How to Repair the Caulk in Your Bathtub

Howdy folks…. Well I had a bit of a weekend project that I completed today. Our bathtub had some old discolored and moldy caulking around the top where the tile meets the tub. Evidently who ever tried to repair it the first time just applied some clear silicone sealer on top of the damaged caulk and it looked horrible.

What happens when you do a repair like that, is the mold that is underneath the rubber silicone will continue to grow mold and eventually it will turn the silicone a brownish black color. And believe me, it looked horrible. So I took on the do it yourself project of fixing it, and it turned out pretty good if I do say so myself.

But lucky for you, I was thinking about my readers when I tackled this project. So I thought I would document the step I took during the repair and share it with you in case you ever need some help doing something like this.

Photo of utility KnifeRemove the Old Caulk and Mold

So in the first step is to remove all the old caulk and sanitize the area so the mold will be killed. This way it will not continue to grow once you’ve repaired the joint where the tile meets the bathtub. So as you can see from the image, I used a simple utility knife and used it to cut along the top of the tub and the bottom of the tile in order to loosen the bond of the existing caulk and silicone. Once it was good and loose, I went along the edges using a putty knife to scrape the old stuff out of the crevices. It wasn’t as easy as it sounds, but with a little elbow grease, it all came out fairly easy. The total time it took to remove the old Photo of a Putty Knifecaulk and silicone was probably about an hour.


I used an old measuring pitcher to collect all the trash I collected as I went. This makes your clean up way easier in the end. You will actually be surprised at how much dirty gunk you will retrieve. If your bathtub is very old it can collect a lot of mildew and grime over the years. That stuff is terrible on your allergies and health. But once you’ve remedied the situation, it is easy to keep it under control from Photo of old mildew infested caulk and silicone.that point on. Take a look at all the goodies I collected out of this tub.


Killing the Mildew and Germs

After you’ve gotten all the old caulk, germs and mildew out of the grout line then comes the next step. This step is crucial to preserving the cleanliness of the new seal you’re going to put on your tub. You need to get some concentrated bleach cleaner, or you can use diluted bleach. Thoroughly spray the Photo of spray bottle with bleachinfected areas with the bleach solution and let it sit for at least an hour so it can eat away at all the mold and mildew. This will sanitize the area as well as kill all the germs that may be hiding in there. It is some good safety advice to wear a protective mask when working with the bleach. It’s not safe to breathe in the fumes. Even an simple painters mask will work. If you do not have one, they are super cheap at the hardware store, or at least get a cloth and hold over your mouth and nose while spraying.

Scrub the Area Thoroughly

After you’ve let the bleach solution sit in the cracks and crevices for at least an hour, then it’s a good idea to take a scrub brush and thoroughly scrub the area until it is well cleaned. This will also help remove any extra loose caulking that may still be on the surface area. If you have a wire brush this will work good Photo of scrub brushtoo. But be careful, you don’t want to scratch the surface of your tub. Especially if it’s a porcelain finish.

Once you’ve finished scrubbing the tub real good, then you can get a cup or possibly a measuring pitcher like I used and fill it with water and use it to rinse out the cleaned area really well. Make sure all areas are clean and no signs of mildew or mold are present. If you still see signs of mold or mildew, then repeat the process of bleaching the area.  When you are certain the area is good and clean, then jump back down to this part of the post to continue on.

Dry the Surface Real Good

After you’re finished cleaning and rinsing, then dry the area really well with a dry cloth. Next get a clean, dry cloth and some rubbing alcohol. Yep that right, rubbing alcohol. Moisten the cloth with the rubbing alcohol generously and rub it over the surface of the photo of scrubbing the bathtubarea you’re repairing. This will help to evaporate any left over moisture that may be hiding in the cracks and crevices. Once you’re sure it good and dry, then let it sit for about 30 minutes before going on to this next step.

Filling in the Cracks

Now that our tub is nice and dry. Everything is clean and the old caulking is out of the way, it’s time to fill in some cracks. If you have any areas that have deep crevices you may want to get a small tube of caulk to run along those edges to make sure everything is sealed well. I do not recommend a rubber silicone for this type of project. Be sure to get the white caulk, your hardware specialist can direct you to the right stuff. After applying a small bead along the seams of the crevices, then take you finger and run it along the edges to push it into the cracks and make a smoother, cleaner looking caulk line. Most caulk will recommend letting it sit for 72 hours after the application so that it may fully cure.
Photo of caulk strip

Applying the Caulk Strip

Ok, once our caulk is dry, it’s time to apply the caulk strip. You can purchase this at any hardware store and it comes in a small role like pictured on the left. This stuff isn’t actually caulk, but it’s a plastic water barrier that has a sticky backing on it that will adhere to the tile and tub. This stuff is really good and it seals out any moisture and will prevent mold and mildew from forming in your tub again.

This stuff is really easy to apply and only takes a few minutes. First you want to measure out three strips. Measure the length of your tub and cut one strip to go along the length of the back side of the tub. Then measure the width of the tub and cut two more strips, one for each end of the tub. Now it’s time to apply it.

The backing on this has two adhesive strips running down the length of it, and a folding Photo of folded caulk stripcrease in between them. So take your long piece and fold it in half, making sure the adhesive is on the outside once folded. It’s probably a good idea at this time to put the strip up against the area you want to apply it and just make sure the fit is correct. That way if you cut it too long or it doesn’t fit properly, this will give you a chance to correct the situation before it’s stuck down.

Then peel the backing off of the strip down to about twelve inches or so, just enough to Photo pealing backing off of caulk stripgive you room to begin application. Starting in the corner, place the caulk strip in the proper position and then wedge it into the crease where the tub and tile meet, forming a 90 degree angle.

You do not have to press firmly, just gently push it down toward the tub first, and then the part that meets the wall. It’s important not to stretch, pull or rub your hand along the strip while applying. Just lightly press it into place.  Continue doing this along all three side of the tub until installation is complete. Then go back around the caulk strip and firmly press the Photo of applying caulk stripstrip down using your fingers to ensure a good seal. It’s best not to use your tub for at least 12 hours after installation.

Finishing Up After the Job

Now we’ve completely finished our project and the tub looks great! No more mold or mildew and a nice clean looking barrier to keep out moister so it will not come back.

Of course all jobs have a clean up after their over. So be sure to dispose of the old mold and mildew infested caulking that you removed. It’s good to not throw it in your household Photo of finished bathtubtrash. If you have a trash can or dumpster outside of the house, please use them instead. Mold spores and mildew can become airborne and it’s not good to be breathing in that stuff. Then of course return any tools you used during the job back to their rightful place. You don’t want anyone to accidentally cut themselves on a utility knife or something.

So there you have it, simple and easy and it can save you a ton of money by not having to call out the professionals. By the next morning you should be using you nice squeaky clean tub without having to look at that terrible mildew ever again. Hope this post is helpful to some of my readers. May all your home projects be successful!


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Founder of Odd Random Thoughts and plenty of things on the mind. I love bizarre and interesting information and will always form a unique opinion on it. If you have an interest in strange and unusual subjects and would like to share what you've learned, please feel free to Apply to Become a Contributor.  I would love to hear from you!

Robert Tuttle

Founder of Odd Random Thoughts and plenty of things on the mind. I love bizarre and interesting information and will always form a unique opinion on it. If you have an interest in strange and unusual subjects and would like to share what you've learned, please feel free to Apply to Become a Contributor.  I would love to hear from you!


  1. good job really amazing work and experience

  2. Useful and innovative idea man !! Thanks for the share and keep sharing ! :-)

  3. Good stuff, excellent information for property managers who handle their own make readies.

  4. I’ve hever heard of caulk being in strips before. This is a wonderful invention.

  5. When should you consider a mold testing? When there is a musty smell, but you cannot find any visual evidence, when there is visual evidence and you need to determine the extent of infestation and damage, when there is no visual evidence or smell, but a member of the family has persistent symptoms (sensitivities vary by individual), when you need help locating the source of the water that’s causing the mold, when you’re buying or selling a home, when you need a formal plan to remove the mold and repair the damage, when you need someone to supervise mold removal and repairs.

    Find out more at Mold Testing Services

    • I’m allow this link to post in your comment because I find it very relevant to the discussion. I appreciate you bringing this to the table. Many folks do not know that it’s very important to get a mold inspection especially if you discover mold within your walls or behind sheet rock. A mold infestation can make members of your household extremely sick if it’s not treated right away. Thank for your input on this Joseph. :)
      Robert Tuttle recently posted…What is a Lobotomy and Can it Cure DepressionMy Profile

  6. andersonsrodriquez

    Very easy and convenient to use in repairing a caulk in the bathtub. Thanks for sharing this idea.

  7. For one I love your anti spam box “I am not a Vampire” On a more serious note. Thank you for the detailed description of how you cleaned your bathtub. I went through and cleaned mine following your steps and it’s practically sparkling.

  8. House Cleaning Wellington

    I love this article!! I would like to wash our bathroom with a good cleaner!!Amazing article!Thanks for this article!!

  9. Robert,
    very informative. What brand/type of caulk and caulk strip did you use (or recommend) ?


  10. I think we should be check per month bathtub !! There is need to maintain the internal part of our bathroom !! If you will not be check then it would be possible the water pipe can be linked or may insects are moving there then it will be harmful for you !!

  11. A nice thing that you know how to repair any bathroom or bathtub problems.

  12. Nice guide, this will make it easy for anyone to follow and get the job done correctly…

  13. You make this look so easy! I tried to recaulk my tub and made a huge mess. The caulk strip seems to be so much more convenient and less messy than the stuff I got. I did want to thank you for pointing out the need to get rid of mildew when the old caulk is removed. It’s like painting moldy walls; the mold is still there and you’ve given it a dark damp place to grow. Using the bleach solution will definitely make sure any spores left are gone.

    • Hi Jamie and thank you for the feedback.

      With any household project there’s normally a bit of elbow grease involved and this project was no exception. As you mentioned ridding the surface areas of any mold spores and mildew left behind after removing the old caulk is of utmost importance. Mold is like a plague and will spread and grow rapidly, that stuff is very nasty and can make you and your family very sick.

      The caulk strip does make this project quite easy, but if you intend to use it, be sure the surface area is completely dry before applying the strip or it may break loose from the tub and tile and that means buying a whole new package of caulk strip and redoing the job.

      Wishing you the best in your home improvement projects!

      Best Regards,
      Robert Tuttle recently posted…What Does it Mean When Someone Has Perfect Pitch?My Profile

  14. Thank you for the advice! I also meant to ask if you have a certain brand of caulk strip you suggest to use, given that I’m sure not all are made equally.

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