Black mold on exterior wall: treat myself or call professional?« Back to Previous Page

What you've described—black spots clustering on an exterior wall, especially near a window—is a common issue in Dubai due to the high humidity interacting with cooler indoor AC temperatures, causing condensation. The wall behind the wardrobe is a cold spot with poor air circulation, creating an ideal environment for mould.

For a small area (under one square meter), you can attempt to treat it yourself. Move the wardrobe away to expose the wall fully. Wear an N95 mask and gloves. Clean the area with a mixture of detergent and water, or a solution of white vinegar. Do not use bleach, as it only removes the colour and can push the mould deeper into porous materials like drywall. After cleaning, ensure the area is completely dried. Address the moisture source: check the window seal for leaks and consider using a dehumidifier in the room to maintain humidity below 60%.

If the mould covers a larger area, has a strong, musty odour, or returns quickly after cleaning, a professional inspection is recommended. Exterior wall leaks can be complex, often requiring thermal imaging to find the exact condensation point. Professionals can also conduct air and surface sampling to identify the mould type, which is crucial if anyone in the household has respiratory sensitivities. In many cases, the wall may need to be opened to properly dry the cavity and address the root cause.