of the architectural heritage has been extended and is not limited to objects of “outstanding universal historical, artistic or scientific value”  (art. 1) or of a significant age, but also covers buildings and architectural complexes of local cultural and social importance. Therefore, the exclusion of all protected architectural buildings and complexes from ongoing city life would cause a kind of “museumization” of large urban areas. The adaptive reuse of the architectural heritage fits well with the assumptions of revitalisation, combining the postulate of taking care of the heritage and its protection with the use of existing architectural resources and adapting them to current social, marketing and economic needs.
In the case of large post-industrial areas located in downtown areas, adaptive reuse also provides a valuable opportunity to include previously closed and inaccessible areas in the city’s life. The actions undertaken, however, must be carefully considered. The clarification of the new social and economic role and cultural significance prevents the fragmentation of urban space and the violation of its historical layout as a result of adaptive reuse. Regardless of the adopted functional programme (cultural, commercial, etc.), the process of revival and adaptive reuse of large post-industrial complexes must be combined with a consistent, prospective and comprehensive reflection on the city and the processes, transformations and metamorphoses taking place in it, as well as their impact on the architectural and urban planning, but also on the social changes they initiate.
Introducing a new function into the old walls is, in many cases, the only way to save the degrading architectural heritage of the city and thus preserve its identity and architectural continuity. However, the excessive aestheticisation of the place and historical buildings, aimed primarily at meeting contemporary requirements, may lead to a loss of historical values. In the case of significant modifications of the architectural tissue and the aestheticisation of space, the former objects become more of a visual sign than a real testimony of the past and a carrier of collective memory. A clear tension arises between authenticity (of tangible and intangible values) and the introduced change. The loss of the original function alone creates new contexts and meanings. At the same time, the introduction of a different function adapted to current needs provides it with a new, contemporary meaning.
In this context, the issues connected with the adaptive reuse of architectural heritage are also associated with the idea of sustainable development, referring first of all to its key statement about guaranteeing a development that satisfies the needs of the contemporary generation, without compromising the chances of future generations to satisfy their needs . In this respect, with regard to the architectural heritage, the most important thing is to introduce changes that will be satisfactory for contemporary society and at the same time will not exclude the future understanding and perception of the artefact as a testimony of the past.
The conviction—formed in the 19th century and established in the 20th century, by modernists, among others—about the need to clearly distinguish between the “old” and the “new” led to a specific tension or even conflict between modern architectural designs and concepts and the architectural heritage existing in cities. However, since the end of the twentieth century, concepts that are closer to the traditional approach accompanying communities over the centuries have become more visible. Before the revolutionary changes in the approach to the past initiated at the turn of the 18th and 19th centuries, buildings from the past were preserved and maintained for as long as they were of use. This approach did not rule out giving selected monuments a special meaning, which, after Alois Riegl, can be described as “commemorative value”. At the same time, the “memory” of times, events or figures from the past, as well as respect for them, did not exclude the interference with the original material substance of the monument, its modernisation or functional or aesthetic change.