PVC toilet flanges

1530 Views 11 Replies 6 Participants Last post by Yodaman, Mar 1, 2020

ablodneyget

Discussion Starter · Feb 17, 2020

Good evening,

A while ago I hired out a total redo of the DWV system that included a new PVC toilet flange for the bathroom. The rough-in passed inspection. My tile guy then put tile on 1/2" cement board which left the toilet flange 1/4" below the finished floor.

I have a new toilet ready to install along with a Korky wax-free seal and a couple PVC flange extenders. (This is my first time setting a toilet, and I figure the Korky seal will give me a better shot at fixing the placement or shimming in case I goof.)

Scouring the internet I found some anecdotes about PVC flanges not holding up and cracking where the closet bolts go through. A glued flange extender would beef it up and make it less prone to cracking, I'd think.

The Korky seal's literature says it will work by itself with the flange at its present height. I plan to test fit it tomorrow to see if it compresses as intended.

Would it be a better idea to first solvent weld a PVC extender?

Any experience here on the forum with the Korky seals?

Next time, I'll install the flange myself AFTER the tile...

A.

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joecaption

· #2 · Feb 17, 2020

Two mess ups, the tile guy should have know enough to use 1/4" not 1/2" for a floor.
I also would have used a PVC flange with a stainless steel ring.

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Old Thomas

· #3 · Feb 17, 2020

The flange should have been on top of the finished floor. If you have access from below cut the pipe, pull out the flange, build up the area beloW it and install the flange the right way. If no access, use two wax rings and forget about it.

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chandler48

· #4 · Feb 17, 2020

This particular ring will allow setting of rings below the surface or above. The blue ring is used for below and it is removed for at or above surface installations. We used them on a remodel of two bathrooms this past week. They seem to work very well. https://www.homedepot.com/p/NEXT-by-Danco-Perfect-Seal-Toilet-Wax-Ring-with-Bolts-10826X/206393853

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Yodaman

· #5 · Feb 17, 2020 (Edited)

I swear by the Korky seals and use them exclusively now. As long as you have the correct seal stack for your flange height it will work perfectly.

I prefer the PVC with the SS flange, but have used the solid PVC in the past.
I wouldn't change a thing. People that break the PVC flange likely over tightened it. If their floor is uneven, or seal is too thick, rather than correct it, they probably overtighten to compensate.

Set your toilet down without the seal first and see if it rocks. If so, shim it until stable. Mark your shim placement, remove and add in seal. This should help to prevent overtightening to stop the rock

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ablodneyget

Discussion Starter · #6 · Feb 19, 2020 (Edited)

joecaption said:
Two mess ups, the tile guy should have know enough to use 1/4" not 1/2" for a floor.
I also would have used a PVC flange with a stainless steel ring.

I agree about the tile. We discussed the height and he assured me it would be flush or, at most, 1/8" off. It's a good 1/4" high at the transition and ticks me off every time I catch my toe on it. :vs_mad:

The tile was the first to go down. Hardwood wasn't until months later, at which point the issue became obvious.

Live and learn!

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ablodneyget

Discussion Starter · #7 · Feb 19, 2020

Yodaman said:
I swear by the Korky seals and use them exclusively now. As long as you have the correct seal stack for your flange height it will work perfectly.

I prefer the PVC with the SS flange, but have used the solid PVC in the past.
I wouldn't change a thing. People that break the PVC flange likely over tightened it. If their floor is uneven, or seal is too thick, rather than correct it, they probably overtighten to compensate.

Set your toilet down without the seal first and see if it rocks. If so, shim it until stable. Mark your shim placement, remove and add in seal. This should help to prevent overtightening to stop the rock

The toilet will definitely need about 1/8" shimming on either side, because the tile is slightly higher at the rear.

I just measured the depth again--it's 3/8" below, not 1/4". I set the toilet on the single Korky seal, and it did not compress much at all. That's definitely pushing the limit. Have you successfully stacked those seals like they claim you can?

Here's what I'm up against from the top side. I want to make this right---a leaky toilet is why I had to tear the bathroom out in the first place. I have access from below (crawlspace). The 3" waste line stub from the lateral has already been cut and coupled once because the inspector failed the first waste line installation and the plumber had to redo it. I may be able to cut it off and re-extend the 3" line one more time.

If I do replace the flange, would PVC spacers go underneath before it's screwed down to the floor?

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Nealtw

· #8 · Feb 19, 2020

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Yodaman

· #9 · Feb 19, 2020

First question, yes I have stacked the seals as instructed and with out incident. And I would still do that in lieu of redo.

If you want to cut out the flange and redo, I would probably make a plywood shim and glue and screw it down. But a PVC riser would also work. Use a long enough screws to pass thru it and grab the subfloor beneath, pvc will not have much holding power. And use a flange with a SS metal flange.

Last, since you already had a problem and do not want to repeat, do not caulk around the base of toilet after install. If the seal were to leak, it is better to see running across the floor so it can be corrected rather than keeping it concealed with the toilet base perimeter. JMHO, happy trails

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ablodneyget

Discussion Starter · #10 · Mar 1, 2020

Here's an update. I decided to try solvent welding a flange extender with a matching hole pattern onto the existing flange to bring it up flush with the floor. I'd never solvent welded anything other than interference-fit pipe joints so decided to give it a test yank after it cured. The whole assembly pulled out of the sanitary Y 12" below the floor. The plumber never glued it!

The 3" riser already has a repair coupling on it. I think it's probably best to just go new with a PVC + stainless ring flange as was suggested.

The floor is almost an

inch thick with the tile.

Possible fixes that come to mind:

Add PVC flange extenders under a brand new flange to raise it.
Cut a circular piece of plywood with a circular hole as a spacer
Solvent weld the existing mess in (least favorite)

Can PVC flange extenders go UNDER a new flange to lift it to the proper position?

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Nealtw

· #11 · Mar 1, 2020

Can PVC flange extenders go UNDER a new flange to lift it to the proper position?

Line everything up so the screw holes line up and hold down bolts can go right to the bottom.

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Yodaman

· #12 · Mar 1, 2020

IMHO - option 2, with a wood spacer glued down. I would use Advantech, but always a few scrapes laying around.

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