OK, wax ring on toilet was leaking so replaced using a Korky's waxless flange gasket kit. I read on several forums that over time, the foam part of the seal can leak which I believe is what has happened to mine. The cast iron pipe coming out of the floor causes the flange to sit about 3/8' to 1/2" higher than the surrounding floor. Because of the higher sitting flange, I had to use toilet shims to level the toilet.

Several forums I've read say the toilet MUST sit flat and level on the floor. In order to accomplish this I will need to take a saw and cut the cast iron pipe down about 3/8" or so. In addition, the floor itself (tile) is not exactly level.

After cutting down the cast iron pipe 3/8" or so, I'm thinking about installing this Oatey kit:

https://www.homedepot.com/p/Oatey-Twist-N-Set-4-in-PVC-Open-Toilet-Flange-436512/100062268

Also, does anyone have recommendations as to what type of saw to use to cut the original cast iron pipe approx 3/8"??

Why not use the traditional wax ring?

I am planning on using a traditional wax ring. I need to know:

1. Should I leave the current cast iron pipe as is sticking approx 3/8" above the floor?

or

2. Cut the cast iron pipe so the flange sits level or just under floor level.

If I need to cut the cast iron pipe, what type of saw or device would be best to use, i.e. Sawzall, Dremel, cutting torch, etc.?

I might set up some plastic to catch any sparks. Use a small 4 or 5 inch grinder With a narrow disk. As you can work it at floor level. Stuff something in the pipe to catch any pieces you may drop in there.


The flange kit you show is not a bad ideal. As long as the Od is smaller than the id of the cast pipe. As it gets close to the flange. Although it has the rubber to prevent sewer gas from getting in the house at the lowere end I see. . So I suspect it is purpose designed.


Of course check for wood rot in the area you have to screw the flange down. Again as long as the neck is the same diameter and I suspect it will be as the cast pipe. Near the flange all should go well. You do want to feel a friction fit when it slides in the cast iron as well. If not remove the rubber and build up some level of plastic tape under the rubber to make it so. Once again though being purpose designed I suspect no issue. With sewer gas.

Now I do not know how off level the floor is. Front to back or side to side or both. I would measure the base of the toilet and use a level to figure if I need to do anything else before starting. I would not want the flange badly tilted. Actually what you are proposing is what a professional would probably do in your case anyways.

I always use the wax seal that incorporates a plastic extension into the drain. They are very common. If they make a difference or not I have no ideal. They cost about the same so why not? Also do not get too aggressive when tightening down the toilets securing hardware. That plastic flange may not be the strongest. Sometimes I tighten down and let the seal squeeze out a little before tightening down more.

I leave you with remember I am not a professional in this area.

You do want the flange bottom on top of the floor. Not recessed into the floor. I just re read you post.

When I install the wax ring I warm the toilet and the ring with a heat lamp. The slightly warm ring conforms better to the flange.

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Thank you for the replies. By the way, the floor is tile over a concrete slab. I sat a level on the floor both vertical and horizontal, the bubble was slightly off barely touching one of the lines in the sight glass. Perhaps the house has settled a bit over the years, I don't know.

I like the grinder idea and stuffing rags down the pipe to catch debris. Since I have never done this type of repair before I am thinking of trying to source a piece of scrap cast iron drain pipe to practice on FIRST.

Practice makes perfect!

I was not clear perhaps. Using the thin blade on the grinder to actually cut into the side of the pipe was my intention. I post this just to avoid someone just grinding down the pipe.


I also was unaware that you were on concrete. This is much better in general overall with an old toilet that has been seal leaking. If the old anchors for the toilet were good. You may not have to really anchor the flange itself that heavily.


Actually what may be easier overall after I gave it some thought. There is a brass flange that is designed to go on over that cast iron pipe that is above the concrete I believe. The id of the flange is the same as the od of the cast iron pipe. A seal of silicone on the flange to the pipe would be good enough. I believe I have seen them but never used them.


Remember I am not a tradesman in this area. At this point I would ask any older plumber although the newer guys are probably familiar with this as well. It almost sounds like in the original installation it was just left out. You may still be almost forced to use the plastic one. As the bottom height of the flange almost should match the tile height. Or the flange may need a shim itself.


Not being a professional I am not certain of the compression range of the wax seal .Double wax sealing though is not uncommon either. Lay your level across the tile and mention if there is still some cast iron pipe above the edge of the level. That add on flange for cast Iron is probably available in plastic as well.


I better stop now before I give you a stroke. There is a possibility that whoever installed that toilet itself did not know what they were doing. Odd that I have not done that much work on cast iron drainage systems. Other than cutting enterance points to facilitate Ts and Ys. Incidentally I have no use for long term durability of foam seals. There is no adhesive factor probably in comparison to a wax seal. Plus over time the foam probably relaxes. Or breaks down. On the other hand a wax seal may not stand substantial movement.

Being 78 years old. I may even be getting a little forgetful. I have lived with women so long now I almost forget what freedom was like.

That was a thought I had. Those 1/16 approx thickness disks are pretty handy. Dangerous as hell, even with the guard one must use caution. Ask me how I know. Healed up fine though.

Since the floor will not allow the ideal angle, will probably need to cut it an eighth or so above the floor, will be a less than perfect cut, could then use a thicker grinding disk to get flush with the floor.

And I agree, the sparks can cause grief on finished surfaces. Even using the ugliest work blankets you have piled around it to catch the sparks from migrating will work. A huge amount could get smoldering going but unlikely to be an insurmountable problem. A spray bottle on hand can be useful. Dampening everything up ahead of time a good idea.

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

Cart before the horse...

Did the toilet rock with the original wax gasket? If it didn't, DO NOT cut the flange down, buy yourself another wax gasket and do the job properly. The waxless ones will degrade much faster than the wax will and require a much larger space between the flange and the base of the toilet to fit.

If you do replace the flange with the plastic "screw-in" style, you must anchor the flange to the floor. Since you're on concrete, you will need a hammer drill and expansion fasteners to do it. The toilet bolts to the flange, without anchoring the flange to the floor (or the pipe for cast iron), the toilet will rock and can pull off the floor/pipe.

The toilet must be rock-free if you want the wax ring to last. Consider using caulking around the base. A lot of plumbers frown on this, but I'm pretty sure it's because they like callbacks.

Another tip: SKIP the wax rings with the plastic funnel built in. They rarely (if ever) stay aligned when the toilet is pressed down and can cause water to splash out or cause nuisance clogs due to the misalignment with the drain horn on the toilet trap.

A rock-free toilet with a properly-installed wax ring will be trouble-free for decades.

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Yes, the toilet rocked with the old wax gasket. I installed the new Korky's wax free gasket and used plastic shims around the bottom of the toilet to stop the rocking. There haven't been any problems with the new install until the last few days, intermittent leaking of water around the base of the toilet.

I’ve been skeptical all along of the waxless flange seal thing - have yet to try it. The toilet wax is pretty wild stuff. Seriously inert material.

__________________
Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

Rather than cutting the pipe I would get a 3/8” piece of Hdpe and cut it to the shape of the toilet base with a hole for the flange

Oddly enough the toilet hasn't leaked for the past week. I noticed the shim I placed on the front of the toilet has slipped out of place but that is about the only thing that has changed. Weird.