Current trends towards saving energy and designing sustainable buildings result in most designers focusing on achieving the best thermal parameters, thereby neglecting a careful moisture analysis. Excessive moisture content in building partitions degrades the mechanical properties of materials, reduces thermal insulation properties (which leads to an increase in the demand for thermal energy) and worsens the microclimate in rooms. Modern digital solutions help create appropriate models of partitions that work for many years in good environmental conditions. According to the analysis of air parameters, 1 m³ of air at 20 °C contains approx. 17.3 g of water. When the temperature of the air reaches the dew point temperature, water vapour condenses. The dew point depends on air temperature and relative air humidity; for instance, at the same air temperature of 20 °C, the dew point temperature at 40% relative air humidity is 6 °C, whereas at 90% relative humidity, it is over 18 °C. This means that the higher the value of relative humidity in the room at a certain temperature, the lower the temperature that will cause condensation. The article presents a numerical analysis of the insulation work of flexible materials within the layers of ventilated partitions in an 8-year simulated period of varying environmental conditions. The aim of the article is to analyze different models and variants of ventilated partition operation with respect to the advisability of using a vapour barrier to avoid the problem of destruction of thermal insulation and finishing layers of a ventilated roof.

As climate changes progress we are dealing with violent and excessive environmental actions. However, the impacts of loads acting on a building object caused by unlikely phenomena such as: fire, explosion, flood, vehicle impact, plane impact, excessive snowfall, and excess wind gusts are still being ignored when analyzing the structure of building objects in the combinatorics of loads. The paper presents a multi-criteria approach to accidental actions and analyzes design situations and load combinations in relation to accidental actions. The existing legal acts were used to define the concept of a construction disaster. The authors verified, on the basis of applicable legal acts and design guidelines, individual analysis strategies for ensuring the safety of building objects and divided them into consequence classes of structural damage. They collected and analyzed the number of construction disasters which occurred in Poland between 1995–2019 (25 years) based on the data from the General Office of Building Control. The number of disasters was divided by voivodeships and causes and supplemented with the data on the number of people injured. The article presents the direction of research development that could be undertaken in order to eliminate future catastrophes caused by the omission of the analysis of the impact of accidental actions at the design stage. Statistical analyses were carried out to show whether land use, population density, and weather factors (wind) affect the number of recorded disasters. It has been shown that regions that have preserved the sustainable development of their territories are less vulnerable to disasters resulting from extreme weather events.

The use of layered or hollow floors in the construction of buildings obviously reduces the self-weight of the slab, and their design requires some expertise. In the present work, a sensitivity analysis and numerical homogenization were used to select the most important characteristics of bubble deck floors that have a direct or indirect impact on their load capacity. From the extensive case study, conclusions were drawn regarding the optimal selection of geometry, materials, and the arrangement and size of air voids in such a way as to ensure high stiffness of the cross-section and at the same time maximally reduce the self-weight of the slabs. The conducted analyses showed that the height of the slab and the geometry of the voids had the greatest impact on the load-bearing capacity. The concrete class and reinforcement used are of secondary importance in the context of changes in load-bearing capacity. Both the type of steel and the amount of reinforcement has a rather small or negligible influence on the bubble deck stab stiffness. Of course, the geometry of the voids and their arrangement and shape have the greatest influence on the drop in the self-weight of the floor slabs. Based on the presented results of the sensitivity analysis combined with numerical homogenization, a set of the most important design parameters was ordered and selected for use in the optimization procedure.

Wind action belongs to loads that are environmentally variable. Wind action is included in the basic combination of loads, whereas hurricane wind action is classified as a unique combination. Due to large gusts of wind, the roof coverings of large-scale buildings are exposed to detachment of their cover layer. The article presents the effects of over-normative wind, which occurred on January 19, 2018 and was named the cyclone Frederic/David. The purpose of the article is to show that in design of roof coverings made of large-format materials, such as membranes, it is crucial to accept wind load values properly in order to ensure a right spacing between fasteners. The presented results might be an important contribution to the debate on the necessity for increasing the fundamental value of the basic wind velocity in the perimeter and corner zones of large-format roofs.