Fungal defacement in dwellings is a widespread problem and has been extensively studied in cool and cold climates. In Canada, 10% of the housing stock in the 1980s was reported to have dampness and mold. In the United Kingdom, inquiries conducted by the Building Research Establishment indicate that 27% of the housing stock is affected. In a study for the national housing society, the Belgian Building Research Institute mentions that 20% to30% of the low-income houses have mold problems. In 300-dwelling survey, the Fraunhofer Institut fur Bauphysik, Germany, reported that 40% of the dwellings visited suffered from mold.