How to caulk a bathtub

If you find the cracked, moldy caulk around your bathtub thwarting your post-shower utopia, it’s time to replace it. Here’s how to caulk a bathtub or shower right the first time:

What You'll Need

  • Lexel®

    Lexel® synthetic rubber elastomeric sealant is the superior alternative to silicone caulk in clarity, adhesion, elasticity and paintability.

    Learn More
  • MildewFree*

    Mildew-resistant sealant guaranteed to stay mildew-free for 7 years, or we'll pay someone to re-do the sealing job for you.

    Learn More
  • 1

    Gather tools

    You’ll need: 
    • One of the products listed above
    • Utility knife for removing old caulk and opening the caulking tube
    • McKanica® Silicone Caulk Remover or similar product if silicone is present
    • Caulk gun
    • Painter’s tape (optional)
    • Beading tools,small foam brushes, or your trusty fingers for tooling
    • Damp rags for clean-up
    • Some mold-killing, caulk-fixing moves 

  • 2

    Clean out existing caulk and broken grout

    If you want your caulking job to stick and stretch for years to come, make sure you remove both old grout and old caulk. If silicone is present, use a silicone caulk remover. Fill the tub with water (so the joint is at its widest), then dry the surface with a clean towel. 

    Step 2




  • 3

    Apply the caulk

    Think smooth: a steady hand is necessary for a smooth bead, and mind-over-matter works. Apply the bead 1/8”-1/4” wide to ensure there’s enough there to both stick to the joint and stretch with movement. 

  • 4

    Tool (smooth) the bead

    Use your finger, a beading tool or foam brushes to smooth the bead. This provides best adhesion and greater longevity. For a super-neat bead, outline the joint with blue painter’s tape before applying the caulk, then remove it before the caulk dries for a professional looking finish.

    Step 5



  • 5

    Clean up

    Use soapy water* or mineral spirits** to clean up tools and surfaces. Drain the water from the tub, then stand back and admire your handy work.

     *for MildewFree
    **for Lexel

 Special Tip

We get it: you don’t want to caulk a bathtub every year. Trust us, we don't want you to be reading our "How to caulk your bathtub" post every year. Do yourself a favor and protect the job you just finished by cleaning. Routine cleaning will keep soap scum and mold from attacking the caulk, which helps it last longer. Yay!