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Basement toilet redo, toliet flange question

6647 Views 10 Replies 5 Participants Last post by  TheEplumber
New member, first question :thumbup:

I'm redoing a toilet mistake in my basement. The first time my toilet flange was too high and the toilet rocked. No problem, right? Shim it and caulk it. Wrong. Learn and live I guess. The wax ring compressed and started leaking. :furious:

Now I want to do it right, but don't want to cut the 4" stubbed out pipe too short because it's encased in concrete. So I've got one shot at this.

1) Do I tile right up to the 4" pipe, grout, insert flange and fasten through finished floor

2) Do I cut pipe off flush with basement subfloor, install flange, and tile up to it then

Note: sub floor is concrete, flange is a slip inside type (no gluing), and the flange thickness is exactly 7/16".

See attached picture if it helps


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Should also note that the pipe is currently sticking out 9/16" and the tile with mortar height is 3/8".
You will get several different answers---I like the flange attached to the subfloor (concrete) and tile around it----

By the way--that slip in rubber gasketed flange does not meet code in many areas---solvent weld (glued) is required here--
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I'll add my location right now, I agree attached to the sub floor is what i was thinking but wanted a second or third opinion. So what I am looking at then is cutting the pipe down flush with the concrete. Gluing in the flange as well as securing it to the sub floor with concrete screws. Then tile up to it. Since I'm trashing the slip in flange here's a few more questions.

1) The flanges at my local store have different thickness, should I shoot for one that winds up flush with my finished floor or slightly higher?

2) It seems the plastic flanges are thicker than the stainless steel ones. If get a stainless one it's going to be well below the finished floor height of 3/8"

Thanks for any replies
Avoid the plastic flanges---use the stainless steel---the PVC flanges frequently crack or otherwise fail---

Simply use a wax extender ring and bolt set----you will be fine----
The toilet flange is suppose to sit on top of the finished floor. All toilets have a recessed well around their outlet spigot to accept the flange. I agree with Mike on the SS over all plastic. No contest. Us all non corrosive parts. I would anchor down the flange in this case with all stainless wedge anchors. Use the SSflange with PVC Bell that Glues inside your 4 inch pipe.

The weight of the toilet should NEVER rest on the flange.
Thanks for the replies. I've scraped my PVC flange for the one in the pictures below. First picture shows that the flange height is nearly exact with finished floor, meaning if I go with Oh'Mick's suggestion the 4" stub will be cut flush with concrete sub floor.

Second picture shows that the distance between outlet of toilet and toilet itself is 3/4".

So if installed on top of concrete sub floor I'd need a wax ring slightly taller than 3/4" to make a proper seal.
But if installed on top of finished floor, the 3/4" (on picture #2) minus the 3/8" in flange height (of picture #1). I'd need a wax ring slightly taller than 3/8" is this correct or am I over thinking it?

And if install over finished floor, that kinda rules out any flooring changes down the road without headaches doesn't it.

Thanks again I'm just trying to get different opinions and hopefully this will help someone else out in the process.


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I agree with jagans that the bottom of the flange rests on the finished floor as in diagram #1 below. There have been many discussions on the board about which way is proper.


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Thanks for the responses
I'll post more pics as I go along if anyone is interested
You are over thinking this
I vote for on top- especially when using SS flange. They seem to have the lowest profile and won't interfere with the toilet.
cut the pipe off below top of tile
lay tile
glue and anchor flange set toilet using a standard ring
sit down and enjoy
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