How to permanently remove mold from exterior wall??« Back to Previous Page

Black mould on an exterior wall facing the marina is a very common issue here, directly caused by the high humidity and the temperature difference between the air-conditioned room and the hot, moist outside air. This creates condensation inside the wall cavity, providing the perfect damp environment for mould to grow unseen until it becomes visible.

For a permanent solution, you must address the moisture source first. Simply wiping the visible mould away will not stop it from returning. Start by moving the wardrobe away from the wall to allow air to circulate. Thoroughly dry the affected area with a fan heater or dehumidifier; this is a critical step before any cleaning.

Once the wall is completely dry, wear an N95 mask and gloves to protect yourself. Scrub the mould stains with a solution of white vinegar or a dedicated mould remover. Avoid using bleach, as it only removes the colour and does not kill the mould roots, allowing it to grow back.

The most important long-term fix is to manage the humidity and prevent condensation. Ensure your AC is running efficiently and consistently to dehumidify the air. Consider using a moisture-absorbing product like a desiccant bag behind the furniture. Improving cross-ventilation in the room whenever the external humidity is lower can also help significantly.

If the mould covers a large area (generally more than one square meter), has a persistent musty odour, or returns quickly after cleaning, the moisture intrusion within the wall structure may be severe. In such cases, a professional inspection with thermal imaging is needed to identify the exact condensation points and recommend structural solutions to prevent recurrence.