Are All Toilet Flanges The Same Size

A toilet flange is under the closet and is designed to connect your unit with the bathroom floor and the sewer line. Unfortunately, many homeowners only start thinking about the size and type of toilet flange when their toilets start malfunctioning. It’s very important that you choose a toilet flange that perfectly fits this very critical unit in your bathroom for the best results. But are all toilet flanges the same size? Here is a detailed guide on toilet flange sizes and types to help you make an informed decision.

How Do I Know What Toilet Flange To Use?

Today’s market offers many different types of flanges, depending on the type of pipe it is connected to. Depending on the application, some materials used for manufacturing toilet flanges are brass, PVC, ABS, cast iron, and other materials. The choice of flange for a toilet varies depending on the material of the DWV pipe that it is connected to. For instance, if you have a PVC pipe installation, you should install a PVC flange for the connection.

Sizes of Toilet Flanges

Standard 4×3 flanges

This is the most common type of flange that many homeowners use. Its top part is four inches wide, and the bottom part is only three inches in diameter. The top of this flange fits directly into a toilet, whereas the bottom fits into a drain. This site is the most common and fits most residential and public toilets, and it can be found in most hardware or plumbing stores.

Push-tite flanges

These flanges are very easy to install — you simply need to apply a thin layer of adhesive to adhere them to the floor. They fit into the bores of your pipes easily and are suitable for piping that is heavy. You will find that push-tite flanges are extremely resistant to extreme conditions, which means that they can withstand heat, harsh cleaning chemicals, and moisture.

Three-inch flanges

It’s very easy to install three-inch flanges on a bathroom drain if your plumbing system supports the exact sizes of the flanges. We should mention that four-inch flanges are rare and are unlikely to be used. Four-inch flanges require that you use wider drain pipes to put water out of the toilet, which is hard to imagine for a modern bathroom.

Three-inch flange
Three-inch flange

Odd-sized flanges

Any flange that doesn’t fit the abovementioned sizes is odd-sized. For example, a flange that is 5 inches long can only fit into the standard piping system; it’s the only way to adjust the toilet and maintain the flow of wastewater. That is why it is not unusual to find diameters of 7 inches (top) and 3 1/2 inches (bottom). An unusually shaped flange requires an extension kit to fit into a standard piping system. This is the only way to move the waste pipe and make the toilet functional.

Toilet flange shapes

While most toilet flanges may seem the same, some of them have exceptional shapes. For instance, regular are round in shape and very popular with toilets with round-shaped drain openings, deep seal flanges that dive deeper into the outlet pipe and offset flanges that can easily adjust to different toilet floor settings. That means if your toilet gas is a weirdly-placed outlet, you’ll use the offset flange option to seal the drains properly. The offset toilet flanges are great, considering that they have bending abilities due to their unique elbow shapes.

Types of Toilet Flanges

Below are the most common types of toilet flanges:

PVC toilet flanges

Many bathrooms in residential and commercial properties have plastic toilet flanges because they are very easy to install and maintain. PVC flanges are lightweight and very affordable. They are also extremely strong. One drawback of using PVC toilet flanges is that they require a specific, perfect installation. For instance, if your bathroom floor is uneven, your plastic flange will break sooner than usual. 

That’s because PVC elements are more fragile than other materials. It’s impossible for PVC pipes to withstand huge pressures if they are not tightly sealed. However, a way to fix this problem is to use an ABS plastic flange. It is even lighter and stronger than plastic flanges that are used in bathrooms. It is lighter and stronger, and easier to install than PVC flanges. But, of course, ABS flanges are more expensive.

Stainless steel flanges

Stainless steel is strong, and it is highly durable. It will probably last you for years or even decades. You must regularly maintain and clean the flanges you install on your toilets. There are many different kinds of flanges made from stainless steel, but the most popular option is number 304. It is a heavy metal made from chromium and nickel (13% each) and has a high melting point. You can find some of these flanges with a special coating that protects them from oxidation.

Brass toilet flanges

Brass flanges were once common in bathrooms but are not as common as they used to be. This is because brass is prone to oxidizing when it comes in contact with moisture and air. 

Brass flanges are strong and durable. They can withstand heat and pressure and are easily cleaned and disinfected. You can find flanges that come in different shapes and sizes, giving you a wide range of options for your bathroom.

Copper toilet flanges

Copper flanges are also a great choice for toilets because they are able to resist corrosion and are very durable. Many people buy soft copper flanges to connect their toilets because of their easier installation and durability. 

Some people choose soft copper flanges, but those with a rigid shape need to have an elbow-shaped joint to fix them to the toilet outlet. One benefit of using copper is that it is resistant to fungi, viruses, and bacteria, which makes it a great choice for your average bathroom.

Aluminum toilet flanges

There aren’t many toilet flanges made from aluminum, but they’re worth mentioning. Aluminum is lightweight, but that doesn’t mean it can’t withstand a lot of pressure and also provides many other benefits. Manufacturers rarely use aluminum alone to make toilet flanges. Instead, they add other metals, such as zinc, copper, and manganese, to give the flanges a stronger and more durable appearance.

Cast iron toilet flanges

Cast iron is a strong, high-carbon iron alloy that enables it to maintain a stable form even when heated. The high carbon content and fine crystallization make it flexible enough to be used in any shape you want. It is also tough to wear and durable, so flanges in bathrooms made from cast iron are likely to last many years. 

Cast iron flanges only fit iron pipes, and as a result, any other plumbing system with non-iron components, such as plastic, is not compatible with the cast iron flanges. In other words, Cast iron flanges are only suitable for pipes made of iron, so you shouldn’t use non-iron parts in your plumbing system.

Replacing a toilet flange
Replacing a toilet flange

When To Replace Toilet Flanges

When should you replace the old toilet flange? You may notice that your toilet does not work properly, but a few warning signals may indicate that the problem is with the toilet’s flange.

Leaky base

The first sign that your flange is broken is if you are experiencing water leaking from the base of your toilet. If there is water not flowing from your toilet’s flange or around the toilet, it means the flange and its seal are faulty. When this happens, you need to remove the flange from the bottom of the toilet bowl and replace the right parts.

Loose toilet

Do you have a toilet unit that is sometimes wobbly? If it’s doing that, a worn-out flange and a loose wax ring are probably at fault. If you want to know if the flange on your toilet is strong, push it down a little bit with your palm. If the toilet bowl is firmly attached to the base of the toilet, you won’t be able to break it. If the bowl keeps moving freely when you push it, the flange is probably worn out and needs a replacement.

Bathroom smells weird

In some cases, you won’t notice any changes in the way your toilet works. But you can’t miss an unpleasant odor coming from your bathroom. It is a sign that the toilet flange is damaged and leaking down the drain. 

Although continuous ventilation and exhaust fans can help you temporarily, the only permanent solution to the problem is replacing the toilet flange and the corresponding ring that holds your toilet’s flange in place. If those things don’t perform well, you should immediately have them all replaced.

If you have not replaced the flanges of your toilet for a long time, it’s time to be proactive in doing so. Moreover, you need to keep in mind that investing in the right size and type of toilet flange is also very important to get it right and avoid future costly bathroom repairs.

Wrap Up

The standard size of toilet flanges is 4×3 inches. However, depending on the manufacturer you choose to work with, you can find a different range of odd sizes on the market. You might think all flanges are the same size, but different manufacturers offer other products. Thanks to modern-day standardization, you can rest assured of finding a flange size and type that suits your specific needs.


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