For a hidden patch of that size, especially behind furniture, a professional inspection is strongly advised. Do not attempt to clean it yourself, as disturbing it can release a large number of spores into the air. You need a company that specializes in mold inspection and remediation, not a general handyman.

Look for a provider that starts with a proper assessment, including moisture mapping to find the water source (often condensation from an AC unit or a minor leak) and air/surface sampling to identify the mold type. They should be able to explain Dubai Municipality and DHA guidelines for remediation. The cleanup process itself should involve containment of the area, HEPA filtration, and safe removal of contaminated materials.

The most credible firms will provide before-and-after documentation, often from their own microbiology lab, to verify the spore count has been returned to safe levels. This is the evidence you need for peace of mind. Focus on companies that emphasize this diagnostic approach.