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Thread: Toliet Flange question

  1. #1

    Default Toliet Flange question

    Hi everyone. I have a quick question. I am remodeling my bathroom, and I removed the mud bed/mosaic tile job to install a new floor. The subfloor was water damaged and rotted under the toilet, so I removed a secton about 22" wide by 32" long. I sistered some joists for nailers, and got the floor down nice. The problem is, the toilet flange (PVC)ties into the main drain right next to a joist, and then it goes down the wall. There was no way to remove the flange (I wanted to) and reinstall after the sublfoor and tile were installed. So, I had to cut the 3/4" ply section out to fit over the flange (7 1/8" diameter). This is a 3 inch drain, so now I have a significant gap around the flange. I am not sure if this is ok, as the flange is pretty much free standing now, with nothing to screw it to. The height of the finished floor will be too high to get under the flange also, so I really dont know what to do. Does this flange need support, or will the toilet sit on the surrounding tile and be supported by that? The bottom of the flange is 5/8" from the subfloor, and the finished floor ( 3/8" tile, 1/4" cbu, 1/8" (+/-) mortar ) should be right around 3/4". So overall the flange top should be about 1/4" above finished floor. Any help would be greatly appreciated!! thanks guys!


  2. #2
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Cave Creek, Arizona

    Default flange

    The flange does not support the toilet in any way. Its only purpose is to provide a seal to the toilet. If the pipe is secure enough so that it cannot move when the toilet bolts are tightened, then you will not have to secure the flange.
    Last edited by hj; 09-17-2005 at 02:07 PM. Reason: text

  3. #3
    DIY Senior Member sulconst2's Avatar
    Join Date
    Jul 2005
    old bridge nj


    just to make it look better. cut your patch of plywood at the drain and install in 2 pieces. this way you can get under the flange. as long as the grain of the plywood runs perpendicular to the joists it will be just as strong. plus you should install a second layer of plywood. 1 1/4" is min. in jersey.

  4. #4


    Thanks for the advice guys! I tried the 2 piece ply first, but couldnt get any more nailers in to support it that way.The room is very small, and the toilet is right next to the outside wall, so made this tough. The flange is pretty stable, it goes right into an elbow that immediately goes through a joist then down the wall. I can wiggle it, but it doesnt move much. I might just be able to hit a stud with a screw through it, so I'll try that. I know this isnt ideal, but just wanted to make sure I am ok this way. I have a 7 1/4" Diameter hole in the subfloor, will have same in hardibacker and will tile to flange. It is essentially free standing, tile will not fit underneath it. Thanks again for the help!



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