Toilet Flange Replacement

written by: Cory Q

You know what the crowning achievement of our modern society is? Indoor plumbing. Think about it. One would consider camping, noted for its lack of plumbing, to not be a modern exercise. One might even say of someone who lives in a place without indoor plumbing that they are suffering from a lack of modern conveniences. This modernization comes with a price. That price in one way is added complexity. That price in another way is the filthy chore of moving this waste out of your home. I will warn you right now: You may have to stick you hand down the sewer pipe to accomplish this task I am about to describe.

A toilet flange is a device that, unless you have had cause to remove and replace a toilet, one would never know existed. Go look at your toilet. See, on the sides, near the ground, how there is a bolt on each side of the base? The bolts you see are coming up from the flange (they are T shaped and I will call them flange bolts from here on). The toilet flange is the marvelous piece that connects the outflow pipe to the toilet and the toilet to the floor.

I learned how to replace this item when I was remodeling the upstairs bathroom at Fortress Q. I will now impart what I learned, but if my instructions are not clear, hire someone to do this. I don't want your house damaged by messed up crazy internet advice plumbing.

Step 1: Remove the toilet.
To do this you should shut off the water, loosen the water supply hose, flush the toilet to empty it of as much water as you can, and by loosening the nuts that stick up on both sides of the toilet. (Remember where you put those nuts, washers, and flange bolts. You will need them at the end.) Once those nuts are loose, lift the toilet off the ground. Be ready to put the toilet somewhere that you can drain the rest of the water out of it. I used the bathtub.

Step 2: Clean the flange.
The toilet actually seals to the floor via a wax ring. That wax residue will need to be cleaned off the flange. I use a putty knife to accomplish this. I will warn you that this wax is very sticky. Once you have cleared away the old wax, inspect the flange and remove the screws that hold the flange to the floor. The flange will still be attached to the outflow pipe, but it should now be loose in the cut out in the floor.

Step 3: Assess the damage and go to the hardware store.
In my case it was clear that the flange was cracked, as a quarter of it came loose with the wax. If the flange is in good shape, you are basically good to go when you need to replace the toilet. Just remember to get another wax ring (readily available at any hardware store for a couple bucks) and follow the directions on the box. So, you have to go to the hardware store for, at minimum, a new wax ring. If, like me, the flange is damaged, you will need more pieces. You will need a pipe coupling, a length of pipe the same diameter as the existing pipe, some PVC glue, and a new flange. It is very important to measure the pipe coming out of the floor before you run off and get new parts. Most sewer pipes are going to be 4 inch or 3 inch. All told, the pieces needed here are still pretty cheap. I think it came to around $20. I got my parts from Home Depot.

Step 4: Cutting off the old flange.
This is where things get to be a pain. I did this the hard way, so I will save you some time. I had no idea how all these parts fit together or what exactly I was looking at. Using a hacksaw pressed against the floor (because the flange is flush with the floor), I cut just the top lip of the flange off. This way I could see how all the pieces fit together. This means that I later had to do more cutting as I realized how the pieces fit together. To make it easy, here is a side view of how this should all look.

You should cut on the red line. I accomplished this by using a Dremel with a reinforced cutting disk on the inside of the pipe. It took about 10 minutes. Try not to think about where you are putting your hand.

Step 5: Fitting the new pipe and flange.
This step is pretty easy. Once the old pipe and flange are cut off, fit the coupling onto the pipe you just cut. Fit the length of new pipe into the coupling. Before you mark the new pipe, make sure that the coupling and new pipe are relatively snug (enough so you can get them out again) so the height will be accurate. Mark the new pipe to just below the level of the floor. Remove the new pipe and coupling from the cut off pipe. Cut off the new pipe with a hack saw. At this point you should have a) a cut pipe in the floor b) a coupling c) a short length of new pipe and d) the toilet flange. It will look roughly like this before you start installing the new pieces.

Next is to glue all these pieces together. There is a warning on the PVC glue bottle that says you should only use that viscous substance in a well ventilated area. I'm here to tell you they aren't kidding! The smell is incredibly strong! So, quickly swab the interior of the coupling with the glue, press that into place. Repeat the swabbing of the glue with the two remaining pieces. The glue seals the pieces together and makes the system watertight. Make sure that if the flange you got doesn't have a moveable collar (the red metal piece in the above picture) that you line the slotted spaces for the flange bolts up with where the toilet with go before everything is secured down.

Step 6: Remounting the flange to the floor and the bolts to the flange.
OK. There should now be a pipe coming out of the floor with a flange mounted on it. Nice work. If you managed to line the slots up for the flange bolts correctly (unlike what I did the first time… thank goodness I got a flange with a rotate-able collar!) and get the flange flush with the floor cutout, great job! The task is nearly complete. Next, run screws through the toilet flange down into the floor. Once the toilet flange is immobile, thread the flange bolts upward in the flange. These, again, are the T shaped bolts that hold the toilet to the flange.

Step 7: Wax ring and the toilet returns.
The final step is upon us! The floor is now ready to receive the toilet. Firmly press the new wax ring on to the bottom of the toilet. Pick the toilet up, line it up with the flange bolts, and set the toilet down. Press the toilet firmly into place. All that is left is to put the washer and nut back on the flange bolts and tighten them down. Reconnect the water and turn the valve on and you are one again graced with the most impressive of modern luxuries.

Congratulations! You have fixed your plumbing and replaced a toilet!

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