Dealing with mildew in bathroom caulk

Mildew and mould are fungi that thrive in moist, poorly-ventilated areas. Look out for dark lines appearing around the edge and joints of your bath tub, shower stall or sink. Your bathroom caulk seal may be in need of replacement.

SIU_recaulking the tub_mildew lines_20140824Diagnosis: Regular cleaning or bleaching of the caulk line fails to remove the pink, orange or black staining. When the latex caulking wears down and becomes dry and brittle, or the silicone caulking works loose over time, moisture combined with soap suds and dirt can develop behind the caulk and breed mildew.

Solution: Check the condition of your caulking at least once a year and be prepared to replace it regularly, especially between tenants or when prepping your home for sale.

Steps to remedy:

  1. Remove the old caulk by scraping out with a paint scraper, tip of a screwdriver, razor or special caulk-removing tool:
    SIU_recaulking the tub_remove caulk_20140824
  2. Clean and treat the joint for mildew; leave to dry completely:
    SIU_recaulking the tub_clean and dry_20140824
  3. Re-caulk the joints with specially-formulated, mildew-resistant bathroom caulk; a silicone-based caulk is preferable, as water-based caulks only last 6 months. Use white, rather than transparent, for a longer-lasting clean look.
    SIU_recaulking the tub_finish_20140824
  4. Some caulk solutions set within an hour, others require 24 hours before using the bath or shower.
    SIU_recaulking the tub_recaulk_20140824

Prevention: Reduce mildew growth by starving it of food and moisture!

  1. Minimize soap residue: wash down shower walls or the tiles around the bath tub with water to remove soap suds after use.
  2. Remove excess moisture with a squeegee or cloth.
  3. Open the shower door or curtain to dry faster.
  4. Run the bathroom fan for 15 minutes after showering or open the window to increase circulation and reduce air moisture.
  5. Clean weekly with with mild bleach solution (or baking soda, vinegar, hydrogen peroxide or other anti-mildew cleaners).

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