Perfect height of Toilet flange from finished floor

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by isotope, Jul 13, 2018.

  1. isotope

    isotope New Member

    May 21, 2018
    I am trying to determine what is the best height for a toilet flange to be placed at relative to the finished floor. I know that we can just install one or, sometimes, even 2 thick wax rings for toilet drain pipes that are cut too low. However, I am not a big fan of thick messy wax rings. So, I just am looking for some opinions on this.

    My questions are primarily related to new construction, but it’s also applicable to remodel situations as well. Do you cut the vertical toilet pipe flush with the finished floor? Or do you cut a little bit higher? As far as the placement of the flange, I’ve actually heard of some plumbers saying that the flange should be maybe a 1/4” or 3/8” higher than the finished floor, but I am afraid that too high will result in an unstable, rocking toilet. Where do you cut the vertical toilet pipe and what’s your thoughts on the best toilet flange height?
  2. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    You will see lots of posts that say the ideal is for the flange to sit on the finished floor. You will not find significant disagreement on that. That typically puts the top of of the flange above the finished floor by about 1/4 to 3/8 inches.

    Mechanically, that is good. You don't want the pipe to carry the stress. The floor and the screws into the floor carry the load.

    How high to cut the pipe will vary with the flange.

    Closet flanges with metal rings are preferred where there is a preference, and stainless steel is most preferred I think.

    If the floor will be a "floating floor" then other methods can be used.
    Last edited: Jul 13, 2018
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  4. Treeman

    Treeman Member

    Jan 29, 2010
  5. Tuttles Revenge

    Tuttles Revenge New Member

    Oct 15, 2014
    I've only encountered one Toto toilet one time that didn't want to sit well on a flange installed directly on the finished floor and I had to shim it up a bit. Otherwise all of my installations are done using 4" pipe through the floor so that the flange can be cut at toilet installation and the flange sits on the finished floor.
  6. kreemoweet

    kreemoweet In the Trades

    Sep 7, 2009
    Seattle. WA
    Where I live, the plumbing inspectors demand that toilet flanges be installed as part of the "rough-in", i.e. well before
    the finish floor is usually installed. This is when the better plumbers show their stuff, and insert appropriately sized
    spacers under the flanges, so that the flange will end up being at the same height it would be if it were set directly
    on the finish floor.
  7. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    To work around that, I guess an outside compression closet flange could be put on an extra-tall riser. That would be reusable.

    Alternatively, how about a cheap closet flange on an extra-high riser, that would be cut later, and the cheap glued closet flange gets discarded?
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