The present paper describes a technical-economic analysis of thermomodernization works in multifamily buildings and public utility facilities constructed with the use of both traditional and industrialized technologies (prefabricated large-panel concrete, Zeranska brick), built before 1990. 1441 buildings located in 7 towns were analysed. The energy consumption indicator of the buildings undergoing the analysis was the indicator of heat load demand per cubic capacity, which was established on the basis of site inspections and technical documentation. The obtained results were used in analysing the cost-effectiveness of the suggested thermomodernization works. The following were adopted as criteria of the investment effectiveness: the ‘Simple Pay Back Time’ (SPBT), reducing the amounts of particulate matter and sulphur dioxide polluting the air, and heat load saving (amounting to a few or even several megawatts, which, in the case of a small town, is often sufficient to cover a prospective increase in heat load demand).

This paper presents the possibility for setting heated building foundations at a depth lower than the level of „zero” isothermal line. In order for the foundation not to be susceptible to damage due to its exposure to negative temperatures, an appropriate thermal insulation was proposed. For the suggested thermal insulation - by means of numerical methods - a calculation of temperature distribution in the vicinity of the foundations was carried out. Based on the analysis of the obtained results, an optimal setting depth for insulated foundations was proposed.

The article presents the destructive influence of external factors on building partitions in selected historic buildings made from made full-bodied solid ceramic bricks. The external factors are an additional element that adversely affects the maintaining of historic buildings in a good technical condition, and they are complementary to a number of harmful factors that destructively act upon on such buildings. In order to estimate the range of damage in historic buildings, selected buildings that have been exposed to external factors for a long time in the Podlaskie and Warmińsko-Mazurskie Voivodships were analysed.

The subject matter of this manuscript concerns the analysis and identification of microorganisms that pose a threat to human health and, in particular, mold fungi occurring in historical buildings. Surfaces infected by fungal spores pose a threat to the structure and the health of both visitors to historical buildings and professionals working in them. Research was undertaken to fill in the defects in building partitions with a supplementary layer of biochar in order to eliminate, or partially reduce, the possibility of contamination with and development of harmful mold fungi. In the designed cement mixture, biochar was used as a filler, the task of which was to eliminate the causes that lead to the development of harmful mold fungi. Microbiological analyses of the surface of walls and air in selected buildings were carried out before and after the application of supplementary biochar layers. The inhibitory properties of the material used against the presence and growth of mold fungi were observed. The average number of microorganisms isolated on the tested partitions decreased by between 70 and 100%. As a consequence, the use of this material significantly influenced the air quality of the rooms, which is important for protecting the health of people at work, as well as those visiting historical buildings.