Another toilet flange question.

Hello, first off I want to say I searched the forums forever, but could not find the info I need. So here is another floor flange question. I have a 3" ABS stub up for my new construction toilet installation. I read that the flange should be installed on top of the finished flooring. So I installed the tile floor. Then I cut off the stub out pipe flush with the top surface of the tile floor. I first tried an internal fit flange. This flange has a small lip molded just below the bottom of the flange. So when I slide this flange on and it bottoms out on the top of the pipe, it sits up off the floor too high. I test fit the toilet on it (Kohler Persuade) to see if there was enough room for "fudge". No way. Toilet sits completely on top of flange and not the floor. So yesterday I spent an hour chiseling out around the pipe to try an outside fit flange, and when I slip that one on, it too sits too high. The outside fit flange has a "stop" molded into it that keeps the drain pipe from sliding right through the flange. However the stop in the flange it lower than the bottom side of the mounting ring of the flange. So when you slide this on the pipe, it doesn't sit flush with the tile surface either.

So my guess is that I should have cut the top of the drain waste pipe off level with the concrete slab and not the tile floor? Any help will be much appreciated. How do I now cut the pipe down? A dremel cut off wheel from the inside of the pipe?

If anyone is interested you can see the house I am building at www.livingwithbigfoot.com
Thanks, Todd.

It's easier with a 4", as you can use an internal mount flange on that size pipe. You need enough room around the 3" pipe to get the flange seated. Some careful measurements will tell you how deep that socket is in the flange. Then, you'll be able to figure out how far down to cut the pipe off. They make a special tool to cut pipe off from inside, but for a one-time use, a Dremmel (I've used my Rotozip) will work. Look closely at the flange, often instead of being a square corner between the flange and the socket, it's curved or at an angle. You need enough room around the pipe for that to not hit the tile as well or it won't go all the way down.

Last, on plastic pipe, the socket of the flange is slightly tapered (at least on PVC, and I think on ABS). This means that it is difficult and sometimes impossible to fully seat the pipe in the socket of the flange until it is lubricated with the glue. Once you've done that, you have one chance, so, you must measure carefully.

It's okay to have the pipe not quite seat fully in the socket, but it should be close.

If you didn't notch the tile, you may need a diamond bit to drill through it for anchoring the flange. Because the fitting is slightly tapered, until the glue sets, it can push itself back off the pipe somewhat. If it does that and you don't notice, it's a big pain. Either be prepared to screw it in place right away, or set something heavy on it until the glue sets. The flange should set flat on top of the finished flooor.

The Dremel tool will work. There are cutters that can also do the job, but if you have the Dremel, use it. The cut does not have to be absolutely perfect all the way around, just no high spots that will hold the flange up too high. A few small low spots won't hurt anything. Dry fitting ABS or PVC doesn't work well, just rely on the tape measure. You're on the right track using a flange that fits on the outside of the pipe because the internal fit restricts 3" pipe diameter too much. Do not use a wax ring that has the plastic horn, they cause problems and are not necessary. Good luck with the Kohler.

Dang Jim, you always get the jump on me. At least we agree on things.

Thanks for the advice guys. I am still curious what the correct procedure should have been. It kind of bugs me that I have to cut the pipe from the inside now! I have been trying to do it all the right way since I laid the rough plumbing under the slab last year. Does the average plumber have to go through this trial and error every time, and cut down the pipe after the floor guys are done? Is there a standard procedure? For example, do you cut the pipe of flush with the slab? Or measure down 1" from finish floor height? Or measure down 1" from slab height? I figure that there has got to be a "regular" way it is done. And I am aware about wrapping the pipe to allow for the outside fit flange. Matter of fact, that's how it was, then I saw that I had an internal fit flange, so I filled all around the pipe with thinset while I was tiling! Then decided to go with the external fitting flange as the internal one would not sit down tight due to that extended circle that is molded on the bottom side of it. Jeeez.... Thanks for the info again.

Solution.

So I just returned from HD with a third flange. All mfg. by Oatey. This one I bought tonight will actually work without cutting the pipe "below flush" with the finished floor height. It has no lip or stop in it so the flange can actually slide all the way down to the floor and the pipe will still be in the neck of the closet flange. This model seems to be engineered better. The bottom of the taper of the flange is level or even with the bottom side of the flange ring.

Model number 43506 ABS did not work. Weird lip on bottom prevented flange from sitting down all the way.

Model number 43556/48470 ABS did not work. Molded lip on inside of flange lower than bottom of large flange ring. Would not sit down all the way either.

Model number 43512/43494 ABS and Steel. Third time is a charm! This one works. Pipe can freely slide all the way in and the flange will sit flat on the floor. Yeah.

flange

Now you know one of the reasons I ALWAYS use a 3x4 spigot closet bend. 4"external flanges do not have that problem. They slide down as far as necessary and then you cut the pipe off. In your case you are just going to have to use one of several methods to cut the pipe down and then use and outside flange.

update...

Model number 43512/43494 ABS and Steel did work, but I still had to cut the pipe down about a 1/2" to get it below the bottom of the funnel shape inside the flange. Otherwise there was an area between the pipe and the flange that looked like it would hold solids and cause problems. So anyhow it is all glued in place now and ready for toilet. I started mounting my toilet brackets into my new tile floor. The toilet is a full skirt, and has its own brackets rather than mounting to the closet flange. The directions said to drill 2" deep for the lag bolt anchors and bolts. It should have said 2 1/2" though as I cracked my new tile putting in the first bolt. The second one I drilled to 2 1/2" and the anchor sat all the way in and the bolt did not pull the anchor back up to crack the tile like the 2" hole did! Nothing like cracking a brand new tile right under the closet flange you just installed! I love DIY.

I Live In Texas, So I Dont Know Whats Available Where You Live, But Here We Can Get Flanges With No Stop In Them, Both Inside And Over The Pipe, Try Your Local Plumbing Supply