Some types of cement-based grout can benefit from an appropriate grout sealer. A sealer may reduce the amount of moisture and dirt that penetrates the porous surface, making future cleaning easier.
However, not every grout product requires the same treatment. Follow the grout or tile manufacturer’s instructions before applying a sealer.
What If the Black Marks Are Mold?
Dark grout is not always caused simply by dirt. In consistently damp environments, especially bathrooms and poorly ventilated areas, black or dark spotting may sometimes be associated with mold or mildew.
Cleaning the visible discoloration is useful, but preventing excessive moisture is equally important. Improve ventilation, repair leaks, dry wet surfaces, and address persistent dampness whenever possible.
If discoloration repeatedly returns despite cleaning, or if grout is cracked, deteriorating, or permanently stained, cleaning alone may not solve the problem. Damaged grout may need to be repaired or replaced.
When a Commercial Grout Cleaner May Be Better
