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Gap Between Tub and Vinyl Floor? Fill It Professionally

When you discover an unsightly gap between your tub and vinyl floor, you may assume poor workmanship is to blame. Possibly, but the gap may form due to simple expansion and contraction.

You will want to make sure that your tub did not cause the gap by leaking. Replacing the tub is one possible solution. In most other cases, your tub is fine, and you need to repair the gap to prevent water damage under the vinyl.

Gap Between Tub and Vinyl Floor

You can hire a professional or follow the steps below, save tons of money, and find out how you can DIY the job professionally.

How To Fix or Seal a Gap Between the Tub and Vinyl Floor

If you lay a new vinyl floor and see a gap above a ¼ inch between the vinyl and tub, the gap is large for aesthetic and practical reasons. To repair the gap, apply caulk or trim with adhesive, whichever looks better in your bathroom.

Choose How To Fill the Gap

You have several methods you can choose to fill the gap, but the options essentially come down to two choices: caulk or trim made out of plastic or rubber.

Many online guides only tell you how to caulk the gap, and with trim, you can also use caulk to make the trim look nice. Using caulk with trim is optional and depends on the kind of trim you use.

In terms of looks, the caulk will blend in and appear to be a white line dividing the floor and tub. The trim will stick out more and look like a design choice to have something that breaks up the transition from floor to tub.

Assemble Your Tools

The tools for caulk and trim are slightly different.


  • Bleach
  • Bowl
  • Old toothbrush
  • Silicone (glue plastic trim or rubber trim without pre-attached adhesive)
  • Utility knife and/or strong scissors
  • Trim of choice


  • Dish soap
  • Painters tape
  • Bleach
  • Bowl
  • Old toothbrush
  • Utility knife
  • Putty knife
  • Kitchen & Bath caulk adhesive (look for mildew resistant)

The Trim Method

Trim is not a single product made of one material. There are wood trims, plastic trims, and rubber trims. For our purposes, we want to stick with plastic or rubber. I like rubber quarter-round better than plastic because rubber resists mold and fungus and lasts a long time.

Rubber also makes a great choice if you want to put in a trim that breaks up the floor and tub with volume. Rubber trim will not look as substantial as baseboards separating walls and floors, but the decorative effect is similar.

There are slightly different methods for attaching trims to the gap between the tub and vinyl floor, but the principle is the same. An adhesive, either in the gap or on the trim, dries and holds the trim in place.

Caulk Applaying

We have bleach, a bowl, and an old toothbrush on the list because you should clean the area first. Bleach will kill any mold or mildew. Put water in the bowl, a capful of bleach, and dip the toothbrush into the mixture. Scrub off any discoloration with the toothbrush.

The putty knife or utility knife may help clean the area if the toothbrush cannot scrub a stain off.

Some rubber trims have 3M tape, which holds extremely well, already applied, and you only have to measure the length of the gap, cut the trim, expose the tape, and seal the trim over the gap.

Applying trim is easy and takes less time than caulk. The important thing to be sure to do is to push the trim into the gap with some downward pressure. 

Pushing downward and inward secures the trim against the floor and tub equally without a gap.

Silicone adhesive allows you to move the trim a bit if necessary. The adhesive takes a day to dry and set, so there is plenty of time to make minor adjustments.

If you have rubber with 3M tape, the trim slides into place easily, but once the tape sticks, you cannot move the trim again.

Finally, take some tape and stick some strips over the trim. The tape helps the trim to set in the right place and warns anyone else in the house not to touch anything.

If you have a small gap between the rubber trim and anything else, use the caulking method below to seal the gap.

The Caulk Method

In the caulking method, the bowl serves two purposes. First, you use bleach and water in the same way as the trim method to clean the area.

Once you finish cleaning, dump the bowl and put in some fresh water with a bit of soap. You can set the bowl aside for now and get the tape. Before using the tape, you may have to dry the tub and floor around the gap.

Use the tape as a guide to avoid smearing any caulk on the floor or tub. Applying the tape may seem like a bit of a tedious step in the beginning, but in the end, you will be happy when you remove the tape to reveal a clean caulk line.

Carefully stick the tape on the vinyl floor flush with the gap. Do the same where the tub meets the gap. The gap you leave between the tape will be your caulk line, so make sure the space looks how you want the caulk to look.

Once the tape looks right, you are ready to apply the caulk. You will probably open a new tube, so cut the tip at a 45° angle. The caulk for this job probably comes in a squeeze tube. If not, add a caulk gun to the materials list.

When you apply the caulk, do not worry about unevenness or how straight the line is. The time taken to apply the tape pays off during application. Once the caulk covers the whole gap, set the bowl of soapy water nearby.

Whenever you apply caulk, you always finish the job with a wet finger, at the very least. The soap in the water makes smoothing the caulk easier. With a wet index finger, press the caulk into the gap by dragging your finger and making a compact line.

The tape is there because some of the caulk will smear on the tape. The only caulk we want to keep is the amount necessary to fill the gap. Always keep your finger wet. For the length of a bathtub, you will probably re-wet your finger two to four times.

Once you make the caulk smooth, slowly and carefully pull up the tape. If you laid the tape correctly, a clean line of caulk should be the only thing remaining. Once the tape is off, I like to wet my finger and go over the caulk one more time in case the tape disturbed any caulk in the gap.

The Caulk Method

Finally, let the caulk dry overnight, and the gap should not pose a threat for many years.


Sealing a gap between a tub and a vinyl floor is pretty simple. However, there are always surprises that may arise and create questions.

How do you remove caulk before applying fresh caulk?

Removing the caulk depends on the age of the caulk. Old caulk may require a chemical remover that you apply the day before and remove with caulk removing tools, if necessary.

For newer caulk, you should be able to get the job done with your utility and putty knives or another type of scraping tool.

Test your caulk by trying to make cuts first. Sometimes a razor blade works the best. If you can use a knife, always do so to avoid exposure to potentially harmful chemicals.

Can I make caulk at home?

Yes, but nobody recommends doing so because you cannot make long-lasting caulk with a homemade recipe. Store-bought caulk lasts for years which homemade caulk cannot do. Furthermore, you might not notice when water damage begins.

All you need to make homemade caulk is wood glue and baking soda. Caulk is extremely thick, like toothpaste. Mix a few tablespoons of baking soda into the glue until you form a paste-like consistency.

You can apply the caulk with a tube or with popsicle sticks.

Is sealing gaps in the bathroom with caulk necessary?

Sealing gaps in the bathroom in places that will get wet is necessary. You do not have to use caulk. Caulk is cheap, effective, long-lasting, and attractive when done right. You might as well make life easier on yourself.

In Closing

Sealing a gap between the tub and vinyl floor is a simple, inexpensive fix that can prevent thousands of dollars in water damage down the road. If you have a gap in the bathroom, you have to use a seal of some sort.

Caulk and trims both work effectively and last for years, so the decision of which to use is mainly a style choice. If you do a good job planning the work and take precautions, there is no reason that the result will not look professional.

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