A group of old apartment houses with the age over 100 years (that is those carried out before the First World War) takes an important place in polish building resources. Technical maintenance of apartment houses, traditional methods erected, is nowadays and will be a valid problem in the nearest future. The results of the work refer to the general population, estimated for 600 objects, that is about 20% of municipal downtown apartment houses in Wrocław.

The purpose of the research was to identify an influence of widely considered maintenance of apartment houses on a degree and intensity of their elements’ deterioration. The goal of the work has been fulfilled by symptoms’ analysis of declining of inspected elements’ exploitation values, that is identification of mechanics of their defects arising.

The range of the work has required creation of original qualitative model of pinpointed defects and its transfer into quantitative one. It has made possible to analyse the reason - effect phenomena „defect - technical wear” relevant to the most important elements of Wroclaw downtown district’s apartment houses. The research procedure has been conducted in accordance of fuzzy sets theory which made possible to describe qualitative model of pinpointed defects and its transfer into a quantitative one.

The paper contains synthetic and analytical test results and model solutions for technical maintenance and wear problems of apartment houses traditionally structured. The crucial methodological aspect of the research is striving to minimize the subjectivity of expert assessment while technical investigation of old buildings. The cause and effect between the occurrence of damage to the elements of the rental houses, treated as an expression of the conditions for their maintenance, and the size of the technical process of wear of these elements was determined on a representative, purpose-appropriate, sample of 102 residential buildings erected in the second half of the 19th and early 20th centuries in downtown Wrocław (Poland) district. Rational maintenance of existing buildings is nowadays significant issue for their proprieties. Therefore, there is constant need to find a research method that may lead to well thought out building maintenance management. The goal of undergone research was to search influence of apartment houses maintenance on the grade and intensity of their deterioration. As to fulfil the research objective the group of engineers identified symptoms of the technical wear growth, which means performed identification of causes and effects responsible for the defects appearance. The range of the work demanded elaboration of a new qualitative model of detected defects and its transfer into a quantitative model. Therefore, such approach enabled to establish the reason - effect connection ‘defect - technical wear’ related to the crucial structural parts of investigated apartment houses.

This research paper presents the results of the analyses of the course of technical wear over time carried out for residential masonry buildings located in the mining area of the Lublin Coal Basin (LCB). As a result of the conducted analyses, models of the course of technical wear over time were obtained for the entire building development and for groups of buildings, taking into account the conducted renovation works and preventive structural protection. By comparing the parameters of the developed models, statistically significant differences in the course of technical wear resulting from the quality of maintenance and the use of preventive measures were identified. In addition, the durability of individual groups of structures was estimated and compared. Based on a comparison of the course of technical wear of 22-year-old building structures, unrenovated and with similar structural and material solutions, it was found that the rate of increase in technical wear after 50 years of use is on average 3.5% lower than in the case of unprotected buildings. In addition, the use of preventive structural protection extends the durability of the analysed building structures by an average of over 13 years. The obtained results may e.g. help owners or managers optimise the Maintenance Management of building structures.