How to Replace Caulk Around Your Shower or Tub

Caulk around your shower or tub takes a beating—constant moisture, temperature swings, and movement from the house settling all conspire to crack, yellow, or separate it from the wall. When it fails, water finds its way behind the tile or into the walls, and suddenly you're facing mold, rot, and expensive repairs. Replacing caulk is one of those jobs that looks trivial until you actually do it poorly. The difference between sloppy caulk and a clean, professional line comes down to three things: removing the old material completely, preparing the gap so it's dry and clean, and taking your time with application. This is not a shortcut job, but it's absolutely something a homeowner can do in an afternoon. The work is straightforward and the tools are cheap. You'll need patience more than skill. The satisfaction is immediate—your bathroom looks maintained instead of neglected, and you've actually solved a water problem before it becomes expensive.

1. Remove the old caulk completely. Use a caulk removal tool, old butter knife, or utility knife to slice along both edges of the bead and pry it away from the surface. Work at a shallow angle to avoid gouging the tile or tub. It's tedious work—don't rush it. Any old caulk left behind will cause the new caulk to fail.
2. Clean out the gap completely. Vacuum out loose debris with a shop vac or handheld vac. Then wipe the entire seam with a dry cloth, then again with a cloth barely dampened with mineral spirits or rubbing alcohol. The gap must be dry and clean or the new caulk won't adhere. Wait 10 minutes after wiping to let it air dry.
3. Mask the sides of the seam if you want a clean edge. Run painter's tape along the tile and tub edge on both sides of the gap where you plan to caulk. Leave the gap itself exposed. Press the tape down firmly so caulk doesn't seep underneath. This step takes an extra five minutes but makes the final result look professional.
4. Cut the caulk tube at the right angle and load the gun. Cut the tube nozzle at a 45-degree angle, roughly 1/8 inch from the tip. Load the tube into the caulking gun with the plunger seated against the back. Squeeze the handle a few times to seat the plunger against the tube's back plug. You're ready to go when caulk begins to appear at the nozzle.
5. Apply caulk in a steady, continuous bead. Hold the gun at 45 degrees to the seam and apply steady pressure while moving along the gap in one continuous motion. Don't stop and start—this creates weak points. Move at a pace where the caulk fills the gap and slightly overflows onto the tile and tub. You'll smooth it down next.
6. Smooth the caulk immediately with a wet tool. Dip your index finger or a caulk smoothing tool in cool water and run it along the bead in one slow, steady stroke. Press lightly so you're not pushing the caulk out of the gap. Work in sections so the caulk doesn't start to skin over. You'll see the excess caulk gather on the tool; wipe it on a damp cloth between passes.
7. Remove the tape while the caulk is still wet. Peel the painter's tape away from the tile and tub at a shallow angle, working from one end to the other. Do this while the caulk is still wet, not after it's dried. A clean tape removal line is what makes amateur caulk work look professional.
8. Let it cure fully before running water. Silicone caulk typically needs 24 to 48 hours to cure fully, depending on humidity and the specific product. Check your tube—some fast-cure formulas set in 4 hours. Don't shower or run hot water along the seam until full cure time has passed. If you shower too early, you'll have a weak seal that will fail within months.