I purchased my home from flippers who did a non-permitted bathroom renovation. As I am replacing toilets, the toilet flange for one of the bathrooms seems to be completely abysmal - looking for advice on how to fix this. The existing flange is a Nibco 5851 4x3. I bought a new flange today thinking I could easily cut off the old one at the lip and then chisel it to remove the old one as I have done several times with PVC. Looking for the best way to fix this. I should note, about 12" or so down, I can see where the existing flange is cemented into the pipe. Ideas I have to fix this:

  • Put a 3x4 flange into this flange and cement it all together and call it a day. This would lead to the flange existing ~ 1/4" above the flooring.

  • Same as number 1 but cut the lip off the existing flange so it sits more flush

  • Cut out (via an inside pipe cutter) the existing flange, add coupler, install new flange

This is on the second floor. However, the area is not accessible for a repair from the downstairs. Looking for advice/help, thank you!

enter image description here

  • 1
    What problem are you trying to solve? "Abysmal" isn't a useful description.
    – isherwood
    Dec 11, 2023 at 22:21

2 Answers 2


The flange should stand proud of the finished floor (in fact, it should be attached on top of the finished floor. So your concern about it being "...1/4 above the flooring..." is a non issue. It should also be screwed down to the floor to minimize movement.

I don't see anything wrong with your actual flange other than the height (too low) and that it is not screwed down. If it were me, I would screw down the existing flange to the subfloor below (OSB subfloor is visible in your picture) and get a "riser/spacer" to raise the height. These are readily available at plumbing shops and, when installed according to the manufacturer's instructions, will rectify the height problem.

proper flange install height:

enter image description here pic courtesy of Oatey, toilet installation equipment manufacturer

flange spacer example:

enter image description here

Pic also courtesy of Oatey

  • I cut a piece of the lip off of the existing flange basically at the subfloor level attempting to separate the existing glued in flange. There are also some chisel strike marks where I first tried to split the existing flange. Photos: imgur.com/a/zfuFS3H Dec 12, 2023 at 0:43

I would use the inside cutter and simply cut off the old flange, and replace with an Oatey Twist-N-Set flange, or similar. Actually, I probably wouldn't bother with the inside cutter since I don't have one, but I do have an angle grinder.

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