To create an effective ventilation of the foundation it is necessary to connect the hollow space to the outside: this can be done creating openings of diameter 80/120 mm in the perimeter beams of the foundation every 3.5 to 4.0 m; the required connection PVC pipes and metallic anti-intrusion grids must be considered. The ventilation openings must be placed at a higher level on the southern face of the building (warmer side) vs. the northern face (colder side), in order to create a natural stack effect. Any portions of the hollow space separated by foundation beams should be connected to each other by openings as described above.