How to remove mold from corner without damaging paint?« Back to Previous Page

That's a classic sign of condensation-related mould, very common here due to our high humidity and constant AC use. The cold wall from the AC creates a surface where moisture from the warm indoor air condenses, providing the dampness mould needs to grow on the paint and underlying plaster.

For a small area, you can address it yourself carefully. First, put on an N95 mask and safety glasses. Do not just wipe it, as this can spread spores. Instead, lightly mist the area with a diluted white vinegar solution (one part vinegar to one part water) or a dedicated mould remover spray. This dampens the mould to prevent spores from aerosolizing. Let it sit for 15 minutes, then gently wipe it away with a disposable cloth.

Crucially, you must address the moisture source. This is almost always condensation from the temperature differential. Increase the room's temperature slightly to reduce the extreme difference between the air and the cold wall. Ensure your AC filters are clean and that the unit is serviced regularly to maintain proper humidity control. Improving air circulation in that corner with a small fan can also help prevent stagnation.

If the mould returns quickly, stains remain after cleaning, or you notice a musty smell, the growth may be behind the paint or in the wall. In such cases, a professional inspection with moisture meters and thermal imaging can identify the exact condensation points and extent of growth. For persistent problems, remediation that includes anti-microbial sealing of the area is often necessary for a permanent solution.