How do I concrete under and around a new toilet flange?

[pope411]

Hi this is my first post after finding useful answers on this forum from google searches for years.

I was putting in a new toilet and discovered the previous owner had the old toilet attached to a plastic flange that was not attached to a very rusted out cast iron toilet flange. This was beyond my scope so I had a plumber come out. They tried to fit an adapter inside the pipe but it was too big. They said the only way was to jack hammer it up and put new ABS plumbing in.

I had them do that. At the end they said they could pour concrete or I'd save $100 if I did it myself, so I said sure I'll save the money. Now I'm looking at this thing, and red toilet flange is held captive by the black part. I am not sure how I am going to pour concrete underneath the red part so that it can still spin and the closet bolts will fit in there.

Any help appreciated. Thanks.

 

[pope411]

Here are some more photos.

After pulling the old toilet, the closet bolt on the left was not attached to anything put this plastic which was flapping up on this side. The closet bolt on the right magically tucked under a bit of cast iron.

Removed:

Exposing the old one:

 

[Sponsor]

 

[Terry]

To leave a space for the closet bolts, you can push some bowl wax in there or plumbers putty. Then you can pour the concrete knowing you've blocked out that space.

Is that cast coming from that hub? Or lead? If it is cast, then the coupling there is fine.
What you have before was a flange extension. It was doing nothing for you. I tried them once and unless they are stuck down with Silicone they don't seal. I don't use them anymore. I do use something like those to raise a flange from below.

 

[Reach4]

I had them do that. At the end they said they could pour concrete or I'd save $100 if I did it myself, so I said sure I'll save the money. Now I'm looking at this thing, and red toilet flange is held captive by the black part. I am not sure how I am going to pour concrete underneath the red part so that it can still spin and the closet bolts will fit in there.

Are you sure the closet flange with the red is glued in place? Maybe it is just pressed down, and you can lift it off. I

 

[pope411]

Yes it is cast iron coming from the hub. I'll try to pack some wax in there to block space out. The red part still rotates, should I twist it so the end of the slots will be where bolts go, or can bolts end up anywhere along those slotted paths?

Yes, the plumber glued that flange on. I called him, he said throw some concrete in and it will be fine.

 

[Cacher_Chick]

It's a bit after the fact now, but ideally the flange would not have been installed until after the floor was finished.

The riser pipe should be the only thing coming up through the floor, wrapped with a layer of foam or cardboard to allow for a gap between the pipe and the concrete. Once the concrete is set, the tile can be redone and the flange should be installed and screwed down on the top of the tile.

 

[alane24]

I'm sort of in the same situation as you. What was the process for jackhammering the floor? Did you take certain precautions so as to not crack the slab? Just wondering what all is involved in doing this before I commit to it.

 

[Cacher_Chick]

I'm sort of in the same situation as you. What was the process for jackhammering the floor? Did you take certain precautions so as to not crack the slab? Just wondering what all is involved in doing this before I commit to it.

I cut an outline in the concrete with a diamond blade and then break it up with a sledge. The piping is normally bedded in the dirt below the floor, not poured in the concrete.

Once the line is exposed, it will often be a no-brainer to just cut off the existing and replace the closet bend and flange with new.