Black spots after heavy dew: DIY clean or call pro?« Back to Previous Page

Black spots appearing after heavy dew indicate condensation issues, which are common in Dubai's climate due to high humidity and year-round AC use. The wall-ceiling junction is a prime spot for dampness to accumulate. For a small patch (under 1 square foot), a DIY approach may suffice. A solution of white vinegar (undiluted) or diluted bleach (1 part bleach to 10 parts water) can be effective for surface mould. Scrub gently, wear an N95 mask and gloves, and ensure the area is completely dry afterward. The key is fixing the moisture source—improve ventilation, wipe down condensation, and check if your AC is set too cold, creating a temperature differential.

However, given the symptoms you describe—children coughing—and the location (bedroom), a professional inspection is strongly advised. Coughing suggests potential spore inhalation, and what's visible on the surface is often just a fraction of the growth within the wall cavity. A proper inspection involves moisture meters and thermal imaging to find the dampness source, plus air or surface sampling to identify the mould species. This is crucial, as some types, like Aspergillus, are common here and can exacerbate respiratory issues. Companies with their own microbiology labs can provide this specific analysis. For a villa that's three years old, it’s also worth checking if the external sealant or insulation has degraded, a frequent issue with temperature fluctuations. If the spots return after cleaning, that confirms a hidden moisture problem requiring professional remediation.