**6. Conclusions**

Walls are vertical partitions of buildings, which have been improved for many years not only to provide them with the required load-bearing capacity, but also to provide them with adequate protection against the external environment. The article, giving the example of a few selected external partitions of buildings, recalls the solutions applied over the last 200 years and a short history of their evolution to modern requirements. From a physical point of view, attention is drawn not only to the permanent problem of heat loss accompanying the building envelope, but also to the condensation and accumulation of moisture within it. The use of newer technologies did not solve this problem at all, and even showed how little is needed to damage such a structure the more complicated the structure is. New materials have improved the thermal insulation of partitions, but at the same time have made them more sensitive to both external and internal moisture, including condensation.

**Author Contributions:** Conceptualization, D.B. and L.B.; methodology, L.B.; software, D.B.; validation, D.B., L.B., Z.M. and K.R.; formal analysis, L.B.; investigation, D.B., L.B. and Z.M.; resources, D.B., L.B. and Z.M.; data curation, L.B. and D.B.; writing—original draft preparation, L.B. and D.B.; writing—review and editing, L.B.; visualization, L.B. and K.R.; supervision, D.B. and L.B.; project administration, L.B.; funding acquisition, Z.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
