• Home
  • /
  • Blog
  • /
  • How to Install a Toilet Flange on A Concrete Floor
Installing a Toilet Flange

How to Install a Toilet Flange on A Concrete Floor

Is your toilet flange damaged? Do you need to install a new flange on your toilet drain? If so, you have come to the right place.

Installing a toilet flange can be confusing and frustrating, especially if the surface is concrete and if you’ve never done it before. There are so many steps, and it’s hard to know where to start.

Luckily, we’re here to help. In this article, we’ll walk you through each step of the process so that you can install your toilet flange like a pro. With this, you’ll be able to enjoy your new toilet right away.

But before we proceed with the installation process, let’s begin with the tools you will need.

Preparation in Installing or Replacing a Toilet Flange

The first thing you need to do is gather all the tools and materials you will need for the job. This will make the installation process smoother and less likely to cause frustration. You will need:

  • Gloves
  • Screwdriver
  • Hacksaw or a power saw
  • Measuring tape
  • Putty knife
  • Hammer
  • New screws (if needed)
  • New T-bolts (if needed)
  • New wax ring (if needed)

Now that you have all the tools you need, it’s time to start the installation.

Installing a Toilet Flange on A Concrete Floor: The Step-by-Step Process

Step #1: Remove the Old Flange

first step is to remove the old flange

The first step is to remove the old flange. You can unscrew the bolts that hold the flange in place. If the bolts are rusted or stuck, you may need a grinder to get them out.

Once the bolts are out, you should be able to pull the flange out if needed. You can try prying it out with a screwdriver or a putty knife if it’s stuck.

Step #2: Scrape off the Old Wax Ring

removing the wax ring and cleaning the area around the drain

Now that the flange is out, you need to remove the old wax ring. You can do this by scraping it off with a putty knife. Be sure to get all of the wax off so that the new wax ring will adhere properly.

Step #3: Clean the Area around the Drain

Once the wax ring is removed, you need to clean the area around the drain. This will ensure that the new flange is attached appropriately.

You can use a brush and some soapy water to clean the area. If there is any rust or build-up, you may need to use a power drill with a wire brush attachment to remove it.

Step #4: Measure the Size of the Flange

measuring and buying the right flange size

Now that the area is clean, you need to measure the size of the flange. This will ensure that you get the correct size flange for your toilet.

Most flanges are either 3 or 4 inches in diameter. To measure the diameter, you will need to use a tape measure.

Step #5: Select the Correct Size Flange

Once you know the diameter of the flange, you need to select the correct size. If you’re not sure which size to get, you can always ask a salesperson at the hardware store for help.

One way to ensure that you get the right size flange is to take the old one to the store. Just make sure that the old flange is clean and free of any wax or build-up.

Step #6: Set the Toilet Flange in Place

installing the flange

The next step is to set the new flange in place. You will need to align the flange with the drain to line up the bolt holes. It would help if you also considered the distance from the wall.

Most flanges are designed to be installed about 12 inches from the wall to the center of the flange. However, you may need to adjust this based on the size of your toilet. Our favorite flanges to install are twist in flanges which you can pick up from your local Home Depot. You can check them out here. 

Step #7: Drill Holes for the Screws

Once the flange is in place, you need to drill holes for the screws in the concrete. You will need to use a concrete drill bit that is slightly smaller than the screws.

The number of screws you need will depend on the size of the flange. Most flanges require four screws to hold them in place.

Step #8: Install the Screws

Once the holes are drilled, you can install the screws. You will need to use a screwdriver to tighten them in place. Be sure not to overtighten the screws as this can damage the flange and may cause the toilet to leak from the base.

Step #9: Place the New Wax Ring on the Flange

placing the new wax ring to the flange

Now that the flange is installed, you need to place the wax ring on top. The ring should fit snugly around the flange.

If you’re not sure which size wax ring to get, you can always ask a salesperson at the hardware store for help.

Step #10: Set the Toilet Bowl in Place

installing the bowl and connecting the water line

Now that the wax ring is in place, you can set the toilet bowl in place. You will need to align the bolt holes with the holes on the flange. Once the bowl is in place, you can start to tighten the bolts.

Step #11: Connect the Water Supply Line

The final step is to connect the water supply line to the toilet. You will need to screw the line into the fitting on the bottom of the tank.

Once the line is tight, you can turn on the water supply and flush the toilet to check for leaks. If there are no leaks, then you’re done! You’ve successfully installed a toilet flange.

If you want to know more about the entire toilet installation process, from removing to installing a new toilet, you can check out our article about How to Remove a Toilet and Replace It With a New One.


Installing a toilet flange is a relatively easy do-it-yourself project. Just be sure to measure the flange and select the correct size. Also, you should remember is that the screws must be hand tight only; overtightening them may cause the flange to break.

However, if you have doubts about your plumbing skills, it’s always best to call a professional plumber to help you install your toilet flange or even your entire toilet. This can save you time, money, and headaches because they know how to do it quickly and efficiently.

If you live in Lower Mainland Canada and need a trustworthy and experienced plumber to install your toilet flange, Your Guy Plumbing is here to assist you 24/7. We offer toilet installation and repair, as well as other plumbing services to meet all of your needs.

Contact us today for a free no-obligation consultation so we can help you find the perfect plumbing solution for your home or business.

John Relampago

About the author

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Call Today For Fast, Fair and Reliable Service