2 Ways on How to Correct Toilet Flange That Is Too High

By: Jan Hajek | Date Posted: March 23, 2017

If there is a part of our house that we want to look good and function well, it would be our bathroom, especially the toilet! It is an important place in every household that we cannot afford at any one time for it to be dysfunctional or else it will create so much discomfort to everyone.

Over time our restrooms called for an overhaul. Most often when renovating, we want to change almost everything, especially toilet bowls. In toilet bowl replacement, there are usually problems that we can encounter in the process and it could either be “toilet flange too low” or “toilet flange too high.” In this article, we shall discuss the latter.

What is it about the toilet flange? Do we need it?

Before we even go further with any discussion, it is best that we know what a toilet flange exactly is. A toilet flange is a device that joins your toilet bowl into the septic tank pipe. They come in various materials such as PVC or cast iron. The flange is bolted to the floor to secure the toilet bowl. With the flange is a gasket used to ensure that you will not have a leaky toilet.

toilet flange too high1

Do you know that if there is no such thing as a toilet flange you will not be enjoying an indoor toilet? The flange essentially functions as a funnel device that channels the water and wastes into the sewer pipe and away to the septic tank. Apart from this primary purpose, it is also utilized to raise toilets.

How to go about a toilet flange that is too high

So now that you are currently renovating your bathroom. You decided to change your toilet bowl and you have pulled out the old one and had your floor retiled. You are now getting ready to install the new toilet bowl and then you discover that the toilet flange is too high. What should you do?

​You do not want to proceed with the toilet installation in this situation. It would help if you did something to correct the floor height mismatch. In this case, you will need some building up to do with the floor.

How to correct a toilet flange too high

The succeeding discussion will walk you through on what to do when confronted with such a problem. Here you have options. It all depends on what works best and practical for you. But first and foremost you will have to measure how high the toilet flange is from the floor. You need to be accurate on this one so that you will not waste materials and time to redo everything. In this step, you would like to determine how many inches you will have to append to the subfloor to attain the height where the flange is sitting well on the floor eliminating the gap.

Option 1: Using a cement board for floor build-up

1.1 Filling in the gap

If the gap between the subfloor and the outer circle of the flange is just about ¾ inch, the cement backer board and a tile on top will do the trick. What is amazing when you use backer boards is that you do not have to be troubled when it comes to any swelling because they are dimensionally stable. Remember that swell causes tiles to crack and you do not want that to happen. It will cost you for the replacement not to mention the hassle it will create.

1.2 Measure the floor area

Identify the floor area that you would include in building up your subfloor. Here you will determine the number of pieces of backer boards.​

1.3 Measure the radius of the toilet flange

This will allow you to create a circular shape on the backer boards. You will need a pencil or chalk and a compass for this to accurately make the hole. You may want to start with 4 pieces of backer boards. Put it together to make a bigger square. Referencing at the center of the bigger square, draw the circle. Add a ½ inch to the measurement of the circle. Cut the circle and break the bigger square. Snug the backer board around the flange.

1.4 Spread mortar on the entire floor area you need to build up

Evenly spread mortar on the area you need to build up and set the boards while the mortar is still wet. Secure the boards with screws. Corrosion-resistant screw is advisable. Spread mortar to seal around the outer flange as well as in between boards.

1.5. Set the tiles

Spread tile adhesive over the backer board and set tiles. Make sure that the tiles should close the gap. When the tiles are set and the tile adhesive has dried, you can screw the flange on the floor and proceed with the toilet bowl installation.

Option 2: Using plywood for floor build-up

2.1 Cut the plywood

Determine how much plywood you will be using and cut this to applicable sizes. How big the plywood you will use will definitely depend on the floor area. You will need a circular saw and sawhorses for this step.

2.2 Measure distance

Measure the distance between the nearest wall and the center of the toilet flange. Get this measurement into the plywood with the use of a pencil. Measure the distance between the adjacent wall that’s closest to the toilet flange towards its center. Get this measurement into the plywood. ​

2.3 Take the radius of the toilet flange.

Add a ½ inch to the measurement and get this measurement into the plywood. Draw the circle using a compass. Cut the circle using a suitable woodcutting tool.

2.4 Get the plywood to fit the toilet flange

Make adjustments when necessary to ensure that the plywood is snugly fit. Secure the plywood with screws and glue. Make sure this is done well to avoid any squeaking in the future. You are now ready to set up the toilet bowl.

This video shows another way of correcting a toilet flange too high.

Do you have what it takes to fix a toilet flange that is too high? Well, I am certain that I have furnished you with enough information to do it on your own. All you need to do is to build up the subfloor as shown in the two options presented above.

More takeaway tips:

Remember to use a wax ring between the toilet flange and the toilet bowl. When you have secured the toilet flange, place the wax ring on it before setting the toilet on top. The wax ring is a gasket that serves to seal the flange and the toilet which helps in avoiding leaks. When the toilet is up, it’s time to bolt it. You might consider using a brass bolt over a steel bolt. This is mainly because brass is resistant to moisture and thus, you do not have to deal with corrosion.

While a toilet flange that is too high can be corrected by lowering the flange, this will be more time-consuming and costly compared to building a subfloor. So this guide is not only effective but practical as well!

If you are a DIY homeowner, check those articles too:

How to Cut Tempered Glass Easily

8 Excellent Alternatives To Drywall In The Basement


Can a toilet flange be too high?

Yes, if a toilet flange is too high, it can lead your toilet to leak water and rock back and forth when used.

How long should a toilet flange last?

A toilet flange can last for 20 to 30 years without replacement.

How high should a toilet flange sit above the floor?

The `ID`eal flange height is 1/4 inch above the finished floor.

Thank you for reading!

Jan Hajek

I am an experienced writer. I write about home improvement topics such as construction, electrical work, plumbing, security and safety, interior design, exterior design, tools and woodworking, gardening, and garage organization. I love helping people improve their homes and make them more enjoyable places to live.

Click Here to Leave a Comment Below 0 comments