Toilet flange

[Chrys]

Hi,

I am remodeling a half bathroom and I have to replace the toilet flange since the old one sits too high. The current flange is brass and is soldered on a 3 inch copper pipe. I am planning on cutting the copper a few inches above the 90 degree elbow and replacing with PVC, using a Fernco coupling. My question is can I install a 3 inch flange using a 3 inch PVC coupling to connect it to the pipe? If I use a 3 inch outside flange I will have to install it before the floor goes on and I am concerned that there is a chance that it will not sit on top of the tile on the right height.

 

[Cacher_Chick]

You would be much better off sweating on a new flange on at the proper height and then trimming off the excess pipe.

 

[Sponsor]

 

[Chrys]

The pipe is there from the late 60’s and there is a bunch of corrosion on it. I think it will be better to be replaced. Will what I described above work?

 

[Reach4]

The pipe is there from the late 60’s and there is a bunch of corrosion on it. I think it will be better to be replaced.

Is there a reason you want to replace it other than it is old and looks corroded? It might clean up just fine, and be good for another 50 years.

 

[Chrys]

And the flange sits higher the what the finished floor is going to be.

 

[Reach4]

And the flange sits higher the what the finished floor is going to be.

If the top is 3/8 above the floor, it would be no problem with wax, usually. 7/16 might work; might not.

 

[Chrys]

It’s more than 5/8 of an inch. The old toilet was shimmed.

 

[Terry]

You can get a shielded coupling that mates PVC to copper. How much pipe do you have to work with?

 

[Chrys]

I have around 6 inches of pipe to work with. I got one of the couplings in the picture to connect the pvc with the copper. My question is can I use a 3 inch pvc coupling to connect the pipe with a 3 inch flange. The coupling will sit outside of the 3 inch pipe. And then when the floor is done I will glue the flange in the inside of the coupling. The end of the flange will touch the end of the pipe. Can I do that without issues down the road?

 

[Cacher_Chick]

You need the correct banded coupler to transition from the copper pipe to PVC pipe. You need at least 2" of good copper to secure the coupling to. The PVC pipe can be installed with some excess length and then trimmed to the correct length once the finished floor is in place. With 3" pipe, I prefer a flange that fits around the outside of the pipe, as that leaves the full i.d. of the pipe to flush through.

 

[Chrys]

Won’t the 3 inch pvc coupling do the same thing though? It will fit outside the 3 inch pvc pipe and the the flange that has the same ID and OD with the pipe will fit inside the coupling. That way will not be any change in diameter.

 

[Cacher_Chick]

When you are standing in the PVC isle in the store, try putting those together and you will see. Flanges are made 2 different ways, they either fit inside the pipe, or outside the pipe. The flange will not fit inside the coupler properly unless you put a piece of pipe in it first.

 

[Chrys]

Please see the pictures below. There are 2 options that I think will work. 3 inch coupling or 4/3 inch reducer.

 

[Reach4]

There is a third type of flange called spigot. Its tail is the same OD as a PVC pipe. I doubt that you will want to grab the flange directly with your banded coupler, but the spigot type is the one you would want in that case.

How about an Oatey 42253? That would go outside of a 3-inch PVC pipe. It is a compression type. No glue.

 

[Chrys]

Will that be ok? Up to code and won’t cause leaks?

 

[Reach4]

https://www.oatey.com/ASSETS/DOCUMENTS/ITEMS/EN/cast-iron-closet-flange-submittal-1.pdf

Permitted. Premium. I am not a plumber. It seems to me that when you glue, you need to get it right the first time. A practiced plumber is going to get it right almost all of the time. However the do-over potential would have a bigger potential advantage for the less experienced.

 

[Jadnashua]

What you don't want to do is use a flange that will end up having less than that 3" full diameter opening all the way through the pipe and fittings you replace.

What might be easiest, if you can find one, would be a flange that would fit over the 3" riser that doesn't have an internal hub. That would allow you to leave the riser long, then when the finished floor was in, as long as you left enough space round the pipe, you could add the cement and push the new flange down tight to the floor. AFter the cement set, you could cut off the excess pipe sticking through the flange and anchor it to the floor.

Note, if you're tiling the floor, it makes life easier if you notch out the tile for the mounting screws that mount the flange to the subflooring. Otherwise, you need to drill holes in the tile, and that can be time consuming.

 

[Chrys]

On the first picture. You can see that the OD and ID of the pipe and flange are the same.
Second picture is everything together with the repair coupling. That way I will have 3” throughout.

 

[Cacher_Chick]

You can do that, but it creates another joint in the system, and unless you have access from below, it would be harder to get the height correct than if you just brought the 3" riser up though the floor.