How to Remove and Replace Bathtub Caulk

Caulk is the first line of defense against rot and water damage in your bathroom, yet it is often the most neglected. Over time, that crisp, white bead shrinks, cracks, or turns black with mildew, allowing water to seep behind your tub surround and into the wall structure. Replacing it is a high-impact, low-cost project that instantly refreshes the room. Done well, the repair should look invisible and last for years. The secret isn't in the fancy tools you buy, but in how thoroughly you clear away every trace of the old material. If you skip the cleaning phase or leave behind remnants of the previous seal, the new caulk will not stick, and you will be back here in six months doing it all over again.

  1. Slice the Old Bead. Use a sharp utility knife or a specialized caulk removal tool to slice along both the top and bottom edges of the existing caulk bead. Maintain a steady pressure to ensure the blade cuts through the material without gouging the tub or tile finish.
  2. Clear Out the Scraps. Pull the loose caulk strips away with your fingers or a pair of needle-nose pliers. Use a plastic scraper to gently scrape away any stubborn residue, taking care not to chip the grout or finish.
  3. Scrub and Degrease. Scrub the entire gap with a stiff nylon brush and a mixture of water and dish soap to remove soap scum. Once clean, wipe the area down thoroughly with isopropyl alcohol on a lint-free cloth to strip away any remaining oils.
  4. Tape for Perfect Lines. Apply painter's tape along the tub edge and the wall edge, leaving a gap of about 1/4 inch where the caulk bead should sit. This ensures your final line is perfectly straight and prevents messy smears on the tile.
  5. Lay a Smooth Bead. Cut the nozzle of your silicone caulk tube at a 45-degree angle to create an opening slightly smaller than the gap width. Use a caulking gun to lay a continuous, even bead along the entire seam.
  6. Smooth and Remove Tape. Wet a finger or a caulk-smoothing tool with a tiny amount of soapy water and slide it along the bead to press the silicone into the seam and shape it into a smooth concave profile. Immediately pull the painter's tape away at a 45-degree angle before the caulk begins to skin over.