"Wiertelnicy" - those were City officers appointed by the City Council to oversee the construction industry in the old Krakow. Preserved in the state Archives are the City books of records that contain minutes and rapports regarding the activities of the "Wiertelnics" - often referred to as the "construction police" or as it probably would be more adequate the old-time city engineers. The "wiertelnics" conducted site reviews. The preserved documentation of their activities such as divisions and subdivisions of real property; preformed estimates of value of real property; damage assessment (particularly, as it was pertaining to border or division walls, and prescription of construction works that were necessary to ensure building and construction safety constitutes an very important source of historic documentation in regard to city engineering as it allows to follow not only the history of the physical constructions of buildings and dwellings themselves, but also the technology and technical solutions i.e. plumbing or other necessary adaptations needed by particular workshops or craftsmen's sites. It can be observed that some solutions that were used by the owners of the buildings were frequently cost driven and consequently of a very provisory nature. Later on, much greater investments were necessary to avoid imminent "construction catastrophes". The information contained in the City public records of the "Wiertelnic's Deeds" give also some insights that are not directly related to the construction requirements or activities themselves, but were the predominant factors that determined the physical shape of the building or a site.