How to Caulk a Bathtub

No doubt caulking around a bathtub is important – it not only creates a good seal between the bathtub and the walls and floors, but it also makes the entire thing look nicer.

In this guide, I’ll talk about everything you need to know about the topic ranging from a detailed overview of how to caulk a bathtub all the way to answers to some of the most commonly asked questions about the topic.

How to Caulk a Bathtub

How to Caulk a Bathtub

Let’s start with a step-by-step overview of the process. It can get a bit messy, but it’s nothing overly difficult.

Step 1: Remove the Old Caulking

Removing the old caulking before applying new caulking is extremely important. You don’t want to apply new caulking over old caulking, because that’s just asking for trouble. You can use something like a 1/2-inch wood chisel or a razor scraper to remove the old caulking.

That said, for certain tub materials, to avoid causing damage, mainly severe scratching, try using a utensil made of plastic. In most cases, a plastic scraper is your best bet. Make sure to place your chisel flush against the bathtub and, using small and quick strokes, chisel away at the old caulking.

Keep doing this until you have removed all old caulking. If necessary, you may need to use some high-quality tweezers to pull out any remaining chunks of caulking that you were unable to remove with the chisel.

Step 2: Clean the Area

Now that the caulking is removed, to make sure that the new caulking can adhere properly to the edge of the tub and to your walls and floors, the area needs to be cleaned, and quite thoroughly too.

First, use a vacuum to suck up any and all pieces of loose caulking that you can find. Old chunks of caulking will prevent the new caulking from taking hold, and it will end up causing gaps and cracks.

If there are still chunks remaining, use some denatured alcohol to loosen and remove them. With that done, you now need to wipe the area down. The main point of that is to make sure that there is no mildew present. Wear some gloves, mix about 100 ml of bleach with a gallon of water, and thoroughly wipe the area down with a sponge or a cloth.

Try to have all windows open when doing this to avoid getting sick from the bleach fumes. Before you can move onto the next step, you need to let everything dry thoroughly and completely. Existing water will ruin caulking that has not yet dried. If there are still any wet spots the next day, use a hairdryer to dry everything off.

Step 3: Get Your Caulking and Caulking Gun

Of course, you are going to need some caulking and a caulking gun. Well, technically, you can caulk without a gun, but we still recommend getting one as it will make the job that much easier.

Caulking guns are all the same, so just buy a basic one. It doesn’t have to be anything overly special. However, what does matter here is the type of caulking you use, particularly in relation to the material that the bathtub is made of.

First off, make sure that you get caulking designed for “kitchen and bath” or for “tub and tile”. Yes, there are different kinds of caulking, so this is very important. Moreover, if you have a fiberglass tub, silicone caulking is best, and for ceramic tubs, acrylic latex caulking is best.

With your items purchased, you can now get to the meat and potatoes of it all.

Step 4: Tape Off the Area

To ensure that you don’t make a huge mess, or in other words, so you don’t get caulking all over the tub and the walls, use painter’s tape to tape the area off. Put tape on either side of the lines being caulked, so you are only left with the area to be caulked visible.

Try to use some kind of ruler or measuring utensil to ensure straightness. It’s going to look much better if everything is even and straight.

Step 5: Load Your Caulking Gun and Caulk

With everything ready to go, insert the tube of caulking into the gun, snip the front of the nozzle on the tube off, and then push the stick of the caulking gun through the rear seal of the tube to break it. Squeeze just a little bit of caulking out of the tube, and then wipe it off, just to make sure that there are no air pockets.

Now, hold the caulking gun at a 45-degree angle in relation to the seam being filled with caulking, and make sure to hold the tip of the nozzle as close to the seam as possible, if not right inside of the seam.

Slowly squeeze the trigger of the caulking gun to apply it into the seam, making sure to move the caulking gun at a decent pace, while maintaining a steady motion. You don’t want to speed up or slow down at any point, or else you will be left with uneven caulking. It’s all about being smooth and steady.

Step 6: Smooth the Caulking Out and Remove the Tape

You will inevitably be left with some imperfections after having applied the caulking. To make the caulking flat and concave, so it looks nice, and to really press the caulking down into the seam, use a damp cloth or a damp rag, put it on your finger, press your finger down into the seam, and run your finger along it.

Remove any excess caulking that is left on the rag or cloth. Make sure to run your finger in one continuous line without any pauses.

Right after you do this, you want to remove the tape. Do not leave the tape on there for too long. If the caulking gets too tacky and dry before you remove the tape, once you go to remove the tape, you will end up pulling the caulking right off along with the tape. You may have to smooth the caulking out again after you have removed the tape.

If you are left with small ridges after having removed the tape, particularly in areas where two pieces of tape met, you may need to use a bit of extra caulking and your smoothing rag to even it all out. You will now need to let it dry, which depending on the type of caulking, may take a couple of days.

Mistakes to Avoid, Tips & Tricks

Here are some tips and tricks for you to follow when re-caulking your bathtub:

  • It helps if you buy high-quality caulking and a good caulking gun. There are some caulking guns out there that are cheap and don’t function properly.
  • If there are any large gaps, do not try to use a ton of caulking to plug them. This will not work.
  • You have to remove 100% of the old caulking for this project to turn out right.
  • Remember that the tip of the caulking tube should be cut at a 45-degree angle, as this will allow for the best precision when applying it to small seams.
  • Always use painter’s tape to tape the surrounding area off, or else you will probably end up making quite the mess.

Frequently Asked Questions About Caulking Around Bathtubs

Finally, let’s answer some of your most pressing questions about how to caulk a bathtub.

Should you caulk between the tub and the floor?

Yes, you should apply caulking between the tub and the floor. This will ensure that when water splashes or drips out of the tub, it does not get in between the tub and the floor. You don’t want water getting under the tub, because this can cause wood to rot, and at the very least, it can end up allowing stinky mildew and mold to grow.

What type of caulk is the best for caulking around a bathtub?

As mentioned in the guide above, what type of caulking you use depends on the tub material, although general “kitchen and bath” caulk should work fine. For fiberglass tubs, silicone caulking is best, and for ceramic tubs, latex caulking is usually considered best.

How long should you wait after caulking before using the bathtub?

Most people say that you need to wait at least 12 hours to use a tub after caulking, but this is only the best-case scenario. Realistically, depending on the temperature and humidity, it can take up to 24 hours or longer for caulking to completely cure.

It’s best to read the instructions for the particular caulking you purchased.

Do you need to fill the tub with water before caulking?

Absolutely not. Your bathtub needs to be 100% clean and dry before you start caulking. Water is not something that should be part of this equation.

Can you caulk over old caulk?

No, you cannot caulk over old caulking. Ok, so sure, you can try, but it won’t produce good results. It’s like continuously slapping new tire patches over the same hole in a tire over and over again. It just doesn’t work.

You need to remove the old caulk before applying the new stuff.

Summary

There you have it, folks, how to re-caulk a bathtub from A to Z.

A really important thing to keep in mind here is that the quality of your tools and materials will make a huge difference, so don’t cheap out. A high-quality tube of caulk and a good caulking gun can make a world of difference.