* How to Shim a Toilet

Just in case you are wondering what it means to shim a toilet, this means that you are placing small wedges underneath the base of the toilet between the toilet and the floor in order to level it and to stop it from wobbling.

If the toilet is wobbly, it could pose a serious danger to anybody who is elderly or disabled and moreover, a wobbling toilet can also cause the wax seal that connects the toilet plumbing to the main plumbing to break, which can then cause water from the toilet to leak out onto the floor.

Therefore, if you have a wobbly toilet, it is quite important that you shim it – and that is exactly what we are about to teach you.

How to Shim a Toilet

Rubber vs. Plastic Toilet Shims: Which to Use?

OK, so when it comes to toilet shims, the two main material choices that you have to go with include plastic and rubber. Sure, in the rest of your house you might use wooden shims, but let’s face it, that is not ideal to use in the bathroom, especially around a toilet when there is moisture involved because wood rots, which therefore means that plastic and rubber are the materials of choice.

Plastic Shims

Plastic Toilet Leveling Shims Now, when it comes to plastic shims, these are an ideal choice to go with because they are extremely durable and moreover you can find both soft plastic shims and hard plastic shims. The fact that plastic shims are so sturdy, strong, and stable often makes them the go-to choice for many people. Moreover, this type of shim is also very easy to use.

What also needs to be said is that most plastic toilet shims are made out of post-consumer recycled plastic, which means that they are somewhat eco-friendly.

However, this is not to say that plastic shims do not come with their problems. One of the main problems that plastic shims suffer from is that they can be very slippery and therefore aren’t always that stable or may even come loose over time, as they can simply slip out from between the toilet and the floor.

Another con that you are faced with when it comes to plastic shims is that they are pre-scored in certain locations. Unless you have a multi-tool to cut a shim to a specific length you will be stuck using the ones that you can buy, and this is also a problem in terms of thickness because if a toilet shim is too thin you cannot glue plastic ones together to make a thicker one. Simply put, with plastic toilet shims, you are stuck using what you can buy.

Rubber Shims

Rubber Shims When it comes down to it, due to all of the disadvantages of plastic shims that we just discussed, most people are going to choose rubber shims, and this is what we recommend as well. Rubber shims, although they might not be quite as durable as hard plastic shims, are still more than durable enough to last literally for decades, so this really shouldn’t be a problem.

Moreover, rubber shims are also very soft so they won’t scratch your floor or your toilet. Next, rubber shims are also somewhat malleable and can be cut into shape as needed, and you could also glue various rubber shims together, as the rubber will stick when using super glue or other strong adhesives.

The only downside to using rubber shims is that you really can’t use a mallet or hammer to pound them into the opening, but this is not a huge deal. When it comes down to it, rubber shims are probably the much better choice to go with one compared to plastic shims.

How to Shim a Toilet

Right now we are going to provide you with a step-by-step instructional on how to shim a toilet that is wobbly and potentially even leaking.

Step 1: Turn Off the Water Supply

First and foremost, before you remove the toilet, you do need to shut off the water flowing into the toilet. At this point, you should also flush the toilet and hold the lever down as long as possible in order to drain as much water as you can. Now remove the lid of the toilet tank and put it in a safe spot. Use a sponge or a cloth to remove any remaining water. Now you can disconnect the water supply from the toilet.

With that done, you can now remove the toilet.

Step 2: Remove the Toilet

Using a wrench you will need to unscrew the nuts off of the bolts on each side of the toilet. With the bolts removed, hold the toilet securely by the bowl and rock it back and forth to break the wax seal. Lift the toilet off and then place it on some newspapers or a towel.

You are going to want to use a rag or a plug to plug the drainpipe to prevent noxious smells and sewer gases from coming up into your bathroom. You now want to remove the old wax ring. Beware that wax rings cannot be reused, so if you remove the toilet and break the seal you will need to replace it.

Use a putty knife or any other similar tool to scrape away any old wax that is remaining on the toilet outlet or the toilet flange. At this point, you can also inspect the toilet flange to see if it needs to be replaced.

Step 3: Scope the Area

OK, so now you actually want to install the toilet without the wax ring. This is simply so you can determine where you will need to shim the toilet and how high the shims will need to be in order to stop the toilet from wobbling.

At this point, you want to use your shims and cut them to shape in order to stop a toilet from wobbling. Once the toilet is secure, you can then mark the areas where the shims need to go. Now remove the toilet.

Step 4: Replace the Wax Ring

Remember, your toilet does need to have that wax ring, so at this point, you will need to replace it. Being careful to be very gentle, slide the wax ring onto the toilet outlet. Be very careful not to deform or damage it. In case you don’t want to use a wax ring, you can also use rubber gasket seats.

Step 5: Mount the Toilet and Shim it

With the wax ring or rubber gasket in place, all you have to do now is remove the rag from the drainpipe and then lift the toilet above the flange to align it with the bolts and then put it down gently. Once the toilet is sat down in place, you can then insert the shims as you marked in the previous steps. With the shims in place, you now want to bold the toilet down as securely as it will go.

Make sure not to tighten the bolts too much because most of the toilet is going to be made out of ceramic and ceramic can crack easily. At this point, you can sit on the toilet to see whether or not it is wobbly. If it is still wobbly, you may need to repeat the previous steps to correct any errors that you may have made. If the toilet is no longer wobbly, you can cut away the end of the shims in order to reduce their visual appearance.

Step 6: Turn the Water Back On

At this point, all you have to do is to reconnect the toilet’s water supply and turn it back on. Your toilet is now shimmed and functioning perfectly.

Are There Any Alternatives to Using Toilet Shims?

If you don’t want to invest money in toilet shims, you can always use washers, coins, or any other such flat objects that you can easily slide between the toilet and the ground. With that being said, there is simply nothing better than a good old rubber shim, so we do recommend using those.

Mistakes to Avoid, Tips & Tricks

Before we let you go, here are some final tips:

  • Don’t try cutting plastic shims down to size because it just won’t work. You will just end up making a mess.
  • Don’t try gluing plastic shims together to make a thicker shim, because plastic really cannot be glued together. There are not many adhesives that can adhere one piece of plastic to another.
  • If you have to cut rubber shims down to sides, make sure that you use a very sharp knife that is not going to shred the rubber.
  • If you need to glue rubber shims together, make sure to use an adhesive that is rated to adhere one piece of rubber to another.
  • When using a mallet or hammer to insert the shims, be extremely careful because one wrong strike could completely crack your toilet.


As you can see, shimming a wobbly and leaking toilet is really not all that hard, but with that being said, if your toilet wobbles, especially if you see water leaking out from under the toilet, then you absolutely do need to take care of the problem. It’s not a hard task, but it is a necessary one.