Concepts of remedial treatments of historic buildings using ventilated floors, with a few exceptions, are with considerable popularity preferred by the representatives of monument protection. The fact that they require small interventions in the masonry is of great benefit for compliance with the methodology of cultural heritage protection, as is the fact that such interventions do not compromise the structural analysis of buildings. These concepts have gained great popularity also because they can be considered kind of a "return" to historical example. With these technologies we return to the methods and principles that the ancient Egyptians were already familiar with. The paradox is that these methods are used for many centuries, until today they are only proposed on the basis of empiricism. There is no proven relationship and calculation nor any literature that would address the airflow in floors, ventilation ducts and galleries around the base building construction. The remaining problem is the draft of air cavities in general. The exact calculation of airflow in the underfloor cavity has not yet been formulated. To assessment the airflow in the air cavity the recently often used CFD simulations can be employed. Using simulation, respective design cycles, which shall be ultimately verified by laboratory experiments and also by in situ measurements, may be accelerated.