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How to Fix Large Gap Between Tub and Floor : DIY 4 Steps

How to Fix Large Gap Between Tub and Floor the Easy Way

Last Updated on December 17, 2022

Many homes have an issue with the bathtub and floor not leveling out perfectly, leaving a gap that can be both unsightly and insecure. Water can seep under the tub, possibly causing considerable damage to the floor and walls.

It can also provide an opening for pests like insects and rodents to enter the home. The gap is usually caused by a combination of factors, including settlement of the house, normal expansion and contraction of the materials, and even changes in humidity.

If your tub doesn’t fit snugly against the ground, you may be wondering how to fix the large gap between the tub and the floor. Fortunately, there is a straightforward way to resolve this challenge.

You can easily fix the empty area between your faucet and the surface with some basic tools and knowledge. So don’t wait any longer. Get started on fixing that pesky issue today.

How to Fix Large Gap Between Tub and Floor?

How to Fix Large Gap Between Tub and Floor

Most tubs are installed flush with the surrounding floor, leaving a small gap between the edge of the vessel and the subfloor. At the same time, this gap serves an extremely valuable purpose, such as allowing water to drain away from the tub and preventing it from becoming waterlogged.

It can also be visually disturbing and provide the right environment for mildew growth. This is why it must be sealed. Here we will provide you with a step-by-step guide so that you can accomplish the task.

Tools You Will Need:

Before starting the gap-fixing process, it is recommended to gather the following tools. It will be wise to have these materials on hand before starting the project so that you do not have to pause in the middle to run to the store.

  • Tape measure, yardstick, or ruler
  • Caulk gun (if using latex caulk)
  • Foam backer rod (if using filler material)
  • Putty knife
  • Clean cloth or paper towel

When you gather all these tools, you are ready to start fixing the gap.

Step 1: Measure the Tub-to-Floor Gap

The first step to fixing the gap between your bathtub and the surface of your bathroom is to measure the size of the distance. In most cases, the gap should be no more than a quarter-inch wide. If it’s any wider, you may want to consider using expanding foam insulation instead.

This will help you determine how much sealant or fixer you’ll need. To get an accurate measurement, it is best to use a tape measure, yardstick, or ruler. When you know the amount of space you have, you can proceed to the next step.

Step 2: Choose the Right Caulk or Filler Material

Now that you know how wide the gap is, you can select a suitable caulk or filler. If the gap is less than 1/4-inch wide, then you can use a latex caulk. Latex caulk is easy to apply, and it’s also easy to remove if you need to make any adjustments.

It’s a good choice for small spaces because it’s flexible and doesn’t lose its flexibility or crack over time, so no cracks or shrinking will occur.

The gap needs to be wider than 1/4 inch, then you’ll need to use a foam backer rod. It is a long, cylindrical piece of foam that helps to fix big gaps. It’s also flexible, so it won’t crack or shrink over time.

You can find foam backer rods at most hardware stores. Once you’ve selected the ideal caulk material, you’re ready to move on to step three.

Step 3: Apply the Filler/Caulk

Then you will need to apply the caulking or filler material in the gaps. If you are using a caulk gun, cut the tip of the tube at a 45-degree angle and puncture the seal inside the nozzle.

Insert the tube into the gun and squeeze the trigger to dispense the caulk. For best results, apply the caulk slowly and evenly as you apply the caulk.

If you are applying packing material, such as putty, scoop out a small amount using a putty knife and apply it to the hole. Again, use a smooth, even motion when fixing the gap. Afterward, you apply your sealant, allowing it to dry completely.

Step 4: Remove Excess Filler

Now that caulk or any other fixer material is in place. It’s time to remove the excess. This can be done with a putty knife, but for a neater finish, use your fingers. First, run your finger along the joint to smooth out any caulk and create a uniform seal.

Then, wipe with a cloth or paper towel away from any excess material that might have squeezed out onto the tile or floor. Be sure to clean off your finger periodically to avoid making a mess.

Whenever you’re satisfied with the results, you can step back and admire your handiwork. With just a little time and effort, you’ve created a tight, weatherproof seal that will keep your bathroom looking its best for years to come.

These are the steps you need to follow in order to fix the void between your tub and floor. By following these simple instructions, you can ensure that your bathroom is sealed properly and looks great.

What Causes a Large Gap Between the Bathtub and the Floor?

What Causes a Large Gap Between the Bathtub and the Floor

Every year, homeowners spend hundreds of dollars repairing water damage that occurs because this gap wasn’t adequately sealed. So it is very important to figure out what is causing the void and then take the necessary steps to fix it. Here are some of the most common causes of this large void:

The Tub Was Not Installed Properly

A gap that exists between the bottom of the jacuzzi and the floor of the bathroom is most commonly caused by improper installation of the tub. When the tub is installed, there should be a bead of caulking placed around the edge where it meets the floor.

This caulking helps to create a waterproof seal that prevents moisture from entering. Over time, this seal can degrade, allowing water to slowly seep through and cause the wood around it to rot.

The caulking may have been improperly applied in the first place, leaving gaps that allow water to pass through. In either case, replacing the caulking is usually the best way to fix the situation.

The Tub Has Shifted

One possible cause of a large gap at the bottom of a bathroom tub could be that the sink is out of place. This can happen over time, as the weight of the sink along with the water inside it puts pressure on the floor.

The tiles or grout around a bathtub may also crack, allowing water to seep underneath and loosen the foundation. In some cases, this can cause the entire unit to shift out of place.

If you notice that your tub is significantly bigger than the surrounding area, it’s important to have a professional inspect your bathroom to determine the cause. Otherwise, you may be at risk of serious loss to your home.

The Floor Has Settled

The Floor Has Settled

Though it may seem like your tub is sitting pretty on top of your floor, there are actually a few things that can cause it to become misaligned. One such thing is settling.

As your home ages, the foundation beneath the bathroom sink can begin to settle, creating a gap between the two surfaces. This is often most noticeable in homes with a concrete slab foundation, as concrete is known for settling over time.

If you have young children in your home, they could easily fall through the gap and injure themselves. As such, it is valuable to identify the cause of the incident and take corrective action promptly.

There is Damage to the Tub

There’s a fourth reason why there’s too much space between the basin and its floor: it’s damaged. Over time, excessive use can cause cracks and chips in ceramics, which can then lead to bigger holes.

Also, if the plunge bath is not sufficiently supported, it may start to sag, creating even larger gaps. In either case, it is important to have the issue repaired as soon as possible to prevent further deterioration of the tub and the surrounding area.

Once the problem has been fixed, you should be able to once again enjoy a tight seal with your bathroom.

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Improper Caulking

It is also possible for there to be a large distance from the tub to the floor due to improper caulking. Over time, silicone caulk can become cracked or worn away, leaving an opening for water to seep through. Improper application of the material may result in gaps.

If the stick caulk is not applied evenly or if it is not smoothed out properly, it will not create a tight seal. As a result, water will be able to work its way behind the tub and cause trouble to the subfloor.

To avoid this problem, make sure to use high-quality sealant and ensure that it is applied correctly. These are the five most common reasons for tubs to have a space between them and the floor.

Whenever you notice a gap, you should take action to prevent further deterioration. Depending on the cause, you may be able to resolve the issue yourself, or you may need to call in a professional.


We will take a look at some frequently asked questions about large gaps around tubs. Hopefully, this will allow you to better understand what’s going on.

1. What is the Best Filler for Large Gaps?

What is the Best Filler for Large Gaps?

While there are several options, sanded caulk is one of the best ways to close a large area. Sanded caulk is explicitly designed for gaps larger than 1/8 inch, and it can provide a much more seamless finish than regular silicone.

On top of that, the filler is also much easier to apply, as it can be squeezed directly into the space. As a result, sanded caulk is the best option for fixing a large gap created by a tub and floor.

2. How Do You Finish Tile Next to a Bathtub?

When tiling around a bathtub, the process is very similar to tiling any other surface. The main thing to keep in mind is that the floor tile needs to be properly sealed so that water does not seep behind it and cause damage.

To begin, apply a layer of thin-set mortar to the area where the tile will be installed. Then, start at the bottom and work your way up, laying each piece in place.

Once all of the tiles are in place, use a caulk gun to apply a bead of sealant along the seams. Finally, use a grout float to apply over the entire surface. Once the grout has dried, your new tile will be waterproof and ready for use.

3. How Do You Stop Water From Seeping Behind a Bathtub?

Seeping water can cause a lot of problems in your bathroom. Not only can it ruin your flooring and wall, but it also encourages the growth of mold and mildew.

Sealing the area behind your tub is one way to prevent water from seeping through. You can use caulk or silicone sealant in order to seal any openings between the plunge bath and the wall.

It may be necessary to apply a waterproof membrane behind it. This will create an extra barrier that will help to keep water out. By taking these steps, you can help to protect your bathroom from water stains.

4. Is Grout Needed Between the Tile and Tub?

Whenever it comes time for you to install new tiles in your bathroom, you may wonder whether or not you need to use grout. While it is not strictly necessary to put adhesive on the tile, doing so can provide a number of benefits.

First, the grout helps to fix any gaps between the mosaic and the jacuzzi, creating a watertight seal that will prevent moisture from seeping behind the material.

The glue also keeps the surface in place, making it less likely to come loose over time. Finally, this finish gives the tile a finished look and can help to camouflage any imperfections on the surface of the tub.

For these reasons, many homeowners choose to use grout when installing new tiles in their bathrooms.


Perhaps, the information provided above will help you to understand how to fix the large gap between tub and floor. By taking action to fix the gap, you can prevent further damage and maintain the appearance of your bathroom.

In order to achieve the best results, choose the right filler for the job and try to apply it as seamlessly as possible. You may have found some benefits from this article.

Remember that you should always take precautionary actions before starting to work on something in your house. If possible, please make sure to clean the area thoroughly before applying any of these materials, and follow the directions carefully.

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How to Fix Large Gap Between Tub and Floor : DIY 4 Steps

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