Moldy bathroom grout: DIY fix or call a pro?« Back to Previous Page

The grout between the tiles in our master bathroom at our villa in Jumeirah has started turning black, and the damp smell is getting stronger, especially after showers. We tried scrubbing it with bleach, but it came back within a week. I'm worried it's behind the walls. Is this something I can handle myself with a stronger product from ACE, or do I need to call a professional mold removal company, and what kind of cost am I looking at for a bathroom this size?
Posted by Daniel Torres
Asked on March 28, 2026 10:55 am
Based on your description of the recurring black growth and persistent damp smell in your Jumeirah villa, this is a classic case of a systemic mold issue that a DIY approach will not resolve. Bleach is a surface-level biocide that does not address the root cause and is ineffective on porous materials like grout, where the mold mycelium (the root structure) has penetrated deeply. The strong, musty odor is a significant indicator that microbial volatile organic compounds (MVOCs) are present, strongly suggesting hidden mold growth, likely within the wall cavity behind the tiles.

The UAE's high humidity, especially in coastal areas like Jumeirah, combined with condensation from air conditioning and steam from showers, creates a perfect environment for mold. The problem is not the visible growth on the grout lines; it is the persistent moisture source feeding it. This requires professional intervention.

A certified mold inspector will use tools like a borescope to inspect behind walls and moisture meters to pinpoint the exact source of the moisture intrusion—which could be a failed waterproofing membrane, a tiny pipe leak, or condensation within the wall. Attempting a stronger chemical from ACE could temporarily bleach the color but will not eradicate the colony, posing health risks from fuming chemicals in a confined space and potentially driving the mold further into the substrate.

For a master bathroom, professional remediation involving containment, HEPA vacuuming, antimicrobial application, and addressing the moisture source typically ranges from AED 2,500 to AED 7,000, depending on the extent of the damage. Given the potential for structural damage and health implications, a professional inspection is not just recommended but essential.

I strongly advise you to contact a certified professional for a thorough assessment. You can reach our team at Saniservice for a comprehensive inspection and quote by calling 800-MOLDS or emailing hello@saniservice.com.
Posted by Sani Admin
Answered on March 30, 2026 4:28 pm