Small black spots in humid apartment closet. Professional needed?« Back to Previous Page

Small black spots appearing on an exterior wall during a period of high humidity are almost certainly mould, a very common issue in Dubai due to the climate. This is likely caused by a small temperature difference between the air-conditioned interior and the hot, humid exterior, leading to condensation inside the wall that mould spores feed on.

For a small, contained area you've just noticed, you can attempt to clean it yourself. Wear a mask and gloves. Use a mixture of white vinegar and water or a diluted bleach solution (1 part bleach to 10 parts water) to scrub the area. The goal is to completely remove the discolouration, not just bleach it. Afterwards, ensure the area is thoroughly dried and increase ventilation to the closet. A dehumidifier or running the AC consistently can help manage moisture.

However, because this is on an exterior wall, the real concern is what you cannot see inside the wall cavity. Surface cleaning may be a temporary fix if the condensation issue persists internally. If the spots return quickly, cover a larger area than first visible, or if you notice a musty smell, a professional inspection is warranted. They use moisture meters and thermal cameras to locate the source of the dampness within the structure, which is critical for a permanent solution. In many older Dubai buildings, this can stem from minor cracks or insufficient insulation that need to be addressed.