Ask a Pro: How Do I Stop Mold Coming Back in My Bathroom?

The question: "I scrub the black spots off my shower grout and the bathroom ceiling, but they are back within a few weeks. What am I doing wrong?"

The pro's answer

When mold keeps coming back, cleaning is only half the problem. The real cause is moisture that never gets a chance to dry. Here is what pros usually recommend:

1. Fix the airflow

• Run the exhaust fan during every shower and for 20 to 30 minutes after.
• Check the fan actually vents outside, not into the attic.
• If the fan is weak or noisy, an electrician can replace it with a quieter, stronger one.

2. Replace moldy caulk

Mold that has grown into caulk cannot be cleaned out. Cut it out, let the area dry fully, and apply new mildew-resistant silicone.

3. Clean and seal the grout

Grout is porous and soaks up water. After a deep clean, a grout sealer keeps water out so mold has nothing to grow on. Reseal about once a year in a busy shower.

4. Look for hidden leaks

Mold on a ceiling or wall away from the shower can mean a leak above or behind it. A plumber can check before it becomes a bigger repair.

Send your own question

Have a question about your home? Send it through our contact page. We will put it to pros on CSI Elite Services and share the best answers here.