Learn How to Effectively Re-caulk a Bathtub

Smartlydwelling is independent – we research, test, and rate the top products to help you make the right buying choice. We sometimes use affiliate links and may receive a small commission on your purchase. Learn more…

Has mold and mildew started to show in your frayed aging caulk? Perhaps it was applied carelessly, not only making it look bad but also the perfect place for mold to begin to grow. Lack of attention and maintenance in the bathroom can often result in leaks around the tub and, over time, lead to structural damage. When it comes to stopping leaks, you definitely don’t want any failures, which the caulk is there for. Remember that you should never caulk over an old caulk with mold and mildew growing on it. It just doesn’t adhere well.

It’s time for your old caulk to go! Luckily for you, giving your tub a new seal with a few simple tools is easy and affordable. We’ll help you restore your bathtub’s overall stability by adequately removing the old caulk and giving you an excellent trick for getting perfect caulking lines every time for your safety and peace of mind! There’s nothing glamorous here, just the real deal, so let’s get to it!

Table of Contents

What Type of Caulk Should You Use?

Caulk is the most crucial part of this DIY project. Typically you’d want to choose one which will suit the material it goes on and your level of expertise in applying the caulk. In this case, that would need to be a waterproof caulk that contains a biocide, which resists mold and mildew. The two main types? Silicone and Acrylic Latex! 

  1. Silicone caulk adheres best to slick. Cleaning it with water, unfortunately, won’t work. It requires mineral spirits, releasing a strong odor until cured. While it lasts longer than acrylic latex, it is a lot harder to work with and is not as forgiving as Latex. However, with its flexibility under all conditions, it’s the best for nonporous surfaces such as glass, ceramic tile, and metal. If you’re not patient and careful, it can get messy and result in a more difficult job when it’s time for its removal.
  2. On the other hand, Latex is the best for uneven mismatched porous surfaces like stone tiles or wood trim found at the base of the tub. It doesn’t smell anywhere near silicone. Over time it can dry, resulting in cracks, and it requires more frequent replacement than silicone. When it comes to the skill requirement for application, it’s very beginner-friendly. Running a wet finger along the bead can quickly fix a mistake, and It’s easier to clean off a surface it’s applied to. To match sink and tub glazes, acrylic Latex comes in a variety of colors.
  3. Nowadays, some manufacturers offer a mix of both worlds. This caulk is recognized for easy application but has extended longevity compared to plain Latex. Whichever option you chose to fit your needs, remember to remove the old caulk before applying a new one. Neither one will bond if the residue isn’t adequately removed from the old caulk.

Essential Tools & Materials Needed to Re-caulk a Bathtub

  • Razor Blade
  • Utility knife
  • Putty knife
  • Oscillating tool
  • Rags or non-abrasive Sponge
  • Paper towels
  • Caulk Gun
  • Caulk for bathroom use
  • Painter’s Tape
  • Mineral spirits or White Vinegar
  • Vacuum cleaner

Bathtub Re-caulking Instructions

Before getting started with the steps below, it’s crucial to ensure that the tub is adequately dried out. We want to reduce the moisture as much as possible as we replace the caulking, so using an exhaust fan will help keep the bathroom well-ventilated. Whenever working on the tub, cover it with a rag, so it doesn’t get scratched. If any debris is scraped off the wall weather, it’s caulking or grout; you don’t want any of that old stuff to fall down the drain and clog it.

Step 1: Removing the Existing Caulk

There’s no sure-fire way to remove silicone caulking. Whatever knife you’re using, make sure it’s a thin blade. It’s a pretty labor-intensive process. You will want to be diligent and make sure you get all the old caulking, or the new caulking won’t stick. If your tub is not made out of steel, use a plastic razor blade to prevent scratches.

  • You’re trying to keep the angle of the knife, chisel flush, or oscillating tool as low as possible. Get between the tub and the caulking. Then the tile and the caulking, to slowly cut it off the tub. 
  • Slice away the old caulk with small, quick strokes. This will cleanly scrape off the old caulk from the surface.
  • Try to get one area started, then if you’re lucky, grip it and pull along to get it to come off all as one, but it doesn’t always work.
  • After you’ve removed the old caulk around the tub, perform a visual audit, and look for missed spots. If you find a caulk that’s hard to reach, use tweezers to pry it out.

Step 2: Clean and Prepare the Surface

It’s always a good idea to have a vacuum cleaner close by to help clean up late work and prepare the new caulk’s surface. 

  • Remove small remaining pieces of caulk with denatured alcohol and a soft rag.
  • Clean along the seams with your cleaner and a small stiff brush.
  • For any mildew or mold, choose only one of the following mixtures—a solution of bleach and water, mineral spirits, or white vinegar. Make sure to protect yourself by wearing gloves and have the room ventilated.
  • Wipe the area with a rag or soft cloth and let it dry completely before moving forward.

If the bathtub was used that day, water would naturally affect the walls, with water infiltrating behind them slowly dripping down the tub, essentially ruining the caulk. While an exhaust fan will help in such instances, if a crack is wet, use a hairdryer to speed up the process and prevent future mold outbreaks.

Step 3: Mask Off the Caulking Area

To get neat and straight lines, you’ll want to use painter’s tape to mask off all the areas top and bottom where you don’t wish silicone to go. 

  • Lay down the painter’s tape all the way around the perimeter of the top and up the walls.
  • Space the two rows of tape by finding the largest gap between the tiles, tub/shower. You’ll want to ensure that the tape is 1/16 away from the grout line on the tub’s deck. Typically, the silicone’s width goes amid the two pieces of the tape should be approx 1/8 inches.
  • Then onto the wall, you can come up a 16th off the top’s depth and apply the tape. Like that, you’ll want to mask off the entire perimeter of the tub. This’ll help achieve straight lines and make cleanup more comfortable and faster.

Step 4: Cut, Apply and Smooth Out the Caulk

Once the entire bathtub perimeter has been masked, you’re ready to start applying silicone. There is a pretty sizable difference between bad silicone and good silicone in terms of how much antifungal resistance a silicone contains. Don’t buy the cheapest silicone you can. Your choice of caulk might depend on how soon you’ll need to use the bathtub and the silicone’s drying time. Get the “Kitchen and Bath” stuff and get one of the higher grade ones. 

  • You’ll need to cut the tip of your silicone tub somewhere at a 45-degree angle with a utility knife and load the caulking gun with the tube in place.
  • What you’re trying to accomplish here is cut the opening to the same size as the line of silicone that you’re trying to apply.
  • Start applying the silicone with an even pace and pressure by steadily squeezing it out into the corners. 
  • Take some time as the bead will end up being too thin and eventually break in the seal full of bubbles; On the other hand, going too slow will lead to waste of material, and you’ll end up with a mess to be cleaned.
  • Don’t worry too much if the line isn’t perfect because that’s exactly why the masking tape was laid down.
  • Tool with your finger to form a concave shape, or alternatively use an edging tool. Do at least two passes everywhere, pressing the silicone caulking into the corner. Have a rag or paper towel handy to wipe the excess caulk off your finger.

Step 5: Peel the Painters Tape

As soon as you’re done caulking, without hesitation, start removing the tape while the caulk is still wet. Pull off at a steep angle one strip at a time while focusing on the caulk seam to remain untouched by the tape. To remove tiny ridges left from the tape, you’ll want to clean your hands first and then back to smoothening the bead by giving it one last run with your finger. You don’t want to ruin your fabulous work by making the new grout lines hospitable for mold to grow, so allow 24 hours for the caulking to completely cure before using the tub.


What’s Causing a Bathtub Caulk to Keep on Cracking?

Bathtubs and showers are no stranger to water deposits and the buildup of old soap, which can be the direct caulk inhibitor from forming a rock-solid watertight joint. Before caulking the bathtub joints, be sure to repair or replace damaged tiles, including structural damage. If the tub itself is not sufficiently supported underneath, you’ll want to fill your tub before caulking. The movement of weight(people) standing in the shower can inevitably make the caulk crack. Hence, as a mimic filling the tub helps weigh down the tub, so your caulk line doesn’t pull when using the tub. 

What to Clean the Bathtub Caulk With?

When it comes to maintaining your tub’s grout, bleach and baking soda are both inexpensive and proven caulk cleaning solutions. Use a disposable paintbrush and apply the cleaning solution to the moldy spots on your caulk. Bleach is toxic, and you want to keep it off your skin, so handle it with care and ensure proper ventilation as the caulk is soaking.

How Often Should You Re-caulk a Tub?

Generally, the caulk around your tub should last approximately five years. The timetable might change. Replacing the caulk depends on a variety of factors such as: what type and quality of caulk were used, condition of the surface, how it was applied, humidity levels which can cause mold and mildew to grow behind it.