How to Recaulk a Bathtub

How to Recaulk a Bathtub. Does the caulk around your bathtub have ugly black marks? Or maybe it is actually loose in some sections, with little rubber strings hanging down.

The black marks are mildew and the loose caulking allows water to get between your bathtub and the walls, creating the perfect environment for mold to grow. It's time to recaulk your bathtub.

  1. Assemble all the tools and materials you'll need for the project.

  2. Start by removing the old caulking. Cut the existing caulk along the edge of the bathtub and along the wall using the utility knife (or a razor blade), then pull it off.

  3. Spread silicon caulk remover (available at any home center) on any caulk remnants and in the seam between the bathtub and the wall. Leave it for a couple of hours (follow the directions on the package).

  4. Using the edge of your putty knife, remove any caulk remnants and dig out any buried in the seam. Since you applied the silicon caulk remover, it should pull out easily.

  5. Clean the bathtub edge and the walls with rubbing alcohol to ensure any traces of mildew or mold are gone. You could also use water mixed with chlorine bleach to do this. Allow it to dry thoroughly.

  6. Apply painter's tape along the walls and bathtub edge, about 1/4 inch from the seam.

  7. Insert the tube of silicon caulk into the caulking gun and cut the tip on a 45-degree angle.

  8. Fill the tub with water. This is necessary because the weight of the water will open the seam between the tub and the walls, ensuring you end up with a wide enough bead of caulk so it won't stretch and crack over time.

  9. Starting in one corner, run a bead of caulk along one edge of the bathtub. Keep constant pressure on the trigger and pull the gun in the opposite direction from where the tip is pointing. Run a continuous bead along one side of the tub. At the end of the run, release the trigger and lift the caulking gun.

  10. Clean the tip of the caulking tube with a cloth or a paper towel, then repeat the process for the other walls of the bathtub.

  11. Dampen your fingertip and run it along the beads of caulk you have just applied to smooth and spread them.

  12. Wait 10 or 15 minutes, then carefully remove the painter's tape. Peel it at a 45-degree angle away from the fresh caulk to avoid smearing.

  13. Allow the caulk to set up for 24 hours before using the tub or shower.

  14. Recaulk the tub whenever you notice big sections torn away or excessive mildew.

  15. Tip

    There are inexpensive tools available at your home center designed to remove old caulk as well as smooth and spread fresh caulking. If you decide to use one of these tools, you may not need to use painter's tape. Wetting your finger with liquid dish soap (rather than water) may allow your finger to smooth the caulk without any of it sticking to you.


    Be sure you get caulk that is marked for kitchen and bath use. It is especially formulated to fight mold and mildew. Ordinary caulk will not resist mildew. If your existing caulk is badly damaged and water has gotten between the tub and the wall, don't apply new caulk on the same day you remove the old caulk. Leave the seam open and if possible put a fan in the room so the moving air can thoroughly dry the area.