Toilet flange height

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by joewadd, May 18, 2013.

  1. joewadd

    joewadd New Member

    Joined:
    Dec 17, 2012
    Location:
    Winchester CA
    Hello,
    I am installing a new toilet in my shop with cement floor so where should the correct height of the flange be?

    My plastic flange is almost a 1/2" thick .450 to be exact so should the bottom of the flange rest on the top of the cement surface?

    Someone told me the top of the flange should be level with the floor surface that doesn't seem right.

    Thanks for any help.
    Joe
     
  2. cwhyu2

    cwhyu2 Consultant

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    Aug 11, 2007
    Occupation:
    Consultant
    Location:
    Cincinnati OH
    Bottom of flange on top of finished floor.

     
    Last edited by a moderator: Sep 1, 2018
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    IF you haven't installed the flange yet, please do not use the all plastic one- pick one that has a SS metal ring. You'll want to anchor it with some lead anchors or maybe some Tapcons. The all plastic ones are a problem waiting to happen. Should someone bump the toilet, that small plastic slot will likely crack. And yes, all toilet flanges are designed to sit on TOP of the FINISHED floor, and to be securely fastened. Now, something like a CI flange on CI pipe in a concrete floor should be strong enough without further fastening, but that isn't what you have.
     
  5. Hammerlane

    Hammerlane Member

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    Oct 22, 2011
    Location:
    Ohio
    Usually a debate about this issue. .But I agree bottom of flange on top of finished floor. #1 below.
     

    Attached Files:

    Last edited: May 19, 2013
  6. hj

    hj Moderator & Master Plumber Staff Member

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    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    What's to debate? The only proper way is to have the flange on top of the finished floor.
     
  7. joewadd

    joewadd New Member

    Joined:
    Dec 17, 2012
    Location:
    Winchester CA
    The only flange I could find at Lowes was the plastic with a 3" slip in area and my pipe is 3" so I had to put a coupler to connect the flange to pipe.

    I haven't mounted the flange yet so I can change to a better one, but I did glue the coupler to the 3" pipe. If I need to cut off the coupler I only have 2 1/8 straight left to work with.

    The issue I had was finding a flange to adapt to the 3" pipe the current one is the same size as the pipe3".

    If I get a flange to go over the 3" pipe you have the lip or edge of the pipe to restrict flow, not that it would, I thought smooth transition was better.
     
  8. Gary Swart

    Gary Swart In the Trades

    Joined:
    Sep 1, 2004
    Location:
    Yakima, WA
    When you have to use a 3" flange, it should NOT fit inside the drainpipe. This cuts the diameter of the pipe too much. Suggest you find a better supply house for materials and get the recommended flange.
     
  9. joewadd

    joewadd New Member

    Joined:
    Dec 17, 2012
    Location:
    Winchester CA
    I picked up an Oatey brand flange that has a stainless flange that spins on plastic and it will go over the 3" pipe, is this the one to use.
     
  10. wjcandee

    wjcandee Wise One

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    Apr 27, 2012
    Location:
    New York, NY
    There ya go.
     
  11. how2do

    how2do Handy Tom

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    Handy Tom - Repairing Your Home
    Location:
    Pawleys Island, SC
    As far as flow and any restriction to the waste line...that's a misnomer...the maximum diameter of most toilet outlets is 2 inches...some I have seen are 2-1/4" but that all depends on the manufacturer's casting mold. The correct method is to mount the toilet flange on top of the finished floor. Below is a cutaway showing the distance between the toilet and flange...

    Set-Rite_Cutaway.jpg
     
    Last edited: May 19, 2013
  12. Buddy H

    Buddy H New Member

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    May 27, 2017
    Location:
    Maryland
    If you have a floating floor in bath i dont recomend installing on floating. Shoot down a spacer for flange on concrete but leave floating able to move. Thats what all the plumbers on here are leaving out since they dont do floors. Dont pinch the floating with the flange!
     
  13. Pexuniverse

    Pexuniverse New Member

    Joined:
    Jun 27, 2017
    Location:
    Brooklyn, New York
    And if it is installed in a floating floor you'll probably want to add flange supports to keep your flange in place. This video shows supports on a closet flange. And you'll notice the flange is above the floor.
     
  14. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I think you may not understand the floating floor thing.

    I was expecting that your video was going to show the use of spacers to get the height right, without pinning the flooring into place.
     
  15. TotoHugo

    TotoHugo New Member

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    Sep 4, 2019
    Location:
    quebec
    Dear Terry,

    Question for a total renovation of bathroom. I am putting a new sub floor, 1 1/8โ€ plywood, i reconnected my old cast iron 4โ€ to be able to use 4โ€ ABS for the toilet. Now the points:
    1) At the LOWES where i go, there is only ABS toilet flange. Good enough? I mean: i have the brass ones but if i use that i need to buy also the lead . I can do it but it becomes very very expensive...
    2) Love the idea of putting nuts to old the brass bolts...!
    3) I was hoping to see a video of you putting the flange on a NEW floor to see how you "merge" the tiles with the flange. Do you simply install the flange (and ABS glue naturally if it's the case) on the tiles and drill the holes to old the flange thru the tiles/subfloor (predrilling with diamond bit or carbide...)
    4) I think that from looking at the video again, the BOTTOM of your flange is at the same height as the finish floor BUT not on it. It looks like the flange is secured that on the subfloor... ?
    5) You didn't do the caulking all the way to the end...? why ? And why not just clear 100% Silicone ?

    It's about it for now!

    Thanks for sharing your knowledge.

    Hugo
     
  16. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    ABS is fine for a closet flange. Normally glued to the pipe with ABS cement.
    Double nutting the closet bolts is more secure, it's how I buy them. Home Centers that deal with homeowners don't typically carry them that way.
    In my area, it's pretty common to have the flange installed to the subfloor and then the flooring is built up around it, requiring two wax rings in most cases.
    If you install the flange over the finished flooring, then one wax ring will do. Either way, the flange gets secured to the floor. If the tile is under the flange, then that gets drilled.
    Most inspectors expect you to leave the caulking off at the back in case there is a bad seal. The idea being that if it's leaking, it's best to know right away, or at least before the wood floor rots through and you step through the floor into the crawl space.
    I use the clear polyseamseal caulking. I'm not a fan of Silicone, as it's extremely hard for the next plumber if the toilet ever needs to be lifted again. If the next bowl is a different shape, removing the Silicone can be a problem.
     
  17. TotoHugo

    TotoHugo New Member

    Joined:
    Sep 4, 2019
    Location:
    quebec

    Dear Terry,

    Hard to tell you how much i appreciate the quality of you intervention ; you are among the only one who answers, precisely and quickly. Well the Loctite is a challenge to find in Quebec... Anyway, I will put the bottom of the ABS flange leveled with ceramics but not over it (will cut the ceramic around the OD diameter of the flange) put brass nuts on the T bolts. Thank you again. Ah, i forgot; thanks for the caulking explanation.
     
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