[Vermont Maple]

Hi guys,

I have a bathroom remodel in progress and have an unusual/challenging situation with my closet flange and a new porcelein tile floor I'm about to put in. First some quick background.

There was a problem with the old toilet that caused significant leaking, forcing me to pull off the old tile and replace that section of subfloor which had rotted. The existing flange (metal ring around ABS pipe) was still mostly structurally sound, but did have some degradation and one of the bolt slots was broken. I thought a repair kit would take care of it, so left the flange in place while I blocked out the area and put in a new section of subfloor, cut fairly tight up against the ABS pipe for maximum support.

At this point I started worrying about the flange again, so brought in a plumber to take a look. Since it was now blocked in pretty tight, he suggested not trying to remove the old flange but instead to leave it there and basically just build over it. He said he could attach a short extension to the ABS, mount a new flange above it, and drill though the old metal flange ring to anchor it once I had the tile in.

With that as the plan, I went ahead and poured self-leveling underlayment, which required me to dam off the outside perimeter of the flange so it would not pour down through the hole in the subfloor. The attached image shows how this now looks.

At this point I'm ready to start tiling, but now I'm realizing I could have a problem with not enough structural support under the tile where the new flange will be, since the underlayment does not cover the flange area. Unless I fill in that space with something, it would leave a donut-shaped inner lip of unsupported tile where the drill holes would be done for the new flange. That seems very risky in terms of the potential to crack or break the tile if there's any kind of flex or torque.

I'm thinking the solution to this may be to fill that donut-shaped space with something to give it more structural support. Some extra tile mortar filled into the gap maybe could do the trick, but I'm not sure how well it would hold up once I start drilling the holes to mount the new flange. If the mortar crumbles, it may not help. I'm really not sure what other options there could be to provide the needed structure.

I know this is complicated and hopefully my explanation of this is clear. Any advice on how to deal with this would be most welcome!

 

[chandler48]

Is your toilet going to be installed using this hole? If so, use extension ring(s) siliconed and screwed over your existing flange to bring it to the proper height, slightly above the tile. https://www.homedepot.com/p/Oatey-1-4-in-PVC-Flange-Spacer-435192/303864021

 

[Vermont Maple]

Hi Chandler, thanks a lot for the response. Yes, this is the hole the toilet will be installed on.

Interesting idea to just build up from the existing flange with extenders. One possible problem is that one of the bolt slots on the original closet flange is broken, so I can't use it to anchor the closet bolt on that side. Can the slots on the extender itself be used to anchor the bolts instead, assuming the extender is anchored down to the subfloor solidly? How would that hold up over time given that the extenders are made from plastic? And I probably need to raise the flange by 3/4 inch or more. Would you foresee any issues stacking a couple of 1/2 inch extenders or maybe 3 1/4" extenders, given the same issue of needing to anchor them down as I described?

 

[chandler48]

Most all flanges nowadays are plastic, so once you silicone and screw these down to the subfloor, you will use longer bowl bolts and they will lock in just the same as your original metal one. Make sure you position the flange extenders properly so the lock works.

 

[Vermont Maple]

Ok, I'll give this approach a try. One thing though that I'm pretty concerned about is making sure I have a tight seal all the way through. I'm going to have one extender sitting on top of the existing partly corroded metal ring, for starters. I've seen multiple DIY videos where plumbers are using anything from wax rings to plumber's putty to silicone caulk (and sometimes even a combination of two) to create that bottom seal. Any thoughts on the best way to do this given the extender will be screwed down on top of the old metal flange ring (and may even need to be shimmed to get it level)?

Second thing: I will have to stack at least two spacers, maybe even three to get it to the height I need. Is silicone caulk between those additional spacers sufficient to ensure a water-tight and long lasting seal?

 

[huesmann]

Here's another option: https://www.homedepot.com/p/Oatey-1-4-in-1-5-8-in-Toilet-Flange-Extender-Kit-43400/305537804

 

[udraft]

When the plumber repaired my old rotted flange, he just put a new flange right into the old one w/self-tapping screws. The wax ring will seal that mess just fine.
The short of it is I would avoid putting the hold down bolts thru tile.

 

[Vermont Maple]

@huesmann, funny you mention the Oatey extender/repair kit, I found that on the web yesterday and was out buying one when you responded with that reco. Looks like a nearly ideal solution for my needs.

Just to be clear though, is the recommendation to put a wax ring between the old flange and the first extender to seal around the area at the bottom? Oatey provides a foam gasket for this purpose, but I wouldn't trust it to be water tight given the irregular shape of the old degraded flange. I ask this because I've seen other recommendations to use things like silicone caulk or plumber's putty which are pliable and can squeeze into gaps to create the seal. But wax presumably would do the same.

So the stack would look like this:
Subfloor -> Old flange -> wax ring(?) -> extenders (with silicone caulk between if I need multiple) -> yellow Oatey flange -> top wax ring -> toilet.
Does that make sense?

 

[huesmann]

How much height will you need to make up between old flange and finished floor elevation? Your "finished" flange should be anywhere from flush to about 1/4" proud of FF.