Moisture and Condensation in Residential Buildings in a Relatively Dry Region

It is not unusual to face moisture problems in buildings in cold climates and wet regions. It is, however, unusual to have the same problem in a relatively dry region such as Jordon, which has moderate weather conditions and mild winters. Nevertheless, a significant proportion of houses and residential apartments in Jordan are affected. The monitoring of inside air conditions, wall surface temperatures, ventilation and living style has shown that a high relative humidity (RH >75%) occurs at walls resulting in possible condensation. These conditions, with visible or invisible condensation, enhance mould growth and damage walls. This apparently results from actual living conditions which fall short of comfort conditions due to high energy cost, poverty, limited ventilation and poor wall thermal insulation. Measurements indicated that actual inside wall surface temperatures were occasionally below the dew point. This was confirmed by a simple thermal analysis of typical walls showing the possible drop of inside surface temperatures down to 11oC. Additional factors to the problem in this region include lack of building quality control, the demand for cheap housing in which ventilation and thermal specifications are not a priority and in which heating is only intermittent heating.