Mold under shower sealant: DIY or call professional?« Back to Previous Page

The black and green spots under the silicone sealant are a classic sign of mould growth, and the persistent humidity in your JVC apartment is the primary cause. Bathrooms here are perfect breeding grounds due to constant condensation from showers and year-round AC use creating temperature differentials.

For a small, surface-level patch (less than a square foot), a thorough DIY cleaning can be effective. Wear a mask and gloves. Scrub the area with a dedicated mould remover or a solution of white vinegar or diluted bleach. The critical step is to let the area dry completely for 24-48 hours with a dehumidifier or fan running before applying new, high-quality silicone sealant. If the mould has penetrated behind the tiles or into the grout, DIY cleaning will only address the surface and it will return.

You should strongly consider a professional assessment if the mould reappears quickly after cleaning, if the area is larger than a square foot, or if household members experience worsened allergy symptoms or respiratory irritation. Professionals use moisture meters to find hidden dampness you can't see and can take samples for lab analysis to identify the species, which determines the appropriate remediation method. This is crucial for ensuring the root cause of the moisture is addressed, not just the visible growth. In many cases, the wall behind the tiles needs to be inspected for saturation.