Smoothing the Way: How to Level a Toilet on an Uneven Floor.

To level a toilet on an uneven floor, use shims or adjustable toilet flanges. Are you a homeowner struggling with a wobbly toilet on an inconsistent floor?

An unlevelled toilet is not only unsightly, but it can also cause leaks and even damage the plumbing system in the long run. Fortunately, you can fix this problem on your own without the need for professional assistance. One way to level a toilet is to use shims, which are small tapered wedges that can fill the gap between the toilet base and the floor.

Another option is to use adjustable toilet flanges, which can be adjusted to fit the height of the floor and provide a level surface. This article will guide you through the easy steps to level your toilet on an uneven floor, and help you avoid any leaky or costly mishaps.

Why Does Uneven Flooring Cause Toilet Problems?

Understanding Why Uneven Flooring Causes Toilet Issues

One of the most challenging aspects of toilet installation is ensuring that it is level. Unfortunately, uneven flooring is a common reality in many homes, and this can cause problems with installation or lead to the toilet wobbling over time.

In this section of the article, we will discuss the reasons why uneven flooring can cause difficulties during toilet installation.

Common Reasons For Uneven Flooring And Toilet Problems

Installing a toilet on an uneven floor can be tricky, and the following are some of the most common reasons why uneven flooring can make toilet installation a challenge:

  • Natural deterioration of the floor over time
  • Changes in the plumbing that could result in the floor shifting
  • The effects of moisture over time
  • Structural weakness in the floorboard or subfloor
  • Errors during the installation of the subfloor
  • Inconsistencies in the tile or other covering materials installed over the subfloor

Effects Of Uneven Flooring On Toilets

An uneven floor can destabilize a toilet over time, causing it to rock back and forth, loosen bolts and create gaps between the toilet and floor. This can lead to leaks or even worse, a broken toilet. Here are some of the most common problems you may experience when toilet installation takes place on an uneven floor:

  • Leaks around the base of the toilet
  • Bowing and breaking of toilet seals
  • Cracks in the toilet tank or bowl
  • Loose or wobbly toilet
  • Uneven flushes, leading to clogging, and other water issues

It’s clear that uneven flooring is a leading cause of toilet instability and leaks. In the next section, we will delve deeper into the different approaches you can take to level your toilet and keep it in place.

Tools And Materials Needed

So, you’ve got a wobbly toilet that’s driving you crazy? Don’t worry; we’ve got you covered! Leveling a toilet on an uneven floor can seem daunting, but it’s a simple task that anyone can do with the right tools and materials.

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In this guide, we’ll walk you through the steps and everything you need to complete the job.

To level your toilet, you’ll need some basic tools and materials. Here’s a comprehensive list of what you’ll need:

  • Level
  • Adjustable wrench
  • Rubber shims
  • Caulking gun
  • Silicone caulk
  • Screwdriver
  • Putty knife
  • Bucket

Let’s take a closer look at each tool and material and its specific use:


A level is used to determine whether a surface is even or uneven. It helps in checking whether the toilet is sloping or flat and making adjustments where necessary.

Adjustable Wrench

An adjustable wrench, sometimes called a crescent wrench, allows you to tighten or loosen bolts and nuts of different sizes. You’ll need it to remove and reattach the bolts that hold the toilet to the floor.

Rubber Shims

Rubber shims are small strips of rubber that you insert between the toilet base and the floor. They fill the gaps created by an uneven floor and support the toilet, preventing it from rocking.

Caulking Gun

A caulk gun is used to apply silicone caulk around the base of the toilet where it meets the floor. This helps to create an airtight seal and prevents water from seeping under the toilet.

Silicone Caulk

Silicone caulk is a waterproof sealant that creates a strong bond between the toilet and the floor. It’s applied around the base of the toilet to prevent leaks and damage that can be caused by water seepage.


A screwdriver is used to remove and reattach the toilet seat if necessary. It’s also used to remove or tighten any screws on the toilet itself.

Putty Knife

A putty knife is used to scrape off old caulk that’s stuck to the floor or toilet.


A bucket is used to catch any water that may spill when you remove the toilet. It’s important to have a bucket on hand because there may be water remaining in the toilet bowl or tank when you disconnect the supply line.

That’s the complete list of tools and materials you’ll need. Make sure you have everything before you start. Are you ready to level your toilet? Let’s get to work!

Step-By-Step Toilet Leveling Process

Measuring The Current Slope Of The Floor

Before you start the toilet leveling process, it is essential to measure the current slope of your bathroom floor. To do this, follow these steps:

  • Place a level on various points across the floor to determine which side is higher.
  • Use a tape measure to measure the distance between the floor and the bottom of the level on both sides of the toilet.
  • Subtract the smaller height from the larger one; this will give you an idea of the slope and height difference.
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Measuring the slope of the floor is important because it helps determine which shims to use and how many of them you will need.

Selecting The Right Type Of Shims

Shims are crucial for leveling toilet on an uneven floor, but not all shims are the same. When selecting shims for leveling your toilet, consider the following:

  • Material: Choose shims made of plastic or rubber because they are durable and resist rotting. Wooden shims should be avoided as they can decay over time.
  • Size: The size of the shim will depend on how much leveling is required. Choose shims that are smaller than the distance between the toilet’s base and the ground.
  • Tapered or straight: It is best to opt for tapered shims because they are easy to adjust and remove if needed.

Performing A Dry Fit Of The Toilet

Before installing the toilet, it is recommended that you perform a dry fit. Dry fitting involves placing the toilet in position without any sealant or bolts before adding shims. Here’s how to do it:

  • Position the toilet over the wax ring and lower it onto the floor.
  • Place a level on top of the toilet bowl and adjust it until it’s level.
  • Check the distance between the toilet’s base and the floor to determine the number of shims required.

The dry fit process helps ensure that the toilet base is level and that the shims are correctly positioned for a stable installation.

Adding Shims To Level The Toilet

Once you have identified the number of shims required, it’s time to add them to your toilet base. Here’s how to do it:

  • Start by placing the tapered shims underneath the toilet base.
  • Use a level to check the levelness of the toilet before adding shims.
  • Insert the shims, making sure that they are evenly distributed.
  • Repeat the process until the toilet is level and stable.

Installing The Toilet And Testing For Stability

After adding the shims, it’s time to install the toilet and check for stability. Follow these steps:

  • Apply a wax seal to the flange and lower the toilet onto it.
  • Tighten the bolts with a wrench, being careful not to overtighten.
  • Check the level of the toilet once again to make sure it’s level.
  • Test for stability by sitting on the toilet and wiggling it while keeping an eye on stability.

Leveling a toilet on an uneven floor may seem difficult, but it’s relatively simple if you follow the right procedure. Measuring the slope of the floor, selecting the right type of shims, performing a dry fit, adding shims, and installing the toilet are the five crucial steps to follow.

Tips And Tricks For Trouble-Free Toilet Leveling On Uneven Floors

Toilet installation can be a daunting task, especially when you have an uneven floor that could cause wobbling and leaks. Here are some helpful tips and tricks to make the process smoother and trouble-free:

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  • Use silicone caulk to secure the toilet to the floor: This will create a tight seal that prevents any water from leaking out of the base.
  • Grip the toilet by the bowl, never the tank: The porcelain of the tank can crack easily due to its weight and fragile construction. Use the bowl to guide the toilet into position instead.
  • Avoid over-tightening nuts and bolts during installation: Over-tightening can cause the toilet to crack or the bolt to snap. Tighten each nut and bolt only until it feels snug and firm, rather than forcing it any further.

When leveling a toilet on an uneven floor, there are a few common challenges that you may encounter. Here are some solutions to help you navigate them with ease:

  • Use shims to level the toilet: These wedge-shaped pieces of plastic or rubber can be placed underneath the toilet’s base to even out the floor. Make sure to use enough shims to keep the toilet level without rocking.
  • Check the flange for damage or wear: The flange is the funnel-shaped pipe that connects the toilet to the sewer line. If it is cracked or worn out, it can cause the toilet to wobble or leak. Replace it as needed before installing the new toilet.
  • Use a level to check for evenness: A spirit level can help you determine which parts of the floor are higher or lower than the rest. Use it to find the areas that need shims and to make sure that the toilet is level once it is installed.

By following these tips and tricks, you can ensure that your toilet installation is a success, even on an uneven or challenging floor. With a bit of patience and attention to detail, your toilet will be stable, secure, and leak-free for years to come.


Leveling a toilet on an uneven floor can be a daunting task, but with the right tools and knowledge, it is achievable. By following the steps outlined in this guide, you can successfully level your toilet and prevent any future leaks or damage.

Remember to always exercise caution when handling tools and materials, and don’t hesitate to seek help if you need it. With patience and persistence, you will have a perfectly level toilet in no time. Regular toilet maintenance is crucial for maintaining a healthy and safe living environment.

Avoiding unnecessary expenses just by mastering this skill is always a welcoming solution. Now that you have all the tips, it’s time to put them into practice!

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