Toilet flange over, or flush, with tile?

Discussion in 'Toilet Forum discussions' started by Fistor, Apr 21, 2008.

  1. Fistor

    Fistor Geotechnical Engineer

    Messages:
    48
    Location:
    Vancouver, BC
    Hi all -

    I have a question about setting the height of a new toilet flange.

    Should the flange...

    1) be set directly on the floor underlay, with tile more or less flush with the flange?
    - OR -
    2) should the flange height account for the tile height? (i.e. overlie the tile?)

    If it is option 2, then would the bolts anchoring the flange need to be drilled through the tile ???

    Thanks!
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Location:
    New England
    The correct location of the flange is on TOP of the finished floor. The bottom of the flange must be flush with the tile, no gaps, or it could end up too high. You don't want a large wax depth from having it too low and if it is too high, the toilet will rock. The seal is engineered to work best with the flange on top of the finished floor.

    If you notch where the anchors need to go prior to setting the tile, you don't have to try to drill through the tile later. Depending on the tile, that may require a diamond bit (hard porcelain is a real pain to drill through!).
  3. Fistor

    Fistor Geotechnical Engineer

    Messages:
    48
    Location:
    Vancouver, BC
    Just a few questions, though - it seems that a porcelain-on-tile contact would be less preferrable, say, than a porcelain on cementboard, in terms of contact, wouldn't it?

    Also, the idea that weight being applied close to the edge of a tile seems a little worrisome as well - isn't there always the outside chance of cracking the edge of the tile?

    Just curious....
  4. Terry

    Terry Administrator Staff Member

    Messages:
    14,808
    Location:
    Bothell, Washington
    The toilet does not set on the flange.
    The flange holds the bolts, that hold down the bowl.
    The flange needs to be secured to the flooring system, or the bowl will pull the flange up.
    There is normally a gap between the flange, and the bottom of the bowl, and that is why it is normally sealed with wax.
  5. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,309
    Location:
    Yakima WA
    Too bad more folks haven't asked this question before they set the flange on the sub floor and later wonder why the toilet leaks around the wax ring. Or just as bad, setting the flange so that it is sticking up above the finished floor and wondering why the toilet rocks. By asking the question now, you have saved yourself a great deal of grief.
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
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    If your tile is properly supported and you either notch the tile prior to installation or make appropriately sized holes with the proper bit, the tile should not crack. This also assumes your subfloor and structure is up to design specs. Porcelain may require a diamond bit...some can be drilled with a good carbide, but not all. The key to cutting hard materials like this is keeping the cutting tool cool which usually means wetting it like your wetsaw used when cutting a tile.
  7. Fistor

    Fistor Geotechnical Engineer

    Messages:
    48
    Location:
    Vancouver, BC
    OK, thanks for the all the fast answers guys, I think I have this straight (let me know if not)...

    - the base of the flange must be on the surface of the tile, which extends as far as the cutout in the floor (for the riser)
    - there is no (downward) weight on the tiles directly beneath the flange, as the weight of the toilet is carried further out, at the edge of the toilet base
    - the purpose of the flange is twofold: to hold down the down the toilet (rather than support it), and to provide an area to put the seal

    Assuming all that is correct, I have it straight now, and it makes sense. My confusion stemmed from the misplaced idea that the flange would take up a lot/most of the weight of the toilet, which is why it seemed not so great to support that weight on the edges of cut tiles. (Also, there are a few people I know who claimed that it should not be on the tiles, but they are also people who are more... casual... about details).

    Thanks again for all the answers! :)
  8. Gary Swart

    Gary Swart In the Trades

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    7,309
    Location:
    Yakima WA
    I do believe you've got the picture.
  9. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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