Black bathroom grout: DIY fix or call a professional?« Back to Previous Page

The grouting between the tiles in our Deira apartment's bathroom has started turning black in the corners, and there's a really damp smell that hits you when you walk in. It's gotten worse since the humidity spiked a couple of weeks ago. I tried scrubbing it with bleach, but it just came back. Is this something I can fix myself with a better cleaning product, or do I need to call in a professional for this?
Posted by Neha Chauhan
Asked on March 30, 2026 8:38 pm
Based on your description, this is a classic case of mold growth, exacerbated by the high ambient humidity in Deira and the constant condensation cycles created by hot showers and year-round air conditioning. The black discoloration in the grout is likely Aspergillus or Cladosporium, common indoor molds in the UAE.

While bleach appears to remove the surface stain, it is a ineffective and temporary solution. Bleach is water-based, meaning it adds moisture that the mold feeds on, and its chemical structure cannot penetrate porous materials like grout to kill the hyphae (root structure) beneath the surface. This is why the growth returns aggressively.

For a small, surface-level issue, a proper DIY approach involves using a dedicated, non-bleach-based EPA-approved fungicidal cleaner, improving ventilation by running the exhaust fan for at least 30 minutes after showering, and diligently wiping down wet surfaces. However, your mention of a persistent "damp smell" is a significant red flag. This indicates that the moisture problem is not superficial. The leak or condensation is likely penetrating behind the tiles or into the substrate (wall/floor structure), facilitating hidden growth that you cannot see or effectively treat yourself.

Under Dubai Municipality regulations, addressing underlying moisture sources is mandatory for effective remediation. A professional inspection is strongly recommended. We use borescopes to inspect cavities and moisture meters to pinpoint the source of the dampness, which could be a leaking pipe, failed waterproofing, or severe interstitial condensation. Attempting to fix this without identifying the source will result in chronic recurrence and potential health issues.

For a definitive diagnosis and a permanent solution, I advise you to contact our team at Saniservice. Call us at 800-MOLDS (800-66537) or email hello@saniservice.com for a comprehensive assessment and a remediation plan that complies with local health and safety standards.
Posted by Sani Admin
Answered on April 2, 2026 12:56 am