Technical Management of Residential Buildings—The Idea of Implementing Predictive Approach Elements for Sustainable Maintenance

Abstract

This article presents the issue of sustainably managing of the technical maintenance of multi-family residential buildings with diverse characteristics. The results of this research conducted on entities managing real estate in a real estate market in the city of Poznan (0.5 million inhabitants) are presented along with comments, with attention drawn to the commonness of the approaches used in building maintenance management. Of particular note is the reactive approach (which, in extreme cases, turns out to be unreliable and does not guarantee the absence of restrictions in the possibility of using housing resources) and the practical lack of application of the proactive-predictive approach. The main features of the approaches used in management are presented, and selected examples are used to demonstrate the advantage of proactive approaches in the economic, social, and environmental aspects. This article presents arguments for the implementation of proactive management strategies, including predictive maintenance. Due to financial and technical limitations, our model is presented in support of the technical management of buildings with predictive elements. The model is based on case-based reasoning (CBR). An important element of the model is the knowledge acquisition system, which uses mandatory technical condition inspections resulting from the applicable law and inspection protocols created as a result. The proposed model is not as expensive as using full predictive maintenance using sensor infrastructure devices, and at the same time allows advanced reasoning and solves the practical problems of maintaining housing resources.

1. Introduction

The maintenance of residential buildings is an issue that is extremely important for society and its development [1,2]. One of the basic social needs of man is to provide shelter, i.e., a housing stock that provides appropriate comfort for use and regeneration. Numerous scientific studies have examined the relationship between the development of housing construction and the development of society. It is noted that the development of housing construction and its maintenance at an appropriate technical level has a direct impact on the economic stability of society, which translates into a greater sense of social security [3,4]. Along with the development of housing construction, an increase is observed in the following: population density, the development of external infrastructure, including public transport, and the development of industry. Contemporary research focuses on how the development of housing construction contributes to the sustainable development of cities through the use of ecological materials, renewable energy sources, and spatial planning that minimizes the negative impact on the environment [5,6,7]. However, the development of housing construction which, as indicated earlier, stimulates the development of cities, is not the only consideration in this topic. The sustainable maintenance of existing housing stock, as indicated by the conducted research and personal observations, is an extremely important and practical issue. It turns out that in maintenance issues, the concept of sustainable maintenance can be defined in terms of economic, environmental, and social aspects. The authors define the concept of sustainable maintenance as a model for the technical management of a building, in which the aim is to ensure the fitness of the object, the building during its operation, without significant restrictions to its use (which corresponds to the social aspects), while maintaining the existing building substance for the longest possible time (which corresponds to the environmental aspects) and preserving the evenness of maintenance costs (which corresponds to the economic aspects). At the same time, within the framework of the conducted research on approaches to building management, the economic aspect was found to be of high importance, followed by the social and environmental aspects. Such a hierarchy seems to result from the regional conditions in which this research was conducted. Awareness of the significance of environmental issues in this aspect of sustainable development combined with the inevitable development of mechanisms, (including in the area of shaping the maintenance policy), may over time cause changes in the hierarchy of the above-mentioned factors. One of the ways to support a solution for the maintenance problems of existing residential buildings, including through a sustainable approach to management, is to appropriately modify the approaches used in the technical management of residential resources. Again, referring to the research conducted, it is possible to indicate a fairly capacious area for modification and improvement within the infrastructure management process.

2. Approaches Used in Shaping the Maintenance Strategy

The appropriate development of the maintenance strategy determines the proper technical condition of the building. Related to this, among other factors, is ensuring the safety and comfort of use of the housing stock [8,9,10] so that it meets social expectations. It should be noted that the development of the maintenance strategy is also, and perhaps primarily, related to economic factors, as these are responsible for decisions made in undertaking any maintenance activities. The distribution of necessary financial outlays for the implementation of the maintenance strategy depends on the adopted strategy. Figure 1 presents the basic classification of maintenance strategies.

In the context of the strategies discussed later in the article, Figure 2 presents the conceptual distribution of financial outlays during the implementation period and long-term use of the building. At this stage, the authors do not have actual data on the distribution of financial outlays, and those presented in Figure 2 result from cost simulation analyses based on the analysis of the actual costs of maintaining a multi-family building, but in a much shorter time perspective.

The reaction strategy is, as indicated by the research results discussed below, the basic strategy for maintaining facilities [12,13,14,15]. It is based on a rather simple approach; the occurrence of a reaction will only be as a result of the occurrence of an event forcing it. In the case of building maintenance, the observed processes related to the implementation of the reaction strategy occur only as intervention processes and take place in situations in which there is already a noticeable deterioration in the technical condition of the building, for example, a failure of its element. Only such events force a response in the form of implementing renovation works. Unfortunately, it often turns out that the renovation works that were forced by the event are not planned, but above all, there is a lack of economic preparation for their implementation. It is noted that in the case of the reaction strategy, as long as there are no circumstances forcing a reaction, this strategy does not generate costs, but when a circumstance forces a reaction to occur, there is a risk of costs. These costs are often significant, may include technical problems, or may require the part of the facility to be excluded from use. When observing the actual management process using the reactive strategy, it can be seen that the costs associated with implementing adequate responses are significant and include not only possible renovation works but also costs resulting from the consequences of limitations occurring at this stage (including the provision of alternative premises).

The implementation maintenance strategy is based on previously established planned and preventive actions for the facility [16,17]. This strategy consists of establishing a fixed and “rigid” schedule for performing specific maintenance and repair works, which should guarantee the full fitness of the building for use at the operational stage. The weak point of this strategy is the relatively high cost of maintenance and repair activities undertaken in accordance with the previously established schedule. The established schedule is not based on the current and actual technical condition of the facility resulting from, for example, a technical condition examination. Rather, it is based on the so-called normative durability of elements, taking into account that the period of use corresponding to the periods of normative durability will not be exceeded in operation, and the maintenance and repair activities will be undertaken well before the expiry of the normative durability. It is noted that the normative strategy, in comparison to the reactive strategy, anticipates the event that forces the undertaking of maintenance and repair activities, potentially preventing its occurrence (the exception may be incidental events resulting from, for example, a sudden change in the manner of use, the impact of above-average external factors, or acts of destruction). Within the implementation strategy, normative durability is taken into account, which does not always reflect the actual condition of the elements of the facility. As a result, works are undertaken that are often not adequate for the actual technical condition, and a case may occur in which some of the works will still be unjustified, and some could be significantly limited.

The group of strategies classified as proactive seems to be a more effective approach to the management and maintenance of facilities. Proactive strategies allow appropriate actions to be taken which are adapted to the actual need in such a way as to simultaneously ensure the fitness of the facility and, at the same time, prevent its use from being limited. As can be seen from Figure 1, proactive strategies are classified into preventive and predictive approaches. In both cases, the common element is knowledge of the condition of the facility and making appropriate decisions based on this knowledge. The preventive approach to building maintenance consists of cyclical supervision of the technical condition by conducting inspections and reviews [18,19,20,21]. In Poland, conducting inspections of buildings, including residential buildings, is a legal obligation of owners and managers [22,23]. It is assumed that reliably conducted inspections and reviews should, in addition to knowledge of the current condition of the building, enable recommendations for necessary maintenance and repair activities, which should be implemented in order, depending on the priorities assigned to them. Mandatory inspections and controls resulting from applicable legal regulations are organized according to the type of building, and while their frequency varies, they occur no less than once a year. Implementation of post-inspection recommendations should ensure the maintenance of proper technical conditions and thus ensure the fitness of the building for safe and unrestricted use. As in the case of the implementation strategy, the preventive approach does not exclude the occurrence of incidental events, the effects of which may reduce the fitness of the facility. However, bearing in mind that a change in the technical condition of a building does not occur abruptly but is spread over time and signaled by earlier symptoms and minor defects, it can be assumed that the inspections carried out will allow for the proper identification of damage before the occurrence of a critical event causing a significant limitation in the use of the facility.

The predictive approach is an evolution of the preventive approach, which uses the development of technology and automation [24,25,26,27,28,29,30]. It makes assumptions, based on data acquisition systems, on the condition of the facility, building forecasts of the occurrence of changes in this condition and related possible events causing limitations in the use of the facility so that they can be actively counteracted. For this purpose, models are built using various inference techniques based on available data regarding the facility. Thanks to the development of technology and the implementation of monitoring (e.g., visual, sensory), the use of automated data acquisition is assumed (Figure 3). Similarly to the preventive approach, it is possible to take appropriate actions in advance to exclude possible disruptions in the use of the facility, reduction of usability, and reduction of costs of both the actions taken and the potential for negative consequences of possible events. The use of automation elements and numerical modeling is a feature of the predictive approach that distinguishes it from the preventive approach.

In the authors’ opinion, proactive approaches can be described as sustainable. With reference to Figure 2, the lower maintenance costs are noted above all. This results primarily from actions taken in advance of the occurrence of an event generating high costs and usually associated with a significant scope of renovation works. The actions that occur in the implemented proactive strategies are designed to maintain the building substance in a constant state of usability, thus providing an opportunity to reduce the costs of its replacement. In addition to the positive financial effect, avoiding the necessity to exclude the facility or part of it from use (which carries particular risk in the case of implementing reactive strategies), creates a social effect in addition to a financial one (no costs for replacement construction). In turn, reducing renovation works and maintaining the existing building substance also provides a positive environmental effect because, in connection with construction works and the incorporation of new materials and simultaneous disposal of residues, the negative impacts on the environment are reduced.

3. Characteristics of the Research Region

Poznan is the fifth largest city in Poland (Figure 4). The city has a population of around 540 thousand, while the Poznan agglomeration is inhabited by around one million people. The city and agglomeration are a strong economic center. The automotive and machinery, pharmaceutical, and food industries have developed there and, in recent decades, the IT industry has also developed. This gives an impulse to the development of housing, for which there is a constant demand. For several years, there has been a dynamic development of the agglomeration and suburbs, while the city center is characterized by stagnation and even the phenomenon of “dying away”.

The size of the city and the developed industry have led to large clusters of housing estates and housing resources of various ages in the urban and agglomeration areas, with varying constructions, technologies, and technical conditions. It is estimated that there are about 70–80 thousand residential buildings in Poznan, which translates into about 280 thousand residential premises. It is noted that the strict center is usually the urban development, which most often dates from the beginning of the 20th century to the 1950s. Locally, there are new buildings that complement the empty spaces between old buildings with architecture similar to those dominant in the city center. Outside the center, buildings constructed in the 1960s until the late 90s dominate. These are multi-family, multistorey buildings constructed using industrialized technologies, where the dominant technology is large reinforced concrete slabs. In addition, smaller buildings are constructed using traditional masonry technologies. In the Poznan agglomeration and in the city’s suburbs, the dominant type of residential development is single-family housing, as well as smaller multi-family housing constructed using traditional technology.

Analysis of statistical data indicates that the housing market in Poznan and the entire province is characterized by dynamics dependent on external factors, and housing production remains at a level higher than the average for the entire country (Figure 5).

The listed buildings have different forms of management (Figure 6) [31,32]. The management of single-family buildings is the responsibility of their owners. In the case of other forms of development, other forms of management can be found. In particular, the boards of housing communities dominate in the case of multi-family buildings both in the city center (old tenement houses) and in the case of several-year-old buildings located outside the center and in the agglomeration. In parallel to housing communities, a significant part of multi-family buildings is managed by a professional property manager. This is an entity with appropriate qualifications, experience, and insurance, that takes over most of the duties related to management from the co-owners. This entity currently does not have to have formal confirmation of qualifications by means of a state exam and license. In addition to the above, a fairly common form of management is the administration at a housing cooperative. Housing cooperatives are entities whose origin is related to the construction stage of buildings currently under their management. Housing cooperatives are a form of management used in buildings belonging to cooperative members. The cooperative, as a legal entity, manages the real estate of its members, taking care of the maintenance of the buildings, conducting renovation investments, and administration. The members of the cooperative have apartments under the principles of cooperative ownership rights or tenancy rights (currently this form is being abandoned in favor of ownership transformations) and have the right to participate in decisions made by the cooperative’s bodies (e.g., supervisory board, general meeting). A specific feature of housing cooperatives is that they most often manage buildings with the same construction technology, comprising large reinforced concrete panels. This is justified by the fact that this technology was dominant in the period of construction of the buildings currently under their management.

4. Analysis of the Results of the Conducted Research

In the years 2021–2023, research was conducted on entities managing residential buildings in the city of Poznan and the Poznan agglomeration, as well as research on the technical condition of selected residential buildings and the expenditures made in recent decades to maintain their condition. The first of the studies was aimed at identifying the approaches and tools used in building management, as well as the problems faced by managers. This study was conducted through a survey and personal interviews. The research covered a total of 59 entities, with the profile of manager activities covering not only residential buildings, although they constituted the majority of the managers’ portfolio, but also cases in which the entities studied managed commercial facilities, such as sports centers and warehouses (Figure 7).

One of the key issues covered by the study was the identification of strategies used in the management of residential buildings. As expected after the initial analysis and observations of the actual condition of the buildings, the dominant approach in management was the reactive strategy (Figure 8).

The justification for such a large share of the implemented reactive maintenance strategy seems to be primarily based on the seemingly low costs of maintenance activities. As it turns out, this apparent cost saving and the related reactive strategy is the effect of the decision-making of property owners who prefer low rent to the certainty of the facility’s reliability, as well as the obligations of property owners to the applicable law regarding the proper maintenance of the technical condition of the property (Figure 9). In the authors’ opinion, this is a negative phenomenon, although quite common.

In addition to the surveys, research was conducted on the effectiveness of maintenance and repair activities carried out by managers, depending on the maintenance strategy used. As the results from previously presented research show, the dominant approach in the management of residential buildings is the reactive approach. Only in selected cases are other approaches used, and from the point of view of the rationality of activities and effects, the proactive approach seems to be optimal. At the same time, it was not found that the predictive approach was used in any case, and the only representative of the proactive strategy was the preventive approach. As a rule, in the authors’ opinion, such an approach should be dominant, because in Poland there are legal foundations for it related to the obligation to conduct cyclical inspections and reviews, as a result of which authorized engineers, after identifying the actual technical condition, formulate recommendations constituting guidelines in the scope of the directions of maintenance and repair activities. As indicated by observations, these orders are unfortunately not implemented, because their execution is related to the provision of appropriate resources. Unfortunately, the prevailing view is that it is not worth taking action unless it is absolutely necessary (related to, among other things, significant operational restrictions). In the event of an absolutely necessary renovation, it turns out that the scope of work is so large and the amount of resources required so large that it is not possible to provide them in a given period. Figure 10 presents the actual cost distribution resulting from historical accounting data and the potential cost distribution that would occur if the recommendations resulting from cyclical technical condition inspections were successively implemented. The case in question concerns a multi-family building in an urban development dating back to around 1925. The actual cost distribution presented in Figure 10 shows that over a long period covering 80–90 years of the building’s use, practically no costs were incurred for renovation works, despite the fact that the post-inspection reports prepared for this building recommended their implementation. As a result, at the turn of 2018 and 2019, there was an event of a significant deterioration of the wooden roof structure, which caused part of the building to be excluded from use and incurred significant costs for a major renovation. In addition to the costs of the major renovation, there were additional costs related to the preparation of technical condition expert opinions and the provision of three replacement premises in connection with the exclusion from use. It should be noted that the owners were not prepared for such large expenditures on these necessary actions. In addition, Figure 10 presents the potential distribution of costs that would occur if the post-inspection recommendations were successively implemented in the analyzed period. If management based on a proactive strategy was implemented there would be a high probability that, at the turn of 2018 and 2019, an event causing such troublesome effects would not have occurred. In addition, the usability of the building would have been higher as a result, and there would have been no need to exclude part of the building from use.

Comparing the costs currently incurred by property owners with the potential costs that would occur if the post-control recommendations were implemented successively in the analyzed period, a clear advantage of the proactive strategy can be seen, which is confirmed by basic statistical indicators. The distribution when using the proactive strategy is even more, with less dispersion of results (verifying the standard deviation indicators), including the average cost value of 8642 Euro, while the total sum of costs in the analyzed period is half of the costs currently incurred (i.e., 181,477 Euro). The asymmetry indicator indicates that in both analyzed cost samples, values lower than the average prevail. Nevertheless, looking from the perspective of the median dividing the population in the proportion 50%/50%, and considering current costs for over 50% of the years, the value of costs exceeded 1968 Euro, and potential costs were approx. 6613 Euro (

Table 1. Statistical measures for the analyzed distribution of actual maintenance costs of a multi-family building from the 1920s and potential costs in the years 2001–2021 (own study).

	Actual Cost Distribution	Potential Cost Distribution
Mean	€19,090	€8642
Standard Error	€11,078	€1312
Median/Quartile 50%	€1968	€6613
Mode	N/D	€6613
Standard Deviation	€50,768	€6010
Sample Variance	€2,577,375,600	€36,124,695
Kurtosis	8.41	1.74
Skewness	3.05	1.11
Range	€191,031	€23,839
Minimum	€905	€1903
Maximum	€191,935	€25,742
Sum	€400,888	€181,487
Quartile 25%	€1323	€2935
Quartile 75%	€5439	€12,323
Counter	21	21

). This means that in the case of the proactive strategy, it is necessary to assume costs for necessary renovation works at a slightly higher level in individual years. A similar conclusion can be reached by analyzing the values of quartiles, whereby for 25% of the years considered the value of costs exceeded 5439 Euro for current costs, and 12,323 Euro for potential costs. In the case of assuming the amount of costs for renovation works at the level of potential costs, the excessive culmination of costs indicated in Figure 10 would not occur.

Moreover, by analysing the differences between current costs and potential costs, it is possible to indicate the average value of costs that can be assumed as a buffer in relation to current costs when applying the preventive strategy (Figure 11,

Table 2. Statistical measures for the analyzed difference between actual maintenance costs and potential costs in the years 2001–2021 (own study).

	Difference Between Actual and Potential Cost
Mean	€5658
Standard Error	€1649
Median/Quartile 50%	€3774
Mode	N/D
Standard Deviation	€7187
Sample Variance	€51,650,735
Kurtosis	1.06
Skewness	0.79
Range	€30,387
Minimum	€6200
Maximum	€24,187
Sum	€107,502
Quartile 25%	€1041
Quartile 75%	€10,179
Counter	21

).

5. Possibilities of Improving the Management Process

By critically analyzing the management approaches used and the results of their application, which is particularly visible in the earlier case study of a multi-family building, for which the cost distribution is presented in Figure 10, the possibilities of improving the technical management process were indicated. The aim of the improvements was primarily to predict and counteract events that could cause significant restrictions in the use of buildings, such as a high and sudden demand for resources, as well as a wide range of necessary renovation works, which would require significant interference in the building substance and its replacement. This is possible by carrying out renovation works of a smaller scope but preceding the categorical necessity of their execution. It was also noted that by modifying the applied approach, it is possible to move from management through a reactive strategy towards proactive strategies, including predictive ones. This will allow for meeting the premises of sustainable management. Referring to the basics of predictive maintenance, including the model presented in Figure 3, it should be noted that predictive maintenance requires systems that allow for condition monitoring, sensor systems, and data acquisition. Examples of such a system are described in [33,34,35,36,37]. These are complex systems, the implementation of which in the case of existing residential buildings with defined technical wear and tear is not economically justified, and from a technical point of view is difficult to implement. Active condition monitoring systems are expensive, while their installation (excluding elements for communicating wirelessly) requires significant modernization of the building structure. Is it therefore possible to implement a predictive strategy for the technical maintenance of residential buildings?

The solution to the posed problem seems to be a modification of the preventive approach, i.e., in accordance with Figure 1, next to the predictive approach, a representative of proactive strategies. As part of the proposal to improve the management process, it is proposed to use review and control procedures that are performed in residential buildings in connection with the legal obligation [22,23,38], which would replace active monitoring of the building’s condition. The justification for this results not only from economic and technical factors but also from the fact that changes in the technical condition of residential buildings are usually not sudden changes. Inspections and checks are a fundamental element of the preventive approach. As a result of the conducted inspections and checks, authorized engineers prepare reports that declare the detailed technical condition of the building and make recommendations for necessary actions. Post-inspection reports constitute documentation of the building’s operation, indicating changes in the technical condition. Recommendations resulting from post-inspection reports should constitute the main direction of the renovation policy for managers. These documents are currently created in paper form and are descriptive in nature, while the description used is individualized. This limits the possibility of comparing reports or sometimes even interpretation. The proposal that would enable the process of obtaining data on the condition of the building is based on the standardization of the post-inspection report, unification of the dictionary used regarding the classes of objects and their elements, signs of wear and tear, and the condition of the object. In addition, it seems necessary to develop a software tool that would generate a report in a standardized form and would also report to the data storage unit. As a result, it would be possible to build a case database, where the main classifier would be the technology and age of the building. The built case database would enable case-based reasoning (CBR) for new cases (buildings not included in the database) in the scope of forecasts regarding changes in the technical condition and necessary expenditures for its maintenance. Therefore, a tool would be created to support the management process based on a mixed preventive and predictive approach (where the preventive approach element is the controls and inspections, additionally resulting from the applicable law, and the preventive approach element would be a database of cases with a mechanism for their selection supporting the inference regarding potential changes in the building condition and necessary outlays), which could be developed during use by increasing the number of cases in the database. Figure 12 and Figure 13 present a diagram of the modified approach.

The proposed approach seems to be applicable in supporting management at the strategic level. Therefore, the correct functioning is based on the assumption that there are no crises or extreme situations (e.g., war conflicts or natural disasters). In the authors’ opinion, unpredictable and incidental situations require actions corresponding to the operational level of management, which is difficult to take into account at the strategic level.

Currently, as part of this research, a database of cases has been built, including buildings constructed using large-panel reinforced concrete technology. The database was created based on the process of digitizing post-inspection protocols in paper form. In order to reduce the size of the database, the text-mining approach [39,40,41] was used. The database contains 54 cases of buildings for which historical changes in the technical condition and financial outlays incurred over the last ten years of the buildings’ operation have been taken into account. Due to the limitations of the existing database in terms of building representation, its use is possible only and exclusively for the purposes of producing forecasts for buildings constructed using large-panel reinforced concrete technology. Based on the knowledge of changes in the technical condition of similar buildings and the necessary financial outlays that have been incurred, it is possible to conduct inferences and forecast further changes in the technical condition and the necessity of outlays for buildings with similar construction technology and similar age of operation. This allows, among other things, the possibility of preparing the necessary actions and outlays in advance, which enables sustainable building management.

When considering the possibilities of using elements of the measurement infrastructure in supporting the technical management of the building, attention was paid to the systems of measuring the consumption of media, such as water, electricity, and heat, which are present in practically every building. These systems increasingly often enable remote reading of the status of measurement devices. Based on the analysis of long-term readings, whether using statistical tools or more complex clustering methods, it is possible to detect changes of an anomalous nature, which would signal the occurrence of potential irregularities in the functioning of the building installation. This would allow for earlier identification of possible damage and failures. Another solution that is potentially possible is the use of video monitoring systems existing in some buildings and their automated analysis in terms of changes in the condition of the building substance. However, in this case, it should be noted that the video systems installed in buildings are usually concentrated in selected parts, most often communication paths, where there is movement of people for whose safety they are responsible. This does not provide the possibility of effective monitoring of the condition of the building substance. Another possibility for obtaining data related to the condition of the facility is to use simple wireless communication devices classified as the Internet of Things (IoT). The presented approaches using common elements of measurement systems or video monitoring seem to be important in operational management, while the previously discussed approach is more suitable for management at the strategic level.

6. Conclusions

It seems obvious that the proper maintenance strategy for residential buildings, which is an important part of building management, is a key element guaranteeing the fitness of the building for full and safe use. Thus, it is also an element guaranteeing sustainable management in the economic, social, and environmental sense. The research conducted covering the city of Poznan and the Poznan agglomeration, which can be generalized as a representative of a larger number of cities, indicates that the dominant approach to the maintenance of residential buildings is the reactive approach, which, in the authors’ opinion, does not correspond to the sustainable approach. This approach does not guarantee fitness, but on the contrary, generates the risk of events, the impact of which has consequences in terms of usability restrictions, high costs, and the need to perform much larger scopes of work than was possible in the period preceding the occurrence of the event. The predictive maintenance strategy indicated as a model has little chance of being popularized in the maintenance, especially in existing residential buildings, mainly due to economic factors and technical limitations of the implementation of monitoring infrastructure. Perhaps in the case of new buildings, especially those of key importance such as public utility buildings (e.g., large communication hubs) where at the design stage attention was also paid to issues covering the operation stage, and the monitoring infrastructure was taken into account, there are full possibilities for implementing the predictive approach. Therefore, in the case of residential buildings, it is reasonable to improve by modifying the approaches used in maintenance. In the authors’ opinion, a mixed approach using existing control and inspection procedures for acquiring data about the facility, which are an element of the preventive approach and at the same time result from the applicable law, combined with standardization of the forms of post-control reports and digitization, can be an alternative to costly monitoring systems. A case base categorized by technology and age of buildings can be a valuable resource which allows conclusions to be drawn for new cases. Thus, it is possible to predict, based on the case-based reasoning system, the technical condition and necessary expenditures, so as to avoid events with negative technical, economic, social and environmental effects, or to prepare for them appropriately in advance.