Low external temperatures and lots of rain can saturate the air inside buildings with steam, especially in humid places like bathrooms and kitchens. If the walls of habitations wouldn′t have a quite low thermic transmittance, their internal walls remained cold and steam condensed on them, causing by that a lot of damages to the buildings. The thermic transmittance of perimetrical walls of buildings has to be as low as possible, also in order to limit the energetic consumption linked to the minor power and minor time of utilisation of the heating and conditioning system as required nowadays for buildings with a good thermic isolation. Another effect is a minor environmental pollution of the cities. This diagram shows you also all the areas where Fiorditufo blocks from 25cm to 37cm are used for the constructions of the walls of buildings. The walls may be plastered, natural or protected by a 15cm long thermo-isolating plastic slab. Furthermore you can see all the areas ÒcoveredÓ with plugging walls made in various ways, but always covered externally with Fiorditufo stones of 11cm or 8cm and with an air-space of 5cm. Looking at the diagram you can see that a wall made by 25 cm Fiorditufo blocks without plastering is sufficient to avoid the up-coming of the phenomenon of condensing in the areas of Palermo, Catania, Messina, Siracusa, Trapani, Cagliari, Reggio Calabria, Agrigento, Naples, Salerno, Pescara, Latina and Sassari. The same wall of 25 cm Fiorditufo blocks is sufficient in order to avoid condensing also in areas of Rome, Florence, Genova, Bari and so on, if plastered at the internal side. A wall made of 37 cm Fiorditufo blocks without plastering avoids the phenomenon of condensing in the areas of Ancona, Perugia, Terni, Siena up to colder regions like Turin, Alessandria, Asti, Aosta, Belluno. Even in the high Aosta valley you could use Fiorditufo blocks by constructing thicker walls or by protecting the walls with an expanded plastic slab with K = 0,035 w/m°K.