Re-Caulk a Tub or Shower

Cracked or moldy caulk lets water seep behind the tub — leading to rotted subfloors and ceiling stains below. A 30-minute job prevents a $3,000 repair.

Difficulty: Easy Time: 1 hr + 24 hr cure Cost: $10–$15
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VentilateCaulk fumes are strong. Open a window and run the bath fan during application and cure.

Tools

Materials

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Steps

  1. 1

    Remove the old caulk

    Score along both sides of the bead with a utility knife, then pull the strip out. Use a plastic caulk-removal tool to dig out anything stuck. Get every shred — new silicone won't bond to old.

  2. 2

    Clean the surface

    Wipe with isopropyl alcohol to remove soap film and mildew spores. Surface must be bone-dry before you caulk.

    Tip: Fill the tub with water first. The weight pulls the tub down slightly; caulking with the tub empty means cracks reappear when someone steps in.
  3. 3

    Tape the lines

    Run painter's tape along both sides of the joint, leaving a ~1/4" gap where the bead will go. This gives you a crisp, professional line.

  4. 4

    Lay the bead

    Cut the tube tip at a 45° angle, opening sized to your joint. Steady, continuous pull along the joint — don't stop mid-line.

  5. 5

    Tool the bead and pull tape

    Run a damp fingertip (or a silicone smoothing tool) along the bead once to shape it. Pull the tape immediately while the caulk is wet.

  6. 6

    Let it cure

    24 hours before water exposure. Drain the tub now if you filled it.

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