How to Properly Caulk a Bathtub

Caulk is the thin, humble barrier standing between your bathroom wall and significant water damage. When the seal fails, water wicks behind the tile, rotting subfloors and growing hidden mold that eventually compromises the entire structure of the bathroom floor. Achieving a clean, professional finish isn't about artistic talent; it is about proper surface preparation. If you skip the cleaning phase or apply new caulk over old, crumbling material, it will peel within months. Done well, a bead of silicone should look seamless, clean, and stay flexible for years to come.

1. Strip Out the Old Bead. Use a utility knife or a specialized caulk removal tool to slice through the old bead along both the wall and the tub. Pull the loose strips away with your fingers or a plastic scraper, taking care not to gouge the tub or tile surfaces.
2. Scrub and Degrease. Scrub the joint with a stiff nylon brush to dislodge any remaining bits of adhesive. Follow this by wiping the entire area thoroughly with denatured alcohol on a clean rag to remove all soap scum and oils.
3. Tape for Sharp Lines. Apply painter's tape to both the wall and the tub, leaving a gap of about 1/8 to 1/4 inch where the new caulk will sit. This creates a crisp, professional line that prevents smears.
4. Lay a Steady Bead. Cut the tip of the silicone tube at a 45-degree angle, making the opening roughly the width of the joint. Apply a steady, continuous bead of caulk by pulling the gun toward you, maintaining constant pressure on the trigger.
5. Smooth It Seamlessly. Run a caulk finishing tool or a gloved finger along the bead to press the silicone into the joint and remove excess material. Do this in one smooth motion, keeping a paper towel handy to wipe the excess off your tool frequently.
6. Peel and Wait. Carefully pull the painter's tape away at a 45-degree angle while the caulk is still wet. Allow the caulk to cure for at least 24 hours before introducing any water to the tub.