When shopping for a new toilet, one of the key features to consider is the rough-in size. The rough-in size refers to the distance between the wall behind the toilet and the center of the waste outlet on the floor. This distance determines the size and shape of the toilet that can be installed in a particular bathroom.
The most common rough-in sizes for residential toilets are 10 and 12 inches. A 10-inch rough-in toilet is typically used in smaller bathrooms, while a 12-inch rough-in toilet is better suited for larger bathrooms.
In this article, we’ll go over the differences between 10 and 12-inch rough-in toilets, so that you can make an informed decision when shopping for a toilet.
What is Toilet Rough-in?
Toilet rough-in refers to the distance between the back wall of the toilet and the center of the waste pipe that carries waste and water away from the toilet. This measurement is important when installing a toilet, as it determines the appropriate size and shape of the toilet to be used.
When a toilet is installed, the waste pipe is typically already in place on the floor or wall. The rough-in measurement is taken from the back wall to the center of the waste pipe, which is typically 3 or 4 inches in diameter. The rough-in measurement can vary depending on the specific plumbing setup of a building, but it is typically between 10 and 14 inches.
When purchasing a toilet, it is important to know the rough-in measurement in order to choose the correct size and shape of the toilet. Toilets come in different sizes and shapes, and some are designed for specific rough-in measurements.
For example, a toilet with a 10-inch rough-in would not fit properly if the rough-in measurement in the bathroom is 14 inches.
Comparing 10 and 12 Inch Rough in Toilet
When choosing between a 10-inch and 12-inch rough-in toilet, it’s important to measure the distance between the wall and the waste outlet to ensure that you get the correct size.
Toilet installation is easiest when the rough-in size matches the size of the toilet, so it’s best to avoid purchasing a toilet with a different rough-in size than the one already in your bathroom. That being said, here are the essential differences between both rough in toilets:
Tendency to Clog
A 10-inch rough-in toilet tends to clog more than a 12-inch rough in toilet and here is the reason why. Every toilet has a trap (either P-trap or S-trap), which is located within the rough-in.
The longer the rough-in, the more the space given for the trap design, and vice versa. This means shorter rough-in toilets may likely have a slightly cramped trap, which is more likely to clog, unlike the 12-inch rough-in toilets.
A 12-inch rough-in toilet uses less water for flushing than a 10-inch toilet. For instance, most 10-inch rough-in toilets use 1.6 gallons per flush whereas 12-inch rough-in toilets use 1.28 gallons of water for flushing. This makes a 12-inch rough-in toilet more efficient at water consumption than a 10-inch toilet.
If you want to reduce your water bill, consider a 12-inch rough-in toilet. However, make sure that you opt for a toilet with an amazing flushing performance to clear waste at a flush.
Performance in Humid Areas
A 12-inch rough-in toilet performs better in humid areas. While a 12-inch rough-in toilet can withstand humidity, a 10-inch rough-in toilet can’t withstand humidity and dampness. This is because a 10-inch rough-in toilet is closer to the wall than the 12-inch rough ins.
The increase in dampness makes 10-inch rough in toilets prone to mold growth. Therefore, if you live in a humid area, choose a 12-inch rough-in toilet.
However, if you are not in a humid climate area, you can skip this as 10 or 12 inches won’t make any difference for you.
Variety of Options
A 10-inch rough-in toilet is mostly used where there is limited space. As a result, 10-inch rough-in toilets are only available in limited options. Most 10-inch rough-in toilets are available as round toilets.
However, a 12-inch rough-in offers lots of options. You can find 12-inch rough in toilets in options like round, elongated, and compact-elongated shapes, and so on.
12-inch rough in toilets are more affordable than 10-inch rough in toilets because they are more common and readily available
10-inch rough-in toilets are found mostly in older homes and are a bit scarce, which makes them more expensive.
How to Replace 10-inch Rough in with 12-inch Rough-in?
A 10-inch rough-in toilet can be replaced with a 12-inch rough-in toilet and a 12-inch rough in toilet can also be replaced by a 10-inch rough in toilet. However, this isn’t an ideal practice and we don’t recommend that you replace 12-inch rough ins with 10-inch rough in toilets.
If you replace a 12-inch with a 10-inch rough-in toilet, there will be about 2 inches of space between the toilet tank and the wall. This may affect the stability and normal functioning of the toilet.
Also, you will have to stretch your hand further to grab the tissue paper if you mount a tissue paper holder.
You can easily convert your 10-inch to a 12-inch rough in using an offset toilet flange. The offset toilet flange adds an extra 2 inches of space for fitting.
Here is an easy step-by-step guide on how to replace your old 10 inch rough in toilet with a new 12 inch rough in toilet:
Flush your toilet:
The first thing you should do is to get rid of any waste in the toilet bowl by flushing the toilet. Make sure that the waste is gone and that the toilet bowl contains only clean water.
Stop the water supply to the toilet tank:
Locate the shutoff valve behind the toilet and turn it off to stop the water supply to the tank. After that, give your toilet one more flush to empty the toilet tank.
Also, remove the tank cover and remove any remaining water in the tank using a sponge or foam.
Disconnect the water supply line:
Carefully disconnect the water supply line connected to the toilet tank by loosening the locknut.
While doing this, place a bucket under the line to catch any excess water, else, water may spill onto your toilet floor.
Remove the old toilet:
If you have a two-piece toilet, carefully disconnect the toilet tank before loosening the toilet bowl from the toilet flange.
If you have a one-piece toilet, you’ll need an extra hand to help you remove the toilet. Place the old toilet on a rag or piece of cloth.
Check this step-by-step guide on how to remove your old toilet to do the job.
Remove the old toilet flange:
Carefully remove the old toilet flange from the drain pipe and toilet floor. Don’t forget to clean off the old wax ring and debris around the drain pipe.
Get an offset toilet flange:
Using a measuring tape, measure the diameter of the drain pipe, it’s usually 3 or 4 inches. Get an offset toilet flange of the same size.
Also, get the wax ring and necessary bolts.
Connect the new flange:
Carefully connect the offset toilet flange you purchased in the step above. Fix the wax ring and tee bolts.
Connect your new toilet:
Connect your new toilet to the offset toilet flange. Make sure that the toilet bowl sits well on the wax ring and tee bolts.
Secure the toilet bowl using the bolts before connecting the toilet tank.
Fill the toilet tank:
Reconnect the water supply line to the toilet tank. Turn on the water supply and fill the toilet tank with water. Flush your new toilet and check out for any leakages, especially around the tank to bowl gasket.
How to Measure Toilet Rough-in Without Removing Toilet
To measure rough-in without removing the toilet, follow these steps:
- Gather the necessary tools and materials, including a tape measure, a pencil, and a notepad for taking notes.
- Locate the waste pipe in the floor under the toilet. This is the pipe that carries waste and water away from the toilet. In most cases, the pipe is centered at the same line as the toilet mounting bolts.
- Place the end of the tape measure at the back wall of the toilet, near the center of the waste pipe.
- Extend the tape measure straight out to the center of the waste pipe, making sure to keep it level and straight.
- Carefully measure the distance between the back wall of the toilet and the center of the waste pipe, and record this measurement on the notepad.
- Compare the measured rough-in to the standard rough-in measurements for toilets, which are typically between 10 and 14 inches.
- Use the measured rough-in to choose the appropriate size and shape of toilet for the bathroom.
It is important to note that this method of measuring rough-in is not always accurate, as the waste pipe may not be perfectly centered or straight with the toilet mounting bolts.
If possible, it is recommended to remove the toilet and measure the rough-in directly from the waste pipe to ensure the most accurate measurement.
Advantages and Disadvantages of 10-inch and 12-inch Rough-in Toilet
Here we go with some of the key pros and cons-
Pros of 10-inch Toilet Rough-in
With a 10-inch rough-in, there are more options available when it comes to choosing a toilet. This is because many toilets are designed for a 10-inch rough-in, giving homeowners more options to choose from in terms of style, shape, and design.
Toilets with a 10-inch rough-in are generally smaller in size, which can be a plus for smaller bathrooms or for homeowners who want to maximize the available space in their bathroom.
Because there are more options available for 10-inch rough-in toilets, homeowners may be able to find a toilet that fits their budget more easily. In addition, smaller toilets may be less expensive to manufacture, which could lead to lower prices for the consumer.
Cons of 10-inch Toilet Rough-in
A 10-inch rough-in toilet may not be compatible with certain plumbing setups, especially if the rough-in measurement in the bathroom is larger than 10 inches. In this case, a toilet with a larger rough-in measurement may be necessary.
Smaller toilets may not be as comfortable to use as larger toilets, especially for taller individuals or those with mobility issues. This can be a significant disadvantage for some homeowners.
Toilets with a smaller rough-in may not be as effective at flushing waste and other debris, which can lead to clogs and other issues. This can be frustrating for homeowners and could lead to additional maintenance and repair costs.
Pros of 12-inch Toilet Rough-in
A 12-inch rough-in toilet is more likely to be compatible with a wider range of plumbing setups, including those with a rough-in measurement of 12 inches or more. This can make it easier to find a toilet that will fit properly in the bathroom.
Toilets with a 12-inch rough-in are generally larger, which can make them more comfortable to use for taller individuals or those with mobility issues. This can be a significant advantage for some homeowners.
Toilets with a larger rough-in are often more effective at flushing waste and other debris, which can help prevent clogs and other issues. This can be a major benefit for homeowners, as it can help save time and money on maintenance and repairs.
Cons of 12-inch Toilet Rough-in
With a 12-inch rough-in, the number of available toilet options may be more limited, especially when compared to toilets with a 10-inch rough-in. This can make it more difficult to find a toilet that fits the desired style, shape, and design of the bathroom.
Toilets with a 12-inch rough-in may be more expensive than those with a smaller rough-in, both in terms of the initial purchase price and the cost of installation. This can be a significant disadvantage for homeowners on a tight budget.
Reduced space-saving potential:
Larger toilets with a 12-inch rough-in can take up more space in the bathroom, which can be a disadvantage for homeowners who want to maximize the available space. This can be especially true for smaller bathrooms or those with limited square footage.
In conclusion, the rough in size of a toilet is an important factor to consider when installing a new toilet. The standard rough in sizes for residential toilets are 10 and 12 inches, with some variations for different types of toilets.
A 10-inch rough-in toilet is typically smaller and can be a good option for small bathrooms or tight spaces, while a 12 inch rough in toilet is typically larger and provides more comfort and support for the user.
Replacing a 10 inch rough in toilet with a 12 inch rough in toilet can be a challenging DIY project, and it may be best to hire a professional plumber to handle the work.
Regardless of the rough in size, it is important to carefully measure and install the toilet to ensure that it fits properly and functions properly.