My question is, right now from the subfloor to the bottom of the flange is 1 3/4". I have to add 1/2" cement board, redguard "painted membrane" and then the tile. I'm looking at about 1" up from the subfloor. so that still make the flange 3/4" of space from the finished floor to the bottom of the flange. What should it be? The old floor was tile and over an inch of concrete and wire. House was built in 1961.

Second question, the sewer line is a 3" copper line with a brass flange, if I have to lower it, i figure I have to torch the pipe and hope it come off, then cut the copper pipe back and then reinstall the brass flange?

thanks

 

If you are measuring to the bottom of the flange then the top (the part that matters) will be even higher. You want the bottom of the flange to sit on top of the finished floor but it can work being as low as flush with the finished floor though it may require doubling up on wax rings depending on your toilet.

 

Is it possible to add plywood to raise the floor? Another option might be to raise the toilet.

 

You're going to have a bad time doing this. 3" copper pipe is difficult to sweat since it requires a lot of heat. A brass fitting even more so.

I like the other options that have been provided, but if you do need to drop it, I would probably recommend cutting off the elbow and flange. Use a no-hub shielded coupling to transition to PVC, add a closet bend and install the flange at the the correct height.

 

Thanks for the replay guys, sorry I have been so busy with work I have not done anything with this project.

I wanted to keep the floor lower so once I'm done with the tile it will line up with the wood floor in the bedroom.

So yes I would have to lower the flange 1 /3/4". That would be from the bottom of the flange to the finished floor.

no-hub shielded coupling to transition to PVC, that is fine, will it last a long time? because I have the stack, the y, a 2' piece then the 45 and the toilet flange, So I would cut into the 2' section and add it there.

Or I saw this PVC flange that has a gasket on it that you put in the copper pipe and turn it to tighten it up and that's it. Not sure how that is.

 

The flange being so high above the floor, someone did something ultra wrong. The underside of the toilet flange needs to be in contact with the subfloor and preferably fastened to the floor to prevent up and down movements from ruining the wax ring. You could cut an oval-ish shape matching the footprint of the toilet out of a piece of plywood, and use that as one giant shim to correct the problem.

 

Yup, will last longer than the bathroom. PVC is rated to last anywhere from 25-50-100 years depending on what you read, but I've never seen PVC fail from its age.

That sounds like a good place to make the transition from copper to pvc. I usually run the PVC high enough to be about 1/2 - 3/4" below the finished floor. Then the flange will adjust for any deviation. Some plumbers just run it a few inches higher than the finished floor and use an oscillating tool or sawzall with a bent blade to cut it to the finished floor.

That's doable. I've used those in cast iron pipes to not have to do the lead and oakum process to attach the flange. If you can cut the pipe to the correct height, that is certainly a possible solution.
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Regardless, the flange should be securely screwed to the subfloor - so the rubber gasket that gets tightened is really only to keep it watertight.

 

okay on the age,

okay

I want to see if I can up sweet that old flange off and then cut the copper pipe and had that PVC gasket fist. I got a second tank just in case. If I can't get it off, option two is cut the pipe and added the no-hub shielded coupling.
Got it, was going to screw it into the cerement board once I install it.