View Full Version : Need Help Extending Toilet Drain Pipe to Raise Flange Up for Floor Level

06-14-2006, 10:22 AM
Here's the situation:

I am remodeling my upstairs bathroom and will be laying new porcelain tile down on the floor. To prepare, I tore out the existing ceramic tile and a 1-inch layer of cement mud. I've got it all cleaned out down to the plywood subfloor. I plan to build up the floor with 1/2 plywood, 1/4 Wonderboard, and 3/8 porcelain tiles.

Here's the weird thing about the closet flanges. The flange that the toilet was connected to was imbedded in the tiles and cement mud layer. It was not glued to the PVC pipes below. It was simply resting inside a second flange that is screwed into the bottom plywood sub floor. So when I tore out the floor and chipped the cement away from the around the flange, I discovered the second flange below. The top flange was screwed into the cement layer with 6 rusty and breaking screws. So I took it out.

Now here is my challenge:

I want to remove the flange in the plywood subfloor and glue in a length of PVC pipe to bring the new flange up to the level of the tiles that I plan to install. I've been told that I should cut out the old flange, glue in a length of PVC pipe higher than I need, then put the floor in around the pipe, cut the pipe off to the approriate height, and glue in a closet flange on top of the tiles. I understand the concept of doing this, but I have never worked with PVC in this way before. I am very handy and I have a dremel tool that could possibly help with cutting out the old flange.

What exactly do I need to do to:
1. Cut off the old flange
2. Install a longer 3 inch pipe
3. Install a new flange on the top of th tiles



06-14-2006, 03:30 PM
A wood saw will cut pvc fine as would a hack saw, sawsall, cable saw (made for this), and even some string. You'll need to cut it off low enough to put in a coupler (basically a tube with a ridge in the middle so you center the two pieces when you glue it to the pipes) and still have enough new pipe to stick the flange onto.You'll also need to keep the hole around the pipe big enough to get the flange to sit down over the pipe and sit flat on the floor. The flange fits on the outside of the 3" pipe and flares out, so its diameter is fairly large compared to just the pipe sticking out of the floor. That dimmension varies by the flange you choose.

If you notch the tile (much easier than trying to drill through them later) when you install them, you can then screw the new flange down into the subflooring. Some porcelain really beg for diamond drill bits if you decide to try to drill rather than notch.

When you are finished, the new flange should sit flat on the top of the new tile, and be firmly fastened to the floor with no gaps under the rim to the floor.

06-14-2006, 08:05 PM
Thanks so much for your detailed response. I understand exacty what needs to be done now. However, I don't understand how I am supposed to cut the current flange off because it is down inside the floor. If I unscrew the flange, will I be able to pull the pipes up far enough to saw from the side? I was thinking that I could put a circular saw blade on my Dremel tool and cut it from the inside of the flange. I just don't understand how to make a level cut when the bottom of the flange is down inside the floor. Thanks.

06-14-2006, 08:14 PM
Can you get at it from the ceiling below? They do make internal pipe cutters. I don't know what they cost, or if you could rent one if they are expensive.

06-19-2006, 12:32 PM
First you may need a certain amount of luck to get everything to work properly together. You can cut the pipe from the inside, the glue a coupling onto the riser pipe. Finally you can either buy a "spigot" flange that glues into the coupling or a piece of pipe with an external flange that fits over the pipe. You cannot cut the riser pipe off until you know which way you are going to do the flange, since the amount to cut off is different with the two methods.

06-19-2006, 03:28 PM
Internal pipe cutters are about $15.