Humidity in buildings generates many disorders or disadvantages. A dry-bulb temperature of the air relatively low, strong moisture and wall surface temperatures very low characterize the interior conditions of the highland dwellings in Reunion Island, during the southern winter. This causes many disorders related to phenomena of condensation on walls: deterioration of the envelope, odor of mould. It is thus, significant to precisely know the evolution of the moisture in a building to avoid any disorder on the frame. In this study we will expose a series of experiments carried out on real residences in order to highlight main parameters of the problem. On the basis of these results, numerical simulations were used to extrapolate the behavior of this building on unusual climatic sequences, holding account various improvements of its constitution. A curative study and a preventive study were carried out on two different types of residences. The aim is to propose solutions to prevent deteriorations of the coatings due to the surface condensation.