Best ACE Hardware product for black bathroom grout mold?« Back to Previous Page

Black grout in humid areas like JVC is almost always a surface mold, typically Cladosporium or Aureobasidium, feeding on soap scum and moisture. For a localized patch, a product like HG Mould Spray from ACE Hardware is effective; it's a chlorine-based cleaner designed for this. Apply it, let it sit for the recommended time to penetrate, then scrub with a stiff brush.

To prevent its return, you must control the humidity. After showers, run your bathroom's exhaust fan for at least 30 minutes. Wipe down wet tiles and grout lines with a squeegee. The constant cycling of your AC creates a significant temperature differential between the cold room and the humid air, leading to condensation on walls and behind fixtures – that dampness is the root cause.

If the discoloration persists after a thorough cleaning or if you notice a musty odor, the mold may have penetrated deep into the porous grout or behind the tiles. In such cases, surface cleaning won't be sufficient. A professional inspection can determine the extent using moisture meters and, if needed, lab analysis to identify if a more problematic species is present, which would require targeted remediation.