How to Re-Caulk a Bathtub (Clean Lines, No Mold)

Moldy, cracked caulk around the tub doesn't just look bad. It can let water get behind the wall. Here's how to replace it with a clean, straight line, even if you've never done it before.

1. Step 1: Remove All The Old Caulk

You can't caulk over old caulk. The new bead won't stick. Slice along both edges of the old caulk with a utility knife, then peel and scrape it out. A plastic putty knife gets the last bits without scratching the tub.

2. Step 2: Clean And Dry

Wipe the joint with rubbing alcohol, to remove soap scum and leftover residue. Then let it dry completely. New caulk won't stick to a wet surface.

3. Step 3: Tape The Lines

Here's the secret to a clean line. Run painter's tape along the tub, and along the wall, leaving a small gap over the joint, about as wide as you want the bead.

4. Step 4: Run The Bead

Use a one hundred percent silicone caulk, made for kitchens and baths. Cut the tip at an angle, with a small opening. Squeeze with steady pressure, and move along the joint in one smooth pass.