I am re-modeling my bathroom and the PVC pipe for the toilet discharge is 3 1/2 inches in diameter. The previous owner of the home had taken a flange cap and cut a hole in it to modify it to fit. I am trying to find a toilet flange that will fit it but they only come in 3" or 4". Does anyone know a way to adapt the 3 1/2" PVC pipe to fit the 3" toilet flange?

I have been doing this for 45 years and never seen a 3.5" PVC pipe, can you take a picture for me? Get under the toilet and check the pipe well below the toilet, it should be 4" or 3". I think he may have plugged a 4" and cut a 3" hole in it, not a plumber for sure.

I don't believe there is such a thing as 3 1/2 PVC pipe, at least I have never seen it. Maybe he took a 3" PVC female flange and glued it inside a 4" pipe, a 3" flange hub will fit into a 4" pipe making it look like 3 1/2". instead of using a 4" female flange and putting over a 4" pipe.

They sell closet rings for every pipe, every dimension, every combination there is. Just get the right ring and put it in.

In the interim: can you take a tape measure, put it over the pipe and snap a clear pic of it ?

Back to you. Milo

I took some pictures for all of you. Thank you for the help. You can see how he tried to groove everything together when he attempted to cut out and use a flange cap since I am assuming he could not find the same flange I am looking for. Any advice?

Measure ID not OD, that's a 3" pvc. Then of course on my smart phone your pic is the size of a pea

Yes, indeed, that's 3" pipe with Test Plug glued over it. As Ballengerb1 said: it is 3" ID pipe. If I am not mistaken I also see closet ring. Just buy 4"x3" wax ring in Home Depot, 2 - brass bolts, knock out the test plug and install the toilet. You are all set. Nothing unusual here. Let us know if you need more help. Back to you. Milo

There is no closet ring over it right now. It sticks up about 1/4" inch above the concrete right now and I will need to cut it off flush to make the closet ring flush with my new floor. Unless I break up the concrete I can't place a flange over the pipe. What's a test plug? How do I knock it out?

I may be wrong - but I think I see closet ring. Prove me wrong. Take hammer and tap around the pipe on that perfectly round surround. Once leftover concrete chips off - it may expose closet ring. Otherwise, cannot imagine what is that perfectly round frame around the pipe...

That is the pipe. It has been ground down by the previous owner. He used a closet ring cap and cut a hole in it and ground them together. I already removed that earlier.

So I have an update that I need some more advice on. So it is a 3" pipe so thank you for helping me with that. It goes down about 1" and then makes a 45 degree angle. Unless I bust up the concrete around it I can't put a new flange over the pipe. The plumbing guy at Lowe's sold me a flange made with a rubber gasket that is made to go into a 3" pipe. Since I have the 45 degree angle to deal with, he told me to measure and cut the insert down. I did this and everything would work fine but with the gasket on it is too big to go into the pipe and without it is kind of loose. If I just take clear silicone and coat the insert with it and then put it into the pipe and screw down the flange, is that going to hold or am I creating a new problem down the road?

Are you saying there are 2 pipes ? One 6" in diameter and INSIDE of it is another pipe 3" in diameter ? What is the filler between these two pipes?

You buy flange that goes OVER the pipe, not inside. You glue it. You don't use silicone. They make rings for all kind of installations. I don't think Lowe's carries more then couple different types. Home Depot seems to be better place to shop for sewer pipe fittings.

Milo I get it, but I can't put anything over the pipe without busting all the concrete up around it. The opening is a 3" PVC pipe. I have to go inside not outside of the pipe. I got the flange below and cut off about 2 inches of it so that it would actually fit into the pipe since it angles very quickly. So I was asking if I didn't use the rubber gasket could I just use silicone to connect the two together--the current pipe and this new flange?


http://www.oatey.com/apps/catalog/instance_assets/images/catalog/productimages/twist_n_set_flng.jpg

This Oatey will fit inside that 3" pipe. Oatey 43654 Flange, Twist-N-Set(R), Closet, 3 In, PVC (http://www.drillspot.com/products/558140/oatey_43654_closet_flange?s=1)

It won't fit without modifying it. The issue is that I have a 45 degree bend 1" below the surface. If I use that the way it is, it is too long inside the pipe. What I want to do is cut all but 1" off that flange and stick it in there. It is too loose without the gasket and too wide with it. I want to know if I can just place silicone around it instead of PVC cement and use that to seal the fit. Is there anything wrong with that? This guy didn't do a lot of stuff right on this house let me tell you.

Djwdub: Unless I am missing something, here are the 4 solutions for your problem. One of them should work.

FYI: All closet rings are glued onto existing 45 degree elbow with ABS Glue.
If you have PVC pipe (white plastic pipe) than same combination apply - but in PVC.


Photo #1: . 3" Fit-In Closet ring installed into 3" Hub on 45 degree bend
Photo #2: 3" Fit-Over Closet ring installed OVER 3" Hub on 45 degree bend
Photo #3: Regular 3" Hub Closet ring that fits over 3" Street 45 degree elbow
4th ring is not present. But this one is a 3"Closet ring that fits directly INSIDE 3" pipe.

No fitting under ground should prevent you from doing it the right way. That includes 45 bend.

Good luck with your project. Milo

What these young plumbers tend to overlook is that a toilet flange isn't needed at all. Back a thousand years ago when I first started there were no flanges or wax seals.

Let me show you how I would handle this.
First off, your toilet bowl has a horn that extends below the floor level directing the flush past the floor and into the pipe. The flange doesn't seal 9off anything. Its only function is to secure the bowl to the floor. The wax seal does that. (Back then we used a ring of plumbers putty.)
Having said all that here's what I would do. Purchase a couple of wood screw closet bolts, (see image) and some 1/4" plastic insert kit. Dry fit the bowl over the hole and mark the holes. Remove the bowl and, using then masonry bit that came with the inserts drill and place the plastic inserts in the drilled holes.
You are now ready to set the toilet.
Place a wax ring over 5the horn and set the toilet, ( giving it a slight twist to set the seal.
Now you can install the wood screw toilet bolts and washers. Connect your supply and your toilet's installed.
If you wish to give your job a professional look grout the base with Dap White Tub and Tile grout.
Now, wasn't that easier then Installing a closet ring? (see image) which would be your second option.
Good luck, Tom