Black mold in closet from moisture? How to remove safely?« Back to Previous Page

Black spots in a closet on an exterior wall are a classic sign of condensation-related mould growth, very common here after periods of high humidity or rain. The wall is likely cooler than the room's air, causing moisture to condense and create the perfect damp environment for mould, especially when airflow is restricted by stored items.

For a small area, you can clean it yourself safely. Wear an N95 mask, gloves, and eye protection. Move everything out of the closet. Mix a solution of one part distilled white vinegar to three parts water or a diluted detergent, scrub the area, and allow it to dry completely. Do not use bleach, as it only removes the colour and does not address the underlying moisture problem.

However, cleaning is only a temporary fix if the moisture source remains. The wall may have trapped moisture from the rain or have a minor leak. You need a professional inspection to identify the exact cause. They will use a moisture meter to check the wall's internal humidity levels and an infrared camera to find any hidden dampness or leaks you cannot see.

For this type of diagnostic work, you should call a building surveyor or a specialised mould inspection company with certified thermographers. They can provide a verified report on the moisture's source and extent. A general handyman or cleaning service will not have the correct equipment for this investigation. Once the inspection is complete and the moisture issue is permanently resolved by a contractor, then a remediation team can safely remove any affected materials and treat the area to prevent regrowth.