If you are installing a new toilet in your bathroom, you may notice that the toilet flange height is not what it needs to be for your new throne. A toilet flange that is too high or too low is a common problem when replacing an old toilet with a newer model, or when you have had new flooring installed in your bathroom. Often, the base of the new toilet is a different thickness to your old toilet, or maybe the floor level has changed with a different thickness of tile or wooden floorboard.
There are a couple of problems that arise when a toilet flange is either too high or too short. If the flange is too high, the toilet may rock side to side, which can damage the wax ring underneath and potentially the floor, too.
If the flange is too short, it may prevent an adequate seal between the toilet and the drain, which can allow sewer gasses and fluids to escape into your home. Not only is this unpleasant but it also presents a health risk due to sewer gases being toxic.
What Should The Height Of A Toilet Flange Be
Ideally, the toilet flange height should be flush with the finished floor. There can be a ¼-inch difference above or below the floor, but no more. This flush to ¼-inch height will ensure a watertight seal when the new toilet is installed.
While most new and existing homes are built with this measurement in mind, remodeling the floor in your bathroom will likely change the toilet flange height, especially if you install the new floor on top of the old floor or choose flooring that is thicker than the existing floor. It is fine to do either of these things, but you will need to adjust the toilet flange height accordingly.
Should A Toilet Flange Be Flush With the Floor
The short answer is yes, the toilet flange should be flush with the existing finished floor. According to most plumbing professionals, the ideal toilet flange height is flush or just on top of the existing finished floor. You have about ¼-inch play above or below the existing floor, which will ensure any wax ring you purchase will fit and seal correctly to prevent the toilet from leaking at the base.
Raising the Flange for a Tiled Floor
If you have recently tiled your bathroom floor, you may notice that the toilet flange is not flush with the new floor. It is likely sitting just below the new floor, which could be a problem when you reinstall the toilet.
The good news is that you can raise the toilet flange to flush with the new floor. To do this, you must remove the flange completely to place a spacer underneath it. Begin by removing the two bolts that hold the flange in place. Pull the flange out of the drain and place it aside. Measure the distance from the top of the new floor to the flange and place a spacer in the drain that matches that measurement. Push the flange down into the drain until it meets the spacer and screw in the bolts to hold it tight.
What If The Toilet Flange Is Too Low
In instances where a new floor is installed around an old flange in the bathroom, the toilet flange height will likely be less than ideal. When this happens, you have a couple of options (aside from placing a spacer) to fix the issue. Below, I’ll tell you your options and then discuss a few concerns I have with each.
Use A Toilet Flange Extender or Spacer
Many home improvement stores carry a variety of flexible and rigid PVC toilet flange extenders, also called spacers. These extenders can be bought separately, or they often come in a kit that contains everything you need to raise your toilet flange height to flush or just above your new flooring. A toilet flange extender is simply the standard funnel that produces a solid pathway from the bowl horn to the toilet flange by sliding into the toilet drainpipe, plus a few spacers to raise the flange position. While most flange extenders work in combination with wax rings, in some instances, they can actually replace the wax ring under a toilet.
I would recommend two options, one being this innovative Danco Extender with Wax Ring. This product allows for water-tight installation even when the flange is up to 1-1/2″ inches below floor level or up to 1/2″ above the floor level. You can purchase the Danco extender from Amazon.com for $12. There are several fitting kit options to choose from including adjustable bolts, so it’s an extremely versatile product.
The other product I recommend is a flange spacer, which you can purchase individually or in a kit form, like the product below. This Oatey kit contains one 1/2-inch spacer and a 3-inch and 4-inch gasket seal, along with the bolt kit. The Oatey toilet flange spacer kit is available to buy from Amazon.com or any other good hardware store.
Using Double Stacked Wax Rings
Stacking two wax rings atop one another is the way most homeowners fix a toilet flange that is too low after new flooring is installed. The fix involves placing a regular wax ring on top of a thicker wax ring with a built-in flange.
While this is one of the easiest and cheapest ways (you can buy the parts for less than $15 at most home improvement stores), it may not be the best way to fix the issue. Here’s why.
- You won’t know if the toilet has been sealed properly until you re-install it and give it a flush.
- If there is any ‘extra’ space between the flange and the bottom of the toilet, the flange bolts may not be supported properly. This could throw the bolts sideways, which could damage the wax ring or crack the porcelain base of the toilet.
- The wax rings may not form a tight bond between themselves, especially if the new flooring is not completely even, resulting in a wobbly toilet.
- Since there is no solid flange for the top wax ring to press against, there may not be a tight seal between the bowl horn and the top wax ring, which could lead to gas or fluid leaks.
- If your toilet clogs or you must use a plunger, the increased pressure could cause the delicate seal between the wax rings to fail.
How Low Is Too Low
On average, anything more than ¼-inch below the existing floor could be too low when it comes to toilet flange height. Of course, every situation is different, so you will need to determine what is ‘too low’ in your case.
If, after installing your new floor, you notice that the toilet flange falls more than ¼-inch below the top of the floor, you must assume it is too low and add a spacer, install an extender, or use two wax rings stacked atop one another to raise the flange to an acceptable height. Failing to do so may allow sewer gasses to escape into your home, cause fluid leaks, or damage your new flooring.
What To Do if Your Toilet Flange Is Too High
Up to this point, I have only talked about what to do if your toilet flange height is too low. In some cases, however, a toilet flange can be too high. When a toilet flange is too high, it can cause the toilet to rock to and fro, which can cause costly damage over time. This happens most commonly when an older toilet is replaced with a newer, sleeker model. By far the easiest option is to use the Danco extender from Amazon.com that I mentioned earlier. This works on flanges positioned up to 1/2″ above the floor level.
There are several solutions that you can deploy to fix this issue, including bridging the gap, raising the floor, and replacing the flange so that your toilet sits solidly on the floor to create a secure seal.
Bridge the Gap
Filling the gap created by a toilet flange that is too high is the most common resolution homeowners choose because it is the easiest and least expensive option. You have a few different options for this fix.
I want to start this section with this warning: plywood is not a permanent solution for a toilet flange that is too high. The reason I say this is because over time plywood can rot and collapse, especially if there is a leak or high moisture in the room. With that said, plywood can be a good ‘placeholder’ until you can fix the issue permanently.
To use plywood to resolve your excess toilet flange height, follow these steps.
- Measure the height and circumference of the plywood you are using. You may need several layers of wood to achieve the correct height.
- Mark the measurements on the plywood and cut each piece accordingly.
- Fit each piece of plywood into place, securing them with glue or screws. Make sure they are level.
- Place the toilet on top of the plywood, ensuring it is level.
- Secure the toilet.
- Check for leaks. If leaking still occurs, you will need to remove the toilet and adjust the plywood as needed to achieve a tighter fit.
Many people prefer to use grout as a way to fix a toilet flange that is too high because it is cheap, easy to use, and durable. To use grout for this purpose, follow the steps below.
- Follow the package directions to mix the grout into a paste.
- Situate the toilet in place, making sure it is level and stable. Use rubber shims as necessary to achieve this.
- Fill the gaps around the base of the toilet with grout. Avoid grouting the shims as you will need to remove them later.
- Allow the grout to dry for 24 hours.
- Remove the shims.
- Fill in the gaps left by the shims with grout.
- Allow the new grout to cure for another 24 hours.
- Install and tighten the tee bolts that hold the toilet in place.
- Ensure the toilet is level.
Using cement to resolve a flange that is too high is ideal since this material creates a solid foundation for the toilet. If the gap between the toilet base and the floor is minimal, cement is your best option.
- Measure the height of the gap and the circumference of the toilet base. Make sure you measure carefully as the height of the gap will determine how many cement boards you will need.
- Mark the boards with the dimensions you measured. Cut each piece – one at a time – including one inch in the middle.
- Spread the cement using a trowel.
- Position the boards on top of the wet cement.
- Using screws, secure the boards.
- Add floor tiles to cover the boards and create a finished look.
- Place the toilet back where it belongs and tighten the tee bolts.
- Check that everything is level.
Note: Cement is not a good option for large gaps created by a toilet flange that is too high. If this is the case, you should consider raising the floor level or replacing the flange itself (more on these options below). The solutions I have provided above are great for DIYers who don’t have the time or budget for a more extensive fix.
Raise the Floor Level
All the solutions I mentioned above will do the trick, but none of them can be called aesthetically pleasing. If you are looking for a better alternative to fixing a toilet flange that is too high, try raising the floor level. Keep in mind that this solution is going to cost more money and take more time than anything I have suggested thus far. If you are up for the challenge, here is what you need to do.
- Measure the height of the gap between the toilet flange and the top of the floor. This will give you the exact thickness of the flooring you need to purchase.
- Remove the toilet and any other fixtures on the floor in the bathroom.
- Remove the old flooring.
- Install the new flooring, making sure it creates a level surface for the toilet to sit on properly.
- Replace the toilet and tighten the tee bolts.
- Ensure that everything is level and leak-free.
Change the Flange
Changing the flange should be a last resort as doing it incorrectly can result in irreparable damage to the drainpipe and the entire system. You should try to make one of the other options work first before turning to replace the flange.
To replace the flange with a shorter one, follow these steps.
- Clean the area around the flange to remove dirt and debris.
- Stuff an old rag or something similar into the flange to stop sewer gases from rising or debris from falling into the pipe.
- Using extreme caution, start removing the outer portion of the flange using a hammer and chisel. You may also use a variable-speed drill to do this, taking off small pieces at a time to avoid damaging the pipe.
- Carefully remove the inner part of the flange without cracking or otherwise damaging the pipe.
- Use a grinder to shorten the pipe until it is flush with the floor.
- Insert the new flange.
- Drill holes in the floor to solidify the new flange in place.
- Place the toilet on the flange and tighten the tee bolts to secure it into place.
If you need a visual aid to help you replace the flange under your toilet, take a look at this video.
FAQs Toilet Flange Height
How do I know if my toilet flange is too high?
A toilet flange that is too high may cause the toilet to wobble or leak. There may also be a gap between the toilet and the floor.
Does the toilet flange go over the pipe?
No, the flange goes inside the pipe to create a watertight seal.
As a retired Master Plumber Jamie has over 30 years of hands-on experience, making his plumbing knowledge second to none. He has also worked on both residential and commercial HVAC installation and repair projects.