How to Re-Caulk a Leaking Shower or Bathtub

Caulk fails. Water finds the gap where the tub or shower meets the wall, seeps behind the tile, and starts its slow work on the framing. You see it happening—discoloration, soft drywall, or that persistent musty smell. The good news is that re-caulking is genuinely one of the easiest repairs you can do, and catching it early saves you thousands in water damage. Silicone caulk is what you need here, not acrylic. It stays flexible, resists mildew better, and lasts longer in a wet environment. The work is straightforward: remove the old caulk, prepare the joint, apply new caulk in one continuous bead, and let it cure. No special skills required.

1. Remove the old caulk completely. Use a caulk removal tool, utility knife, or even an old screwdriver to pry out the existing caulk. Work slowly along the entire joint—tub or shower to wall, corner to corner. Don't rush. Once the bulk is out, use a utility knife at a low angle to scrape away any remaining residue and get down to bare substrate. You want a clean, empty joint before you start fresh.
2. Clean the joint down to raw material. Once the old caulk is out, wipe the joint with a damp cloth to remove dust and debris. If there's any mildew staining or residue, scrub lightly with a bathroom cleaner or a 1:1 white vinegar and water solution. Dry the joint completely with a clean cloth—moisture is the enemy of caulk adhesion. If the substrate is drywall or cement board, you want it visibly dry.
3. Tape the edges to keep lines clean. Run painter's tape along both sides of the joint—one line on the wall, one on the tub or shower lip. Leave a gap of about one-eighth inch between the tape lines. This prevents caulk from spreading onto finished surfaces and gives you a crisp, professional edge. Press the tape down firmly so caulk doesn't seep underneath.
4. Load the caulk gun and establish your angle. Cut the tip of the silicone caulk tube at a 45-degree angle—cut small, about a quarter-inch opening. Load it into the caulk gun. Hold the gun at a 45-degree angle to the joint and position yourself at the start of your line, usually a corner. Steady pressure and a consistent speed matter more than force.
5. Apply caulk in one continuous bead. Squeeze the trigger with steady, even pressure while moving the gun along the joint. Move slowly—you're not racing. Let the caulk fill the gap completely; don't scrimp. Work the entire run in one pass if possible. Stop at corners and let the bead build slightly rather than feathering it thin. One full bead is stronger than multiple thin passes.
6. Smooth the caulk while it's wet. Immediately after applying the bead, use a wet finger, a caulk smoothing tool, or the corner of a damp cloth to press the caulk into the joint and create a smooth concave bead. Work along the line in one direction, pressing down and slightly inward. This embeds the caulk and removes excess. The goal is a smooth, flush line that bridges both surfaces without bulging.
7. Remove tape and let cure fully. Peel the painter's tape away while the caulk is still slightly tacky, not fully cured. Pull at a low angle to avoid disturbing the bead. Discard the tape. Leave the caulk undisturbed for the full cure time—usually 24 hours for silicone, though check your product label. Keep water out of the tub or shower during this window.
8. Test the seal after curing. Once the caulk is fully cured, run water and watch the joint. The bead should channel water toward the drain without pooling or seeping behind. Fill the tub and let it sit for 10 minutes to check for any weeping. If water is bypassing the seal, you may have a gap. Minor gaps can be re-caulked; larger failures mean the substrate underneath needs inspection.