Can I re-caulk around the tub, even though the current caulk (I don't know if it's caulk or silicone-- does it matter?) has black mold on it? Will I need to scrape the existing caulking off and start over?

 

The old caulk will have to be removed before applying new caulk. All surfaces will need to be thoroughly clean and dry before applying new caulk. Use a utility knife to cut out old caulk. Clean surface with paint thinner or other solvent to remove old caulk residue. This will also kill the mold/mildew. Read and follow product directions for application.

Prevent mold/mildew by wiping down tub/shower after each use with chamois or squeegie. Mold/mildew likes damp, soiled, unventilated areas. Keep shower curtain/doors open to allow ventilation in the area. Keep tub/shower clean with disinfecting cleaner. Run bathroom vent fan for at least 30 minutes after bathing to help eliminate moisture from the air.

 

Thanks! I will let all know how this turns out!